/* Global common subexpression elimination/Partial redundancy elimination
and global constant/copy propagation for GNU compiler.
- Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
- Free Software Foundation, Inc.
+ Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+ 2006, 2007 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
-Software Foundation; either version 2, or (at your option) any later
+Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
/* TODO
- reordering of memory allocation and freeing to be more space efficient
#include "cselib.h"
#include "intl.h"
#include "obstack.h"
+#include "timevar.h"
+#include "tree-pass.h"
+#include "hashtab.h"
+#include "df.h"
+#include "dbgcnt.h"
/* Propagate flow information through back edges and thus enable PRE's
moving loop invariant calculations out of loops.
3) Perform copy/constant propagation.
- 4) Perform global cse.
+ 4) Perform global cse using lazy code motion if not optimizing
+ for size, or code hoisting if we are.
5) Perform another pass of copy/constant propagation.
substitutions.
PRE is quite expensive in complicated functions because the DFA can take
- awhile to converge. Hence we only perform one pass. The parameter max-gcse-passes can
- be modified if one wants to experiment.
+ a while to converge. Hence we only perform one pass. The parameter
+ max-gcse-passes can be modified if one wants to experiment.
**********************
the result of the expression is copied to a new register, and the redundant
expression is deleted by replacing it with this new register. Classic GCSE
doesn't have this problem as much as it computes the reaching defs of
- each register in each block and thus can try to use an existing register.
-
- **********************
-
- A fair bit of simplicity is created by creating small functions for simple
- tasks, even when the function is only called in one place. This may
- measurably slow things down [or may not] by creating more function call
- overhead than is necessary. The source is laid out so that it's trivial
- to make the affected functions inline so that one can measure what speed
- up, if any, can be achieved, and maybe later when things settle things can
- be rearranged.
-
- Help stamp out big monolithic functions! */
+ each register in each block and thus can try to use an existing
+ register. */
\f
/* GCSE global vars. */
-/* -dG dump file. */
-static FILE *gcse_file;
-
/* Note whether or not we should run jump optimization after gcse. We
want to do this for two cases.
* If we changed any jumps via cprop.
* If we added any labels via edge splitting. */
-
static int run_jump_opt_after_gcse;
-/* Bitmaps are normally not included in debugging dumps.
- However it's useful to be able to print them from GDB.
- We could create special functions for this, but it's simpler to
- just allow passing stderr to the dump_foo fns. Since stderr can
- be a macro, we store a copy here. */
-static FILE *debug_stderr;
-
/* An obstack for our working variables. */
static struct obstack gcse_obstack;
/* Get the cuid of an insn. */
#ifdef ENABLE_CHECKING
-#define INSN_CUID(INSN) (INSN_UID (INSN) > max_uid ? (abort (), 0) : uid_cuid[INSN_UID (INSN)])
+#define INSN_CUID(INSN) \
+ (gcc_assert (INSN_UID (INSN) <= max_uid), uid_cuid[INSN_UID (INSN)])
#else
#define INSN_CUID(INSN) (uid_cuid[INSN_UID (INSN)])
#endif
{
/* The next setting of this register. */
struct reg_set *next;
- /* The insn where it was set. */
- rtx insn;
+ /* The index of the block where it was set. */
+ int bb_index;
} reg_set;
static reg_set **reg_set_table;
/* This is a list of expressions which are MEMs and will be used by load
or store motion.
Load motion tracks MEMs which aren't killed by
- anything except itself. (ie, loads and stores to a single location).
+ anything except itself. (i.e., loads and stores to a single location).
We can then allow movement of these MEM refs with a little special
allowance. (all stores copy the same value to the reaching reg used
for the loads). This means all values used to store into memory must have
/* Head of the list of load/store memory refs. */
static struct ls_expr * pre_ldst_mems = NULL;
+/* Hashtable for the load/store memory refs. */
+static htab_t pre_ldst_table = NULL;
+
/* Bitmap containing one bit for each register in the program.
Used when performing GCSE to track which registers have been set since
the start of the basic block. */
static regset reg_set_bitmap;
/* For each block, a bitmap of registers set in the block.
- This is used by expr_killed_p and compute_transp.
+ This is used by compute_transp.
It is computed during hash table computation and not by compute_sets
as it includes registers added since the last pass (or between cprop and
gcse) and it's currently not easy to realloc sbitmap vectors. */
/* Array, indexed by basic block number for a list of insns which modify
memory within that block. */
static rtx * modify_mem_list;
-bitmap modify_mem_list_set;
+static bitmap modify_mem_list_set;
/* This array parallels modify_mem_list, but is kept canonicalized. */
static rtx * canon_modify_mem_list;
-bitmap canon_modify_mem_list_set;
+
+/* Bitmap indexed by block numbers to record which blocks contain
+ function calls. */
+static bitmap blocks_with_calls;
+
/* Various variables for statistics gathering. */
/* Memory used in a pass.
static int gcse_subst_count;
/* Number of copy instructions created. */
static int gcse_create_count;
-/* Number of constants propagated. */
-static int const_prop_count;
-/* Number of copys propagated. */
-static int copy_prop_count;
+/* Number of local constants propagated. */
+static int local_const_prop_count;
+/* Number of local copies propagated. */
+static int local_copy_prop_count;
+/* Number of global constants propagated. */
+static int global_const_prop_count;
+/* Number of global copies propagated. */
+static int global_copy_prop_count;
\f
-/* These variables are used by classic GCSE.
- Normally they'd be defined a bit later, but `rd_gen' needs to
- be declared sooner. */
-
-/* Each block has a bitmap of each type.
- The length of each blocks bitmap is:
-
- max_cuid - for reaching definitions
- n_exprs - for available expressions
-
- Thus we view the bitmaps as 2 dimensional arrays. i.e.
- rd_kill[block_num][cuid_num]
- ae_kill[block_num][expr_num] */
-
-/* For reaching defs */
-static sbitmap *rd_kill, *rd_gen, *reaching_defs, *rd_out;
-
-/* for available exprs */
-static sbitmap *ae_kill, *ae_gen, *ae_in, *ae_out;
-
-/* Objects of this type are passed around by the null-pointer check
- removal routines. */
-struct null_pointer_info
-{
- /* The basic block being processed. */
- basic_block current_block;
- /* The first register to be handled in this pass. */
- unsigned int min_reg;
- /* One greater than the last register to be handled in this pass. */
- unsigned int max_reg;
- sbitmap *nonnull_local;
- sbitmap *nonnull_killed;
-};
+/* For available exprs */
+static sbitmap *ae_kill, *ae_gen;
\f
static void compute_can_copy (void);
static void *gmalloc (size_t) ATTRIBUTE_MALLOC;
static void *gcalloc (size_t, size_t) ATTRIBUTE_MALLOC;
static void *grealloc (void *, size_t);
static void *gcse_alloc (unsigned long);
-static void alloc_gcse_mem (rtx);
+static void alloc_gcse_mem (void);
static void free_gcse_mem (void);
static void alloc_reg_set_mem (int);
static void free_reg_set_mem (void);
-static int get_bitmap_width (int, int, int);
static void record_one_set (int, rtx);
-static void replace_one_set (int, rtx, rtx);
-static void record_set_info (rtx, rtx, void *);
-static void compute_sets (rtx);
+static void record_set_info (rtx, const_rtx, void *);
+static void compute_sets (void);
static void hash_scan_insn (rtx, struct hash_table *, int);
static void hash_scan_set (rtx, rtx, struct hash_table *);
static void hash_scan_clobber (rtx, rtx, struct hash_table *);
static void hash_scan_call (rtx, rtx, struct hash_table *);
static int want_to_gcse_p (rtx);
static bool can_assign_to_reg_p (rtx);
-static bool gcse_constant_p (rtx);
-static int oprs_unchanged_p (rtx, rtx, int);
-static int oprs_anticipatable_p (rtx, rtx);
-static int oprs_available_p (rtx, rtx);
+static bool gcse_constant_p (const_rtx);
+static int oprs_unchanged_p (const_rtx, const_rtx, int);
+static int oprs_anticipatable_p (const_rtx, const_rtx);
+static int oprs_available_p (const_rtx, const_rtx);
static void insert_expr_in_table (rtx, enum machine_mode, rtx, int, int,
struct hash_table *);
static void insert_set_in_table (rtx, rtx, struct hash_table *);
-static unsigned int hash_expr (rtx, enum machine_mode, int *, int);
-static unsigned int hash_expr_1 (rtx, enum machine_mode, int *);
-static unsigned int hash_string_1 (const char *);
+static unsigned int hash_expr (const_rtx, enum machine_mode, int *, int);
static unsigned int hash_set (int, int);
-static int expr_equiv_p (rtx, rtx);
+static int expr_equiv_p (const_rtx, const_rtx);
static void record_last_reg_set_info (rtx, int);
static void record_last_mem_set_info (rtx);
-static void record_last_set_info (rtx, rtx, void *);
+static void record_last_set_info (rtx, const_rtx, void *);
static void compute_hash_table (struct hash_table *);
static void alloc_hash_table (int, struct hash_table *, int);
static void free_hash_table (struct hash_table *);
static void compute_hash_table_work (struct hash_table *);
static void dump_hash_table (FILE *, const char *, struct hash_table *);
-static struct expr *lookup_expr (rtx, struct hash_table *);
static struct expr *lookup_set (unsigned int, struct hash_table *);
static struct expr *next_set (unsigned int, struct expr *);
static void reset_opr_set_tables (void);
-static int oprs_not_set_p (rtx, rtx);
+static int oprs_not_set_p (const_rtx, const_rtx);
static void mark_call (rtx);
static void mark_set (rtx, rtx);
static void mark_clobber (rtx, rtx);
static void mark_oprs_set (rtx);
static void alloc_cprop_mem (int, int);
static void free_cprop_mem (void);
-static void compute_transp (rtx, int, sbitmap *, int);
+static void compute_transp (const_rtx, int, sbitmap *, int);
static void compute_transpout (void);
static void compute_local_properties (sbitmap *, sbitmap *, sbitmap *,
struct hash_table *);
static int try_replace_reg (rtx, rtx, rtx);
static struct expr *find_avail_set (int, rtx);
static int cprop_jump (basic_block, rtx, rtx, rtx, rtx);
-static void mems_conflict_for_gcse_p (rtx, rtx, void *);
-static int load_killed_in_block_p (basic_block, int, rtx, int);
-static void canon_list_insert (rtx, rtx, void *);
+static void mems_conflict_for_gcse_p (rtx, const_rtx, void *);
+static int load_killed_in_block_p (const_basic_block, int, const_rtx, int);
+static void canon_list_insert (rtx, const_rtx, void *);
static int cprop_insn (rtx, int);
static int cprop (int);
static void find_implicit_sets (void);
-static int one_cprop_pass (int, int, int);
-static bool constprop_register (rtx, rtx, rtx, int);
+static int one_cprop_pass (int, bool, bool);
+static bool constprop_register (rtx, rtx, rtx, bool);
static struct expr *find_bypass_set (int, int);
-static bool reg_killed_on_edge (rtx, edge);
+static bool reg_killed_on_edge (const_rtx, const_edge);
static int bypass_block (basic_block, rtx, rtx);
static int bypass_conditional_jumps (void);
static void alloc_pre_mem (int, int);
static void compute_pre_data (void);
static int pre_expr_reaches_here_p (basic_block, struct expr *,
basic_block);
-static void insert_insn_end_bb (struct expr *, basic_block, int);
+static void insert_insn_end_basic_block (struct expr *, basic_block, int);
static void pre_insert_copy_insn (struct expr *, rtx);
static void pre_insert_copies (void);
static int pre_delete (void);
static int hoist_expr_reaches_here_p (basic_block, int, basic_block, char *);
static void hoist_code (void);
static int one_code_hoisting_pass (void);
-static void alloc_rd_mem (int, int);
-static void free_rd_mem (void);
-static void handle_rd_kill_set (rtx, int, basic_block);
-static void compute_kill_rd (void);
-static void compute_rd (void);
-static void alloc_avail_expr_mem (int, int);
-static void free_avail_expr_mem (void);
-static void compute_ae_gen (struct hash_table *);
-static int expr_killed_p (rtx, basic_block);
-static void compute_ae_kill (sbitmap *, sbitmap *, struct hash_table *);
-static int expr_reaches_here_p (struct occr *, struct expr *, basic_block,
- int);
-static rtx computing_insn (struct expr *, rtx);
-static int def_reaches_here_p (rtx, rtx);
-static int can_disregard_other_sets (struct reg_set **, rtx, int);
-static int handle_avail_expr (rtx, struct expr *);
-static int classic_gcse (void);
-static int one_classic_gcse_pass (int);
-static void invalidate_nonnull_info (rtx, rtx, void *);
-static int delete_null_pointer_checks_1 (unsigned int *, sbitmap *, sbitmap *,
- struct null_pointer_info *);
static rtx process_insert_insn (struct expr *);
static int pre_edge_insert (struct edge_list *, struct expr **);
-static int expr_reaches_here_p_work (struct occr *, struct expr *,
- basic_block, int, char *);
static int pre_expr_reaches_here_p_work (basic_block, struct expr *,
basic_block, char *);
static struct ls_expr * ldst_entry (rtx);
static int enumerate_ldsts (void);
static inline struct ls_expr * first_ls_expr (void);
static inline struct ls_expr * next_ls_expr (struct ls_expr *);
-static int simple_mem (rtx);
+static int simple_mem (const_rtx);
static void invalidate_any_buried_refs (rtx);
static void compute_ld_motion_mems (void);
static void trim_ld_motion_mems (void);
static void update_ld_motion_stores (struct expr *);
-static void reg_set_info (rtx, rtx, void *);
-static void reg_clear_last_set (rtx, rtx, void *);
-static bool store_ops_ok (rtx, int *);
+static void reg_set_info (rtx, const_rtx, void *);
+static void reg_clear_last_set (rtx, const_rtx, void *);
+static bool store_ops_ok (const_rtx, int *);
static rtx extract_mentioned_regs (rtx);
static rtx extract_mentioned_regs_helper (rtx, rtx);
static void find_moveable_store (rtx, int *, int *);
static int compute_store_table (void);
-static bool load_kills_store (rtx, rtx, int);
-static bool find_loads (rtx, rtx, int);
-static bool store_killed_in_insn (rtx, rtx, rtx, int);
-static bool store_killed_after (rtx, rtx, rtx, basic_block, int *, rtx *);
-static bool store_killed_before (rtx, rtx, rtx, basic_block, int *);
+static bool load_kills_store (const_rtx, const_rtx, int);
+static bool find_loads (const_rtx, const_rtx, int);
+static bool store_killed_in_insn (const_rtx, const_rtx, const_rtx, int);
+static bool store_killed_after (const_rtx, const_rtx, const_rtx, const_basic_block, int *, rtx *);
+static bool store_killed_before (const_rtx, const_rtx, const_rtx, const_basic_block, int *);
static void build_store_vectors (void);
-static void insert_insn_start_bb (rtx, basic_block);
+static void insert_insn_start_basic_block (rtx, basic_block);
static int insert_store (struct ls_expr *, edge);
static void remove_reachable_equiv_notes (basic_block, struct ls_expr *);
static void replace_store_insn (rtx, rtx, basic_block, struct ls_expr *);
static void free_modify_mem_tables (void);
static rtx gcse_emit_move_after (rtx, rtx, rtx);
static void local_cprop_find_used_regs (rtx *, void *);
-static bool do_local_cprop (rtx, rtx, int, rtx*);
+static bool do_local_cprop (rtx, rtx, bool, rtx*);
static bool adjust_libcall_notes (rtx, rtx, rtx, rtx*);
-static void local_cprop_pass (int);
+static void local_cprop_pass (bool);
static bool is_too_expensive (const char *);
\f
/* Entry point for global common subexpression elimination.
- F is the first instruction in the function. */
+ F is the first instruction in the function. Return nonzero if a
+ change is mode. */
-int
-gcse_main (rtx f, FILE *file)
+static int
+gcse_main (rtx f ATTRIBUTE_UNUSED)
{
int changed, pass;
/* Bytes used at start of pass. */
/* Assume that we do not need to run jump optimizations after gcse. */
run_jump_opt_after_gcse = 0;
- /* For calling dump_foo fns from gdb. */
- debug_stderr = stderr;
- gcse_file = file;
-
/* Identify the basic block information for this function, including
successors and predecessors. */
max_gcse_regno = max_reg_num ();
- if (file)
- dump_flow_info (file);
+ df_note_add_problem ();
+ df_analyze ();
+
+ if (dump_file)
+ dump_flow_info (dump_file, dump_flags);
/* Return if there's nothing to do, or it is too expensive. */
- if (n_basic_blocks <= 1 || is_too_expensive (_("GCSE disabled")))
+ if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
+ || is_too_expensive (_("GCSE disabled")))
return 0;
-
+
gcc_obstack_init (&gcse_obstack);
bytes_used = 0;
information about memory sets when we build the hash tables. */
alloc_reg_set_mem (max_gcse_regno);
- compute_sets (f);
+ compute_sets ();
pass = 0;
initial_bytes_used = bytes_used;
while (changed && pass < MAX_GCSE_PASSES)
{
changed = 0;
- if (file)
- fprintf (file, "GCSE pass %d\n\n", pass + 1);
+ if (dump_file)
+ fprintf (dump_file, "GCSE pass %d\n\n", pass + 1);
/* Initialize bytes_used to the space for the pred/succ lists,
and the reg_set_table data. */
/* Each pass may create new registers, so recalculate each time. */
max_gcse_regno = max_reg_num ();
- alloc_gcse_mem (f);
+ alloc_gcse_mem ();
/* Don't allow constant propagation to modify jumps
during this pass. */
- changed = one_cprop_pass (pass + 1, 0, 0);
+ timevar_push (TV_CPROP1);
+ changed = one_cprop_pass (pass + 1, false, false);
+ timevar_pop (TV_CPROP1);
if (optimize_size)
- changed |= one_classic_gcse_pass (pass + 1);
+ /* Do nothing. */ ;
else
{
+ timevar_push (TV_PRE);
changed |= one_pre_gcse_pass (pass + 1);
/* We may have just created new basic blocks. Release and
recompute various things which are sized on the number of
}
free_reg_set_mem ();
alloc_reg_set_mem (max_reg_num ());
- compute_sets (f);
+ compute_sets ();
run_jump_opt_after_gcse = 1;
+ timevar_pop (TV_PRE);
}
if (max_pass_bytes < bytes_used)
/* It does not make sense to run code hoisting unless we are optimizing
for code size -- it rarely makes programs faster, and can make
them bigger if we did partial redundancy elimination (when optimizing
- for space, we use a classic gcse algorithm instead of partial
- redundancy algorithms). */
+ for space, we don't run the partial redundancy algorithms). */
if (optimize_size)
{
+ timevar_push (TV_HOIST);
max_gcse_regno = max_reg_num ();
- alloc_gcse_mem (f);
+ alloc_gcse_mem ();
changed |= one_code_hoisting_pass ();
free_gcse_mem ();
if (max_pass_bytes < bytes_used)
max_pass_bytes = bytes_used;
+ timevar_pop (TV_HOIST);
}
- if (file)
+ if (dump_file)
{
- fprintf (file, "\n");
- fflush (file);
+ fprintf (dump_file, "\n");
+ fflush (dump_file);
}
obstack_free (&gcse_obstack, gcse_obstack_bottom);
conditional jumps. */
max_gcse_regno = max_reg_num ();
- alloc_gcse_mem (f);
+ alloc_gcse_mem ();
/* This time, go ahead and allow cprop to alter jumps. */
- one_cprop_pass (pass + 1, 1, 0);
+ timevar_push (TV_CPROP2);
+ one_cprop_pass (pass + 1, true, true);
+ timevar_pop (TV_CPROP2);
free_gcse_mem ();
- if (file)
+ if (dump_file)
{
- fprintf (file, "GCSE of %s: %d basic blocks, ",
+ fprintf (dump_file, "GCSE of %s: %d basic blocks, ",
current_function_name (), n_basic_blocks);
- fprintf (file, "%d pass%s, %d bytes\n\n",
+ fprintf (dump_file, "%d pass%s, %d bytes\n\n",
pass, pass > 1 ? "es" : "", max_pass_bytes);
}
obstack_free (&gcse_obstack, NULL);
free_reg_set_mem ();
+
/* We are finished with alias. */
end_alias_analysis ();
- allocate_reg_info (max_reg_num (), FALSE, FALSE);
if (!optimize_size && flag_gcse_sm)
- store_motion ();
+ {
+ timevar_push (TV_LSM);
+ store_motion ();
+ timevar_pop (TV_LSM);
+ }
/* Record where pseudo-registers are set. */
return run_jump_opt_after_gcse;
This is called at the start of each pass. */
static void
-alloc_gcse_mem (rtx f)
+alloc_gcse_mem (void)
{
int i;
+ basic_block bb;
rtx insn;
/* Find the largest UID and create a mapping from UIDs to CUIDs.
CUIDs are like UIDs except they increase monotonically, have no gaps,
- and only apply to real insns. */
+ and only apply to real insns.
+ (Actually, there are gaps, for insn that are not inside a basic block.
+ but we should never see those anyway, so this is OK.) */
max_uid = get_max_uid ();
uid_cuid = gcalloc (max_uid + 1, sizeof (int));
- for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
- {
- if (INSN_P (insn))
- uid_cuid[INSN_UID (insn)] = i++;
- else
- uid_cuid[INSN_UID (insn)] = i;
- }
+ i = 0;
+ FOR_EACH_BB (bb)
+ FOR_BB_INSNS (bb, insn)
+ {
+ if (INSN_P (insn))
+ uid_cuid[INSN_UID (insn)] = i++;
+ else
+ uid_cuid[INSN_UID (insn)] = i;
+ }
/* Create a table mapping cuids to insns. */
max_cuid = i;
cuid_insn = gcalloc (max_cuid + 1, sizeof (rtx));
- for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- CUID_INSN (i++) = insn;
+ i = 0;
+ FOR_EACH_BB (bb)
+ FOR_BB_INSNS (bb, insn)
+ if (INSN_P (insn))
+ CUID_INSN (i++) = insn;
/* Allocate vars to track sets of regs. */
- reg_set_bitmap = BITMAP_XMALLOC ();
+ reg_set_bitmap = BITMAP_ALLOC (NULL);
/* Allocate vars to track sets of regs, memory per block. */
reg_set_in_block = sbitmap_vector_alloc (last_basic_block, max_gcse_regno);
basic block. */
modify_mem_list = gcalloc (last_basic_block, sizeof (rtx));
canon_modify_mem_list = gcalloc (last_basic_block, sizeof (rtx));
- modify_mem_list_set = BITMAP_XMALLOC ();
- canon_modify_mem_list_set = BITMAP_XMALLOC ();
+ modify_mem_list_set = BITMAP_ALLOC (NULL);
+ blocks_with_calls = BITMAP_ALLOC (NULL);
}
/* Free memory allocated by alloc_gcse_mem. */
free (uid_cuid);
free (cuid_insn);
- BITMAP_XFREE (reg_set_bitmap);
+ BITMAP_FREE (reg_set_bitmap);
sbitmap_vector_free (reg_set_in_block);
free_modify_mem_tables ();
- BITMAP_XFREE (modify_mem_list_set);
- BITMAP_XFREE (canon_modify_mem_list_set);
-}
-
-/* Many of the global optimization algorithms work by solving dataflow
- equations for various expressions. Initially, some local value is
- computed for each expression in each block. Then, the values across the
- various blocks are combined (by following flow graph edges) to arrive at
- global values. Conceptually, each set of equations is independent. We
- may therefore solve all the equations in parallel, solve them one at a
- time, or pick any intermediate approach.
-
- When you're going to need N two-dimensional bitmaps, each X (say, the
- number of blocks) by Y (say, the number of expressions), call this
- function. It's not important what X and Y represent; only that Y
- correspond to the things that can be done in parallel. This function will
- return an appropriate chunking factor C; you should solve C sets of
- equations in parallel. By going through this function, we can easily
- trade space against time; by solving fewer equations in parallel we use
- less space. */
-
-static int
-get_bitmap_width (int n, int x, int y)
-{
- /* It's not really worth figuring out *exactly* how much memory will
- be used by a particular choice. The important thing is to get
- something approximately right. */
- size_t max_bitmap_memory = 10 * 1024 * 1024;
-
- /* The number of bytes we'd use for a single column of minimum
- width. */
- size_t column_size = n * x * sizeof (SBITMAP_ELT_TYPE);
-
- /* Often, it's reasonable just to solve all the equations in
- parallel. */
- if (column_size * SBITMAP_SET_SIZE (y) <= max_bitmap_memory)
- return y;
-
- /* Otherwise, pick the largest width we can, without going over the
- limit. */
- return SBITMAP_ELT_BITS * ((max_bitmap_memory + column_size - 1)
- / column_size);
+ BITMAP_FREE (modify_mem_list_set);
+ BITMAP_FREE (blocks_with_calls);
}
\f
/* Compute the local properties of each recorded expression.
ABSALTERED. */
static void
-compute_local_properties (sbitmap *transp, sbitmap *comp, sbitmap *antloc, struct hash_table *table)
+compute_local_properties (sbitmap *transp, sbitmap *comp, sbitmap *antloc,
+ struct hash_table *table)
{
unsigned int i;
obstack_free (®_set_obstack, NULL);
}
-/* An OLD_INSN that used to set REGNO was replaced by NEW_INSN.
- Update the corresponding `reg_set_table' entry accordingly.
- We assume that NEW_INSN is not already recorded in reg_set_table[regno]. */
-
-static void
-replace_one_set (int regno, rtx old_insn, rtx new_insn)
-{
- struct reg_set *reg_info;
- if (regno >= reg_set_table_size)
- return;
- for (reg_info = reg_set_table[regno]; reg_info; reg_info = reg_info->next)
- if (reg_info->insn == old_insn)
- {
- reg_info->insn = new_insn;
- break;
- }
-}
-
/* Record REGNO in the reg_set table. */
static void
new_reg_info = obstack_alloc (®_set_obstack, sizeof (struct reg_set));
bytes_used += sizeof (struct reg_set);
- new_reg_info->insn = insn;
+ new_reg_info->bb_index = BLOCK_NUM (insn);
new_reg_info->next = reg_set_table[regno];
reg_set_table[regno] = new_reg_info;
}
occurring. */
static void
-record_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED, void *data)
+record_set_info (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, void *data)
{
rtx record_set_insn = (rtx) data;
- if (GET_CODE (dest) == REG && REGNO (dest) >= FIRST_PSEUDO_REGISTER)
+ if (REG_P (dest) && REGNO (dest) >= FIRST_PSEUDO_REGISTER)
record_one_set (REGNO (dest), record_set_insn);
}
`reg_set_table' for further documentation. */
static void
-compute_sets (rtx f)
+compute_sets (void)
{
+ basic_block bb;
rtx insn;
- for (insn = f; insn != 0; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- note_stores (PATTERN (insn), record_set_info, insn);
+ FOR_EACH_BB (bb)
+ FOR_BB_INSNS (bb, insn)
+ if (INSN_P (insn))
+ note_stores (PATTERN (insn), record_set_info, insn);
}
\f
/* Hash table support. */
static int
want_to_gcse_p (rtx x)
{
+#ifdef STACK_REGS
+ /* On register stack architectures, don't GCSE constants from the
+ constant pool, as the benefits are often swamped by the overhead
+ of shuffling the register stack between basic blocks. */
+ if (IS_STACK_MODE (GET_MODE (x)))
+ x = avoid_constant_pool_reference (x);
+#endif
+
switch (GET_CODE (x))
{
case REG:
case SUBREG:
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_FIXED:
case CONST_VECTOR:
case CALL:
- case CONSTANT_P_RTX:
return 0;
default:
or from INSN to the end of INSN's basic block (if AVAIL_P != 0). */
static int
-oprs_unchanged_p (rtx x, rtx insn, int avail_p)
+oprs_unchanged_p (const_rtx x, const_rtx insn, int avail_p)
{
int i, j;
enum rtx_code code;
case CONST:
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_FIXED:
case CONST_VECTOR:
case SYMBOL_REF:
case LABEL_REF:
load_killed_in_block_p. A memory reference for a load instruction,
mems_conflict_for_gcse_p will see if a memory store conflicts with
this memory load. */
-static rtx gcse_mem_operand;
+static const_rtx gcse_mem_operand;
/* DEST is the output of an instruction. If it is a memory reference, and
possibly conflicts with the load found in gcse_mem_operand, then set
gcse_mems_conflict_p to a nonzero value. */
static void
-mems_conflict_for_gcse_p (rtx dest, rtx setter ATTRIBUTE_UNUSED,
+mems_conflict_for_gcse_p (rtx dest, const_rtx setter ATTRIBUTE_UNUSED,
void *data ATTRIBUTE_UNUSED)
{
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
- || GET_CODE (dest) == SIGN_EXTRACT
|| GET_CODE (dest) == STRICT_LOW_PART)
dest = XEXP (dest, 0);
/* If DEST is not a MEM, then it will not conflict with the load. Note
that function calls are assumed to clobber memory, but are handled
elsewhere. */
- if (GET_CODE (dest) != MEM)
+ if (! MEM_P (dest))
return;
/* If we are setting a MEM in our list of specially recognized MEMs,
AVAIL_P to 0. */
static int
-load_killed_in_block_p (basic_block bb, int uid_limit, rtx x, int avail_p)
+load_killed_in_block_p (const_basic_block bb, int uid_limit, const_rtx x, int avail_p)
{
rtx list_entry = modify_mem_list[bb->index];
+
+ /* If this is a readonly then we aren't going to be changing it. */
+ if (MEM_READONLY_P (x))
+ return 0;
+
while (list_entry)
{
rtx setter;
/* If SETTER is a call everything is clobbered. Note that calls
to pure functions are never put on the list, so we need not
worry about them. */
- if (GET_CODE (setter) == CALL_INSN)
+ if (CALL_P (setter))
return 1;
/* SETTER must be an INSN of some kind that sets memory. Call
the start of INSN's basic block up to but not including INSN. */
static int
-oprs_anticipatable_p (rtx x, rtx insn)
+oprs_anticipatable_p (const_rtx x, const_rtx insn)
{
return oprs_unchanged_p (x, insn, 0);
}
INSN to the end of INSN's basic block. */
static int
-oprs_available_p (rtx x, rtx insn)
+oprs_available_p (const_rtx x, const_rtx insn)
{
return oprs_unchanged_p (x, insn, 1);
}
MODE is only used if X is a CONST_INT. DO_NOT_RECORD_P is a boolean
indicating if a volatile operand is found or if the expression contains
something we don't want to insert in the table. HASH_TABLE_SIZE is
- the current size of the hash table to be probed.
-
- ??? One might want to merge this with canon_hash. Later. */
+ the current size of the hash table to be probed. */
static unsigned int
-hash_expr (rtx x, enum machine_mode mode, int *do_not_record_p,
+hash_expr (const_rtx x, enum machine_mode mode, int *do_not_record_p,
int hash_table_size)
{
unsigned int hash;
*do_not_record_p = 0;
- hash = hash_expr_1 (x, mode, do_not_record_p);
+ hash = hash_rtx (x, mode, do_not_record_p,
+ NULL, /*have_reg_qty=*/false);
return hash % hash_table_size;
}
-/* Hash a string. Just add its bytes up. */
-
-static inline unsigned
-hash_string_1 (const char *ps)
-{
- unsigned hash = 0;
- const unsigned char *p = (const unsigned char *) ps;
-
- if (p)
- while (*p)
- hash += *p++;
-
- return hash;
-}
-
-/* Subroutine of hash_expr to do the actual work. */
-
-static unsigned int
-hash_expr_1 (rtx x, enum machine_mode mode, int *do_not_record_p)
-{
- int i, j;
- unsigned hash = 0;
- enum rtx_code code;
- const char *fmt;
-
- /* Used to turn recursion into iteration. We can't rely on GCC's
- tail-recursion elimination since we need to keep accumulating values
- in HASH. */
-
- if (x == 0)
- return hash;
-
- repeat:
- code = GET_CODE (x);
- switch (code)
- {
- case REG:
- hash += ((unsigned int) REG << 7) + REGNO (x);
- return hash;
-
- case CONST_INT:
- hash += (((unsigned int) CONST_INT << 7) + (unsigned int) mode
- + (unsigned int) INTVAL (x));
- return hash;
-
- case CONST_DOUBLE:
- /* This is like the general case, except that it only counts
- the integers representing the constant. */
- hash += (unsigned int) code + (unsigned int) GET_MODE (x);
- if (GET_MODE (x) != VOIDmode)
- for (i = 2; i < GET_RTX_LENGTH (CONST_DOUBLE); i++)
- hash += (unsigned int) XWINT (x, i);
- else
- hash += ((unsigned int) CONST_DOUBLE_LOW (x)
- + (unsigned int) CONST_DOUBLE_HIGH (x));
- return hash;
-
- case CONST_VECTOR:
- {
- int units;
- rtx elt;
-
- units = CONST_VECTOR_NUNITS (x);
-
- for (i = 0; i < units; ++i)
- {
- elt = CONST_VECTOR_ELT (x, i);
- hash += hash_expr_1 (elt, GET_MODE (elt), do_not_record_p);
- }
-
- return hash;
- }
-
- /* Assume there is only one rtx object for any given label. */
- case LABEL_REF:
- /* We don't hash on the address of the CODE_LABEL to avoid bootstrap
- differences and differences between each stage's debugging dumps. */
- hash += (((unsigned int) LABEL_REF << 7)
- + CODE_LABEL_NUMBER (XEXP (x, 0)));
- return hash;
-
- case SYMBOL_REF:
- {
- /* Don't hash on the symbol's address to avoid bootstrap differences.
- Different hash values may cause expressions to be recorded in
- different orders and thus different registers to be used in the
- final assembler. This also avoids differences in the dump files
- between various stages. */
- unsigned int h = 0;
- const unsigned char *p = (const unsigned char *) XSTR (x, 0);
-
- while (*p)
- h += (h << 7) + *p++; /* ??? revisit */
-
- hash += ((unsigned int) SYMBOL_REF << 7) + h;
- return hash;
- }
-
- case MEM:
- if (MEM_VOLATILE_P (x))
- {
- *do_not_record_p = 1;
- return 0;
- }
-
- hash += (unsigned int) MEM;
- /* We used alias set for hashing, but this is not good, since the alias
- set may differ in -fprofile-arcs and -fbranch-probabilities compilation
- causing the profiles to fail to match. */
- x = XEXP (x, 0);
- goto repeat;
-
- case PRE_DEC:
- case PRE_INC:
- case POST_DEC:
- case POST_INC:
- case PC:
- case CC0:
- case CALL:
- case UNSPEC_VOLATILE:
- *do_not_record_p = 1;
- return 0;
-
- case ASM_OPERANDS:
- if (MEM_VOLATILE_P (x))
- {
- *do_not_record_p = 1;
- return 0;
- }
- else
- {
- /* We don't want to take the filename and line into account. */
- hash += (unsigned) code + (unsigned) GET_MODE (x)
- + hash_string_1 (ASM_OPERANDS_TEMPLATE (x))
- + hash_string_1 (ASM_OPERANDS_OUTPUT_CONSTRAINT (x))
- + (unsigned) ASM_OPERANDS_OUTPUT_IDX (x);
-
- if (ASM_OPERANDS_INPUT_LENGTH (x))
- {
- for (i = 1; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
- {
- hash += (hash_expr_1 (ASM_OPERANDS_INPUT (x, i),
- GET_MODE (ASM_OPERANDS_INPUT (x, i)),
- do_not_record_p)
- + hash_string_1 (ASM_OPERANDS_INPUT_CONSTRAINT
- (x, i)));
- }
-
- hash += hash_string_1 (ASM_OPERANDS_INPUT_CONSTRAINT (x, 0));
- x = ASM_OPERANDS_INPUT (x, 0);
- mode = GET_MODE (x);
- goto repeat;
- }
- return hash;
- }
-
- default:
- break;
- }
-
- hash += (unsigned) code + (unsigned) GET_MODE (x);
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration.
- This function is called enough to be worth it. */
- if (i == 0)
- {
- x = XEXP (x, i);
- goto repeat;
- }
-
- hash += hash_expr_1 (XEXP (x, i), 0, do_not_record_p);
- if (*do_not_record_p)
- return 0;
- }
-
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- {
- hash += hash_expr_1 (XVECEXP (x, i, j), 0, do_not_record_p);
- if (*do_not_record_p)
- return 0;
- }
-
- else if (fmt[i] == 's')
- hash += hash_string_1 (XSTR (x, i));
- else if (fmt[i] == 'i')
- hash += (unsigned int) XINT (x, i);
- else
- abort ();
- }
-
- return hash;
-}
-
/* Hash a set of register REGNO.
Sets are hashed on the register that is set. This simplifies the PRE copy
return hash % hash_table_size;
}
-/* Return nonzero if exp1 is equivalent to exp2.
- ??? Borrowed from cse.c. Might want to remerge with cse.c. Later. */
+/* Return nonzero if exp1 is equivalent to exp2. */
static int
-expr_equiv_p (rtx x, rtx y)
+expr_equiv_p (const_rtx x, const_rtx y)
{
- int i, j;
- enum rtx_code code;
- const char *fmt;
-
- if (x == y)
- return 1;
-
- if (x == 0 || y == 0)
- return 0;
-
- code = GET_CODE (x);
- if (code != GET_CODE (y))
- return 0;
-
- /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
- if (GET_MODE (x) != GET_MODE (y))
- return 0;
-
- switch (code)
- {
- case PC:
- case CC0:
- case CONST_INT:
- return 0;
-
- case LABEL_REF:
- return XEXP (x, 0) == XEXP (y, 0);
-
- case SYMBOL_REF:
- return XSTR (x, 0) == XSTR (y, 0);
-
- case REG:
- return REGNO (x) == REGNO (y);
-
- case MEM:
- /* Can't merge two expressions in different alias sets, since we can
- decide that the expression is transparent in a block when it isn't,
- due to it being set with the different alias set. */
- if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y))
- return 0;
-
- /* A volatile mem should not be considered equivalent to any other. */
- if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
- return 0;
- break;
-
- /* For commutative operations, check both orders. */
- case PLUS:
- case MULT:
- case AND:
- case IOR:
- case XOR:
- case NE:
- case EQ:
- return ((expr_equiv_p (XEXP (x, 0), XEXP (y, 0))
- && expr_equiv_p (XEXP (x, 1), XEXP (y, 1)))
- || (expr_equiv_p (XEXP (x, 0), XEXP (y, 1))
- && expr_equiv_p (XEXP (x, 1), XEXP (y, 0))));
-
- case ASM_OPERANDS:
- /* We don't use the generic code below because we want to
- disregard filename and line numbers. */
-
- /* A volatile asm isn't equivalent to any other. */
- if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
- return 0;
-
- if (GET_MODE (x) != GET_MODE (y)
- || strcmp (ASM_OPERANDS_TEMPLATE (x), ASM_OPERANDS_TEMPLATE (y))
- || strcmp (ASM_OPERANDS_OUTPUT_CONSTRAINT (x),
- ASM_OPERANDS_OUTPUT_CONSTRAINT (y))
- || ASM_OPERANDS_OUTPUT_IDX (x) != ASM_OPERANDS_OUTPUT_IDX (y)
- || ASM_OPERANDS_INPUT_LENGTH (x) != ASM_OPERANDS_INPUT_LENGTH (y))
- return 0;
-
- if (ASM_OPERANDS_INPUT_LENGTH (x))
- {
- for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--)
- if (! expr_equiv_p (ASM_OPERANDS_INPUT (x, i),
- ASM_OPERANDS_INPUT (y, i))
- || strcmp (ASM_OPERANDS_INPUT_CONSTRAINT (x, i),
- ASM_OPERANDS_INPUT_CONSTRAINT (y, i)))
- return 0;
- }
-
- return 1;
-
- default:
- break;
- }
-
- /* Compare the elements. If any pair of corresponding elements
- fail to match, return 0 for the whole thing. */
-
- fmt = GET_RTX_FORMAT (code);
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- switch (fmt[i])
- {
- case 'e':
- if (! expr_equiv_p (XEXP (x, i), XEXP (y, i)))
- return 0;
- break;
-
- case 'E':
- if (XVECLEN (x, i) != XVECLEN (y, i))
- return 0;
- for (j = 0; j < XVECLEN (x, i); j++)
- if (! expr_equiv_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
- return 0;
- break;
-
- case 's':
- if (strcmp (XSTR (x, i), XSTR (y, i)))
- return 0;
- break;
-
- case 'i':
- if (XINT (x, i) != XINT (y, i))
- return 0;
- break;
-
- case 'w':
- if (XWINT (x, i) != XWINT (y, i))
- return 0;
- break;
-
- case '0':
- break;
-
- default:
- abort ();
- }
- }
-
- return 1;
+ return exp_equiv_p (x, y, 0, true);
}
/* Insert expression X in INSN in the hash TABLE.
unsigned int hash;
struct expr *cur_expr, *last_expr = NULL;
struct occr *antic_occr, *avail_occr;
- struct occr *last_occr = NULL;
hash = hash_expr (x, mode, &do_not_record_p, table->size);
{
antic_occr = cur_expr->antic_occr;
- /* Search for another occurrence in the same basic block. */
- while (antic_occr && BLOCK_NUM (antic_occr->insn) != BLOCK_NUM (insn))
- {
- /* If an occurrence isn't found, save a pointer to the end of
- the list. */
- last_occr = antic_occr;
- antic_occr = antic_occr->next;
- }
+ if (antic_occr && BLOCK_NUM (antic_occr->insn) != BLOCK_NUM (insn))
+ antic_occr = NULL;
if (antic_occr)
/* Found another instance of the expression in the same basic block.
/* First occurrence of this expression in this basic block. */
antic_occr = gcse_alloc (sizeof (struct occr));
bytes_used += sizeof (struct occr);
- /* First occurrence of this expression in any block? */
- if (cur_expr->antic_occr == NULL)
- cur_expr->antic_occr = antic_occr;
- else
- last_occr->next = antic_occr;
-
antic_occr->insn = insn;
- antic_occr->next = NULL;
+ antic_occr->next = cur_expr->antic_occr;
antic_occr->deleted_p = 0;
+ cur_expr->antic_occr = antic_occr;
}
}
{
avail_occr = cur_expr->avail_occr;
- /* Search for another occurrence in the same basic block. */
- while (avail_occr && BLOCK_NUM (avail_occr->insn) != BLOCK_NUM (insn))
+ if (avail_occr && BLOCK_NUM (avail_occr->insn) == BLOCK_NUM (insn))
{
- /* If an occurrence isn't found, save a pointer to the end of
- the list. */
- last_occr = avail_occr;
- avail_occr = avail_occr->next;
+ /* Found another instance of the expression in the same basic block.
+ Prefer this occurrence to the currently recorded one. We want
+ the last one in the block and the block is scanned from start
+ to end. */
+ avail_occr->insn = insn;
}
-
- if (avail_occr)
- /* Found another instance of the expression in the same basic block.
- Prefer this occurrence to the currently recorded one. We want
- the last one in the block and the block is scanned from start
- to end. */
- avail_occr->insn = insn;
else
{
/* First occurrence of this expression in this basic block. */
avail_occr = gcse_alloc (sizeof (struct occr));
bytes_used += sizeof (struct occr);
-
- /* First occurrence of this expression in any block? */
- if (cur_expr->avail_occr == NULL)
- cur_expr->avail_occr = avail_occr;
- else
- last_occr->next = avail_occr;
-
avail_occr->insn = insn;
- avail_occr->next = NULL;
+ avail_occr->next = cur_expr->avail_occr;
avail_occr->deleted_p = 0;
+ cur_expr->avail_occr = avail_occr;
}
}
}
int found;
unsigned int hash;
struct expr *cur_expr, *last_expr = NULL;
- struct occr *cur_occr, *last_occr = NULL;
+ struct occr *cur_occr;
- if (GET_CODE (x) != SET
- || GET_CODE (SET_DEST (x)) != REG)
- abort ();
+ gcc_assert (GET_CODE (x) == SET && REG_P (SET_DEST (x)));
hash = hash_set (REGNO (SET_DEST (x)), table->size);
/* Now record the occurrence. */
cur_occr = cur_expr->avail_occr;
- /* Search for another occurrence in the same basic block. */
- while (cur_occr && BLOCK_NUM (cur_occr->insn) != BLOCK_NUM (insn))
+ if (cur_occr && BLOCK_NUM (cur_occr->insn) == BLOCK_NUM (insn))
{
- /* If an occurrence isn't found, save a pointer to the end of
- the list. */
- last_occr = cur_occr;
- cur_occr = cur_occr->next;
+ /* Found another instance of the expression in the same basic block.
+ Prefer this occurrence to the currently recorded one. We want
+ the last one in the block and the block is scanned from start
+ to end. */
+ cur_occr->insn = insn;
}
-
- if (cur_occr)
- /* Found another instance of the expression in the same basic block.
- Prefer this occurrence to the currently recorded one. We want the
- last one in the block and the block is scanned from start to end. */
- cur_occr->insn = insn;
else
{
/* First occurrence of this expression in this basic block. */
cur_occr = gcse_alloc (sizeof (struct occr));
bytes_used += sizeof (struct occr);
- /* First occurrence of this expression in any block? */
- if (cur_expr->avail_occr == NULL)
- cur_expr->avail_occr = cur_occr;
- else
- last_occr->next = cur_occr;
-
- cur_occr->insn = insn;
- cur_occr->next = NULL;
- cur_occr->deleted_p = 0;
+ cur_occr->insn = insn;
+ cur_occr->next = cur_expr->avail_occr;
+ cur_occr->deleted_p = 0;
+ cur_expr->avail_occr = cur_occr;
}
}
the purposes of GCSE's constant propagation. */
static bool
-gcse_constant_p (rtx x)
+gcse_constant_p (const_rtx x)
{
/* Consider a COMPARE of two integers constant. */
if (GET_CODE (x) == COMPARE
&& GET_CODE (XEXP (x, 1)) == CONST_INT)
return true;
-
/* Consider a COMPARE of the same registers is a constant
- if they are not floating point registers. */
+ if they are not floating point registers. */
if (GET_CODE(x) == COMPARE
- && GET_CODE (XEXP (x, 0)) == REG
- && GET_CODE (XEXP (x, 1)) == REG
+ && REG_P (XEXP (x, 0)) && REG_P (XEXP (x, 1))
&& REGNO (XEXP (x, 0)) == REGNO (XEXP (x, 1))
&& ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0)))
&& ! FLOAT_MODE_P (GET_MODE (XEXP (x, 1))))
return true;
- if (GET_CODE (x) == CONSTANT_P_RTX)
- return false;
-
return CONSTANT_P (x);
}
if (GET_CODE (src) == CALL)
hash_scan_call (src, insn, table);
- else if (GET_CODE (dest) == REG)
+ else if (REG_P (dest))
{
unsigned int regno = REGNO (dest);
rtx tmp;
- /* If this is a single set and we are doing constant propagation,
- see if a REG_NOTE shows this equivalent to a constant. */
- if (table->set_p && (note = find_reg_equal_equiv_note (insn)) != 0
- && gcse_constant_p (XEXP (note, 0)))
+ /* See if a REG_NOTE shows this equivalent to a simpler expression.
+ This allows us to do a single GCSE pass and still eliminate
+ redundant constants, addresses or other expressions that are
+ constructed with multiple instructions. */
+ note = find_reg_equal_equiv_note (insn);
+ if (note != 0
+ && (table->set_p
+ ? gcse_constant_p (XEXP (note, 0))
+ : want_to_gcse_p (XEXP (note, 0))))
src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src);
/* Only record sets of pseudo-regs in the hash table. */
REG_EQUIV notes and if the argument slot is used somewhere
explicitly, it means address of parameter has been taken,
so we should not extend the lifetime of the pseudo. */
- && ((note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) == 0
- || GET_CODE (XEXP (note, 0)) != MEM))
+ && (note == NULL_RTX || ! MEM_P (XEXP (note, 0))))
{
/* An expression is not anticipatable if its operands are
modified before this insn or if this is not the only SET in
- this insn. */
- int antic_p = oprs_anticipatable_p (src, insn) && single_set (insn);
+ this insn. The latter condition does not have to mean that
+ SRC itself is not anticipatable, but we just will not be
+ able to handle code motion of insns with multiple sets. */
+ int antic_p = oprs_anticipatable_p (src, insn)
+ && !multiple_sets (insn);
/* An expression is not available if its operands are
subsequently modified, including this insn. It's also not
available if this is a branch, because we can't insert
/* Record sets for constant/copy propagation. */
else if (table->set_p
&& regno >= FIRST_PSEUDO_REGISTER
- && ((GET_CODE (src) == REG
+ && ((REG_P (src)
&& REGNO (src) >= FIRST_PSEUDO_REGISTER
&& can_copy_p (GET_MODE (dest))
&& REGNO (src) != regno)
modified. Here we want to search from INSN+1 on, but
oprs_available_p searches from INSN on. */
&& (insn == BB_END (BLOCK_FOR_INSN (insn))
- || ((tmp = next_nonnote_insn (insn)) != NULL_RTX
- && oprs_available_p (pat, tmp))))
+ || (tmp = next_nonnote_insn (insn)) == NULL_RTX
+ || oprs_available_p (pat, tmp)))
insert_set_in_table (pat, insn, table);
}
/* In case of store we want to consider the memory value as available in
the REG stored in that memory. This makes it possible to remove
redundant loads from due to stores to the same location. */
- else if (flag_gcse_las && GET_CODE (src) == REG && GET_CODE (dest) == MEM)
+ else if (flag_gcse_las && REG_P (src) && MEM_P (dest))
{
unsigned int regno = REGNO (src);
explicitly, it means address of parameter has been taken,
so we should not extend the lifetime of the pseudo. */
&& ((note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) == 0
- || GET_CODE (XEXP (note, 0)) != MEM))
+ || ! MEM_P (XEXP (note, 0))))
{
/* Stores are never anticipatable. */
int antic_p = 0;
taken off pairwise. */
static void
-canon_list_insert (rtx dest ATTRIBUTE_UNUSED, rtx unused1 ATTRIBUTE_UNUSED,
+canon_list_insert (rtx dest ATTRIBUTE_UNUSED, const_rtx unused1 ATTRIBUTE_UNUSED,
void * v_insn)
{
rtx dest_addr, insn;
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
- || GET_CODE (dest) == SIGN_EXTRACT
|| GET_CODE (dest) == STRICT_LOW_PART)
dest = XEXP (dest, 0);
that function calls are assumed to clobber memory, but are handled
elsewhere. */
- if (GET_CODE (dest) != MEM)
+ if (! MEM_P (dest))
return;
dest_addr = get_addr (XEXP (dest, 0));
alloc_EXPR_LIST (VOIDmode, dest_addr, canon_modify_mem_list[bb]);
canon_modify_mem_list[bb] =
alloc_EXPR_LIST (VOIDmode, dest, canon_modify_mem_list[bb]);
- bitmap_set_bit (canon_modify_mem_list_set, bb);
}
/* Record memory modification information for INSN. We do not actually care
modify_mem_list[bb] = alloc_INSN_LIST (insn, modify_mem_list[bb]);
bitmap_set_bit (modify_mem_list_set, bb);
- if (GET_CODE (insn) == CALL_INSN)
+ if (CALL_P (insn))
{
/* Note that traversals of this loop (other than for free-ing)
will break after encountering a CALL_INSN. So, there's no
need to insert a pair of items, as canon_list_insert does. */
canon_modify_mem_list[bb] =
alloc_INSN_LIST (insn, canon_modify_mem_list[bb]);
- bitmap_set_bit (canon_modify_mem_list_set, bb);
+ bitmap_set_bit (blocks_with_calls, bb);
}
else
note_stores (PATTERN (insn), canon_list_insert, (void*) insn);
the SET is taking place. */
static void
-record_last_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED, void *data)
+record_last_set_info (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, void *data)
{
rtx last_set_insn = (rtx) data;
if (GET_CODE (dest) == SUBREG)
dest = SUBREG_REG (dest);
- if (GET_CODE (dest) == REG)
+ if (REG_P (dest))
record_last_reg_set_info (last_set_insn, REGNO (dest));
- else if (GET_CODE (dest) == MEM
+ else if (MEM_P (dest)
/* Ignore pushes, they clobber nothing. */
&& ! push_operand (dest, GET_MODE (dest)))
record_last_mem_set_info (last_set_insn);
??? hard-reg reg_set_in_block computation
could be moved to compute_sets since they currently don't change. */
- for (insn = BB_HEAD (current_bb);
- insn && insn != NEXT_INSN (BB_END (current_bb));
- insn = NEXT_INSN (insn))
+ FOR_BB_INSNS (current_bb, insn)
{
if (! INSN_P (insn))
continue;
- if (GET_CODE (insn) == CALL_INSN)
+ if (CALL_P (insn))
{
- bool clobbers_all = false;
-#ifdef NON_SAVING_SETJMP
- if (NON_SAVING_SETJMP
- && find_reg_note (insn, REG_SETJMP, NULL_RTX))
- clobbers_all = true;
-#endif
-
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if (clobbers_all
- || TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
+ if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
record_last_reg_set_info (insn, regno);
mark_call (insn);
BB_HEAD (current_bb), table);
/* The next pass builds the hash table. */
-
- for (insn = BB_HEAD (current_bb), in_libcall_block = 0;
- insn && insn != NEXT_INSN (BB_END (current_bb));
- insn = NEXT_INSN (insn))
+ in_libcall_block = 0;
+ FOR_BB_INSNS (current_bb, insn)
if (INSN_P (insn))
{
if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
\f
/* Expression tracking support. */
-/* Lookup pattern PAT in the expression TABLE.
- The result is a pointer to the table entry, or NULL if not found. */
-
-static struct expr *
-lookup_expr (rtx pat, struct hash_table *table)
-{
- int do_not_record_p;
- unsigned int hash = hash_expr (pat, GET_MODE (pat), &do_not_record_p,
- table->size);
- struct expr *expr;
-
- if (do_not_record_p)
- return NULL;
-
- expr = table->table[hash];
-
- while (expr && ! expr_equiv_p (expr->expr, pat))
- expr = expr->next_same_hash;
-
- return expr;
-}
-
/* Lookup REGNO in the set TABLE. The result is a pointer to the
table entry, or NULL if not found. */
static void
clear_modify_mem_tables (void)
{
- int i;
+ unsigned i;
+ bitmap_iterator bi;
- EXECUTE_IF_SET_IN_BITMAP
- (modify_mem_list_set, 0, i, free_INSN_LIST_list (modify_mem_list + i));
+ EXECUTE_IF_SET_IN_BITMAP (modify_mem_list_set, 0, i, bi)
+ {
+ free_INSN_LIST_list (modify_mem_list + i);
+ free_insn_expr_list_list (canon_modify_mem_list + i);
+ }
bitmap_clear (modify_mem_list_set);
-
- EXECUTE_IF_SET_IN_BITMAP
- (canon_modify_mem_list_set, 0, i,
- free_insn_expr_list_list (canon_modify_mem_list + i));
- bitmap_clear (canon_modify_mem_list_set);
+ bitmap_clear (blocks_with_calls);
}
-/* Release memory used by modify_mem_list_set and canon_modify_mem_list_set. */
+/* Release memory used by modify_mem_list_set. */
static void
free_modify_mem_tables (void)
INSN's basic block. */
static int
-oprs_not_set_p (rtx x, rtx insn)
+oprs_not_set_p (const_rtx x, const_rtx insn)
{
int i, j;
enum rtx_code code;
case CONST:
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_FIXED:
case CONST_VECTOR:
case SYMBOL_REF:
case LABEL_REF:
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
- || GET_CODE (dest) == SIGN_EXTRACT
|| GET_CODE (dest) == STRICT_LOW_PART)
dest = XEXP (dest, 0);
- if (GET_CODE (dest) == REG)
+ if (REG_P (dest))
SET_REGNO_REG_SET (reg_set_bitmap, REGNO (dest));
- else if (GET_CODE (dest) == MEM)
+ else if (MEM_P (dest))
record_last_mem_set_info (insn);
if (GET_CODE (SET_SRC (pat)) == CALL)
while (GET_CODE (clob) == SUBREG || GET_CODE (clob) == STRICT_LOW_PART)
clob = XEXP (clob, 0);
- if (GET_CODE (clob) == REG)
+ if (REG_P (clob))
SET_REGNO_REG_SET (reg_set_bitmap, REGNO (clob));
else
record_last_mem_set_info (insn);
}
\f
-/* Classic GCSE reaching definition support. */
-
-/* Allocate reaching def variables. */
-
-static void
-alloc_rd_mem (int n_blocks, int n_insns)
-{
- rd_kill = sbitmap_vector_alloc (n_blocks, n_insns);
- sbitmap_vector_zero (rd_kill, n_blocks);
-
- rd_gen = sbitmap_vector_alloc (n_blocks, n_insns);
- sbitmap_vector_zero (rd_gen, n_blocks);
+/* Compute copy/constant propagation working variables. */
- reaching_defs = sbitmap_vector_alloc (n_blocks, n_insns);
- sbitmap_vector_zero (reaching_defs, n_blocks);
+/* Local properties of assignments. */
+static sbitmap *cprop_pavloc;
+static sbitmap *cprop_absaltered;
- rd_out = sbitmap_vector_alloc (n_blocks, n_insns);
- sbitmap_vector_zero (rd_out, n_blocks);
-}
+/* Global properties of assignments (computed from the local properties). */
+static sbitmap *cprop_avin;
+static sbitmap *cprop_avout;
-/* Free reaching def variables. */
+/* Allocate vars used for copy/const propagation. N_BLOCKS is the number of
+ basic blocks. N_SETS is the number of sets. */
static void
-free_rd_mem (void)
+alloc_cprop_mem (int n_blocks, int n_sets)
{
- sbitmap_vector_free (rd_kill);
- sbitmap_vector_free (rd_gen);
- sbitmap_vector_free (reaching_defs);
- sbitmap_vector_free (rd_out);
+ cprop_pavloc = sbitmap_vector_alloc (n_blocks, n_sets);
+ cprop_absaltered = sbitmap_vector_alloc (n_blocks, n_sets);
+
+ cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
+ cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
}
-/* Add INSN to the kills of BB. REGNO, set in BB, is killed by INSN. */
+/* Free vars used by copy/const propagation. */
static void
-handle_rd_kill_set (rtx insn, int regno, basic_block bb)
+free_cprop_mem (void)
{
- struct reg_set *this_reg;
-
- for (this_reg = reg_set_table[regno]; this_reg; this_reg = this_reg ->next)
- if (BLOCK_NUM (this_reg->insn) != BLOCK_NUM (insn))
- SET_BIT (rd_kill[bb->index], INSN_CUID (this_reg->insn));
+ sbitmap_vector_free (cprop_pavloc);
+ sbitmap_vector_free (cprop_absaltered);
+ sbitmap_vector_free (cprop_avin);
+ sbitmap_vector_free (cprop_avout);
}
-/* Compute the set of kill's for reaching definitions. */
+/* For each block, compute whether X is transparent. X is either an
+ expression or an assignment [though we don't care which, for this context
+ an assignment is treated as an expression]. For each block where an
+ element of X is modified, set (SET_P == 1) or reset (SET_P == 0) the INDX
+ bit in BMAP. */
static void
-compute_kill_rd (void)
+compute_transp (const_rtx x, int indx, sbitmap *bmap, int set_p)
{
- int cuid;
- unsigned int regno;
- int i;
+ int i, j;
basic_block bb;
+ enum rtx_code code;
+ reg_set *r;
+ const char *fmt;
- /* For each block
- For each set bit in `gen' of the block (i.e each insn which
- generates a definition in the block)
- Call the reg set by the insn corresponding to that bit regx
- Look at the linked list starting at reg_set_table[regx]
- For each setting of regx in the linked list, which is not in
- this block
- Set the bit in `kill' corresponding to that insn. */
- FOR_EACH_BB (bb)
- for (cuid = 0; cuid < max_cuid; cuid++)
- if (TEST_BIT (rd_gen[bb->index], cuid))
- {
- rtx insn = CUID_INSN (cuid);
- rtx pat = PATTERN (insn);
+ /* repeat is used to turn tail-recursion into iteration since GCC
+ can't do it when there's no return value. */
+ repeat:
+
+ if (x == 0)
+ return;
- if (GET_CODE (insn) == CALL_INSN)
+ code = GET_CODE (x);
+ switch (code)
+ {
+ case REG:
+ if (set_p)
+ {
+ if (REGNO (x) < FIRST_PSEUDO_REGISTER)
{
- for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
- handle_rd_kill_set (insn, regno, bb);
+ FOR_EACH_BB (bb)
+ if (TEST_BIT (reg_set_in_block[bb->index], REGNO (x)))
+ SET_BIT (bmap[bb->index], indx);
}
-
- if (GET_CODE (pat) == PARALLEL)
+ else
{
- for (i = XVECLEN (pat, 0) - 1; i >= 0; i--)
- {
- enum rtx_code code = GET_CODE (XVECEXP (pat, 0, i));
-
- if ((code == SET || code == CLOBBER)
- && GET_CODE (XEXP (XVECEXP (pat, 0, i), 0)) == REG)
- handle_rd_kill_set (insn,
- REGNO (XEXP (XVECEXP (pat, 0, i), 0)),
- bb);
- }
+ for (r = reg_set_table[REGNO (x)]; r != NULL; r = r->next)
+ SET_BIT (bmap[r->bb_index], indx);
}
- else if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == REG)
- /* Each setting of this register outside of this block
- must be marked in the set of kills in this block. */
- handle_rd_kill_set (insn, REGNO (SET_DEST (pat)), bb);
}
-}
-
-/* Compute the reaching definitions as in
- Compilers Principles, Techniques, and Tools. Aho, Sethi, Ullman,
- Chapter 10. It is the same algorithm as used for computing available
- expressions but applied to the gens and kills of reaching definitions. */
-
-static void
-compute_rd (void)
-{
- int changed, passes;
- basic_block bb;
-
- FOR_EACH_BB (bb)
- sbitmap_copy (rd_out[bb->index] /*dst*/, rd_gen[bb->index] /*src*/);
-
- passes = 0;
- changed = 1;
- while (changed)
- {
- changed = 0;
- FOR_EACH_BB (bb)
+ else
{
- sbitmap_union_of_preds (reaching_defs[bb->index], rd_out, bb->index);
- changed |= sbitmap_union_of_diff_cg (rd_out[bb->index], rd_gen[bb->index],
- reaching_defs[bb->index], rd_kill[bb->index]);
+ if (REGNO (x) < FIRST_PSEUDO_REGISTER)
+ {
+ FOR_EACH_BB (bb)
+ if (TEST_BIT (reg_set_in_block[bb->index], REGNO (x)))
+ RESET_BIT (bmap[bb->index], indx);
+ }
+ else
+ {
+ for (r = reg_set_table[REGNO (x)]; r != NULL; r = r->next)
+ RESET_BIT (bmap[r->bb_index], indx);
+ }
}
- passes++;
- }
- if (gcse_file)
- fprintf (gcse_file, "reaching def computation: %d passes\n", passes);
-}
-\f
-/* Classic GCSE available expression support. */
-
-/* Allocate memory for available expression computation. */
-
-static void
-alloc_avail_expr_mem (int n_blocks, int n_exprs)
-{
- ae_kill = sbitmap_vector_alloc (n_blocks, n_exprs);
- sbitmap_vector_zero (ae_kill, n_blocks);
-
- ae_gen = sbitmap_vector_alloc (n_blocks, n_exprs);
- sbitmap_vector_zero (ae_gen, n_blocks);
-
- ae_in = sbitmap_vector_alloc (n_blocks, n_exprs);
- sbitmap_vector_zero (ae_in, n_blocks);
-
- ae_out = sbitmap_vector_alloc (n_blocks, n_exprs);
- sbitmap_vector_zero (ae_out, n_blocks);
-}
-
-static void
-free_avail_expr_mem (void)
-{
- sbitmap_vector_free (ae_kill);
- sbitmap_vector_free (ae_gen);
- sbitmap_vector_free (ae_in);
- sbitmap_vector_free (ae_out);
-}
+ return;
-/* Compute the set of available expressions generated in each basic block. */
+ case MEM:
+ if (! MEM_READONLY_P (x))
+ {
+ bitmap_iterator bi;
+ unsigned bb_index;
-static void
-compute_ae_gen (struct hash_table *expr_hash_table)
-{
- unsigned int i;
- struct expr *expr;
- struct occr *occr;
+ /* First handle all the blocks with calls. We don't need to
+ do any list walking for them. */
+ EXECUTE_IF_SET_IN_BITMAP (blocks_with_calls, 0, bb_index, bi)
+ {
+ if (set_p)
+ SET_BIT (bmap[bb_index], indx);
+ else
+ RESET_BIT (bmap[bb_index], indx);
+ }
- /* For each recorded occurrence of each expression, set ae_gen[bb][expr].
- This is all we have to do because an expression is not recorded if it
- is not available, and the only expressions we want to work with are the
- ones that are recorded. */
- for (i = 0; i < expr_hash_table->size; i++)
- for (expr = expr_hash_table->table[i]; expr != 0; expr = expr->next_same_hash)
- for (occr = expr->avail_occr; occr != 0; occr = occr->next)
- SET_BIT (ae_gen[BLOCK_NUM (occr->insn)], expr->bitmap_index);
-}
+ /* Now iterate over the blocks which have memory modifications
+ but which do not have any calls. */
+ EXECUTE_IF_AND_COMPL_IN_BITMAP (modify_mem_list_set,
+ blocks_with_calls,
+ 0, bb_index, bi)
+ {
+ rtx list_entry = canon_modify_mem_list[bb_index];
-/* Return nonzero if expression X is killed in BB. */
+ while (list_entry)
+ {
+ rtx dest, dest_addr;
-static int
-expr_killed_p (rtx x, basic_block bb)
-{
- int i, j;
- enum rtx_code code;
- const char *fmt;
+ /* LIST_ENTRY must be an INSN of some kind that sets memory.
+ Examine each hunk of memory that is modified. */
- if (x == 0)
- return 1;
+ dest = XEXP (list_entry, 0);
+ list_entry = XEXP (list_entry, 1);
+ dest_addr = XEXP (list_entry, 0);
- code = GET_CODE (x);
- switch (code)
- {
- case REG:
- return TEST_BIT (reg_set_in_block[bb->index], REGNO (x));
+ if (canon_true_dependence (dest, GET_MODE (dest), dest_addr,
+ x, rtx_addr_varies_p))
+ {
+ if (set_p)
+ SET_BIT (bmap[bb_index], indx);
+ else
+ RESET_BIT (bmap[bb_index], indx);
+ break;
+ }
+ list_entry = XEXP (list_entry, 1);
+ }
+ }
+ }
- case MEM:
- if (load_killed_in_block_p (bb, get_max_uid () + 1, x, 0))
- return 1;
- else
- return expr_killed_p (XEXP (x, 0), bb);
+ x = XEXP (x, 0);
+ goto repeat;
case PC:
case CC0: /*FIXME*/
case CONST:
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_FIXED:
case CONST_VECTOR:
case SYMBOL_REF:
case LABEL_REF:
case ADDR_VEC:
case ADDR_DIFF_VEC:
- return 0;
+ return;
default:
break;
needed at this level, change it into iteration.
This function is called enough to be worth it. */
if (i == 0)
- return expr_killed_p (XEXP (x, i), bb);
- else if (expr_killed_p (XEXP (x, i), bb))
- return 1;
+ {
+ x = XEXP (x, i);
+ goto repeat;
+ }
+
+ compute_transp (XEXP (x, i), indx, bmap, set_p);
}
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
- if (expr_killed_p (XVECEXP (x, i, j), bb))
- return 1;
+ compute_transp (XVECEXP (x, i, j), indx, bmap, set_p);
}
-
- return 0;
}
-/* Compute the set of available expressions killed in each basic block. */
+/* Top level routine to do the dataflow analysis needed by copy/const
+ propagation. */
static void
-compute_ae_kill (sbitmap *ae_gen, sbitmap *ae_kill,
- struct hash_table *expr_hash_table)
+compute_cprop_data (void)
{
- basic_block bb;
- unsigned int i;
- struct expr *expr;
-
- FOR_EACH_BB (bb)
- for (i = 0; i < expr_hash_table->size; i++)
- for (expr = expr_hash_table->table[i]; expr; expr = expr->next_same_hash)
- {
- /* Skip EXPR if generated in this block. */
- if (TEST_BIT (ae_gen[bb->index], expr->bitmap_index))
- continue;
-
- if (expr_killed_p (expr->expr, bb))
- SET_BIT (ae_kill[bb->index], expr->bitmap_index);
- }
+ compute_local_properties (cprop_absaltered, cprop_pavloc, NULL, &set_hash_table);
+ compute_available (cprop_pavloc, cprop_absaltered,
+ cprop_avout, cprop_avin);
}
\f
-/* Actually perform the Classic GCSE optimizations. */
+/* Copy/constant propagation. */
-/* Return nonzero if occurrence OCCR of expression EXPR reaches block BB.
+/* Maximum number of register uses in an insn that we handle. */
+#define MAX_USES 8
- CHECK_SELF_LOOP is nonzero if we should consider a block reaching itself
- as a positive reach. We want to do this when there are two computations
- of the expression in the block.
+/* Table of uses found in an insn.
+ Allocated statically to avoid alloc/free complexity and overhead. */
+static struct reg_use reg_use_table[MAX_USES];
- VISITED is a pointer to a working buffer for tracking which BB's have
- been visited. It is NULL for the top-level call.
+/* Index into `reg_use_table' while building it. */
+static int reg_use_count;
- We treat reaching expressions that go through blocks containing the same
- reaching expression as "not reaching". E.g. if EXPR is generated in blocks
- 2 and 3, INSN is in block 4, and 2->3->4, we treat the expression in block
- 2 as not reaching. The intent is to improve the probability of finding
- only one reaching expression and to reduce register lifetimes by picking
- the closest such expression. */
+/* Set up a list of register numbers used in INSN. The found uses are stored
+ in `reg_use_table'. `reg_use_count' is initialized to zero before entry,
+ and contains the number of uses in the table upon exit.
-static int
-expr_reaches_here_p_work (struct occr *occr, struct expr *expr,
- basic_block bb, int check_self_loop, char *visited)
+ ??? If a register appears multiple times we will record it multiple times.
+ This doesn't hurt anything but it will slow things down. */
+
+static void
+find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
{
- edge pred;
+ int i, j;
+ enum rtx_code code;
+ const char *fmt;
+ rtx x = *xptr;
- for (pred = bb->pred; pred != NULL; pred = pred->pred_next)
- {
- basic_block pred_bb = pred->src;
+ /* repeat is used to turn tail-recursion into iteration since GCC
+ can't do it when there's no return value. */
+ repeat:
+ if (x == 0)
+ return;
- if (visited[pred_bb->index])
- /* This predecessor has already been visited. Nothing to do. */
- ;
- else if (pred_bb == bb)
- {
- /* BB loops on itself. */
- if (check_self_loop
- && TEST_BIT (ae_gen[pred_bb->index], expr->bitmap_index)
- && BLOCK_NUM (occr->insn) == pred_bb->index)
- return 1;
+ code = GET_CODE (x);
+ if (REG_P (x))
+ {
+ if (reg_use_count == MAX_USES)
+ return;
- visited[pred_bb->index] = 1;
- }
+ reg_use_table[reg_use_count].reg_rtx = x;
+ reg_use_count++;
+ }
- /* Ignore this predecessor if it kills the expression. */
- else if (TEST_BIT (ae_kill[pred_bb->index], expr->bitmap_index))
- visited[pred_bb->index] = 1;
+ /* Recursively scan the operands of this expression. */
- /* Does this predecessor generate this expression? */
- else if (TEST_BIT (ae_gen[pred_bb->index], expr->bitmap_index))
+ for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
{
- /* Is this the occurrence we're looking for?
- Note that there's only one generating occurrence per block
- so we just need to check the block number. */
- if (BLOCK_NUM (occr->insn) == pred_bb->index)
- return 1;
-
- visited[pred_bb->index] = 1;
- }
-
- /* Neither gen nor kill. */
- else
- {
- visited[pred_bb->index] = 1;
- if (expr_reaches_here_p_work (occr, expr, pred_bb, check_self_loop,
- visited))
+ /* If we are about to do the last recursive call
+ needed at this level, change it into iteration.
+ This function is called enough to be worth it. */
+ if (i == 0)
+ {
+ x = XEXP (x, 0);
+ goto repeat;
+ }
- return 1;
+ find_used_regs (&XEXP (x, i), data);
}
+ else if (fmt[i] == 'E')
+ for (j = 0; j < XVECLEN (x, i); j++)
+ find_used_regs (&XVECEXP (x, i, j), data);
}
-
- /* All paths have been checked. */
- return 0;
}
-/* This wrapper for expr_reaches_here_p_work() is to ensure that any
- memory allocated for that function is returned. */
+/* Try to replace all non-SET_DEST occurrences of FROM in INSN with TO.
+ Returns nonzero is successful. */
static int
-expr_reaches_here_p (struct occr *occr, struct expr *expr, basic_block bb,
- int check_self_loop)
+try_replace_reg (rtx from, rtx to, rtx insn)
{
- int rval;
- char *visited = xcalloc (last_basic_block, 1);
-
- rval = expr_reaches_here_p_work (occr, expr, bb, check_self_loop, visited);
-
- free (visited);
- return rval;
-}
-
-/* Return the instruction that computes EXPR that reaches INSN's basic block.
- If there is more than one such instruction, return NULL.
+ rtx note = find_reg_equal_equiv_note (insn);
+ rtx src = 0;
+ int success = 0;
+ rtx set = single_set (insn);
- Called only by handle_avail_expr. */
+ /* Usually we substitute easy stuff, so we won't copy everything.
+ We however need to take care to not duplicate non-trivial CONST
+ expressions. */
+ to = copy_rtx (to);
-static rtx
-computing_insn (struct expr *expr, rtx insn)
-{
- basic_block bb = BLOCK_FOR_INSN (insn);
+ validate_replace_src_group (from, to, insn);
+ if (num_changes_pending () && apply_change_group ())
+ success = 1;
- if (expr->avail_occr->next == NULL)
+ /* Try to simplify SET_SRC if we have substituted a constant. */
+ if (success && set && CONSTANT_P (to))
{
- if (BLOCK_FOR_INSN (expr->avail_occr->insn) == bb)
- /* The available expression is actually itself
- (i.e. a loop in the flow graph) so do nothing. */
- return NULL;
-
- /* (FIXME) Case that we found a pattern that was created by
- a substitution that took place. */
- return expr->avail_occr->insn;
+ src = simplify_rtx (SET_SRC (set));
+
+ if (src)
+ validate_change (insn, &SET_SRC (set), src, 0);
}
- else
+
+ /* If there is already a REG_EQUAL note, update the expression in it
+ with our replacement. */
+ if (note != 0 && REG_NOTE_KIND (note) == REG_EQUAL)
+ set_unique_reg_note (insn, REG_EQUAL,
+ simplify_replace_rtx (XEXP (note, 0), from, to));
+ if (!success && set && reg_mentioned_p (from, SET_SRC (set)))
{
- /* Pattern is computed more than once.
- Search backwards from this insn to see how many of these
- computations actually reach this insn. */
- struct occr *occr;
- rtx insn_computes_expr = NULL;
- int can_reach = 0;
-
- for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
- {
- if (BLOCK_FOR_INSN (occr->insn) == bb)
- {
- /* The expression is generated in this block.
- The only time we care about this is when the expression
- is generated later in the block [and thus there's a loop].
- We let the normal cse pass handle the other cases. */
- if (INSN_CUID (insn) < INSN_CUID (occr->insn)
- && expr_reaches_here_p (occr, expr, bb, 1))
- {
- can_reach++;
- if (can_reach > 1)
- return NULL;
+ /* If above failed and this is a single set, try to simplify the source of
+ the set given our substitution. We could perhaps try this for multiple
+ SETs, but it probably won't buy us anything. */
+ src = simplify_replace_rtx (SET_SRC (set), from, to);
- insn_computes_expr = occr->insn;
- }
- }
- else if (expr_reaches_here_p (occr, expr, bb, 0))
- {
- can_reach++;
- if (can_reach > 1)
- return NULL;
+ if (!rtx_equal_p (src, SET_SRC (set))
+ && validate_change (insn, &SET_SRC (set), src, 0))
+ success = 1;
- insn_computes_expr = occr->insn;
- }
- }
+ /* If we've failed to do replacement, have a single SET, don't already
+ have a note, and have no special SET, add a REG_EQUAL note to not
+ lose information. */
+ if (!success && note == 0 && set != 0
+ && GET_CODE (SET_DEST (set)) != ZERO_EXTRACT
+ && GET_CODE (SET_DEST (set)) != STRICT_LOW_PART)
+ note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
+ }
- if (insn_computes_expr == NULL)
- abort ();
+ /* REG_EQUAL may get simplified into register.
+ We don't allow that. Remove that note. This code ought
+ not to happen, because previous code ought to synthesize
+ reg-reg move, but be on the safe side. */
+ if (note && REG_NOTE_KIND (note) == REG_EQUAL && REG_P (XEXP (note, 0)))
+ remove_note (insn, note);
- return insn_computes_expr;
- }
+ return success;
}
-/* Return nonzero if the definition in DEF_INSN can reach INSN.
- Only called by can_disregard_other_sets. */
+/* Find a set of REGNOs that are available on entry to INSN's block. Returns
+ NULL no such set is found. */
-static int
-def_reaches_here_p (rtx insn, rtx def_insn)
+static struct expr *
+find_avail_set (int regno, rtx insn)
{
- rtx reg;
+ /* SET1 contains the last set found that can be returned to the caller for
+ use in a substitution. */
+ struct expr *set1 = 0;
- if (TEST_BIT (reaching_defs[BLOCK_NUM (insn)], INSN_CUID (def_insn)))
- return 1;
+ /* Loops are not possible here. To get a loop we would need two sets
+ available at the start of the block containing INSN. i.e. we would
+ need two sets like this available at the start of the block:
- if (BLOCK_NUM (insn) == BLOCK_NUM (def_insn))
+ (set (reg X) (reg Y))
+ (set (reg Y) (reg X))
+
+ This can not happen since the set of (reg Y) would have killed the
+ set of (reg X) making it unavailable at the start of this block. */
+ while (1)
{
- if (INSN_CUID (def_insn) < INSN_CUID (insn))
- {
- if (GET_CODE (PATTERN (def_insn)) == PARALLEL)
- return 1;
- else if (GET_CODE (PATTERN (def_insn)) == CLOBBER)
- reg = XEXP (PATTERN (def_insn), 0);
- else if (GET_CODE (PATTERN (def_insn)) == SET)
- reg = SET_DEST (PATTERN (def_insn));
- else
- abort ();
+ rtx src;
+ struct expr *set = lookup_set (regno, &set_hash_table);
- return ! reg_set_between_p (reg, NEXT_INSN (def_insn), insn);
+ /* Find a set that is available at the start of the block
+ which contains INSN. */
+ while (set)
+ {
+ if (TEST_BIT (cprop_avin[BLOCK_NUM (insn)], set->bitmap_index))
+ break;
+ set = next_set (regno, set);
}
- else
- return 0;
- }
- return 0;
-}
+ /* If no available set was found we've reached the end of the
+ (possibly empty) copy chain. */
+ if (set == 0)
+ break;
-/* Return nonzero if *ADDR_THIS_REG can only have one value at INSN. The
- value returned is the number of definitions that reach INSN. Returning a
- value of zero means that [maybe] more than one definition reaches INSN and
- the caller can't perform whatever optimization it is trying. i.e. it is
- always safe to return zero. */
+ gcc_assert (GET_CODE (set->expr) == SET);
-static int
-can_disregard_other_sets (struct reg_set **addr_this_reg, rtx insn, int for_combine)
-{
- int number_of_reaching_defs = 0;
- struct reg_set *this_reg;
+ src = SET_SRC (set->expr);
- for (this_reg = *addr_this_reg; this_reg != 0; this_reg = this_reg->next)
- if (def_reaches_here_p (insn, this_reg->insn))
- {
- number_of_reaching_defs++;
- /* Ignore parallels for now. */
- if (GET_CODE (PATTERN (this_reg->insn)) == PARALLEL)
- return 0;
+ /* We know the set is available.
+ Now check that SRC is ANTLOC (i.e. none of the source operands
+ have changed since the start of the block).
- if (!for_combine
- && (GET_CODE (PATTERN (this_reg->insn)) == CLOBBER
- || ! rtx_equal_p (SET_SRC (PATTERN (this_reg->insn)),
- SET_SRC (PATTERN (insn)))))
- /* A setting of the reg to a different value reaches INSN. */
- return 0;
+ If the source operand changed, we may still use it for the next
+ iteration of this loop, but we may not use it for substitutions. */
- if (number_of_reaching_defs > 1)
- {
- /* If in this setting the value the register is being set to is
- equal to the previous value the register was set to and this
- setting reaches the insn we are trying to do the substitution
- on then we are ok. */
- if (GET_CODE (PATTERN (this_reg->insn)) == CLOBBER)
- return 0;
- else if (! rtx_equal_p (SET_SRC (PATTERN (this_reg->insn)),
- SET_SRC (PATTERN (insn))))
- return 0;
- }
+ if (gcse_constant_p (src) || oprs_not_set_p (src, insn))
+ set1 = set;
- *addr_this_reg = this_reg;
- }
+ /* If the source of the set is anything except a register, then
+ we have reached the end of the copy chain. */
+ if (! REG_P (src))
+ break;
- return number_of_reaching_defs;
-}
+ /* Follow the copy chain, i.e. start another iteration of the loop
+ and see if we have an available copy into SRC. */
+ regno = REGNO (src);
+ }
-/* Expression computed by insn is available and the substitution is legal,
- so try to perform the substitution.
+ /* SET1 holds the last set that was available and anticipatable at
+ INSN. */
+ return set1;
+}
- The result is nonzero if any changes were made. */
+/* Subroutine of cprop_insn that tries to propagate constants into
+ JUMP_INSNS. JUMP must be a conditional jump. If SETCC is non-NULL
+ it is the instruction that immediately precedes JUMP, and must be a
+ single SET of a register. FROM is what we will try to replace,
+ SRC is the constant we will try to substitute for it. Returns nonzero
+ if a change was made. */
static int
-handle_avail_expr (rtx insn, struct expr *expr)
+cprop_jump (basic_block bb, rtx setcc, rtx jump, rtx from, rtx src)
{
- rtx pat, insn_computes_expr, expr_set;
- rtx to;
- struct reg_set *this_reg;
- int found_setting, use_src;
- int changed = 0;
-
- /* We only handle the case where one computation of the expression
- reaches this instruction. */
- insn_computes_expr = computing_insn (expr, insn);
- if (insn_computes_expr == NULL)
- return 0;
- expr_set = single_set (insn_computes_expr);
- /* The set might be in a parallel with multiple sets; we could
- probably handle that, but there's currently no easy way to find
- the relevant sub-expression. */
- if (!expr_set)
- return 0;
-
- found_setting = 0;
- use_src = 0;
+ rtx new, set_src, note_src;
+ rtx set = pc_set (jump);
+ rtx note = find_reg_equal_equiv_note (jump);
- /* At this point we know only one computation of EXPR outside of this
- block reaches this insn. Now try to find a register that the
- expression is computed into. */
- if (GET_CODE (SET_SRC (expr_set)) == REG)
+ if (note)
{
- /* This is the case when the available expression that reaches
- here has already been handled as an available expression. */
- unsigned int regnum_for_replacing
- = REGNO (SET_SRC (expr_set));
-
- /* If the register was created by GCSE we can't use `reg_set_table',
- however we know it's set only once. */
- if (regnum_for_replacing >= max_gcse_regno
- /* If the register the expression is computed into is set only once,
- or only one set reaches this insn, we can use it. */
- || (((this_reg = reg_set_table[regnum_for_replacing]),
- this_reg->next == NULL)
- || can_disregard_other_sets (&this_reg, insn, 0)))
- {
- use_src = 1;
- found_setting = 1;
- }
+ note_src = XEXP (note, 0);
+ if (GET_CODE (note_src) == EXPR_LIST)
+ note_src = NULL_RTX;
}
+ else note_src = NULL_RTX;
- if (!found_setting)
- {
- unsigned int regnum_for_replacing
- = REGNO (SET_DEST (expr_set));
-
- /* This shouldn't happen. */
- if (regnum_for_replacing >= max_gcse_regno)
- abort ();
-
- this_reg = reg_set_table[regnum_for_replacing];
-
- /* If the register the expression is computed into is set only once,
- or only one set reaches this insn, use it. */
- if (this_reg->next == NULL
- || can_disregard_other_sets (&this_reg, insn, 0))
- found_setting = 1;
- }
+ /* Prefer REG_EQUAL notes except those containing EXPR_LISTs. */
+ set_src = note_src ? note_src : SET_SRC (set);
- if (found_setting)
+ /* First substitute the SETCC condition into the JUMP instruction,
+ then substitute that given values into this expanded JUMP. */
+ if (setcc != NULL_RTX
+ && !modified_between_p (from, setcc, jump)
+ && !modified_between_p (src, setcc, jump))
{
- pat = PATTERN (insn);
- if (use_src)
- to = SET_SRC (expr_set);
- else
- to = SET_DEST (expr_set);
- changed = validate_change (insn, &SET_SRC (pat), to, 0);
-
- /* We should be able to ignore the return code from validate_change but
- to play it safe we check. */
- if (changed)
- {
- gcse_subst_count++;
- if (gcse_file != NULL)
- {
- fprintf (gcse_file, "GCSE: Replacing the source in insn %d with",
- INSN_UID (insn));
- fprintf (gcse_file, " reg %d %s insn %d\n",
- REGNO (to), use_src ? "from" : "set in",
- INSN_UID (insn_computes_expr));
- }
- }
+ rtx setcc_src;
+ rtx setcc_set = single_set (setcc);
+ rtx setcc_note = find_reg_equal_equiv_note (setcc);
+ setcc_src = (setcc_note && GET_CODE (XEXP (setcc_note, 0)) != EXPR_LIST)
+ ? XEXP (setcc_note, 0) : SET_SRC (setcc_set);
+ set_src = simplify_replace_rtx (set_src, SET_DEST (setcc_set),
+ setcc_src);
}
+ else
+ setcc = NULL_RTX;
- /* The register that the expr is computed into is set more than once. */
- else if (1 /*expensive_op(this_pattrn->op) && do_expensive_gcse)*/)
- {
- /* Insert an insn after insnx that copies the reg set in insnx
- into a new pseudo register call this new register REGN.
- From insnb until end of basic block or until REGB is set
- replace all uses of REGB with REGN. */
- rtx new_insn;
-
- to = gen_reg_rtx (GET_MODE (SET_DEST (expr_set)));
-
- /* Generate the new insn. */
- /* ??? If the change fails, we return 0, even though we created
- an insn. I think this is ok. */
- new_insn
- = emit_insn_after (gen_rtx_SET (VOIDmode, to,
- SET_DEST (expr_set)),
- insn_computes_expr);
+ new = simplify_replace_rtx (set_src, from, src);
- /* Keep register set table up to date. */
- record_one_set (REGNO (to), new_insn);
+ /* If no simplification can be made, then try the next register. */
+ if (rtx_equal_p (new, SET_SRC (set)))
+ return 0;
- gcse_create_count++;
- if (gcse_file != NULL)
+ /* If this is now a no-op delete it, otherwise this must be a valid insn. */
+ if (new == pc_rtx)
+ delete_insn (jump);
+ else
+ {
+ /* Ensure the value computed inside the jump insn to be equivalent
+ to one computed by setcc. */
+ if (setcc && modified_in_p (new, setcc))
+ return 0;
+ if (! validate_change (jump, &SET_SRC (set), new, 0))
{
- fprintf (gcse_file, "GCSE: Creating insn %d to copy value of reg %d",
- INSN_UID (NEXT_INSN (insn_computes_expr)),
- REGNO (SET_SRC (PATTERN (NEXT_INSN (insn_computes_expr)))));
- fprintf (gcse_file, ", computed in insn %d,\n",
- INSN_UID (insn_computes_expr));
- fprintf (gcse_file, " into newly allocated reg %d\n",
- REGNO (to));
+ /* When (some) constants are not valid in a comparison, and there
+ are two registers to be replaced by constants before the entire
+ comparison can be folded into a constant, we need to keep
+ intermediate information in REG_EQUAL notes. For targets with
+ separate compare insns, such notes are added by try_replace_reg.
+ When we have a combined compare-and-branch instruction, however,
+ we need to attach a note to the branch itself to make this
+ optimization work. */
+
+ if (!rtx_equal_p (new, note_src))
+ set_unique_reg_note (jump, REG_EQUAL, copy_rtx (new));
+ return 0;
}
- pat = PATTERN (insn);
+ /* Remove REG_EQUAL note after simplification. */
+ if (note_src)
+ remove_note (jump, note);
+ }
+
+#ifdef HAVE_cc0
+ /* Delete the cc0 setter. */
+ if (setcc != NULL && CC0_P (SET_DEST (single_set (setcc))))
+ delete_insn (setcc);
+#endif
- /* Do register replacement for INSN. */
- changed = validate_change (insn, &SET_SRC (pat),
- SET_DEST (PATTERN
- (NEXT_INSN (insn_computes_expr))),
- 0);
+ run_jump_opt_after_gcse = 1;
- /* We should be able to ignore the return code from validate_change but
- to play it safe we check. */
- if (changed)
- {
- gcse_subst_count++;
- if (gcse_file != NULL)
- {
- fprintf (gcse_file,
- "GCSE: Replacing the source in insn %d with reg %d ",
- INSN_UID (insn),
- REGNO (SET_DEST (PATTERN (NEXT_INSN
- (insn_computes_expr)))));
- fprintf (gcse_file, "set in insn %d\n",
- INSN_UID (insn_computes_expr));
- }
- }
+ global_const_prop_count++;
+ if (dump_file != NULL)
+ {
+ fprintf (dump_file,
+ "GLOBAL CONST-PROP: Replacing reg %d in jump_insn %d with constant ",
+ REGNO (from), INSN_UID (jump));
+ print_rtl (dump_file, src);
+ fprintf (dump_file, "\n");
}
+ purge_dead_edges (bb);
- return changed;
+ return 1;
}
-/* Perform classic GCSE. This is called by one_classic_gcse_pass after all
- the dataflow analysis has been done.
-
- The result is nonzero if a change was made. */
-
-static int
-classic_gcse (void)
+static bool
+constprop_register (rtx insn, rtx from, rtx to, bool alter_jumps)
{
- int changed;
- rtx insn;
- basic_block bb;
-
- /* Note we start at block 1. */
-
- if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
- return 0;
+ rtx sset;
- changed = 0;
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb)
+ /* Check for reg or cc0 setting instructions followed by
+ conditional branch instructions first. */
+ if (alter_jumps
+ && (sset = single_set (insn)) != NULL
+ && NEXT_INSN (insn)
+ && any_condjump_p (NEXT_INSN (insn)) && onlyjump_p (NEXT_INSN (insn)))
{
- /* Reset tables used to keep track of what's still valid [since the
- start of the block]. */
- reset_opr_set_tables ();
+ rtx dest = SET_DEST (sset);
+ if ((REG_P (dest) || CC0_P (dest))
+ && cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn), from, to))
+ return 1;
+ }
- for (insn = BB_HEAD (bb);
- insn != NULL && insn != NEXT_INSN (BB_END (bb));
- insn = NEXT_INSN (insn))
- {
- /* Is insn of form (set (pseudo-reg) ...)? */
- if (GET_CODE (insn) == INSN
- && GET_CODE (PATTERN (insn)) == SET
- && GET_CODE (SET_DEST (PATTERN (insn))) == REG
- && REGNO (SET_DEST (PATTERN (insn))) >= FIRST_PSEUDO_REGISTER)
- {
- rtx pat = PATTERN (insn);
- rtx src = SET_SRC (pat);
- struct expr *expr;
-
- if (want_to_gcse_p (src)
- /* Is the expression recorded? */
- && ((expr = lookup_expr (src, &expr_hash_table)) != NULL)
- /* Is the expression available [at the start of the
- block]? */
- && TEST_BIT (ae_in[bb->index], expr->bitmap_index)
- /* Are the operands unchanged since the start of the
- block? */
- && oprs_not_set_p (src, insn))
- changed |= handle_avail_expr (insn, expr);
- }
+ /* Handle normal insns next. */
+ if (NONJUMP_INSN_P (insn)
+ && try_replace_reg (from, to, insn))
+ return 1;
- /* Keep track of everything modified by this insn. */
- /* ??? Need to be careful w.r.t. mods done to INSN. */
- if (INSN_P (insn))
- mark_oprs_set (insn);
- }
- }
+ /* Try to propagate a CONST_INT into a conditional jump.
+ We're pretty specific about what we will handle in this
+ code, we can extend this as necessary over time.
- return changed;
+ Right now the insn in question must look like
+ (set (pc) (if_then_else ...)) */
+ else if (alter_jumps && any_condjump_p (insn) && onlyjump_p (insn))
+ return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, to);
+ return 0;
}
-/* Top level routine to perform one classic GCSE pass.
-
- Return nonzero if a change was made. */
+/* Perform constant and copy propagation on INSN.
+ The result is nonzero if a change was made. */
static int
-one_classic_gcse_pass (int pass)
+cprop_insn (rtx insn, int alter_jumps)
{
+ struct reg_use *reg_used;
int changed = 0;
+ rtx note;
- gcse_subst_count = 0;
- gcse_create_count = 0;
+ if (!INSN_P (insn))
+ return 0;
- alloc_hash_table (max_cuid, &expr_hash_table, 0);
- alloc_rd_mem (last_basic_block, max_cuid);
- compute_hash_table (&expr_hash_table);
- if (gcse_file)
- dump_hash_table (gcse_file, "Expression", &expr_hash_table);
+ reg_use_count = 0;
+ note_uses (&PATTERN (insn), find_used_regs, NULL);
- if (expr_hash_table.n_elems > 0)
- {
- compute_kill_rd ();
- compute_rd ();
- alloc_avail_expr_mem (last_basic_block, expr_hash_table.n_elems);
- compute_ae_gen (&expr_hash_table);
- compute_ae_kill (ae_gen, ae_kill, &expr_hash_table);
- compute_available (ae_gen, ae_kill, ae_out, ae_in);
- changed = classic_gcse ();
- free_avail_expr_mem ();
- }
+ note = find_reg_equal_equiv_note (insn);
- free_rd_mem ();
- free_hash_table (&expr_hash_table);
+ /* We may win even when propagating constants into notes. */
+ if (note)
+ find_used_regs (&XEXP (note, 0), NULL);
- if (gcse_file)
+ for (reg_used = ®_use_table[0]; reg_use_count > 0;
+ reg_used++, reg_use_count--)
{
- fprintf (gcse_file, "\n");
- fprintf (gcse_file, "GCSE of %s, pass %d: %d bytes needed, %d substs,",
- current_function_name (), pass, bytes_used, gcse_subst_count);
- fprintf (gcse_file, "%d insns created\n", gcse_create_count);
- }
+ unsigned int regno = REGNO (reg_used->reg_rtx);
+ rtx pat, src;
+ struct expr *set;
- return changed;
-}
-\f
-/* Compute copy/constant propagation working variables. */
+ /* Ignore registers created by GCSE.
+ We do this because ... */
+ if (regno >= max_gcse_regno)
+ continue;
-/* Local properties of assignments. */
-static sbitmap *cprop_pavloc;
-static sbitmap *cprop_absaltered;
+ /* If the register has already been set in this block, there's
+ nothing we can do. */
+ if (! oprs_not_set_p (reg_used->reg_rtx, insn))
+ continue;
-/* Global properties of assignments (computed from the local properties). */
-static sbitmap *cprop_avin;
-static sbitmap *cprop_avout;
+ /* Find an assignment that sets reg_used and is available
+ at the start of the block. */
+ set = find_avail_set (regno, insn);
+ if (! set)
+ continue;
-/* Allocate vars used for copy/const propagation. N_BLOCKS is the number of
- basic blocks. N_SETS is the number of sets. */
+ pat = set->expr;
+ /* ??? We might be able to handle PARALLELs. Later. */
+ gcc_assert (GET_CODE (pat) == SET);
-static void
-alloc_cprop_mem (int n_blocks, int n_sets)
-{
- cprop_pavloc = sbitmap_vector_alloc (n_blocks, n_sets);
- cprop_absaltered = sbitmap_vector_alloc (n_blocks, n_sets);
+ src = SET_SRC (pat);
- cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
- cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
-}
+ /* Constant propagation. */
+ if (gcse_constant_p (src))
+ {
+ if (constprop_register (insn, reg_used->reg_rtx, src, alter_jumps))
+ {
+ changed = 1;
+ global_const_prop_count++;
+ if (dump_file != NULL)
+ {
+ fprintf (dump_file, "GLOBAL CONST-PROP: Replacing reg %d in ", regno);
+ fprintf (dump_file, "insn %d with constant ", INSN_UID (insn));
+ print_rtl (dump_file, src);
+ fprintf (dump_file, "\n");
+ }
+ if (INSN_DELETED_P (insn))
+ return 1;
+ }
+ }
+ else if (REG_P (src)
+ && REGNO (src) >= FIRST_PSEUDO_REGISTER
+ && REGNO (src) != regno)
+ {
+ if (try_replace_reg (reg_used->reg_rtx, src, insn))
+ {
+ changed = 1;
+ global_copy_prop_count++;
+ if (dump_file != NULL)
+ {
+ fprintf (dump_file, "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
+ regno, INSN_UID (insn));
+ fprintf (dump_file, " with reg %d\n", REGNO (src));
+ }
-/* Free vars used by copy/const propagation. */
+ /* The original insn setting reg_used may or may not now be
+ deletable. We leave the deletion to flow. */
+ /* FIXME: If it turns out that the insn isn't deletable,
+ then we may have unnecessarily extended register lifetimes
+ and made things worse. */
+ }
+ }
+ }
-static void
-free_cprop_mem (void)
-{
- sbitmap_vector_free (cprop_pavloc);
- sbitmap_vector_free (cprop_absaltered);
- sbitmap_vector_free (cprop_avin);
- sbitmap_vector_free (cprop_avout);
+ return changed;
}
-/* For each block, compute whether X is transparent. X is either an
- expression or an assignment [though we don't care which, for this context
- an assignment is treated as an expression]. For each block where an
- element of X is modified, set (SET_P == 1) or reset (SET_P == 0) the INDX
- bit in BMAP. */
+/* Like find_used_regs, but avoid recording uses that appear in
+ input-output contexts such as zero_extract or pre_dec. This
+ restricts the cases we consider to those for which local cprop
+ can legitimately make replacements. */
static void
-compute_transp (rtx x, int indx, sbitmap *bmap, int set_p)
+local_cprop_find_used_regs (rtx *xptr, void *data)
{
- int i, j;
- basic_block bb;
- enum rtx_code code;
- reg_set *r;
- const char *fmt;
-
- /* repeat is used to turn tail-recursion into iteration since GCC
- can't do it when there's no return value. */
- repeat:
+ rtx x = *xptr;
if (x == 0)
return;
- code = GET_CODE (x);
- switch (code)
+ switch (GET_CODE (x))
{
- case REG:
- if (set_p)
- {
- if (REGNO (x) < FIRST_PSEUDO_REGISTER)
- {
- FOR_EACH_BB (bb)
- if (TEST_BIT (reg_set_in_block[bb->index], REGNO (x)))
- SET_BIT (bmap[bb->index], indx);
- }
- else
- {
- for (r = reg_set_table[REGNO (x)]; r != NULL; r = r->next)
- SET_BIT (bmap[BLOCK_NUM (r->insn)], indx);
- }
- }
- else
- {
- if (REGNO (x) < FIRST_PSEUDO_REGISTER)
- {
- FOR_EACH_BB (bb)
- if (TEST_BIT (reg_set_in_block[bb->index], REGNO (x)))
- RESET_BIT (bmap[bb->index], indx);
- }
- else
- {
- for (r = reg_set_table[REGNO (x)]; r != NULL; r = r->next)
- RESET_BIT (bmap[BLOCK_NUM (r->insn)], indx);
- }
- }
+ case ZERO_EXTRACT:
+ case SIGN_EXTRACT:
+ case STRICT_LOW_PART:
+ return;
+ case PRE_DEC:
+ case PRE_INC:
+ case POST_DEC:
+ case POST_INC:
+ case PRE_MODIFY:
+ case POST_MODIFY:
+ /* Can only legitimately appear this early in the context of
+ stack pushes for function arguments, but handle all of the
+ codes nonetheless. */
return;
- case MEM:
- FOR_EACH_BB (bb)
- {
- rtx list_entry = canon_modify_mem_list[bb->index];
+ case SUBREG:
+ /* Setting a subreg of a register larger than word_mode leaves
+ the non-written words unchanged. */
+ if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) > BITS_PER_WORD)
+ return;
+ break;
- while (list_entry)
- {
- rtx dest, dest_addr;
+ default:
+ break;
+ }
- if (GET_CODE (XEXP (list_entry, 0)) == CALL_INSN)
- {
- if (set_p)
- SET_BIT (bmap[bb->index], indx);
- else
- RESET_BIT (bmap[bb->index], indx);
- break;
- }
- /* LIST_ENTRY must be an INSN of some kind that sets memory.
- Examine each hunk of memory that is modified. */
+ find_used_regs (xptr, data);
+}
- dest = XEXP (list_entry, 0);
- list_entry = XEXP (list_entry, 1);
- dest_addr = XEXP (list_entry, 0);
+/* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall;
+ their REG_EQUAL notes need updating. */
- if (canon_true_dependence (dest, GET_MODE (dest), dest_addr,
- x, rtx_addr_varies_p))
- {
- if (set_p)
- SET_BIT (bmap[bb->index], indx);
- else
- RESET_BIT (bmap[bb->index], indx);
- break;
- }
- list_entry = XEXP (list_entry, 1);
- }
- }
+static bool
+do_local_cprop (rtx x, rtx insn, bool alter_jumps, rtx *libcall_sp)
+{
+ rtx newreg = NULL, newcnst = NULL;
- x = XEXP (x, 0);
- goto repeat;
+ /* Rule out USE instructions and ASM statements as we don't want to
+ change the hard registers mentioned. */
+ if (REG_P (x)
+ && (REGNO (x) >= FIRST_PSEUDO_REGISTER
+ || (GET_CODE (PATTERN (insn)) != USE
+ && asm_noperands (PATTERN (insn)) < 0)))
+ {
+ cselib_val *val = cselib_lookup (x, GET_MODE (x), 0);
+ struct elt_loc_list *l;
- case PC:
- case CC0: /*FIXME*/
- case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_VECTOR:
- case SYMBOL_REF:
- case LABEL_REF:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return;
+ if (!val)
+ return false;
+ for (l = val->locs; l; l = l->next)
+ {
+ rtx this_rtx = l->loc;
+ rtx note;
- default:
- break;
- }
+ /* Don't CSE non-constant values out of libcall blocks. */
+ if (l->in_libcall && ! CONSTANT_P (this_rtx))
+ continue;
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
+ if (gcse_constant_p (this_rtx))
+ newcnst = this_rtx;
+ if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
+ /* Don't copy propagate if it has attached REG_EQUIV note.
+ At this point this only function parameters should have
+ REG_EQUIV notes and if the argument slot is used somewhere
+ explicitly, it means address of parameter has been taken,
+ so we should not extend the lifetime of the pseudo. */
+ && (!(note = find_reg_note (l->setting_insn, REG_EQUIV, NULL_RTX))
+ || ! MEM_P (XEXP (note, 0))))
+ newreg = this_rtx;
+ }
+ if (newcnst && constprop_register (insn, x, newcnst, alter_jumps))
{
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration.
- This function is called enough to be worth it. */
- if (i == 0)
+ /* If we find a case where we can't fix the retval REG_EQUAL notes
+ match the new register, we either have to abandon this replacement
+ or fix delete_trivially_dead_insns to preserve the setting insn,
+ or make it delete the REG_EQUAL note, and fix up all passes that
+ require the REG_EQUAL note there. */
+ bool adjusted;
+
+ adjusted = adjust_libcall_notes (x, newcnst, insn, libcall_sp);
+ gcc_assert (adjusted);
+
+ if (dump_file != NULL)
{
- x = XEXP (x, i);
- goto repeat;
+ fprintf (dump_file, "LOCAL CONST-PROP: Replacing reg %d in ",
+ REGNO (x));
+ fprintf (dump_file, "insn %d with constant ",
+ INSN_UID (insn));
+ print_rtl (dump_file, newcnst);
+ fprintf (dump_file, "\n");
}
-
- compute_transp (XEXP (x, i), indx, bmap, set_p);
+ local_const_prop_count++;
+ return true;
+ }
+ else if (newreg && newreg != x && try_replace_reg (x, newreg, insn))
+ {
+ adjust_libcall_notes (x, newreg, insn, libcall_sp);
+ if (dump_file != NULL)
+ {
+ fprintf (dump_file,
+ "LOCAL COPY-PROP: Replacing reg %d in insn %d",
+ REGNO (x), INSN_UID (insn));
+ fprintf (dump_file, " with reg %d\n", REGNO (newreg));
+ }
+ local_copy_prop_count++;
+ return true;
}
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- compute_transp (XVECEXP (x, i, j), indx, bmap, set_p);
}
+ return false;
}
-/* Top level routine to do the dataflow analysis needed by copy/const
- propagation. */
-
-static void
-compute_cprop_data (void)
+/* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall;
+ their REG_EQUAL notes need updating to reflect that OLDREG has been
+ replaced with NEWVAL in INSN. Return true if all substitutions could
+ be made. */
+static bool
+adjust_libcall_notes (rtx oldreg, rtx newval, rtx insn, rtx *libcall_sp)
{
- compute_local_properties (cprop_absaltered, cprop_pavloc, NULL, &set_hash_table);
- compute_available (cprop_pavloc, cprop_absaltered,
- cprop_avout, cprop_avin);
-}
-\f
-/* Copy/constant propagation. */
+ rtx end;
-/* Maximum number of register uses in an insn that we handle. */
-#define MAX_USES 8
+ while ((end = *libcall_sp++))
+ {
+ rtx note = find_reg_equal_equiv_note (end);
-/* Table of uses found in an insn.
- Allocated statically to avoid alloc/free complexity and overhead. */
-static struct reg_use reg_use_table[MAX_USES];
+ if (! note)
+ continue;
-/* Index into `reg_use_table' while building it. */
-static int reg_use_count;
+ if (REG_P (newval))
+ {
+ if (reg_set_between_p (newval, PREV_INSN (insn), end))
+ {
+ do
+ {
+ note = find_reg_equal_equiv_note (end);
+ if (! note)
+ continue;
+ if (reg_mentioned_p (newval, XEXP (note, 0)))
+ return false;
+ }
+ while ((end = *libcall_sp++));
+ return true;
+ }
+ }
+ XEXP (note, 0) = simplify_replace_rtx (XEXP (note, 0), oldreg, newval);
+ df_notes_rescan (end);
+ insn = end;
+ }
+ return true;
+}
-/* Set up a list of register numbers used in INSN. The found uses are stored
- in `reg_use_table'. `reg_use_count' is initialized to zero before entry,
- and contains the number of uses in the table upon exit.
+#define MAX_NESTED_LIBCALLS 9
- ??? If a register appears multiple times we will record it multiple times.
- This doesn't hurt anything but it will slow things down. */
+/* Do local const/copy propagation (i.e. within each basic block).
+ If ALTER_JUMPS is true, allow propagating into jump insns, which
+ could modify the CFG. */
static void
-find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
+local_cprop_pass (bool alter_jumps)
{
- int i, j;
- enum rtx_code code;
- const char *fmt;
- rtx x = *xptr;
-
- /* repeat is used to turn tail-recursion into iteration since GCC
- can't do it when there's no return value. */
- repeat:
- if (x == 0)
- return;
+ basic_block bb;
+ rtx insn;
+ struct reg_use *reg_used;
+ rtx libcall_stack[MAX_NESTED_LIBCALLS + 1], *libcall_sp;
+ bool changed = false;
- code = GET_CODE (x);
- if (REG_P (x))
+ cselib_init (false);
+ libcall_sp = &libcall_stack[MAX_NESTED_LIBCALLS];
+ *libcall_sp = 0;
+ FOR_EACH_BB (bb)
{
- if (reg_use_count == MAX_USES)
- return;
+ FOR_BB_INSNS (bb, insn)
+ {
+ if (INSN_P (insn))
+ {
+ rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
- reg_use_table[reg_use_count].reg_rtx = x;
- reg_use_count++;
+ if (note)
+ {
+ gcc_assert (libcall_sp != libcall_stack);
+ *--libcall_sp = XEXP (note, 0);
+ }
+ note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
+ if (note)
+ libcall_sp++;
+ note = find_reg_equal_equiv_note (insn);
+ do
+ {
+ reg_use_count = 0;
+ note_uses (&PATTERN (insn), local_cprop_find_used_regs,
+ NULL);
+ if (note)
+ local_cprop_find_used_regs (&XEXP (note, 0), NULL);
+
+ for (reg_used = ®_use_table[0]; reg_use_count > 0;
+ reg_used++, reg_use_count--)
+ {
+ if (do_local_cprop (reg_used->reg_rtx, insn, alter_jumps,
+ libcall_sp))
+ {
+ changed = true;
+ break;
+ }
+ }
+ if (INSN_DELETED_P (insn))
+ break;
+ }
+ while (reg_use_count);
+ }
+ cselib_process_insn (insn);
+ }
+
+ /* Forget everything at the end of a basic block. Make sure we are
+ not inside a libcall, they should never cross basic blocks. */
+ cselib_clear_table ();
+ gcc_assert (libcall_sp == &libcall_stack[MAX_NESTED_LIBCALLS]);
}
- /* Recursively scan the operands of this expression. */
+ cselib_finish ();
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
+ /* Global analysis may get into infinite loops for unreachable blocks. */
+ if (changed && alter_jumps)
{
- if (fmt[i] == 'e')
- {
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration.
- This function is called enough to be worth it. */
- if (i == 0)
- {
- x = XEXP (x, 0);
- goto repeat;
- }
-
- find_used_regs (&XEXP (x, i), data);
- }
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- find_used_regs (&XVECEXP (x, i, j), data);
+ delete_unreachable_blocks ();
+ free_reg_set_mem ();
+ alloc_reg_set_mem (max_reg_num ());
+ compute_sets ();
}
}
-/* Try to replace all non-SET_DEST occurrences of FROM in INSN with TO.
- Returns nonzero is successful. */
+/* Forward propagate copies. This includes copies and constants. Return
+ nonzero if a change was made. */
static int
-try_replace_reg (rtx from, rtx to, rtx insn)
+cprop (int alter_jumps)
{
- rtx note = find_reg_equal_equiv_note (insn);
- rtx src = 0;
- int success = 0;
- rtx set = single_set (insn);
-
- validate_replace_src_group (from, to, insn);
- if (num_changes_pending () && apply_change_group ())
- success = 1;
+ int changed;
+ basic_block bb;
+ rtx insn;
- /* Try to simplify SET_SRC if we have substituted a constant. */
- if (success && set && CONSTANT_P (to))
+ /* Note we start at block 1. */
+ if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
{
- src = simplify_rtx (SET_SRC (set));
-
- if (src)
- validate_change (insn, &SET_SRC (set), src, 0);
+ if (dump_file != NULL)
+ fprintf (dump_file, "\n");
+ return 0;
}
- /* If there is already a NOTE, update the expression in it with our
- replacement. */
- if (note != 0)
- XEXP (note, 0) = simplify_replace_rtx (XEXP (note, 0), from, to);
-
- if (!success && set && reg_mentioned_p (from, SET_SRC (set)))
+ changed = 0;
+ FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb)
{
- /* If above failed and this is a single set, try to simplify the source of
- the set given our substitution. We could perhaps try this for multiple
- SETs, but it probably won't buy us anything. */
- src = simplify_replace_rtx (SET_SRC (set), from, to);
+ /* Reset tables used to keep track of what's still valid [since the
+ start of the block]. */
+ reset_opr_set_tables ();
- if (!rtx_equal_p (src, SET_SRC (set))
- && validate_change (insn, &SET_SRC (set), src, 0))
- success = 1;
+ FOR_BB_INSNS (bb, insn)
+ if (INSN_P (insn))
+ {
+ changed |= cprop_insn (insn, alter_jumps);
- /* If we've failed to do replacement, have a single SET, don't already
- have a note, and have no special SET, add a REG_EQUAL note to not
- lose information. */
- if (!success && note == 0 && set != 0
- && GET_CODE (XEXP (set, 0)) != ZERO_EXTRACT
- && GET_CODE (XEXP (set, 0)) != SIGN_EXTRACT)
- note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
+ /* Keep track of everything modified by this insn. */
+ /* ??? Need to be careful w.r.t. mods done to INSN. Don't
+ call mark_oprs_set if we turned the insn into a NOTE. */
+ if (! NOTE_P (insn))
+ mark_oprs_set (insn);
+ }
}
- /* REG_EQUAL may get simplified into register.
- We don't allow that. Remove that note. This code ought
- not to happen, because previous code ought to synthesize
- reg-reg move, but be on the safe side. */
- if (note && REG_P (XEXP (note, 0)))
- remove_note (insn, note);
+ if (dump_file != NULL)
+ fprintf (dump_file, "\n");
- return success;
+ return changed;
}
-/* Find a set of REGNOs that are available on entry to INSN's block. Returns
- NULL no such set is found. */
+/* Similar to get_condition, only the resulting condition must be
+ valid at JUMP, instead of at EARLIEST.
-static struct expr *
-find_avail_set (int regno, rtx insn)
-{
- /* SET1 contains the last set found that can be returned to the caller for
- use in a substitution. */
- struct expr *set1 = 0;
+ This differs from noce_get_condition in ifcvt.c in that we prefer not to
+ settle for the condition variable in the jump instruction being integral.
+ We prefer to be able to record the value of a user variable, rather than
+ the value of a temporary used in a condition. This could be solved by
+ recording the value of *every* register scanned by canonicalize_condition,
+ but this would require some code reorganization. */
- /* Loops are not possible here. To get a loop we would need two sets
- available at the start of the block containing INSN. ie we would
- need two sets like this available at the start of the block:
+rtx
+fis_get_condition (rtx jump)
+{
+ return get_condition (jump, NULL, false, true);
+}
- (set (reg X) (reg Y))
- (set (reg Y) (reg X))
+/* Check the comparison COND to see if we can safely form an implicit set from
+ it. COND is either an EQ or NE comparison. */
- This can not happen since the set of (reg Y) would have killed the
- set of (reg X) making it unavailable at the start of this block. */
- while (1)
- {
- rtx src;
- struct expr *set = lookup_set (regno, &set_hash_table);
+static bool
+implicit_set_cond_p (const_rtx cond)
+{
+ const enum machine_mode mode = GET_MODE (XEXP (cond, 0));
+ const_rtx cst = XEXP (cond, 1);
- /* Find a set that is available at the start of the block
- which contains INSN. */
- while (set)
+ /* We can't perform this optimization if either operand might be or might
+ contain a signed zero. */
+ if (HONOR_SIGNED_ZEROS (mode))
+ {
+ /* It is sufficient to check if CST is or contains a zero. We must
+ handle float, complex, and vector. If any subpart is a zero, then
+ the optimization can't be performed. */
+ /* ??? The complex and vector checks are not implemented yet. We just
+ always return zero for them. */
+ if (GET_CODE (cst) == CONST_DOUBLE)
{
- if (TEST_BIT (cprop_avin[BLOCK_NUM (insn)], set->bitmap_index))
- break;
- set = next_set (regno, set);
+ REAL_VALUE_TYPE d;
+ REAL_VALUE_FROM_CONST_DOUBLE (d, cst);
+ if (REAL_VALUES_EQUAL (d, dconst0))
+ return 0;
}
+ else
+ return 0;
+ }
- /* If no available set was found we've reached the end of the
- (possibly empty) copy chain. */
- if (set == 0)
- break;
-
- if (GET_CODE (set->expr) != SET)
- abort ();
-
- src = SET_SRC (set->expr);
+ return gcse_constant_p (cst);
+}
- /* We know the set is available.
- Now check that SRC is ANTLOC (i.e. none of the source operands
- have changed since the start of the block).
+/* Find the implicit sets of a function. An "implicit set" is a constraint
+ on the value of a variable, implied by a conditional jump. For example,
+ following "if (x == 2)", the then branch may be optimized as though the
+ conditional performed an "explicit set", in this example, "x = 2". This
+ function records the set patterns that are implicit at the start of each
+ basic block. */
- If the source operand changed, we may still use it for the next
- iteration of this loop, but we may not use it for substitutions. */
+static void
+find_implicit_sets (void)
+{
+ basic_block bb, dest;
+ unsigned int count;
+ rtx cond, new;
- if (gcse_constant_p (src) || oprs_not_set_p (src, insn))
- set1 = set;
+ count = 0;
+ FOR_EACH_BB (bb)
+ /* Check for more than one successor. */
+ if (EDGE_COUNT (bb->succs) > 1)
+ {
+ cond = fis_get_condition (BB_END (bb));
- /* If the source of the set is anything except a register, then
- we have reached the end of the copy chain. */
- if (GET_CODE (src) != REG)
- break;
+ if (cond
+ && (GET_CODE (cond) == EQ || GET_CODE (cond) == NE)
+ && REG_P (XEXP (cond, 0))
+ && REGNO (XEXP (cond, 0)) >= FIRST_PSEUDO_REGISTER
+ && implicit_set_cond_p (cond))
+ {
+ dest = GET_CODE (cond) == EQ ? BRANCH_EDGE (bb)->dest
+ : FALLTHRU_EDGE (bb)->dest;
- /* Follow the copy chain, ie start another iteration of the loop
- and see if we have an available copy into SRC. */
- regno = REGNO (src);
- }
+ if (dest && single_pred_p (dest)
+ && dest != EXIT_BLOCK_PTR)
+ {
+ new = gen_rtx_SET (VOIDmode, XEXP (cond, 0),
+ XEXP (cond, 1));
+ implicit_sets[dest->index] = new;
+ if (dump_file)
+ {
+ fprintf(dump_file, "Implicit set of reg %d in ",
+ REGNO (XEXP (cond, 0)));
+ fprintf(dump_file, "basic block %d\n", dest->index);
+ }
+ count++;
+ }
+ }
+ }
- /* SET1 holds the last set that was available and anticipatable at
- INSN. */
- return set1;
+ if (dump_file)
+ fprintf (dump_file, "Found %d implicit sets\n", count);
}
-/* Subroutine of cprop_insn that tries to propagate constants into
- JUMP_INSNS. JUMP must be a conditional jump. If SETCC is non-NULL
- it is the instruction that immediately precedes JUMP, and must be a
- single SET of a register. FROM is what we will try to replace,
- SRC is the constant we will try to substitute for it. Returns nonzero
- if a change was made. */
+/* Perform one copy/constant propagation pass.
+ PASS is the pass count. If CPROP_JUMPS is true, perform constant
+ propagation into conditional jumps. If BYPASS_JUMPS is true,
+ perform conditional jump bypassing optimizations. */
static int
-cprop_jump (basic_block bb, rtx setcc, rtx jump, rtx from, rtx src)
+one_cprop_pass (int pass, bool cprop_jumps, bool bypass_jumps)
{
- rtx new, set_src, note_src;
- rtx set = pc_set (jump);
- rtx note = find_reg_equal_equiv_note (jump);
+ int changed = 0;
- if (note)
+ global_const_prop_count = local_const_prop_count = 0;
+ global_copy_prop_count = local_copy_prop_count = 0;
+
+ if (cprop_jumps)
+ local_cprop_pass (cprop_jumps);
+
+ /* Determine implicit sets. */
+ implicit_sets = XCNEWVEC (rtx, last_basic_block);
+ find_implicit_sets ();
+
+ alloc_hash_table (max_cuid, &set_hash_table, 1);
+ compute_hash_table (&set_hash_table);
+
+ /* Free implicit_sets before peak usage. */
+ free (implicit_sets);
+ implicit_sets = NULL;
+
+ if (dump_file)
+ dump_hash_table (dump_file, "SET", &set_hash_table);
+ if (set_hash_table.n_elems > 0)
{
- note_src = XEXP (note, 0);
- if (GET_CODE (note_src) == EXPR_LIST)
- note_src = NULL_RTX;
+ alloc_cprop_mem (last_basic_block, set_hash_table.n_elems);
+ compute_cprop_data ();
+ changed = cprop (cprop_jumps);
+ if (bypass_jumps)
+ changed |= bypass_conditional_jumps ();
+ free_cprop_mem ();
}
- else note_src = NULL_RTX;
- /* Prefer REG_EQUAL notes except those containing EXPR_LISTs. */
- set_src = note_src ? note_src : SET_SRC (set);
+ free_hash_table (&set_hash_table);
- /* First substitute the SETCC condition into the JUMP instruction,
- then substitute that given values into this expanded JUMP. */
- if (setcc != NULL_RTX
- && !modified_between_p (from, setcc, jump)
- && !modified_between_p (src, setcc, jump))
+ if (dump_file)
{
- rtx setcc_src;
- rtx setcc_set = single_set (setcc);
- rtx setcc_note = find_reg_equal_equiv_note (setcc);
- setcc_src = (setcc_note && GET_CODE (XEXP (setcc_note, 0)) != EXPR_LIST)
- ? XEXP (setcc_note, 0) : SET_SRC (setcc_set);
- set_src = simplify_replace_rtx (set_src, SET_DEST (setcc_set),
- setcc_src);
+ fprintf (dump_file, "CPROP of %s, pass %d: %d bytes needed, ",
+ current_function_name (), pass, bytes_used);
+ fprintf (dump_file, "%d local const props, %d local copy props, ",
+ local_const_prop_count, local_copy_prop_count);
+ fprintf (dump_file, "%d global const props, %d global copy props\n\n",
+ global_const_prop_count, global_copy_prop_count);
}
- else
- setcc = NULL_RTX;
+ /* Global analysis may get into infinite loops for unreachable blocks. */
+ if (changed && cprop_jumps)
+ delete_unreachable_blocks ();
- new = simplify_replace_rtx (set_src, from, src);
+ return changed;
+}
+\f
+/* Bypass conditional jumps. */
- /* If no simplification can be made, then try the next register. */
- if (rtx_equal_p (new, SET_SRC (set)))
- return 0;
+/* The value of last_basic_block at the beginning of the jump_bypass
+ pass. The use of redirect_edge_and_branch_force may introduce new
+ basic blocks, but the data flow analysis is only valid for basic
+ block indices less than bypass_last_basic_block. */
- /* If this is now a no-op delete it, otherwise this must be a valid insn. */
- if (new == pc_rtx)
- delete_insn (jump);
- else
+static int bypass_last_basic_block;
+
+/* Find a set of REGNO to a constant that is available at the end of basic
+ block BB. Returns NULL if no such set is found. Based heavily upon
+ find_avail_set. */
+
+static struct expr *
+find_bypass_set (int regno, int bb)
+{
+ struct expr *result = 0;
+
+ for (;;)
{
- /* Ensure the value computed inside the jump insn to be equivalent
- to one computed by setcc. */
- if (setcc && modified_in_p (new, setcc))
- return 0;
- if (! validate_change (jump, &SET_SRC (set), new, 0))
- {
- /* When (some) constants are not valid in a comparison, and there
- are two registers to be replaced by constants before the entire
- comparison can be folded into a constant, we need to keep
- intermediate information in REG_EQUAL notes. For targets with
- separate compare insns, such notes are added by try_replace_reg.
- When we have a combined compare-and-branch instruction, however,
- we need to attach a note to the branch itself to make this
- optimization work. */
+ rtx src;
+ struct expr *set = lookup_set (regno, &set_hash_table);
- if (!rtx_equal_p (new, note_src))
- set_unique_reg_note (jump, REG_EQUAL, copy_rtx (new));
- return 0;
+ while (set)
+ {
+ if (TEST_BIT (cprop_avout[bb], set->bitmap_index))
+ break;
+ set = next_set (regno, set);
}
- /* Remove REG_EQUAL note after simplification. */
- if (note_src)
- remove_note (jump, note);
+ if (set == 0)
+ break;
- /* If this has turned into an unconditional jump,
- then put a barrier after it so that the unreachable
- code will be deleted. */
- if (GET_CODE (SET_SRC (set)) == LABEL_REF)
- emit_barrier_after (jump);
- }
+ gcc_assert (GET_CODE (set->expr) == SET);
-#ifdef HAVE_cc0
- /* Delete the cc0 setter. */
- if (setcc != NULL && CC0_P (SET_DEST (single_set (setcc))))
- delete_insn (setcc);
-#endif
+ src = SET_SRC (set->expr);
+ if (gcse_constant_p (src))
+ result = set;
- run_jump_opt_after_gcse = 1;
+ if (! REG_P (src))
+ break;
- const_prop_count++;
- if (gcse_file != NULL)
- {
- fprintf (gcse_file,
- "CONST-PROP: Replacing reg %d in jump_insn %d with constant ",
- REGNO (from), INSN_UID (jump));
- print_rtl (gcse_file, src);
- fprintf (gcse_file, "\n");
+ regno = REGNO (src);
}
- purge_dead_edges (bb);
-
- return 1;
+ return result;
}
+
+/* Subroutine of bypass_block that checks whether a pseudo is killed by
+ any of the instructions inserted on an edge. Jump bypassing places
+ condition code setters on CFG edges using insert_insn_on_edge. This
+ function is required to check that our data flow analysis is still
+ valid prior to commit_edge_insertions. */
+
static bool
-constprop_register (rtx insn, rtx from, rtx to, int alter_jumps)
+reg_killed_on_edge (const_rtx reg, const_edge e)
{
- rtx sset;
+ rtx insn;
- /* Check for reg or cc0 setting instructions followed by
- conditional branch instructions first. */
- if (alter_jumps
- && (sset = single_set (insn)) != NULL
- && NEXT_INSN (insn)
- && any_condjump_p (NEXT_INSN (insn)) && onlyjump_p (NEXT_INSN (insn)))
- {
- rtx dest = SET_DEST (sset);
- if ((REG_P (dest) || CC0_P (dest))
- && cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn), from, to))
- return 1;
- }
+ for (insn = e->insns.r; insn; insn = NEXT_INSN (insn))
+ if (INSN_P (insn) && reg_set_p (reg, insn))
+ return true;
- /* Handle normal insns next. */
- if (GET_CODE (insn) == INSN
- && try_replace_reg (from, to, insn))
- return 1;
+ return false;
+}
- /* Try to propagate a CONST_INT into a conditional jump.
- We're pretty specific about what we will handle in this
- code, we can extend this as necessary over time.
-
- Right now the insn in question must look like
- (set (pc) (if_then_else ...)) */
- else if (alter_jumps && any_condjump_p (insn) && onlyjump_p (insn))
- return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, to);
- return 0;
-}
+/* Subroutine of bypass_conditional_jumps that attempts to bypass the given
+ basic block BB which has more than one predecessor. If not NULL, SETCC
+ is the first instruction of BB, which is immediately followed by JUMP_INSN
+ JUMP. Otherwise, SETCC is NULL, and JUMP is the first insn of BB.
+ Returns nonzero if a change was made.
-/* Perform constant and copy propagation on INSN.
- The result is nonzero if a change was made. */
+ During the jump bypassing pass, we may place copies of SETCC instructions
+ on CFG edges. The following routine must be careful to pay attention to
+ these inserted insns when performing its transformations. */
static int
-cprop_insn (rtx insn, int alter_jumps)
+bypass_block (basic_block bb, rtx setcc, rtx jump)
{
- struct reg_use *reg_used;
- int changed = 0;
- rtx note;
+ rtx insn, note;
+ edge e, edest;
+ int i, change;
+ int may_be_loop_header;
+ unsigned removed_p;
+ edge_iterator ei;
- if (!INSN_P (insn))
- return 0;
+ insn = (setcc != NULL) ? setcc : jump;
+ /* Determine set of register uses in INSN. */
reg_use_count = 0;
note_uses (&PATTERN (insn), find_used_regs, NULL);
-
note = find_reg_equal_equiv_note (insn);
-
- /* We may win even when propagating constants into notes. */
if (note)
find_used_regs (&XEXP (note, 0), NULL);
- for (reg_used = ®_use_table[0]; reg_use_count > 0;
- reg_used++, reg_use_count--)
+ may_be_loop_header = false;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->flags & EDGE_DFS_BACK)
+ {
+ may_be_loop_header = true;
+ break;
+ }
+
+ change = 0;
+ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
{
- unsigned int regno = REGNO (reg_used->reg_rtx);
- rtx pat, src;
- struct expr *set;
+ removed_p = 0;
+
+ if (e->flags & EDGE_COMPLEX)
+ {
+ ei_next (&ei);
+ continue;
+ }
- /* Ignore registers created by GCSE.
- We do this because ... */
- if (regno >= max_gcse_regno)
- continue;
+ /* We can't redirect edges from new basic blocks. */
+ if (e->src->index >= bypass_last_basic_block)
+ {
+ ei_next (&ei);
+ continue;
+ }
- /* If the register has already been set in this block, there's
- nothing we can do. */
- if (! oprs_not_set_p (reg_used->reg_rtx, insn))
- continue;
+ /* The irreducible loops created by redirecting of edges entering the
+ loop from outside would decrease effectiveness of some of the following
+ optimizations, so prevent this. */
+ if (may_be_loop_header
+ && !(e->flags & EDGE_DFS_BACK))
+ {
+ ei_next (&ei);
+ continue;
+ }
- /* Find an assignment that sets reg_used and is available
- at the start of the block. */
- set = find_avail_set (regno, insn);
- if (! set)
- continue;
+ for (i = 0; i < reg_use_count; i++)
+ {
+ struct reg_use *reg_used = ®_use_table[i];
+ unsigned int regno = REGNO (reg_used->reg_rtx);
+ basic_block dest, old_dest;
+ struct expr *set;
+ rtx src, new;
- pat = set->expr;
- /* ??? We might be able to handle PARALLELs. Later. */
- if (GET_CODE (pat) != SET)
- abort ();
+ if (regno >= max_gcse_regno)
+ continue;
- src = SET_SRC (pat);
+ set = find_bypass_set (regno, e->src->index);
- /* Constant propagation. */
- if (gcse_constant_p (src))
- {
- if (constprop_register (insn, reg_used->reg_rtx, src, alter_jumps))
+ if (! set)
+ continue;
+
+ /* Check the data flow is valid after edge insertions. */
+ if (e->insns.r && reg_killed_on_edge (reg_used->reg_rtx, e))
+ continue;
+
+ src = SET_SRC (pc_set (jump));
+
+ if (setcc != NULL)
+ src = simplify_replace_rtx (src,
+ SET_DEST (PATTERN (setcc)),
+ SET_SRC (PATTERN (setcc)));
+
+ new = simplify_replace_rtx (src, reg_used->reg_rtx,
+ SET_SRC (set->expr));
+
+ /* Jump bypassing may have already placed instructions on
+ edges of the CFG. We can't bypass an outgoing edge that
+ has instructions associated with it, as these insns won't
+ get executed if the incoming edge is redirected. */
+
+ if (new == pc_rtx)
{
- changed = 1;
- const_prop_count++;
- if (gcse_file != NULL)
- {
- fprintf (gcse_file, "GLOBAL CONST-PROP: Replacing reg %d in ", regno);
- fprintf (gcse_file, "insn %d with constant ", INSN_UID (insn));
- print_rtl (gcse_file, src);
- fprintf (gcse_file, "\n");
- }
- if (INSN_DELETED_P (insn))
- return 1;
+ edest = FALLTHRU_EDGE (bb);
+ dest = edest->insns.r ? NULL : edest->dest;
}
- }
- else if (GET_CODE (src) == REG
- && REGNO (src) >= FIRST_PSEUDO_REGISTER
- && REGNO (src) != regno)
- {
- if (try_replace_reg (reg_used->reg_rtx, src, insn))
+ else if (GET_CODE (new) == LABEL_REF)
{
- changed = 1;
- copy_prop_count++;
- if (gcse_file != NULL)
+ dest = BLOCK_FOR_INSN (XEXP (new, 0));
+ /* Don't bypass edges containing instructions. */
+ edest = find_edge (bb, dest);
+ if (edest && edest->insns.r)
+ dest = NULL;
+ }
+ else
+ dest = NULL;
+
+ /* Avoid unification of the edge with other edges from original
+ branch. We would end up emitting the instruction on "both"
+ edges. */
+
+ if (dest && setcc && !CC0_P (SET_DEST (PATTERN (setcc)))
+ && find_edge (e->src, dest))
+ dest = NULL;
+
+ old_dest = e->dest;
+ if (dest != NULL
+ && dest != old_dest
+ && dest != EXIT_BLOCK_PTR)
+ {
+ redirect_edge_and_branch_force (e, dest);
+
+ /* Copy the register setter to the redirected edge.
+ Don't copy CC0 setters, as CC0 is dead after jump. */
+ if (setcc)
{
- fprintf (gcse_file, "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
- regno, INSN_UID (insn));
- fprintf (gcse_file, " with reg %d\n", REGNO (src));
+ rtx pat = PATTERN (setcc);
+ if (!CC0_P (SET_DEST (pat)))
+ insert_insn_on_edge (copy_insn (pat), e);
}
- /* The original insn setting reg_used may or may not now be
- deletable. We leave the deletion to flow. */
- /* FIXME: If it turns out that the insn isn't deletable,
- then we may have unnecessarily extended register lifetimes
- and made things worse. */
+ if (dump_file != NULL)
+ {
+ fprintf (dump_file, "JUMP-BYPASS: Proved reg %d "
+ "in jump_insn %d equals constant ",
+ regno, INSN_UID (jump));
+ print_rtl (dump_file, SET_SRC (set->expr));
+ fprintf (dump_file, "\nBypass edge from %d->%d to %d\n",
+ e->src->index, old_dest->index, dest->index);
+ }
+ change = 1;
+ removed_p = 1;
+ break;
}
}
+ if (!removed_p)
+ ei_next (&ei);
}
-
- return changed;
+ return change;
}
-/* Like find_used_regs, but avoid recording uses that appear in
- input-output contexts such as zero_extract or pre_dec. This
- restricts the cases we consider to those for which local cprop
- can legitimately make replacements. */
+/* Find basic blocks with more than one predecessor that only contain a
+ single conditional jump. If the result of the comparison is known at
+ compile-time from any incoming edge, redirect that edge to the
+ appropriate target. Returns nonzero if a change was made.
-static void
-local_cprop_find_used_regs (rtx *xptr, void *data)
-{
- rtx x = *xptr;
+ This function is now mis-named, because we also handle indirect jumps. */
- if (x == 0)
- return;
+static int
+bypass_conditional_jumps (void)
+{
+ basic_block bb;
+ int changed;
+ rtx setcc;
+ rtx insn;
+ rtx dest;
- switch (GET_CODE (x))
- {
- case ZERO_EXTRACT:
- case SIGN_EXTRACT:
- case STRICT_LOW_PART:
- return;
+ /* Note we start at block 1. */
+ if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
+ return 0;
- case PRE_DEC:
- case PRE_INC:
- case POST_DEC:
- case POST_INC:
- case PRE_MODIFY:
- case POST_MODIFY:
- /* Can only legitimately appear this early in the context of
- stack pushes for function arguments, but handle all of the
- codes nonetheless. */
- return;
+ bypass_last_basic_block = last_basic_block;
+ mark_dfs_back_edges ();
- case SUBREG:
- /* Setting a subreg of a register larger than word_mode leaves
- the non-written words unchanged. */
- if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) > BITS_PER_WORD)
- return;
- break;
+ changed = 0;
+ FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb,
+ EXIT_BLOCK_PTR, next_bb)
+ {
+ /* Check for more than one predecessor. */
+ if (!single_pred_p (bb))
+ {
+ setcc = NULL_RTX;
+ FOR_BB_INSNS (bb, insn)
+ if (NONJUMP_INSN_P (insn))
+ {
+ if (setcc)
+ break;
+ if (GET_CODE (PATTERN (insn)) != SET)
+ break;
- default:
- break;
+ dest = SET_DEST (PATTERN (insn));
+ if (REG_P (dest) || CC0_P (dest))
+ setcc = insn;
+ else
+ break;
+ }
+ else if (JUMP_P (insn))
+ {
+ if ((any_condjump_p (insn) || computed_jump_p (insn))
+ && onlyjump_p (insn))
+ changed |= bypass_block (bb, setcc, insn);
+ break;
+ }
+ else if (INSN_P (insn))
+ break;
+ }
}
- find_used_regs (xptr, data);
-}
+ /* If we bypassed any register setting insns, we inserted a
+ copy on the redirected edge. These need to be committed. */
+ if (changed)
+ commit_edge_insertions ();
-/* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall;
- their REG_EQUAL notes need updating. */
+ return changed;
+}
+\f
+/* Compute PRE+LCM working variables. */
-static bool
-do_local_cprop (rtx x, rtx insn, int alter_jumps, rtx *libcall_sp)
-{
- rtx newreg = NULL, newcnst = NULL;
+/* Local properties of expressions. */
+/* Nonzero for expressions that are transparent in the block. */
+static sbitmap *transp;
- /* Rule out USE instructions and ASM statements as we don't want to
- change the hard registers mentioned. */
- if (GET_CODE (x) == REG
- && (REGNO (x) >= FIRST_PSEUDO_REGISTER
- || (GET_CODE (PATTERN (insn)) != USE
- && asm_noperands (PATTERN (insn)) < 0)))
- {
- cselib_val *val = cselib_lookup (x, GET_MODE (x), 0);
- struct elt_loc_list *l;
+/* Nonzero for expressions that are transparent at the end of the block.
+ This is only zero for expressions killed by abnormal critical edge
+ created by a calls. */
+static sbitmap *transpout;
- if (!val)
- return false;
- for (l = val->locs; l; l = l->next)
- {
- rtx this_rtx = l->loc;
- rtx note;
+/* Nonzero for expressions that are computed (available) in the block. */
+static sbitmap *comp;
- if (l->in_libcall)
- continue;
+/* Nonzero for expressions that are locally anticipatable in the block. */
+static sbitmap *antloc;
- if (gcse_constant_p (this_rtx))
- newcnst = this_rtx;
- if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
- /* Don't copy propagate if it has attached REG_EQUIV note.
- At this point this only function parameters should have
- REG_EQUIV notes and if the argument slot is used somewhere
- explicitly, it means address of parameter has been taken,
- so we should not extend the lifetime of the pseudo. */
- && (!(note = find_reg_note (l->setting_insn, REG_EQUIV, NULL_RTX))
- || GET_CODE (XEXP (note, 0)) != MEM))
- newreg = this_rtx;
- }
- if (newcnst && constprop_register (insn, x, newcnst, alter_jumps))
- {
- /* If we find a case where we can't fix the retval REG_EQUAL notes
- match the new register, we either have to abandon this replacement
- or fix delete_trivially_dead_insns to preserve the setting insn,
- or make it delete the REG_EUAQL note, and fix up all passes that
- require the REG_EQUAL note there. */
- if (!adjust_libcall_notes (x, newcnst, insn, libcall_sp))
- abort ();
- if (gcse_file != NULL)
- {
- fprintf (gcse_file, "LOCAL CONST-PROP: Replacing reg %d in ",
- REGNO (x));
- fprintf (gcse_file, "insn %d with constant ",
- INSN_UID (insn));
- print_rtl (gcse_file, newcnst);
- fprintf (gcse_file, "\n");
- }
- const_prop_count++;
- return true;
- }
- else if (newreg && newreg != x && try_replace_reg (x, newreg, insn))
- {
- adjust_libcall_notes (x, newreg, insn, libcall_sp);
- if (gcse_file != NULL)
- {
- fprintf (gcse_file,
- "LOCAL COPY-PROP: Replacing reg %d in insn %d",
- REGNO (x), INSN_UID (insn));
- fprintf (gcse_file, " with reg %d\n", REGNO (newreg));
- }
- copy_prop_count++;
- return true;
- }
- }
- return false;
-}
+/* Nonzero for expressions where this block is an optimal computation
+ point. */
+static sbitmap *pre_optimal;
-/* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall;
- their REG_EQUAL notes need updating to reflect that OLDREG has been
- replaced with NEWVAL in INSN. Return true if all substitutions could
- be made. */
-static bool
-adjust_libcall_notes (rtx oldreg, rtx newval, rtx insn, rtx *libcall_sp)
-{
- rtx end;
+/* Nonzero for expressions which are redundant in a particular block. */
+static sbitmap *pre_redundant;
- while ((end = *libcall_sp++))
- {
- rtx note = find_reg_equal_equiv_note (end);
+/* Nonzero for expressions which should be inserted on a specific edge. */
+static sbitmap *pre_insert_map;
- if (! note)
- continue;
+/* Nonzero for expressions which should be deleted in a specific block. */
+static sbitmap *pre_delete_map;
- if (REG_P (newval))
- {
- if (reg_set_between_p (newval, PREV_INSN (insn), end))
- {
- do
- {
- note = find_reg_equal_equiv_note (end);
- if (! note)
- continue;
- if (reg_mentioned_p (newval, XEXP (note, 0)))
- return false;
- }
- while ((end = *libcall_sp++));
- return true;
- }
- }
- XEXP (note, 0) = replace_rtx (XEXP (note, 0), oldreg, newval);
- insn = end;
- }
- return true;
+/* Contains the edge_list returned by pre_edge_lcm. */
+static struct edge_list *edge_list;
+
+/* Redundant insns. */
+static sbitmap pre_redundant_insns;
+
+/* Allocate vars used for PRE analysis. */
+
+static void
+alloc_pre_mem (int n_blocks, int n_exprs)
+{
+ transp = sbitmap_vector_alloc (n_blocks, n_exprs);
+ comp = sbitmap_vector_alloc (n_blocks, n_exprs);
+ antloc = sbitmap_vector_alloc (n_blocks, n_exprs);
+
+ pre_optimal = NULL;
+ pre_redundant = NULL;
+ pre_insert_map = NULL;
+ pre_delete_map = NULL;
+ ae_kill = sbitmap_vector_alloc (n_blocks, n_exprs);
+
+ /* pre_insert and pre_delete are allocated later. */
}
-#define MAX_NESTED_LIBCALLS 9
+/* Free vars used for PRE analysis. */
static void
-local_cprop_pass (int alter_jumps)
+free_pre_mem (void)
{
- rtx insn;
- struct reg_use *reg_used;
- rtx libcall_stack[MAX_NESTED_LIBCALLS + 1], *libcall_sp;
- bool changed = false;
+ sbitmap_vector_free (transp);
+ sbitmap_vector_free (comp);
- cselib_init (false);
- libcall_sp = &libcall_stack[MAX_NESTED_LIBCALLS];
- *libcall_sp = 0;
- for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- {
- if (INSN_P (insn))
- {
- rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
+ /* ANTLOC and AE_KILL are freed just after pre_lcm finishes. */
- if (note)
- {
- if (libcall_sp == libcall_stack)
- abort ();
- *--libcall_sp = XEXP (note, 0);
- }
- note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
- if (note)
- libcall_sp++;
- note = find_reg_equal_equiv_note (insn);
- do
- {
- reg_use_count = 0;
- note_uses (&PATTERN (insn), local_cprop_find_used_regs, NULL);
- if (note)
- local_cprop_find_used_regs (&XEXP (note, 0), NULL);
+ if (pre_optimal)
+ sbitmap_vector_free (pre_optimal);
+ if (pre_redundant)
+ sbitmap_vector_free (pre_redundant);
+ if (pre_insert_map)
+ sbitmap_vector_free (pre_insert_map);
+ if (pre_delete_map)
+ sbitmap_vector_free (pre_delete_map);
- for (reg_used = ®_use_table[0]; reg_use_count > 0;
- reg_used++, reg_use_count--)
- if (do_local_cprop (reg_used->reg_rtx, insn, alter_jumps,
- libcall_sp))
- {
- changed = true;
- break;
- }
- if (INSN_DELETED_P (insn))
- break;
- }
- while (reg_use_count);
- }
- cselib_process_insn (insn);
- }
- cselib_finish ();
- /* Global analysis may get into infinite loops for unreachable blocks. */
- if (changed && alter_jumps)
- {
- delete_unreachable_blocks ();
- free_reg_set_mem ();
- alloc_reg_set_mem (max_reg_num ());
- compute_sets (get_insns ());
- }
+ transp = comp = NULL;
+ pre_optimal = pre_redundant = pre_insert_map = pre_delete_map = NULL;
}
-/* Forward propagate copies. This includes copies and constants. Return
- nonzero if a change was made. */
+/* Top level routine to do the dataflow analysis needed by PRE. */
-static int
-cprop (int alter_jumps)
+static void
+compute_pre_data (void)
{
- int changed;
+ sbitmap trapping_expr;
basic_block bb;
- rtx insn;
+ unsigned int ui;
- /* Note we start at block 1. */
- if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
+ compute_local_properties (transp, comp, antloc, &expr_hash_table);
+ sbitmap_vector_zero (ae_kill, last_basic_block);
+
+ /* Collect expressions which might trap. */
+ trapping_expr = sbitmap_alloc (expr_hash_table.n_elems);
+ sbitmap_zero (trapping_expr);
+ for (ui = 0; ui < expr_hash_table.size; ui++)
{
- if (gcse_file != NULL)
- fprintf (gcse_file, "\n");
- return 0;
+ struct expr *e;
+ for (e = expr_hash_table.table[ui]; e != NULL; e = e->next_same_hash)
+ if (may_trap_p (e->expr))
+ SET_BIT (trapping_expr, e->bitmap_index);
}
- changed = 0;
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb)
+ /* Compute ae_kill for each basic block using:
+
+ ~(TRANSP | COMP)
+ */
+
+ FOR_EACH_BB (bb)
{
- /* Reset tables used to keep track of what's still valid [since the
- start of the block]. */
- reset_opr_set_tables ();
+ edge e;
+ edge_iterator ei;
- for (insn = BB_HEAD (bb);
- insn != NULL && insn != NEXT_INSN (BB_END (bb));
- insn = NEXT_INSN (insn))
- if (INSN_P (insn))
+ /* If the current block is the destination of an abnormal edge, we
+ kill all trapping expressions because we won't be able to properly
+ place the instruction on the edge. So make them neither
+ anticipatable nor transparent. This is fairly conservative. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->flags & EDGE_ABNORMAL)
{
- changed |= cprop_insn (insn, alter_jumps);
-
- /* Keep track of everything modified by this insn. */
- /* ??? Need to be careful w.r.t. mods done to INSN. Don't
- call mark_oprs_set if we turned the insn into a NOTE. */
- if (GET_CODE (insn) != NOTE)
- mark_oprs_set (insn);
+ sbitmap_difference (antloc[bb->index], antloc[bb->index], trapping_expr);
+ sbitmap_difference (transp[bb->index], transp[bb->index], trapping_expr);
+ break;
}
- }
- if (gcse_file != NULL)
- fprintf (gcse_file, "\n");
+ sbitmap_a_or_b (ae_kill[bb->index], transp[bb->index], comp[bb->index]);
+ sbitmap_not (ae_kill[bb->index], ae_kill[bb->index]);
+ }
- return changed;
+ edge_list = pre_edge_lcm (expr_hash_table.n_elems, transp, comp, antloc,
+ ae_kill, &pre_insert_map, &pre_delete_map);
+ sbitmap_vector_free (antloc);
+ antloc = NULL;
+ sbitmap_vector_free (ae_kill);
+ ae_kill = NULL;
+ sbitmap_free (trapping_expr);
}
+\f
+/* PRE utilities */
-/* Similar to get_condition, only the resulting condition must be
- valid at JUMP, instead of at EARLIEST.
-
- This differs from noce_get_condition in ifcvt.c in that we prefer not to
- settle for the condition variable in the jump instruction being integral.
- We prefer to be able to record the value of a user variable, rather than
- the value of a temporary used in a condition. This could be solved by
- recording the value of *every* register scaned by canonicalize_condition,
- but this would require some code reorganization. */
+/* Return nonzero if an occurrence of expression EXPR in OCCR_BB would reach
+ block BB.
-rtx
-fis_get_condition (rtx jump)
-{
- rtx cond, set, tmp, insn, earliest;
- bool reverse;
+ VISITED is a pointer to a working buffer for tracking which BB's have
+ been visited. It is NULL for the top-level call.
- if (! any_condjump_p (jump))
- return NULL_RTX;
-
- set = pc_set (jump);
- cond = XEXP (SET_SRC (set), 0);
-
- /* If this branches to JUMP_LABEL when the condition is false,
- reverse the condition. */
- reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
- && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump));
-
- /* Use canonicalize_condition to do the dirty work of manipulating
- MODE_CC values and COMPARE rtx codes. */
- tmp = canonicalize_condition (jump, cond, reverse, &earliest, NULL_RTX,
- false);
- if (!tmp)
- return NULL_RTX;
-
- /* Verify that the given condition is valid at JUMP by virtue of not
- having been modified since EARLIEST. */
- for (insn = earliest; insn != jump; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && modified_in_p (tmp, insn))
- break;
- if (insn == jump)
- return tmp;
-
- /* The condition was modified. See if we can get a partial result
- that doesn't follow all the reversals. Perhaps combine can fold
- them together later. */
- tmp = XEXP (tmp, 0);
- if (!REG_P (tmp) || GET_MODE_CLASS (GET_MODE (tmp)) != MODE_INT)
- return NULL_RTX;
- tmp = canonicalize_condition (jump, cond, reverse, &earliest, tmp,
- false);
- if (!tmp)
- return NULL_RTX;
+ We treat reaching expressions that go through blocks containing the same
+ reaching expression as "not reaching". E.g. if EXPR is generated in blocks
+ 2 and 3, INSN is in block 4, and 2->3->4, we treat the expression in block
+ 2 as not reaching. The intent is to improve the probability of finding
+ only one reaching expression and to reduce register lifetimes by picking
+ the closest such expression. */
- /* For sanity's sake, re-validate the new result. */
- for (insn = earliest; insn != jump; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && modified_in_p (tmp, insn))
- return NULL_RTX;
+static int
+pre_expr_reaches_here_p_work (basic_block occr_bb, struct expr *expr, basic_block bb, char *visited)
+{
+ edge pred;
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (pred, ei, bb->preds)
+ {
+ basic_block pred_bb = pred->src;
- return tmp;
-}
+ if (pred->src == ENTRY_BLOCK_PTR
+ /* Has predecessor has already been visited? */
+ || visited[pred_bb->index])
+ ;/* Nothing to do. */
-/* Check the comparison COND to see if we can safely form an implicit set from
- it. COND is either an EQ or NE comparison. */
+ /* Does this predecessor generate this expression? */
+ else if (TEST_BIT (comp[pred_bb->index], expr->bitmap_index))
+ {
+ /* Is this the occurrence we're looking for?
+ Note that there's only one generating occurrence per block
+ so we just need to check the block number. */
+ if (occr_bb == pred_bb)
+ return 1;
-static bool
-implicit_set_cond_p (rtx cond)
-{
- enum machine_mode mode = GET_MODE (XEXP (cond, 0));
- rtx cst = XEXP (cond, 1);
+ visited[pred_bb->index] = 1;
+ }
+ /* Ignore this predecessor if it kills the expression. */
+ else if (! TEST_BIT (transp[pred_bb->index], expr->bitmap_index))
+ visited[pred_bb->index] = 1;
- /* We can't perform this optimization if either operand might be or might
- contain a signed zero. */
- if (HONOR_SIGNED_ZEROS (mode))
- {
- /* It is sufficient to check if CST is or contains a zero. We must
- handle float, complex, and vector. If any subpart is a zero, then
- the optimization can't be performed. */
- /* ??? The complex and vector checks are not implemented yet. We just
- always return zero for them. */
- if (GET_CODE (cst) == CONST_DOUBLE)
+ /* Neither gen nor kill. */
+ else
{
- REAL_VALUE_TYPE d;
- REAL_VALUE_FROM_CONST_DOUBLE (d, cst);
- if (REAL_VALUES_EQUAL (d, dconst0))
- return 0;
+ visited[pred_bb->index] = 1;
+ if (pre_expr_reaches_here_p_work (occr_bb, expr, pred_bb, visited))
+ return 1;
}
- else
- return 0;
}
- return gcse_constant_p (cst);
+ /* All paths have been checked. */
+ return 0;
}
-/* Find the implicit sets of a function. An "implicit set" is a constraint
- on the value of a variable, implied by a conditional jump. For example,
- following "if (x == 2)", the then branch may be optimized as though the
- conditional performed an "explicit set", in this example, "x = 2". This
- function records the set patterns that are implicit at the start of each
- basic block. */
+/* The wrapper for pre_expr_reaches_here_work that ensures that any
+ memory allocated for that function is returned. */
-static void
-find_implicit_sets (void)
+static int
+pre_expr_reaches_here_p (basic_block occr_bb, struct expr *expr, basic_block bb)
{
- basic_block bb, dest;
- unsigned int count;
- rtx cond, new;
-
- count = 0;
- FOR_EACH_BB (bb)
- /* Check for more than one successor. */
- if (bb->succ && bb->succ->succ_next)
- {
- cond = fis_get_condition (BB_END (bb));
-
- if (cond
- && (GET_CODE (cond) == EQ || GET_CODE (cond) == NE)
- && GET_CODE (XEXP (cond, 0)) == REG
- && REGNO (XEXP (cond, 0)) >= FIRST_PSEUDO_REGISTER
- && implicit_set_cond_p (cond))
- {
- dest = GET_CODE (cond) == EQ ? BRANCH_EDGE (bb)->dest
- : FALLTHRU_EDGE (bb)->dest;
+ int rval;
+ char *visited = XCNEWVEC (char, last_basic_block);
- if (dest && ! dest->pred->pred_next
- && dest != EXIT_BLOCK_PTR)
- {
- new = gen_rtx_SET (VOIDmode, XEXP (cond, 0),
- XEXP (cond, 1));
- implicit_sets[dest->index] = new;
- if (gcse_file)
- {
- fprintf(gcse_file, "Implicit set of reg %d in ",
- REGNO (XEXP (cond, 0)));
- fprintf(gcse_file, "basic block %d\n", dest->index);
- }
- count++;
- }
- }
- }
+ rval = pre_expr_reaches_here_p_work (occr_bb, expr, bb, visited);
- if (gcse_file)
- fprintf (gcse_file, "Found %d implicit sets\n", count);
+ free (visited);
+ return rval;
}
+\f
-/* Perform one copy/constant propagation pass.
- PASS is the pass count. If CPROP_JUMPS is true, perform constant
- propagation into conditional jumps. If BYPASS_JUMPS is true,
- perform conditional jump bypassing optimizations. */
+/* Given an expr, generate RTL which we can insert at the end of a BB,
+ or on an edge. Set the block number of any insns generated to
+ the value of BB. */
-static int
-one_cprop_pass (int pass, int cprop_jumps, int bypass_jumps)
+static rtx
+process_insert_insn (struct expr *expr)
{
- int changed = 0;
-
- const_prop_count = 0;
- copy_prop_count = 0;
-
- local_cprop_pass (cprop_jumps);
-
- /* Determine implicit sets. */
- implicit_sets = xcalloc (last_basic_block, sizeof (rtx));
- find_implicit_sets ();
+ rtx reg = expr->reaching_reg;
+ rtx exp = copy_rtx (expr->expr);
+ rtx pat;
- alloc_hash_table (max_cuid, &set_hash_table, 1);
- compute_hash_table (&set_hash_table);
+ start_sequence ();
- /* Free implicit_sets before peak usage. */
- free (implicit_sets);
- implicit_sets = NULL;
+ /* If the expression is something that's an operand, like a constant,
+ just copy it to a register. */
+ if (general_operand (exp, GET_MODE (reg)))
+ emit_move_insn (reg, exp);
- if (gcse_file)
- dump_hash_table (gcse_file, "SET", &set_hash_table);
- if (set_hash_table.n_elems > 0)
+ /* Otherwise, make a new insn to compute this expression and make sure the
+ insn will be recognized (this also adds any needed CLOBBERs). Copy the
+ expression to make sure we don't have any sharing issues. */
+ else
{
- alloc_cprop_mem (last_basic_block, set_hash_table.n_elems);
- compute_cprop_data ();
- changed = cprop (cprop_jumps);
- if (bypass_jumps)
- changed |= bypass_conditional_jumps ();
- free_cprop_mem ();
- }
+ rtx insn = emit_insn (gen_rtx_SET (VOIDmode, reg, exp));
- free_hash_table (&set_hash_table);
-
- if (gcse_file)
- {
- fprintf (gcse_file, "CPROP of %s, pass %d: %d bytes needed, ",
- current_function_name (), pass, bytes_used);
- fprintf (gcse_file, "%d const props, %d copy props\n\n",
- const_prop_count, copy_prop_count);
+ if (insn_invalid_p (insn))
+ gcc_unreachable ();
}
- /* Global analysis may get into infinite loops for unreachable blocks. */
- if (changed && cprop_jumps)
- delete_unreachable_blocks ();
+
- return changed;
+ pat = get_insns ();
+ end_sequence ();
+
+ return pat;
}
-\f
-/* Bypass conditional jumps. */
-/* The value of last_basic_block at the beginning of the jump_bypass
- pass. The use of redirect_edge_and_branch_force may introduce new
- basic blocks, but the data flow analysis is only valid for basic
- block indices less than bypass_last_basic_block. */
+/* Add EXPR to the end of basic block BB.
-static int bypass_last_basic_block;
+ This is used by both the PRE and code hoisting.
-/* Find a set of REGNO to a constant that is available at the end of basic
- block BB. Returns NULL if no such set is found. Based heavily upon
- find_avail_set. */
+ For PRE, we want to verify that the expr is either transparent
+ or locally anticipatable in the target block. This check makes
+ no sense for code hoisting. */
-static struct expr *
-find_bypass_set (int regno, int bb)
+static void
+insert_insn_end_basic_block (struct expr *expr, basic_block bb, int pre)
{
- struct expr *result = 0;
+ rtx insn = BB_END (bb);
+ rtx new_insn;
+ rtx reg = expr->reaching_reg;
+ int regno = REGNO (reg);
+ rtx pat, pat_end;
- for (;;)
+ pat = process_insert_insn (expr);
+ gcc_assert (pat && INSN_P (pat));
+
+ pat_end = pat;
+ while (NEXT_INSN (pat_end) != NULL_RTX)
+ pat_end = NEXT_INSN (pat_end);
+
+ /* If the last insn is a jump, insert EXPR in front [taking care to
+ handle cc0, etc. properly]. Similarly we need to care trapping
+ instructions in presence of non-call exceptions. */
+
+ if (JUMP_P (insn)
+ || (NONJUMP_INSN_P (insn)
+ && (!single_succ_p (bb)
+ || single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
{
- rtx src;
- struct expr *set = lookup_set (regno, &set_hash_table);
+#ifdef HAVE_cc0
+ rtx note;
+#endif
+ /* It should always be the case that we can put these instructions
+ anywhere in the basic block with performing PRE optimizations.
+ Check this. */
+ gcc_assert (!NONJUMP_INSN_P (insn) || !pre
+ || TEST_BIT (antloc[bb->index], expr->bitmap_index)
+ || TEST_BIT (transp[bb->index], expr->bitmap_index));
- while (set)
+ /* If this is a jump table, then we can't insert stuff here. Since
+ we know the previous real insn must be the tablejump, we insert
+ the new instruction just before the tablejump. */
+ if (GET_CODE (PATTERN (insn)) == ADDR_VEC
+ || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
+ insn = prev_real_insn (insn);
+
+#ifdef HAVE_cc0
+ /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
+ if cc0 isn't set. */
+ note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
+ if (note)
+ insn = XEXP (note, 0);
+ else
{
- if (TEST_BIT (cprop_avout[bb], set->bitmap_index))
- break;
- set = next_set (regno, set);
+ rtx maybe_cc0_setter = prev_nonnote_insn (insn);
+ if (maybe_cc0_setter
+ && INSN_P (maybe_cc0_setter)
+ && sets_cc0_p (PATTERN (maybe_cc0_setter)))
+ insn = maybe_cc0_setter;
}
+#endif
+ /* FIXME: What if something in cc0/jump uses value set in new insn? */
+ new_insn = emit_insn_before_noloc (pat, insn, bb);
+ }
- if (set == 0)
- break;
+ /* Likewise if the last insn is a call, as will happen in the presence
+ of exception handling. */
+ else if (CALL_P (insn)
+ && (!single_succ_p (bb)
+ || single_succ_edge (bb)->flags & EDGE_ABNORMAL))
+ {
+ /* Keeping in mind SMALL_REGISTER_CLASSES and parameters in registers,
+ we search backward and place the instructions before the first
+ parameter is loaded. Do this for everyone for consistency and a
+ presumption that we'll get better code elsewhere as well.
- if (GET_CODE (set->expr) != SET)
- abort ();
+ It should always be the case that we can put these instructions
+ anywhere in the basic block with performing PRE optimizations.
+ Check this. */
- src = SET_SRC (set->expr);
- if (gcse_constant_p (src))
- result = set;
+ gcc_assert (!pre
+ || TEST_BIT (antloc[bb->index], expr->bitmap_index)
+ || TEST_BIT (transp[bb->index], expr->bitmap_index));
- if (GET_CODE (src) != REG)
- break;
+ /* Since different machines initialize their parameter registers
+ in different orders, assume nothing. Collect the set of all
+ parameter registers. */
+ insn = find_first_parameter_load (insn, BB_HEAD (bb));
- regno = REGNO (src);
- }
- return result;
-}
+ /* If we found all the parameter loads, then we want to insert
+ before the first parameter load.
+ If we did not find all the parameter loads, then we might have
+ stopped on the head of the block, which could be a CODE_LABEL.
+ If we inserted before the CODE_LABEL, then we would be putting
+ the insn in the wrong basic block. In that case, put the insn
+ after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */
+ while (LABEL_P (insn)
+ || NOTE_INSN_BASIC_BLOCK_P (insn))
+ insn = NEXT_INSN (insn);
-/* Subroutine of bypass_block that checks whether a pseudo is killed by
- any of the instructions inserted on an edge. Jump bypassing places
- condition code setters on CFG edges using insert_insn_on_edge. This
- function is required to check that our data flow analysis is still
- valid prior to commit_edge_insertions. */
+ new_insn = emit_insn_before_noloc (pat, insn, bb);
+ }
+ else
+ new_insn = emit_insn_after_noloc (pat, insn, bb);
-static bool
-reg_killed_on_edge (rtx reg, edge e)
-{
- rtx insn;
+ while (1)
+ {
+ if (INSN_P (pat))
+ {
+ add_label_notes (PATTERN (pat), new_insn);
+ note_stores (PATTERN (pat), record_set_info, pat);
+ }
+ if (pat == pat_end)
+ break;
+ pat = NEXT_INSN (pat);
+ }
- for (insn = e->insns; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && reg_set_p (reg, insn))
- return true;
+ gcse_create_count++;
- return false;
+ if (dump_file)
+ {
+ fprintf (dump_file, "PRE/HOIST: end of bb %d, insn %d, ",
+ bb->index, INSN_UID (new_insn));
+ fprintf (dump_file, "copying expression %d to reg %d\n",
+ expr->bitmap_index, regno);
+ }
}
-/* Subroutine of bypass_conditional_jumps that attempts to bypass the given
- basic block BB which has more than one predecessor. If not NULL, SETCC
- is the first instruction of BB, which is immediately followed by JUMP_INSN
- JUMP. Otherwise, SETCC is NULL, and JUMP is the first insn of BB.
- Returns nonzero if a change was made.
-
- During the jump bypassing pass, we may place copies of SETCC instructions
- on CFG edges. The following routine must be careful to pay attention to
- these inserted insns when performing its transformations. */
+/* Insert partially redundant expressions on edges in the CFG to make
+ the expressions fully redundant. */
static int
-bypass_block (basic_block bb, rtx setcc, rtx jump)
+pre_edge_insert (struct edge_list *edge_list, struct expr **index_map)
{
- rtx insn, note;
- edge e, enext, edest;
- int i, change;
- int may_be_loop_header;
-
- insn = (setcc != NULL) ? setcc : jump;
+ int e, i, j, num_edges, set_size, did_insert = 0;
+ sbitmap *inserted;
- /* Determine set of register uses in INSN. */
- reg_use_count = 0;
- note_uses (&PATTERN (insn), find_used_regs, NULL);
- note = find_reg_equal_equiv_note (insn);
- if (note)
- find_used_regs (&XEXP (note, 0), NULL);
+ /* Where PRE_INSERT_MAP is nonzero, we add the expression on that edge
+ if it reaches any of the deleted expressions. */
- may_be_loop_header = false;
- for (e = bb->pred; e; e = e->pred_next)
- if (e->flags & EDGE_DFS_BACK)
- {
- may_be_loop_header = true;
- break;
- }
+ set_size = pre_insert_map[0]->size;
+ num_edges = NUM_EDGES (edge_list);
+ inserted = sbitmap_vector_alloc (num_edges, expr_hash_table.n_elems);
+ sbitmap_vector_zero (inserted, num_edges);
- change = 0;
- for (e = bb->pred; e; e = enext)
+ for (e = 0; e < num_edges; e++)
{
- enext = e->pred_next;
- if (e->flags & EDGE_COMPLEX)
- continue;
+ int indx;
+ basic_block bb = INDEX_EDGE_PRED_BB (edge_list, e);
- /* We can't redirect edges from new basic blocks. */
- if (e->src->index >= bypass_last_basic_block)
- continue;
+ for (i = indx = 0; i < set_size; i++, indx += SBITMAP_ELT_BITS)
+ {
+ SBITMAP_ELT_TYPE insert = pre_insert_map[e]->elms[i];
- /* The irreducible loops created by redirecting of edges entering the
- loop from outside would decrease effectiveness of some of the following
- optimizations, so prevent this. */
- if (may_be_loop_header
- && !(e->flags & EDGE_DFS_BACK))
- continue;
+ for (j = indx; insert && j < (int) expr_hash_table.n_elems; j++, insert >>= 1)
+ if ((insert & 1) != 0 && index_map[j]->reaching_reg != NULL_RTX)
+ {
+ struct expr *expr = index_map[j];
+ struct occr *occr;
- for (i = 0; i < reg_use_count; i++)
- {
- struct reg_use *reg_used = ®_use_table[i];
- unsigned int regno = REGNO (reg_used->reg_rtx);
- basic_block dest, old_dest;
- struct expr *set;
- rtx src, new;
+ /* Now look at each deleted occurrence of this expression. */
+ for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
+ {
+ if (! occr->deleted_p)
+ continue;
- if (regno >= max_gcse_regno)
- continue;
+ /* Insert this expression on this edge if it would
+ reach the deleted occurrence in BB. */
+ if (!TEST_BIT (inserted[e], j))
+ {
+ rtx insn;
+ edge eg = INDEX_EDGE (edge_list, e);
- set = find_bypass_set (regno, e->src->index);
+ /* We can't insert anything on an abnormal and
+ critical edge, so we insert the insn at the end of
+ the previous block. There are several alternatives
+ detailed in Morgans book P277 (sec 10.5) for
+ handling this situation. This one is easiest for
+ now. */
- if (! set)
- continue;
+ if (eg->flags & EDGE_ABNORMAL)
+ insert_insn_end_basic_block (index_map[j], bb, 0);
+ else
+ {
+ insn = process_insert_insn (index_map[j]);
+ insert_insn_on_edge (insn, eg);
+ }
- /* Check the data flow is valid after edge insertions. */
- if (e->insns && reg_killed_on_edge (reg_used->reg_rtx, e))
- continue;
+ if (dump_file)
+ {
+ fprintf (dump_file, "PRE/HOIST: edge (%d,%d), ",
+ bb->index,
+ INDEX_EDGE_SUCC_BB (edge_list, e)->index);
+ fprintf (dump_file, "copy expression %d\n",
+ expr->bitmap_index);
+ }
- src = SET_SRC (pc_set (jump));
+ update_ld_motion_stores (expr);
+ SET_BIT (inserted[e], j);
+ did_insert = 1;
+ gcse_create_count++;
+ }
+ }
+ }
+ }
+ }
- if (setcc != NULL)
- src = simplify_replace_rtx (src,
- SET_DEST (PATTERN (setcc)),
- SET_SRC (PATTERN (setcc)));
+ sbitmap_vector_free (inserted);
+ return did_insert;
+}
- new = simplify_replace_rtx (src, reg_used->reg_rtx,
- SET_SRC (set->expr));
+/* Copy the result of EXPR->EXPR generated by INSN to EXPR->REACHING_REG.
+ Given "old_reg <- expr" (INSN), instead of adding after it
+ reaching_reg <- old_reg
+ it's better to do the following:
+ reaching_reg <- expr
+ old_reg <- reaching_reg
+ because this way copy propagation can discover additional PRE
+ opportunities. But if this fails, we try the old way.
+ When "expr" is a store, i.e.
+ given "MEM <- old_reg", instead of adding after it
+ reaching_reg <- old_reg
+ it's better to add it before as follows:
+ reaching_reg <- old_reg
+ MEM <- reaching_reg. */
- /* Jump bypassing may have already placed instructions on
- edges of the CFG. We can't bypass an outgoing edge that
- has instructions associated with it, as these insns won't
- get executed if the incoming edge is redirected. */
+static void
+pre_insert_copy_insn (struct expr *expr, rtx insn)
+{
+ rtx reg = expr->reaching_reg;
+ int regno = REGNO (reg);
+ int indx = expr->bitmap_index;
+ rtx pat = PATTERN (insn);
+ rtx set, first_set, new_insn;
+ rtx old_reg;
+ int i;
- if (new == pc_rtx)
- {
- edest = FALLTHRU_EDGE (bb);
- dest = edest->insns ? NULL : edest->dest;
- }
- else if (GET_CODE (new) == LABEL_REF)
- {
- dest = BLOCK_FOR_INSN (XEXP (new, 0));
- /* Don't bypass edges containing instructions. */
- for (edest = bb->succ; edest; edest = edest->succ_next)
- if (edest->dest == dest && edest->insns)
- {
- dest = NULL;
- break;
- }
- }
- else
- dest = NULL;
+ /* This block matches the logic in hash_scan_insn. */
+ switch (GET_CODE (pat))
+ {
+ case SET:
+ set = pat;
+ break;
- /* Avoid unification of the edge with other edges from original
- branch. We would end up emitting the instruction on "both"
- edges. */
-
- if (dest && setcc && !CC0_P (SET_DEST (PATTERN (setcc))))
+ case PARALLEL:
+ /* Search through the parallel looking for the set whose
+ source was the expression that we're interested in. */
+ first_set = NULL_RTX;
+ set = NULL_RTX;
+ for (i = 0; i < XVECLEN (pat, 0); i++)
+ {
+ rtx x = XVECEXP (pat, 0, i);
+ if (GET_CODE (x) == SET)
{
- edge e2;
- for (e2 = e->src->succ; e2; e2 = e2->succ_next)
- if (e2->dest == dest)
- {
- dest = NULL;
- break;
- }
+ /* If the source was a REG_EQUAL or REG_EQUIV note, we
+ may not find an equivalent expression, but in this
+ case the PARALLEL will have a single set. */
+ if (first_set == NULL_RTX)
+ first_set = x;
+ if (expr_equiv_p (SET_SRC (x), expr->expr))
+ {
+ set = x;
+ break;
+ }
}
+ }
- old_dest = e->dest;
- if (dest != NULL
- && dest != old_dest
- && dest != EXIT_BLOCK_PTR)
- {
- redirect_edge_and_branch_force (e, dest);
-
- /* Copy the register setter to the redirected edge.
- Don't copy CC0 setters, as CC0 is dead after jump. */
- if (setcc)
- {
- rtx pat = PATTERN (setcc);
- if (!CC0_P (SET_DEST (pat)))
- insert_insn_on_edge (copy_insn (pat), e);
- }
+ gcc_assert (first_set);
+ if (set == NULL_RTX)
+ set = first_set;
+ break;
- if (gcse_file != NULL)
- {
- fprintf (gcse_file, "JUMP-BYPASS: Proved reg %d in jump_insn %d equals constant ",
- regno, INSN_UID (jump));
- print_rtl (gcse_file, SET_SRC (set->expr));
- fprintf (gcse_file, "\nBypass edge from %d->%d to %d\n",
- e->src->index, old_dest->index, dest->index);
- }
- change = 1;
- break;
- }
- }
+ default:
+ gcc_unreachable ();
}
- return change;
-}
-/* Find basic blocks with more than one predecessor that only contain a
- single conditional jump. If the result of the comparison is known at
- compile-time from any incoming edge, redirect that edge to the
- appropriate target. Returns nonzero if a change was made.
+ if (REG_P (SET_DEST (set)))
+ {
+ old_reg = SET_DEST (set);
+ /* Check if we can modify the set destination in the original insn. */
+ if (validate_change (insn, &SET_DEST (set), reg, 0))
+ {
+ new_insn = gen_move_insn (old_reg, reg);
+ new_insn = emit_insn_after (new_insn, insn);
- This function is now mis-named, because we also handle indirect jumps. */
-
-static int
-bypass_conditional_jumps (void)
-{
- basic_block bb;
- int changed;
- rtx setcc;
- rtx insn;
- rtx dest;
-
- /* Note we start at block 1. */
- if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
- return 0;
-
- bypass_last_basic_block = last_basic_block;
- mark_dfs_back_edges ();
+ /* Keep register set table up to date. */
+ record_one_set (regno, insn);
+ }
+ else
+ {
+ new_insn = gen_move_insn (reg, old_reg);
+ new_insn = emit_insn_after (new_insn, insn);
- changed = 0;
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb,
- EXIT_BLOCK_PTR, next_bb)
+ /* Keep register set table up to date. */
+ record_one_set (regno, new_insn);
+ }
+ }
+ else /* This is possible only in case of a store to memory. */
{
- /* Check for more than one predecessor. */
- if (bb->pred && bb->pred->pred_next)
- {
- setcc = NULL_RTX;
- for (insn = BB_HEAD (bb);
- insn != NULL && insn != NEXT_INSN (BB_END (bb));
- insn = NEXT_INSN (insn))
- if (GET_CODE (insn) == INSN)
- {
- if (setcc)
- break;
- if (GET_CODE (PATTERN (insn)) != SET)
- break;
+ old_reg = SET_SRC (set);
+ new_insn = gen_move_insn (reg, old_reg);
- dest = SET_DEST (PATTERN (insn));
- if (REG_P (dest) || CC0_P (dest))
- setcc = insn;
- else
- break;
- }
- else if (GET_CODE (insn) == JUMP_INSN)
- {
- if ((any_condjump_p (insn) || computed_jump_p (insn))
- && onlyjump_p (insn))
- changed |= bypass_block (bb, setcc, insn);
- break;
- }
- else if (INSN_P (insn))
- break;
- }
+ /* Check if we can modify the set source in the original insn. */
+ if (validate_change (insn, &SET_SRC (set), reg, 0))
+ new_insn = emit_insn_before (new_insn, insn);
+ else
+ new_insn = emit_insn_after (new_insn, insn);
+
+ /* Keep register set table up to date. */
+ record_one_set (regno, new_insn);
}
- /* If we bypassed any register setting insns, we inserted a
- copy on the redirected edge. These need to be committed. */
- if (changed)
- commit_edge_insertions();
+ gcse_create_count++;
- return changed;
+ if (dump_file)
+ fprintf (dump_file,
+ "PRE: bb %d, insn %d, copy expression %d in insn %d to reg %d\n",
+ BLOCK_NUM (insn), INSN_UID (new_insn), indx,
+ INSN_UID (insn), regno);
}
-\f
-/* Compute PRE+LCM working variables. */
-/* Local properties of expressions. */
-/* Nonzero for expressions that are transparent in the block. */
-static sbitmap *transp;
+/* Copy available expressions that reach the redundant expression
+ to `reaching_reg'. */
-/* Nonzero for expressions that are transparent at the end of the block.
- This is only zero for expressions killed by abnormal critical edge
- created by a calls. */
-static sbitmap *transpout;
+static void
+pre_insert_copies (void)
+{
+ unsigned int i, added_copy;
+ struct expr *expr;
+ struct occr *occr;
+ struct occr *avail;
-/* Nonzero for expressions that are computed (available) in the block. */
-static sbitmap *comp;
+ /* For each available expression in the table, copy the result to
+ `reaching_reg' if the expression reaches a deleted one.
-/* Nonzero for expressions that are locally anticipatable in the block. */
-static sbitmap *antloc;
+ ??? The current algorithm is rather brute force.
+ Need to do some profiling. */
-/* Nonzero for expressions where this block is an optimal computation
- point. */
-static sbitmap *pre_optimal;
+ for (i = 0; i < expr_hash_table.size; i++)
+ for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
+ {
+ /* If the basic block isn't reachable, PPOUT will be TRUE. However,
+ we don't want to insert a copy here because the expression may not
+ really be redundant. So only insert an insn if the expression was
+ deleted. This test also avoids further processing if the
+ expression wasn't deleted anywhere. */
+ if (expr->reaching_reg == NULL)
+ continue;
-/* Nonzero for expressions which are redundant in a particular block. */
-static sbitmap *pre_redundant;
+ /* Set when we add a copy for that expression. */
+ added_copy = 0;
-/* Nonzero for expressions which should be inserted on a specific edge. */
-static sbitmap *pre_insert_map;
+ for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
+ {
+ if (! occr->deleted_p)
+ continue;
-/* Nonzero for expressions which should be deleted in a specific block. */
-static sbitmap *pre_delete_map;
+ for (avail = expr->avail_occr; avail != NULL; avail = avail->next)
+ {
+ rtx insn = avail->insn;
-/* Contains the edge_list returned by pre_edge_lcm. */
-static struct edge_list *edge_list;
+ /* No need to handle this one if handled already. */
+ if (avail->copied_p)
+ continue;
-/* Redundant insns. */
-static sbitmap pre_redundant_insns;
+ /* Don't handle this one if it's a redundant one. */
+ if (TEST_BIT (pre_redundant_insns, INSN_CUID (insn)))
+ continue;
-/* Allocate vars used for PRE analysis. */
+ /* Or if the expression doesn't reach the deleted one. */
+ if (! pre_expr_reaches_here_p (BLOCK_FOR_INSN (avail->insn),
+ expr,
+ BLOCK_FOR_INSN (occr->insn)))
+ continue;
-static void
-alloc_pre_mem (int n_blocks, int n_exprs)
-{
- transp = sbitmap_vector_alloc (n_blocks, n_exprs);
- comp = sbitmap_vector_alloc (n_blocks, n_exprs);
- antloc = sbitmap_vector_alloc (n_blocks, n_exprs);
+ added_copy = 1;
- pre_optimal = NULL;
- pre_redundant = NULL;
- pre_insert_map = NULL;
- pre_delete_map = NULL;
- ae_in = NULL;
- ae_out = NULL;
- ae_kill = sbitmap_vector_alloc (n_blocks, n_exprs);
+ /* Copy the result of avail to reaching_reg. */
+ pre_insert_copy_insn (expr, insn);
+ avail->copied_p = 1;
+ }
+ }
- /* pre_insert and pre_delete are allocated later. */
+ if (added_copy)
+ update_ld_motion_stores (expr);
+ }
}
-/* Free vars used for PRE analysis. */
-
-static void
-free_pre_mem (void)
+/* Emit move from SRC to DEST noting the equivalence with expression computed
+ in INSN. */
+static rtx
+gcse_emit_move_after (rtx src, rtx dest, rtx insn)
{
- sbitmap_vector_free (transp);
- sbitmap_vector_free (comp);
-
- /* ANTLOC and AE_KILL are freed just after pre_lcm finishes. */
+ rtx new;
+ rtx set = single_set (insn), set2;
+ rtx note;
+ rtx eqv;
- if (pre_optimal)
- sbitmap_vector_free (pre_optimal);
- if (pre_redundant)
- sbitmap_vector_free (pre_redundant);
- if (pre_insert_map)
- sbitmap_vector_free (pre_insert_map);
- if (pre_delete_map)
- sbitmap_vector_free (pre_delete_map);
- if (ae_in)
- sbitmap_vector_free (ae_in);
- if (ae_out)
- sbitmap_vector_free (ae_out);
+ /* This should never fail since we're creating a reg->reg copy
+ we've verified to be valid. */
- transp = comp = NULL;
- pre_optimal = pre_redundant = pre_insert_map = pre_delete_map = NULL;
- ae_in = ae_out = NULL;
-}
+ new = emit_insn_after (gen_move_insn (dest, src), insn);
-/* Top level routine to do the dataflow analysis needed by PRE. */
+ /* Note the equivalence for local CSE pass. */
+ set2 = single_set (new);
+ if (!set2 || !rtx_equal_p (SET_DEST (set2), dest))
+ return new;
+ if ((note = find_reg_equal_equiv_note (insn)))
+ eqv = XEXP (note, 0);
+ else
+ eqv = SET_SRC (set);
-static void
-compute_pre_data (void)
-{
- sbitmap trapping_expr;
- basic_block bb;
- unsigned int ui;
+ set_unique_reg_note (new, REG_EQUAL, copy_insn_1 (eqv));
- compute_local_properties (transp, comp, antloc, &expr_hash_table);
- sbitmap_vector_zero (ae_kill, last_basic_block);
+ return new;
+}
- /* Collect expressions which might trap. */
- trapping_expr = sbitmap_alloc (expr_hash_table.n_elems);
- sbitmap_zero (trapping_expr);
- for (ui = 0; ui < expr_hash_table.size; ui++)
- {
- struct expr *e;
- for (e = expr_hash_table.table[ui]; e != NULL; e = e->next_same_hash)
- if (may_trap_p (e->expr))
- SET_BIT (trapping_expr, e->bitmap_index);
- }
+/* Delete redundant computations.
+ Deletion is done by changing the insn to copy the `reaching_reg' of
+ the expression into the result of the SET. It is left to later passes
+ (cprop, cse2, flow, combine, regmove) to propagate the copy or eliminate it.
- /* Compute ae_kill for each basic block using:
+ Returns nonzero if a change is made. */
- ~(TRANSP | COMP)
+static int
+pre_delete (void)
+{
+ unsigned int i;
+ int changed;
+ struct expr *expr;
+ struct occr *occr;
- This is significantly faster than compute_ae_kill. */
+ changed = 0;
+ for (i = 0; i < expr_hash_table.size; i++)
+ for (expr = expr_hash_table.table[i];
+ expr != NULL;
+ expr = expr->next_same_hash)
+ {
+ int indx = expr->bitmap_index;
- FOR_EACH_BB (bb)
- {
- edge e;
+ /* We only need to search antic_occr since we require
+ ANTLOC != 0. */
- /* If the current block is the destination of an abnormal edge, we
- kill all trapping expressions because we won't be able to properly
- place the instruction on the edge. So make them neither
- anticipatable nor transparent. This is fairly conservative. */
- for (e = bb->pred; e ; e = e->pred_next)
- if (e->flags & EDGE_ABNORMAL)
+ for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
{
- sbitmap_difference (antloc[bb->index], antloc[bb->index], trapping_expr);
- sbitmap_difference (transp[bb->index], transp[bb->index], trapping_expr);
- break;
- }
+ rtx insn = occr->insn;
+ rtx set;
+ basic_block bb = BLOCK_FOR_INSN (insn);
- sbitmap_a_or_b (ae_kill[bb->index], transp[bb->index], comp[bb->index]);
- sbitmap_not (ae_kill[bb->index], ae_kill[bb->index]);
- }
+ /* We only delete insns that have a single_set. */
+ if (TEST_BIT (pre_delete_map[bb->index], indx)
+ && (set = single_set (insn)) != 0
+ && dbg_cnt (pre_insn))
+ {
+ /* Create a pseudo-reg to store the result of reaching
+ expressions into. Get the mode for the new pseudo from
+ the mode of the original destination pseudo. */
+ if (expr->reaching_reg == NULL)
+ expr->reaching_reg
+ = gen_reg_rtx (GET_MODE (SET_DEST (set)));
- edge_list = pre_edge_lcm (gcse_file, expr_hash_table.n_elems, transp, comp, antloc,
- ae_kill, &pre_insert_map, &pre_delete_map);
- sbitmap_vector_free (antloc);
- antloc = NULL;
- sbitmap_vector_free (ae_kill);
- ae_kill = NULL;
- sbitmap_free (trapping_expr);
+ gcse_emit_move_after (expr->reaching_reg, SET_DEST (set), insn);
+ delete_insn (insn);
+ occr->deleted_p = 1;
+ SET_BIT (pre_redundant_insns, INSN_CUID (insn));
+ changed = 1;
+ gcse_subst_count++;
+
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "PRE: redundant insn %d (expression %d) in ",
+ INSN_UID (insn), indx);
+ fprintf (dump_file, "bb %d, reaching reg is %d\n",
+ bb->index, REGNO (expr->reaching_reg));
+ }
+ }
+ }
+ }
+
+ return changed;
}
-\f
-/* PRE utilities */
-/* Return nonzero if an occurrence of expression EXPR in OCCR_BB would reach
- block BB.
+/* Perform GCSE optimizations using PRE.
+ This is called by one_pre_gcse_pass after all the dataflow analysis
+ has been done.
- VISITED is a pointer to a working buffer for tracking which BB's have
- been visited. It is NULL for the top-level call.
+ This is based on the original Morel-Renvoise paper Fred Chow's thesis, and
+ lazy code motion from Knoop, Ruthing and Steffen as described in Advanced
+ Compiler Design and Implementation.
- We treat reaching expressions that go through blocks containing the same
- reaching expression as "not reaching". E.g. if EXPR is generated in blocks
- 2 and 3, INSN is in block 4, and 2->3->4, we treat the expression in block
- 2 as not reaching. The intent is to improve the probability of finding
- only one reaching expression and to reduce register lifetimes by picking
- the closest such expression. */
+ ??? A new pseudo reg is created to hold the reaching expression. The nice
+ thing about the classical approach is that it would try to use an existing
+ reg. If the register can't be adequately optimized [i.e. we introduce
+ reload problems], one could add a pass here to propagate the new register
+ through the block.
+
+ ??? We don't handle single sets in PARALLELs because we're [currently] not
+ able to copy the rest of the parallel when we insert copies to create full
+ redundancies from partial redundancies. However, there's no reason why we
+ can't handle PARALLELs in the cases where there are no partial
+ redundancies. */
static int
-pre_expr_reaches_here_p_work (basic_block occr_bb, struct expr *expr, basic_block bb, char *visited)
+pre_gcse (void)
{
- edge pred;
+ unsigned int i;
+ int did_insert, changed;
+ struct expr **index_map;
+ struct expr *expr;
- for (pred = bb->pred; pred != NULL; pred = pred->pred_next)
- {
- basic_block pred_bb = pred->src;
+ /* Compute a mapping from expression number (`bitmap_index') to
+ hash table entry. */
- if (pred->src == ENTRY_BLOCK_PTR
- /* Has predecessor has already been visited? */
- || visited[pred_bb->index])
- ;/* Nothing to do. */
+ index_map = XCNEWVEC (struct expr *, expr_hash_table.n_elems);
+ for (i = 0; i < expr_hash_table.size; i++)
+ for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
+ index_map[expr->bitmap_index] = expr;
- /* Does this predecessor generate this expression? */
- else if (TEST_BIT (comp[pred_bb->index], expr->bitmap_index))
- {
- /* Is this the occurrence we're looking for?
- Note that there's only one generating occurrence per block
- so we just need to check the block number. */
- if (occr_bb == pred_bb)
- return 1;
+ /* Reset bitmap used to track which insns are redundant. */
+ pre_redundant_insns = sbitmap_alloc (max_cuid);
+ sbitmap_zero (pre_redundant_insns);
- visited[pred_bb->index] = 1;
- }
- /* Ignore this predecessor if it kills the expression. */
- else if (! TEST_BIT (transp[pred_bb->index], expr->bitmap_index))
- visited[pred_bb->index] = 1;
+ /* Delete the redundant insns first so that
+ - we know what register to use for the new insns and for the other
+ ones with reaching expressions
+ - we know which insns are redundant when we go to create copies */
- /* Neither gen nor kill. */
- else
- {
- visited[pred_bb->index] = 1;
- if (pre_expr_reaches_here_p_work (occr_bb, expr, pred_bb, visited))
- return 1;
- }
+ changed = pre_delete ();
+ did_insert = pre_edge_insert (edge_list, index_map);
+
+ /* In other places with reaching expressions, copy the expression to the
+ specially allocated pseudo-reg that reaches the redundant expr. */
+ pre_insert_copies ();
+ if (did_insert)
+ {
+ commit_edge_insertions ();
+ changed = 1;
}
- /* All paths have been checked. */
- return 0;
+ free (index_map);
+ sbitmap_free (pre_redundant_insns);
+ return changed;
}
-/* The wrapper for pre_expr_reaches_here_work that ensures that any
- memory allocated for that function is returned. */
+/* Top level routine to perform one PRE GCSE pass.
+
+ Return nonzero if a change was made. */
static int
-pre_expr_reaches_here_p (basic_block occr_bb, struct expr *expr, basic_block bb)
+one_pre_gcse_pass (int pass)
{
- int rval;
- char *visited = xcalloc (last_basic_block, 1);
+ int changed = 0;
- rval = pre_expr_reaches_here_p_work (occr_bb, expr, bb, visited);
+ gcse_subst_count = 0;
+ gcse_create_count = 0;
- free (visited);
- return rval;
+ alloc_hash_table (max_cuid, &expr_hash_table, 0);
+ add_noreturn_fake_exit_edges ();
+ if (flag_gcse_lm)
+ compute_ld_motion_mems ();
+
+ compute_hash_table (&expr_hash_table);
+ trim_ld_motion_mems ();
+ if (dump_file)
+ dump_hash_table (dump_file, "Expression", &expr_hash_table);
+
+ if (expr_hash_table.n_elems > 0)
+ {
+ alloc_pre_mem (last_basic_block, expr_hash_table.n_elems);
+ compute_pre_data ();
+ changed |= pre_gcse ();
+ free_edge_list (edge_list);
+ free_pre_mem ();
+ }
+
+ free_ldst_mems ();
+ remove_fake_exit_edges ();
+ free_hash_table (&expr_hash_table);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "\nPRE GCSE of %s, pass %d: %d bytes needed, ",
+ current_function_name (), pass, bytes_used);
+ fprintf (dump_file, "%d substs, %d insns created\n",
+ gcse_subst_count, gcse_create_count);
+ }
+
+ return changed;
}
\f
+/* If X contains any LABEL_REF's, add REG_LABEL_OPERAND notes for them
+ to INSN. If such notes are added to an insn which references a
+ CODE_LABEL, the LABEL_NUSES count is incremented. We have to add
+ that note, because the following loop optimization pass requires
+ them. */
-/* Given an expr, generate RTL which we can insert at the end of a BB,
- or on an edge. Set the block number of any insns generated to
- the value of BB. */
+/* ??? If there was a jump optimization pass after gcse and before loop,
+ then we would not need to do this here, because jump would add the
+ necessary REG_LABEL_OPERAND and REG_LABEL_TARGET notes. */
-static rtx
-process_insert_insn (struct expr *expr)
+static void
+add_label_notes (rtx x, rtx insn)
{
- rtx reg = expr->reaching_reg;
- rtx exp = copy_rtx (expr->expr);
- rtx pat;
-
- start_sequence ();
+ enum rtx_code code = GET_CODE (x);
+ int i, j;
+ const char *fmt;
- /* If the expression is something that's an operand, like a constant,
- just copy it to a register. */
- if (general_operand (exp, GET_MODE (reg)))
- emit_move_insn (reg, exp);
+ if (code == LABEL_REF && !LABEL_REF_NONLOCAL_P (x))
+ {
+ /* This code used to ignore labels that referred to dispatch tables to
+ avoid flow generating (slightly) worse code.
- /* Otherwise, make a new insn to compute this expression and make sure the
- insn will be recognized (this also adds any needed CLOBBERs). Copy the
- expression to make sure we don't have any sharing issues. */
- else if (insn_invalid_p (emit_insn (gen_rtx_SET (VOIDmode, reg, exp))))
- abort ();
+ We no longer ignore such label references (see LABEL_REF handling in
+ mark_jump_label for additional information). */
- pat = get_insns ();
- end_sequence ();
+ if (reg_mentioned_p (XEXP (x, 0), insn))
+ {
+ /* There's no reason for current users to emit jump-insns
+ with such a LABEL_REF, so we don't have to handle
+ REG_LABEL_TARGET notes. */
+ gcc_assert (!JUMP_P (insn));
+ REG_NOTES (insn)
+ = gen_rtx_INSN_LIST (REG_LABEL_OPERAND, XEXP (x, 0),
+ REG_NOTES (insn));
+ if (LABEL_P (XEXP (x, 0)))
+ LABEL_NUSES (XEXP (x, 0))++;
+ }
+ return;
+ }
- return pat;
+ for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ add_label_notes (XEXP (x, i), insn);
+ else if (fmt[i] == 'E')
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ add_label_notes (XVECEXP (x, i, j), insn);
+ }
}
-/* Add EXPR to the end of basic block BB.
+/* Compute transparent outgoing information for each block.
- This is used by both the PRE and code hoisting.
+ An expression is transparent to an edge unless it is killed by
+ the edge itself. This can only happen with abnormal control flow,
+ when the edge is traversed through a call. This happens with
+ non-local labels and exceptions.
- For PRE, we want to verify that the expr is either transparent
- or locally anticipatable in the target block. This check makes
- no sense for code hoisting. */
+ This would not be necessary if we split the edge. While this is
+ normally impossible for abnormal critical edges, with some effort
+ it should be possible with exception handling, since we still have
+ control over which handler should be invoked. But due to increased
+ EH table sizes, this may not be worthwhile. */
static void
-insert_insn_end_bb (struct expr *expr, basic_block bb, int pre)
+compute_transpout (void)
{
- rtx insn = BB_END (bb);
- rtx new_insn;
- rtx reg = expr->reaching_reg;
- int regno = REGNO (reg);
- rtx pat, pat_end;
-
- pat = process_insert_insn (expr);
- if (pat == NULL_RTX || ! INSN_P (pat))
- abort ();
-
- pat_end = pat;
- while (NEXT_INSN (pat_end) != NULL_RTX)
- pat_end = NEXT_INSN (pat_end);
+ basic_block bb;
+ unsigned int i;
+ struct expr *expr;
- /* If the last insn is a jump, insert EXPR in front [taking care to
- handle cc0, etc. properly]. Similarly we need to care trapping
- instructions in presence of non-call exceptions. */
+ sbitmap_vector_ones (transpout, last_basic_block);
- if (GET_CODE (insn) == JUMP_INSN
- || (GET_CODE (insn) == INSN
- && (bb->succ->succ_next || (bb->succ->flags & EDGE_ABNORMAL))))
+ FOR_EACH_BB (bb)
{
-#ifdef HAVE_cc0
- rtx note;
-#endif
- /* It should always be the case that we can put these instructions
- anywhere in the basic block with performing PRE optimizations.
- Check this. */
- if (GET_CODE (insn) == INSN && pre
- && !TEST_BIT (antloc[bb->index], expr->bitmap_index)
- && !TEST_BIT (transp[bb->index], expr->bitmap_index))
- abort ();
-
- /* If this is a jump table, then we can't insert stuff here. Since
- we know the previous real insn must be the tablejump, we insert
- the new instruction just before the tablejump. */
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- insn = prev_real_insn (insn);
+ /* Note that flow inserted a nop a the end of basic blocks that
+ end in call instructions for reasons other than abnormal
+ control flow. */
+ if (! CALL_P (BB_END (bb)))
+ continue;
-#ifdef HAVE_cc0
- /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
- if cc0 isn't set. */
- note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
- if (note)
- insn = XEXP (note, 0);
- else
- {
- rtx maybe_cc0_setter = prev_nonnote_insn (insn);
- if (maybe_cc0_setter
- && INSN_P (maybe_cc0_setter)
- && sets_cc0_p (PATTERN (maybe_cc0_setter)))
- insn = maybe_cc0_setter;
- }
-#endif
- /* FIXME: What if something in cc0/jump uses value set in new insn? */
- new_insn = emit_insn_before (pat, insn);
+ for (i = 0; i < expr_hash_table.size; i++)
+ for (expr = expr_hash_table.table[i]; expr ; expr = expr->next_same_hash)
+ if (MEM_P (expr->expr))
+ {
+ if (GET_CODE (XEXP (expr->expr, 0)) == SYMBOL_REF
+ && CONSTANT_POOL_ADDRESS_P (XEXP (expr->expr, 0)))
+ continue;
+
+ /* ??? Optimally, we would use interprocedural alias
+ analysis to determine if this mem is actually killed
+ by this call. */
+ RESET_BIT (transpout[bb->index], expr->bitmap_index);
+ }
}
+}
- /* Likewise if the last insn is a call, as will happen in the presence
- of exception handling. */
- else if (GET_CODE (insn) == CALL_INSN
- && (bb->succ->succ_next || (bb->succ->flags & EDGE_ABNORMAL)))
- {
- /* Keeping in mind SMALL_REGISTER_CLASSES and parameters in registers,
- we search backward and place the instructions before the first
- parameter is loaded. Do this for everyone for consistency and a
- presumption that we'll get better code elsewhere as well.
+/* Code Hoisting variables and subroutines. */
- It should always be the case that we can put these instructions
- anywhere in the basic block with performing PRE optimizations.
- Check this. */
+/* Very busy expressions. */
+static sbitmap *hoist_vbein;
+static sbitmap *hoist_vbeout;
- if (pre
- && !TEST_BIT (antloc[bb->index], expr->bitmap_index)
- && !TEST_BIT (transp[bb->index], expr->bitmap_index))
- abort ();
+/* Hoistable expressions. */
+static sbitmap *hoist_exprs;
- /* Since different machines initialize their parameter registers
- in different orders, assume nothing. Collect the set of all
- parameter registers. */
- insn = find_first_parameter_load (insn, BB_HEAD (bb));
+/* ??? We could compute post dominators and run this algorithm in
+ reverse to perform tail merging, doing so would probably be
+ more effective than the tail merging code in jump.c.
- /* If we found all the parameter loads, then we want to insert
- before the first parameter load.
+ It's unclear if tail merging could be run in parallel with
+ code hoisting. It would be nice. */
- If we did not find all the parameter loads, then we might have
- stopped on the head of the block, which could be a CODE_LABEL.
- If we inserted before the CODE_LABEL, then we would be putting
- the insn in the wrong basic block. In that case, put the insn
- after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */
- while (GET_CODE (insn) == CODE_LABEL
- || NOTE_INSN_BASIC_BLOCK_P (insn))
- insn = NEXT_INSN (insn);
+/* Allocate vars used for code hoisting analysis. */
- new_insn = emit_insn_before (pat, insn);
- }
- else
- new_insn = emit_insn_after (pat, insn);
+static void
+alloc_code_hoist_mem (int n_blocks, int n_exprs)
+{
+ antloc = sbitmap_vector_alloc (n_blocks, n_exprs);
+ transp = sbitmap_vector_alloc (n_blocks, n_exprs);
+ comp = sbitmap_vector_alloc (n_blocks, n_exprs);
- while (1)
- {
- if (INSN_P (pat))
- {
- add_label_notes (PATTERN (pat), new_insn);
- note_stores (PATTERN (pat), record_set_info, pat);
- }
- if (pat == pat_end)
- break;
- pat = NEXT_INSN (pat);
- }
+ hoist_vbein = sbitmap_vector_alloc (n_blocks, n_exprs);
+ hoist_vbeout = sbitmap_vector_alloc (n_blocks, n_exprs);
+ hoist_exprs = sbitmap_vector_alloc (n_blocks, n_exprs);
+ transpout = sbitmap_vector_alloc (n_blocks, n_exprs);
+}
- gcse_create_count++;
+/* Free vars used for code hoisting analysis. */
- if (gcse_file)
- {
- fprintf (gcse_file, "PRE/HOIST: end of bb %d, insn %d, ",
- bb->index, INSN_UID (new_insn));
- fprintf (gcse_file, "copying expression %d to reg %d\n",
- expr->bitmap_index, regno);
- }
+static void
+free_code_hoist_mem (void)
+{
+ sbitmap_vector_free (antloc);
+ sbitmap_vector_free (transp);
+ sbitmap_vector_free (comp);
+
+ sbitmap_vector_free (hoist_vbein);
+ sbitmap_vector_free (hoist_vbeout);
+ sbitmap_vector_free (hoist_exprs);
+ sbitmap_vector_free (transpout);
+
+ free_dominance_info (CDI_DOMINATORS);
}
-/* Insert partially redundant expressions on edges in the CFG to make
- the expressions fully redundant. */
+/* Compute the very busy expressions at entry/exit from each block.
-static int
-pre_edge_insert (struct edge_list *edge_list, struct expr **index_map)
+ An expression is very busy if all paths from a given point
+ compute the expression. */
+
+static void
+compute_code_hoist_vbeinout (void)
{
- int e, i, j, num_edges, set_size, did_insert = 0;
- sbitmap *inserted;
+ int changed, passes;
+ basic_block bb;
- /* Where PRE_INSERT_MAP is nonzero, we add the expression on that edge
- if it reaches any of the deleted expressions. */
+ sbitmap_vector_zero (hoist_vbeout, last_basic_block);
+ sbitmap_vector_zero (hoist_vbein, last_basic_block);
- set_size = pre_insert_map[0]->size;
- num_edges = NUM_EDGES (edge_list);
- inserted = sbitmap_vector_alloc (num_edges, expr_hash_table.n_elems);
- sbitmap_vector_zero (inserted, num_edges);
+ passes = 0;
+ changed = 1;
- for (e = 0; e < num_edges; e++)
+ while (changed)
{
- int indx;
- basic_block bb = INDEX_EDGE_PRED_BB (edge_list, e);
+ changed = 0;
- for (i = indx = 0; i < set_size; i++, indx += SBITMAP_ELT_BITS)
+ /* We scan the blocks in the reverse order to speed up
+ the convergence. */
+ FOR_EACH_BB_REVERSE (bb)
{
- SBITMAP_ELT_TYPE insert = pre_insert_map[e]->elms[i];
+ changed |= sbitmap_a_or_b_and_c_cg (hoist_vbein[bb->index], antloc[bb->index],
+ hoist_vbeout[bb->index], transp[bb->index]);
+ if (bb->next_bb != EXIT_BLOCK_PTR)
+ sbitmap_intersection_of_succs (hoist_vbeout[bb->index], hoist_vbein, bb->index);
+ }
- for (j = indx; insert && j < (int) expr_hash_table.n_elems; j++, insert >>= 1)
- if ((insert & 1) != 0 && index_map[j]->reaching_reg != NULL_RTX)
- {
- struct expr *expr = index_map[j];
- struct occr *occr;
+ passes++;
+ }
- /* Now look at each deleted occurrence of this expression. */
- for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
- {
- if (! occr->deleted_p)
- continue;
+ if (dump_file)
+ fprintf (dump_file, "hoisting vbeinout computation: %d passes\n", passes);
+}
- /* Insert this expression on this edge if if it would
- reach the deleted occurrence in BB. */
- if (!TEST_BIT (inserted[e], j))
- {
- rtx insn;
- edge eg = INDEX_EDGE (edge_list, e);
+/* Top level routine to do the dataflow analysis needed by code hoisting. */
- /* We can't insert anything on an abnormal and
- critical edge, so we insert the insn at the end of
- the previous block. There are several alternatives
- detailed in Morgans book P277 (sec 10.5) for
- handling this situation. This one is easiest for
- now. */
+static void
+compute_code_hoist_data (void)
+{
+ compute_local_properties (transp, comp, antloc, &expr_hash_table);
+ compute_transpout ();
+ compute_code_hoist_vbeinout ();
+ calculate_dominance_info (CDI_DOMINATORS);
+ if (dump_file)
+ fprintf (dump_file, "\n");
+}
- if ((eg->flags & EDGE_ABNORMAL) == EDGE_ABNORMAL)
- insert_insn_end_bb (index_map[j], bb, 0);
- else
- {
- insn = process_insert_insn (index_map[j]);
- insert_insn_on_edge (insn, eg);
- }
+/* Determine if the expression identified by EXPR_INDEX would
+ reach BB unimpared if it was placed at the end of EXPR_BB.
- if (gcse_file)
- {
- fprintf (gcse_file, "PRE/HOIST: edge (%d,%d), ",
- bb->index,
- INDEX_EDGE_SUCC_BB (edge_list, e)->index);
- fprintf (gcse_file, "copy expression %d\n",
- expr->bitmap_index);
- }
+ It's unclear exactly what Muchnick meant by "unimpared". It seems
+ to me that the expression must either be computed or transparent in
+ *every* block in the path(s) from EXPR_BB to BB. Any other definition
+ would allow the expression to be hoisted out of loops, even if
+ the expression wasn't a loop invariant.
- update_ld_motion_stores (expr);
- SET_BIT (inserted[e], j);
- did_insert = 1;
- gcse_create_count++;
- }
- }
- }
- }
- }
+ Contrast this to reachability for PRE where an expression is
+ considered reachable if *any* path reaches instead of *all*
+ paths. */
- sbitmap_vector_free (inserted);
- return did_insert;
-}
+static int
+hoist_expr_reaches_here_p (basic_block expr_bb, int expr_index, basic_block bb, char *visited)
+{
+ edge pred;
+ edge_iterator ei;
+ int visited_allocated_locally = 0;
-/* Copy the result of EXPR->EXPR generated by INSN to EXPR->REACHING_REG.
- Given "old_reg <- expr" (INSN), instead of adding after it
- reaching_reg <- old_reg
- it's better to do the following:
- reaching_reg <- expr
- old_reg <- reaching_reg
- because this way copy propagation can discover additional PRE
- opportunities. But if this fails, we try the old way.
- When "expr" is a store, i.e.
- given "MEM <- old_reg", instead of adding after it
- reaching_reg <- old_reg
- it's better to add it before as follows:
- reaching_reg <- old_reg
- MEM <- reaching_reg. */
-static void
-pre_insert_copy_insn (struct expr *expr, rtx insn)
-{
- rtx reg = expr->reaching_reg;
- int regno = REGNO (reg);
- int indx = expr->bitmap_index;
- rtx pat = PATTERN (insn);
- rtx set, new_insn;
- rtx old_reg;
- int i;
+ if (visited == NULL)
+ {
+ visited_allocated_locally = 1;
+ visited = XCNEWVEC (char, last_basic_block);
+ }
- /* This block matches the logic in hash_scan_insn. */
- if (GET_CODE (pat) == SET)
- set = pat;
- else if (GET_CODE (pat) == PARALLEL)
- {
- /* Search through the parallel looking for the set whose
- source was the expression that we're interested in. */
- set = NULL_RTX;
- for (i = 0; i < XVECLEN (pat, 0); i++)
- {
- rtx x = XVECEXP (pat, 0, i);
- if (GET_CODE (x) == SET
- && expr_equiv_p (SET_SRC (x), expr->expr))
- {
- set = x;
- break;
- }
- }
- }
- else
- abort ();
-
- if (GET_CODE (SET_DEST (set)) == REG)
- {
- old_reg = SET_DEST (set);
- /* Check if we can modify the set destination in the original insn. */
- if (validate_change (insn, &SET_DEST (set), reg, 0))
- {
- new_insn = gen_move_insn (old_reg, reg);
- new_insn = emit_insn_after (new_insn, insn);
-
- /* Keep register set table up to date. */
- replace_one_set (REGNO (old_reg), insn, new_insn);
- record_one_set (regno, insn);
- }
- else
- {
- new_insn = gen_move_insn (reg, old_reg);
- new_insn = emit_insn_after (new_insn, insn);
-
- /* Keep register set table up to date. */
- record_one_set (regno, new_insn);
- }
- }
- else /* This is possible only in case of a store to memory. */
- {
- old_reg = SET_SRC (set);
- new_insn = gen_move_insn (reg, old_reg);
-
- /* Check if we can modify the set source in the original insn. */
- if (validate_change (insn, &SET_SRC (set), reg, 0))
- new_insn = emit_insn_before (new_insn, insn);
- else
- new_insn = emit_insn_after (new_insn, insn);
-
- /* Keep register set table up to date. */
- record_one_set (regno, new_insn);
- }
-
- gcse_create_count++;
-
- if (gcse_file)
- fprintf (gcse_file,
- "PRE: bb %d, insn %d, copy expression %d in insn %d to reg %d\n",
- BLOCK_NUM (insn), INSN_UID (new_insn), indx,
- INSN_UID (insn), regno);
-}
-
-/* Copy available expressions that reach the redundant expression
- to `reaching_reg'. */
-
-static void
-pre_insert_copies (void)
-{
- unsigned int i, added_copy;
- struct expr *expr;
- struct occr *occr;
- struct occr *avail;
-
- /* For each available expression in the table, copy the result to
- `reaching_reg' if the expression reaches a deleted one.
-
- ??? The current algorithm is rather brute force.
- Need to do some profiling. */
-
- for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
- {
- /* If the basic block isn't reachable, PPOUT will be TRUE. However,
- we don't want to insert a copy here because the expression may not
- really be redundant. So only insert an insn if the expression was
- deleted. This test also avoids further processing if the
- expression wasn't deleted anywhere. */
- if (expr->reaching_reg == NULL)
- continue;
-
- /* Set when we add a copy for that expression. */
- added_copy = 0;
-
- for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
- {
- if (! occr->deleted_p)
- continue;
-
- for (avail = expr->avail_occr; avail != NULL; avail = avail->next)
- {
- rtx insn = avail->insn;
-
- /* No need to handle this one if handled already. */
- if (avail->copied_p)
- continue;
-
- /* Don't handle this one if it's a redundant one. */
- if (TEST_BIT (pre_redundant_insns, INSN_CUID (insn)))
- continue;
-
- /* Or if the expression doesn't reach the deleted one. */
- if (! pre_expr_reaches_here_p (BLOCK_FOR_INSN (avail->insn),
- expr,
- BLOCK_FOR_INSN (occr->insn)))
- continue;
-
- added_copy = 1;
-
- /* Copy the result of avail to reaching_reg. */
- pre_insert_copy_insn (expr, insn);
- avail->copied_p = 1;
- }
- }
-
- if (added_copy)
- update_ld_motion_stores (expr);
- }
-}
-
-/* Emit move from SRC to DEST noting the equivalence with expression computed
- in INSN. */
-static rtx
-gcse_emit_move_after (rtx src, rtx dest, rtx insn)
-{
- rtx new;
- rtx set = single_set (insn), set2;
- rtx note;
- rtx eqv;
-
- /* This should never fail since we're creating a reg->reg copy
- we've verified to be valid. */
-
- new = emit_insn_after (gen_move_insn (dest, src), insn);
-
- /* Note the equivalence for local CSE pass. */
- set2 = single_set (new);
- if (!set2 || !rtx_equal_p (SET_DEST (set2), dest))
- return new;
- if ((note = find_reg_equal_equiv_note (insn)))
- eqv = XEXP (note, 0);
- else
- eqv = SET_SRC (set);
-
- set_unique_reg_note (new, REG_EQUAL, copy_insn_1 (eqv));
-
- return new;
-}
-
-/* Delete redundant computations.
- Deletion is done by changing the insn to copy the `reaching_reg' of
- the expression into the result of the SET. It is left to later passes
- (cprop, cse2, flow, combine, regmove) to propagate the copy or eliminate it.
-
- Returns nonzero if a change is made. */
-
-static int
-pre_delete (void)
-{
- unsigned int i;
- int changed;
- struct expr *expr;
- struct occr *occr;
-
- changed = 0;
- for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i];
- expr != NULL;
- expr = expr->next_same_hash)
- {
- int indx = expr->bitmap_index;
-
- /* We only need to search antic_occr since we require
- ANTLOC != 0. */
-
- for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
- {
- rtx insn = occr->insn;
- rtx set;
- basic_block bb = BLOCK_FOR_INSN (insn);
-
- /* We only delete insns that have a single_set. */
- if (TEST_BIT (pre_delete_map[bb->index], indx)
- && (set = single_set (insn)) != 0)
- {
- /* Create a pseudo-reg to store the result of reaching
- expressions into. Get the mode for the new pseudo from
- the mode of the original destination pseudo. */
- if (expr->reaching_reg == NULL)
- expr->reaching_reg
- = gen_reg_rtx (GET_MODE (SET_DEST (set)));
-
- gcse_emit_move_after (expr->reaching_reg, SET_DEST (set), insn);
- delete_insn (insn);
- occr->deleted_p = 1;
- SET_BIT (pre_redundant_insns, INSN_CUID (insn));
- changed = 1;
- gcse_subst_count++;
-
- if (gcse_file)
- {
- fprintf (gcse_file,
- "PRE: redundant insn %d (expression %d) in ",
- INSN_UID (insn), indx);
- fprintf (gcse_file, "bb %d, reaching reg is %d\n",
- bb->index, REGNO (expr->reaching_reg));
- }
- }
- }
- }
-
- return changed;
-}
-
-/* Perform GCSE optimizations using PRE.
- This is called by one_pre_gcse_pass after all the dataflow analysis
- has been done.
-
- This is based on the original Morel-Renvoise paper Fred Chow's thesis, and
- lazy code motion from Knoop, Ruthing and Steffen as described in Advanced
- Compiler Design and Implementation.
-
- ??? A new pseudo reg is created to hold the reaching expression. The nice
- thing about the classical approach is that it would try to use an existing
- reg. If the register can't be adequately optimized [i.e. we introduce
- reload problems], one could add a pass here to propagate the new register
- through the block.
-
- ??? We don't handle single sets in PARALLELs because we're [currently] not
- able to copy the rest of the parallel when we insert copies to create full
- redundancies from partial redundancies. However, there's no reason why we
- can't handle PARALLELs in the cases where there are no partial
- redundancies. */
-
-static int
-pre_gcse (void)
-{
- unsigned int i;
- int did_insert, changed;
- struct expr **index_map;
- struct expr *expr;
-
- /* Compute a mapping from expression number (`bitmap_index') to
- hash table entry. */
-
- index_map = xcalloc (expr_hash_table.n_elems, sizeof (struct expr *));
- for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
- index_map[expr->bitmap_index] = expr;
-
- /* Reset bitmap used to track which insns are redundant. */
- pre_redundant_insns = sbitmap_alloc (max_cuid);
- sbitmap_zero (pre_redundant_insns);
-
- /* Delete the redundant insns first so that
- - we know what register to use for the new insns and for the other
- ones with reaching expressions
- - we know which insns are redundant when we go to create copies */
-
- changed = pre_delete ();
-
- did_insert = pre_edge_insert (edge_list, index_map);
-
- /* In other places with reaching expressions, copy the expression to the
- specially allocated pseudo-reg that reaches the redundant expr. */
- pre_insert_copies ();
- if (did_insert)
- {
- commit_edge_insertions ();
- changed = 1;
- }
-
- free (index_map);
- sbitmap_free (pre_redundant_insns);
- return changed;
-}
-
-/* Top level routine to perform one PRE GCSE pass.
-
- Return nonzero if a change was made. */
-
-static int
-one_pre_gcse_pass (int pass)
-{
- int changed = 0;
-
- gcse_subst_count = 0;
- gcse_create_count = 0;
-
- alloc_hash_table (max_cuid, &expr_hash_table, 0);
- add_noreturn_fake_exit_edges ();
- if (flag_gcse_lm)
- compute_ld_motion_mems ();
-
- compute_hash_table (&expr_hash_table);
- trim_ld_motion_mems ();
- if (gcse_file)
- dump_hash_table (gcse_file, "Expression", &expr_hash_table);
-
- if (expr_hash_table.n_elems > 0)
- {
- alloc_pre_mem (last_basic_block, expr_hash_table.n_elems);
- compute_pre_data ();
- changed |= pre_gcse ();
- free_edge_list (edge_list);
- free_pre_mem ();
- }
-
- free_ldst_mems ();
- remove_fake_edges ();
- free_hash_table (&expr_hash_table);
-
- if (gcse_file)
- {
- fprintf (gcse_file, "\nPRE GCSE of %s, pass %d: %d bytes needed, ",
- current_function_name (), pass, bytes_used);
- fprintf (gcse_file, "%d substs, %d insns created\n",
- gcse_subst_count, gcse_create_count);
- }
-
- return changed;
-}
-\f
-/* If X contains any LABEL_REF's, add REG_LABEL notes for them to INSN.
- If notes are added to an insn which references a CODE_LABEL, the
- LABEL_NUSES count is incremented. We have to add REG_LABEL notes,
- because the following loop optimization pass requires them. */
-
-/* ??? This is very similar to the loop.c add_label_notes function. We
- could probably share code here. */
-
-/* ??? If there was a jump optimization pass after gcse and before loop,
- then we would not need to do this here, because jump would add the
- necessary REG_LABEL notes. */
-
-static void
-add_label_notes (rtx x, rtx insn)
-{
- enum rtx_code code = GET_CODE (x);
- int i, j;
- const char *fmt;
-
- if (code == LABEL_REF && !LABEL_REF_NONLOCAL_P (x))
- {
- /* This code used to ignore labels that referred to dispatch tables to
- avoid flow generating (slightly) worse code.
-
- We no longer ignore such label references (see LABEL_REF handling in
- mark_jump_label for additional information). */
-
- REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, XEXP (x, 0),
- REG_NOTES (insn));
- if (LABEL_P (XEXP (x, 0)))
- LABEL_NUSES (XEXP (x, 0))++;
- return;
- }
-
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
- add_label_notes (XEXP (x, i), insn);
- else if (fmt[i] == 'E')
- for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- add_label_notes (XVECEXP (x, i, j), insn);
- }
-}
-
-/* Compute transparent outgoing information for each block.
-
- An expression is transparent to an edge unless it is killed by
- the edge itself. This can only happen with abnormal control flow,
- when the edge is traversed through a call. This happens with
- non-local labels and exceptions.
-
- This would not be necessary if we split the edge. While this is
- normally impossible for abnormal critical edges, with some effort
- it should be possible with exception handling, since we still have
- control over which handler should be invoked. But due to increased
- EH table sizes, this may not be worthwhile. */
-
-static void
-compute_transpout (void)
-{
- basic_block bb;
- unsigned int i;
- struct expr *expr;
-
- sbitmap_vector_ones (transpout, last_basic_block);
-
- FOR_EACH_BB (bb)
- {
- /* Note that flow inserted a nop a the end of basic blocks that
- end in call instructions for reasons other than abnormal
- control flow. */
- if (GET_CODE (BB_END (bb)) != CALL_INSN)
- continue;
-
- for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i]; expr ; expr = expr->next_same_hash)
- if (GET_CODE (expr->expr) == MEM)
- {
- if (GET_CODE (XEXP (expr->expr, 0)) == SYMBOL_REF
- && CONSTANT_POOL_ADDRESS_P (XEXP (expr->expr, 0)))
- continue;
-
- /* ??? Optimally, we would use interprocedural alias
- analysis to determine if this mem is actually killed
- by this call. */
- RESET_BIT (transpout[bb->index], expr->bitmap_index);
- }
- }
-}
-
-/* Removal of useless null pointer checks */
-
-/* Called via note_stores. X is set by SETTER. If X is a register we must
- invalidate nonnull_local and set nonnull_killed. DATA is really a
- `null_pointer_info *'.
-
- We ignore hard registers. */
-
-static void
-invalidate_nonnull_info (rtx x, rtx setter ATTRIBUTE_UNUSED, void *data)
-{
- unsigned int regno;
- struct null_pointer_info *npi = (struct null_pointer_info *) data;
-
- while (GET_CODE (x) == SUBREG)
- x = SUBREG_REG (x);
-
- /* Ignore anything that is not a register or is a hard register. */
- if (GET_CODE (x) != REG
- || REGNO (x) < npi->min_reg
- || REGNO (x) >= npi->max_reg)
- return;
-
- regno = REGNO (x) - npi->min_reg;
-
- RESET_BIT (npi->nonnull_local[npi->current_block->index], regno);
- SET_BIT (npi->nonnull_killed[npi->current_block->index], regno);
-}
-
-/* Do null-pointer check elimination for the registers indicated in
- NPI. NONNULL_AVIN and NONNULL_AVOUT are pre-allocated sbitmaps;
- they are not our responsibility to free. */
-
-static int
-delete_null_pointer_checks_1 (unsigned int *block_reg, sbitmap *nonnull_avin,
- sbitmap *nonnull_avout,
- struct null_pointer_info *npi)
-{
- basic_block bb, current_block;
- sbitmap *nonnull_local = npi->nonnull_local;
- sbitmap *nonnull_killed = npi->nonnull_killed;
- int something_changed = 0;
-
- /* Compute local properties, nonnull and killed. A register will have
- the nonnull property if at the end of the current block its value is
- known to be nonnull. The killed property indicates that somewhere in
- the block any information we had about the register is killed.
-
- Note that a register can have both properties in a single block. That
- indicates that it's killed, then later in the block a new value is
- computed. */
- sbitmap_vector_zero (nonnull_local, last_basic_block);
- sbitmap_vector_zero (nonnull_killed, last_basic_block);
-
- FOR_EACH_BB (current_block)
- {
- rtx insn, stop_insn;
-
- /* Set the current block for invalidate_nonnull_info. */
- npi->current_block = current_block;
-
- /* Scan each insn in the basic block looking for memory references and
- register sets. */
- stop_insn = NEXT_INSN (BB_END (current_block));
- for (insn = BB_HEAD (current_block);
- insn != stop_insn;
- insn = NEXT_INSN (insn))
- {
- rtx set;
- rtx reg;
-
- /* Ignore anything that is not a normal insn. */
- if (! INSN_P (insn))
- continue;
-
- /* Basically ignore anything that is not a simple SET. We do have
- to make sure to invalidate nonnull_local and set nonnull_killed
- for such insns though. */
- set = single_set (insn);
- if (!set)
- {
- note_stores (PATTERN (insn), invalidate_nonnull_info, npi);
- continue;
- }
-
- /* See if we've got a usable memory load. We handle it first
- in case it uses its address register as a dest (which kills
- the nonnull property). */
- if (GET_CODE (SET_SRC (set)) == MEM
- && GET_CODE ((reg = XEXP (SET_SRC (set), 0))) == REG
- && REGNO (reg) >= npi->min_reg
- && REGNO (reg) < npi->max_reg)
- SET_BIT (nonnull_local[current_block->index],
- REGNO (reg) - npi->min_reg);
-
- /* Now invalidate stuff clobbered by this insn. */
- note_stores (PATTERN (insn), invalidate_nonnull_info, npi);
-
- /* And handle stores, we do these last since any sets in INSN can
- not kill the nonnull property if it is derived from a MEM
- appearing in a SET_DEST. */
- if (GET_CODE (SET_DEST (set)) == MEM
- && GET_CODE ((reg = XEXP (SET_DEST (set), 0))) == REG
- && REGNO (reg) >= npi->min_reg
- && REGNO (reg) < npi->max_reg)
- SET_BIT (nonnull_local[current_block->index],
- REGNO (reg) - npi->min_reg);
- }
- }
-
- /* Now compute global properties based on the local properties. This
- is a classic global availability algorithm. */
- compute_available (nonnull_local, nonnull_killed,
- nonnull_avout, nonnull_avin);
-
- /* Now look at each bb and see if it ends with a compare of a value
- against zero. */
- FOR_EACH_BB (bb)
- {
- rtx last_insn = BB_END (bb);
- rtx condition, earliest;
- int compare_and_branch;
-
- /* Since MIN_REG is always at least FIRST_PSEUDO_REGISTER, and
- since BLOCK_REG[BB] is zero if this block did not end with a
- comparison against zero, this condition works. */
- if (block_reg[bb->index] < npi->min_reg
- || block_reg[bb->index] >= npi->max_reg)
- continue;
-
- /* LAST_INSN is a conditional jump. Get its condition. */
- condition = get_condition (last_insn, &earliest, false);
-
- /* If we can't determine the condition then skip. */
- if (! condition)
- continue;
-
- /* Is the register known to have a nonzero value? */
- if (!TEST_BIT (nonnull_avout[bb->index], block_reg[bb->index] - npi->min_reg))
- continue;
-
- /* Try to compute whether the compare/branch at the loop end is one or
- two instructions. */
- if (earliest == last_insn)
- compare_and_branch = 1;
- else if (earliest == prev_nonnote_insn (last_insn))
- compare_and_branch = 2;
- else
- continue;
-
- /* We know the register in this comparison is nonnull at exit from
- this block. We can optimize this comparison. */
- if (GET_CODE (condition) == NE)
- {
- rtx new_jump;
-
- new_jump = emit_jump_insn_after (gen_jump (JUMP_LABEL (last_insn)),
- last_insn);
- JUMP_LABEL (new_jump) = JUMP_LABEL (last_insn);
- LABEL_NUSES (JUMP_LABEL (new_jump))++;
- emit_barrier_after (new_jump);
- }
-
- something_changed = 1;
- delete_insn (last_insn);
-#ifdef HAVE_cc0
- if (compare_and_branch == 2)
- delete_insn (earliest);
-#endif
- purge_dead_edges (bb);
-
- /* Don't check this block again. (Note that BB_END is
- invalid here; we deleted the last instruction in the
- block.) */
- block_reg[bb->index] = 0;
- }
-
- return something_changed;
-}
-
-/* Find EQ/NE comparisons against zero which can be (indirectly) evaluated
- at compile time.
-
- This is conceptually similar to global constant/copy propagation and
- classic global CSE (it even uses the same dataflow equations as cprop).
-
- If a register is used as memory address with the form (mem (reg)), then we
- know that REG can not be zero at that point in the program. Any instruction
- which sets REG "kills" this property.
-
- So, if every path leading to a conditional branch has an available memory
- reference of that form, then we know the register can not have the value
- zero at the conditional branch.
-
- So we merely need to compute the local properties and propagate that data
- around the cfg, then optimize where possible.
-
- We run this pass two times. Once before CSE, then again after CSE. This
- has proven to be the most profitable approach. It is rare for new
- optimization opportunities of this nature to appear after the first CSE
- pass.
-
- This could probably be integrated with global cprop with a little work. */
-
-int
-delete_null_pointer_checks (rtx f ATTRIBUTE_UNUSED)
-{
- sbitmap *nonnull_avin, *nonnull_avout;
- unsigned int *block_reg;
- basic_block bb;
- int reg;
- int regs_per_pass;
- int max_reg = max_reg_num ();
- struct null_pointer_info npi;
- int something_changed = 0;
-
- /* If we have only a single block, or it is too expensive, give up. */
- if (n_basic_blocks <= 1
- || is_too_expensive (_ ("NULL pointer checks disabled")))
- return 0;
-
- /* We need four bitmaps, each with a bit for each register in each
- basic block. */
- regs_per_pass = get_bitmap_width (4, last_basic_block, max_reg);
-
- /* Allocate bitmaps to hold local and global properties. */
- npi.nonnull_local = sbitmap_vector_alloc (last_basic_block, regs_per_pass);
- npi.nonnull_killed = sbitmap_vector_alloc (last_basic_block, regs_per_pass);
- nonnull_avin = sbitmap_vector_alloc (last_basic_block, regs_per_pass);
- nonnull_avout = sbitmap_vector_alloc (last_basic_block, regs_per_pass);
-
- /* Go through the basic blocks, seeing whether or not each block
- ends with a conditional branch whose condition is a comparison
- against zero. Record the register compared in BLOCK_REG. */
- block_reg = xcalloc (last_basic_block, sizeof (int));
- FOR_EACH_BB (bb)
- {
- rtx last_insn = BB_END (bb);
- rtx condition, earliest, reg;
-
- /* We only want conditional branches. */
- if (GET_CODE (last_insn) != JUMP_INSN
- || !any_condjump_p (last_insn)
- || !onlyjump_p (last_insn))
- continue;
-
- /* LAST_INSN is a conditional jump. Get its condition. */
- condition = get_condition (last_insn, &earliest, false);
-
- /* If we were unable to get the condition, or it is not an equality
- comparison against zero then there's nothing we can do. */
- if (!condition
- || (GET_CODE (condition) != NE && GET_CODE (condition) != EQ)
- || GET_CODE (XEXP (condition, 1)) != CONST_INT
- || (XEXP (condition, 1)
- != CONST0_RTX (GET_MODE (XEXP (condition, 0)))))
- continue;
-
- /* We must be checking a register against zero. */
- reg = XEXP (condition, 0);
- if (GET_CODE (reg) != REG)
- continue;
-
- block_reg[bb->index] = REGNO (reg);
- }
-
- /* Go through the algorithm for each block of registers. */
- for (reg = FIRST_PSEUDO_REGISTER; reg < max_reg; reg += regs_per_pass)
- {
- npi.min_reg = reg;
- npi.max_reg = MIN (reg + regs_per_pass, max_reg);
- something_changed |= delete_null_pointer_checks_1 (block_reg,
- nonnull_avin,
- nonnull_avout,
- &npi);
- }
-
- /* Free the table of registers compared at the end of every block. */
- free (block_reg);
-
- /* Free bitmaps. */
- sbitmap_vector_free (npi.nonnull_local);
- sbitmap_vector_free (npi.nonnull_killed);
- sbitmap_vector_free (nonnull_avin);
- sbitmap_vector_free (nonnull_avout);
-
- return something_changed;
-}
-
-/* Code Hoisting variables and subroutines. */
-
-/* Very busy expressions. */
-static sbitmap *hoist_vbein;
-static sbitmap *hoist_vbeout;
-
-/* Hoistable expressions. */
-static sbitmap *hoist_exprs;
-
-/* ??? We could compute post dominators and run this algorithm in
- reverse to perform tail merging, doing so would probably be
- more effective than the tail merging code in jump.c.
-
- It's unclear if tail merging could be run in parallel with
- code hoisting. It would be nice. */
-
-/* Allocate vars used for code hoisting analysis. */
-
-static void
-alloc_code_hoist_mem (int n_blocks, int n_exprs)
-{
- antloc = sbitmap_vector_alloc (n_blocks, n_exprs);
- transp = sbitmap_vector_alloc (n_blocks, n_exprs);
- comp = sbitmap_vector_alloc (n_blocks, n_exprs);
-
- hoist_vbein = sbitmap_vector_alloc (n_blocks, n_exprs);
- hoist_vbeout = sbitmap_vector_alloc (n_blocks, n_exprs);
- hoist_exprs = sbitmap_vector_alloc (n_blocks, n_exprs);
- transpout = sbitmap_vector_alloc (n_blocks, n_exprs);
-}
-
-/* Free vars used for code hoisting analysis. */
-
-static void
-free_code_hoist_mem (void)
-{
- sbitmap_vector_free (antloc);
- sbitmap_vector_free (transp);
- sbitmap_vector_free (comp);
-
- sbitmap_vector_free (hoist_vbein);
- sbitmap_vector_free (hoist_vbeout);
- sbitmap_vector_free (hoist_exprs);
- sbitmap_vector_free (transpout);
-
- free_dominance_info (CDI_DOMINATORS);
-}
-
-/* Compute the very busy expressions at entry/exit from each block.
-
- An expression is very busy if all paths from a given point
- compute the expression. */
-
-static void
-compute_code_hoist_vbeinout (void)
-{
- int changed, passes;
- basic_block bb;
-
- sbitmap_vector_zero (hoist_vbeout, last_basic_block);
- sbitmap_vector_zero (hoist_vbein, last_basic_block);
-
- passes = 0;
- changed = 1;
-
- while (changed)
- {
- changed = 0;
-
- /* We scan the blocks in the reverse order to speed up
- the convergence. */
- FOR_EACH_BB_REVERSE (bb)
- {
- changed |= sbitmap_a_or_b_and_c_cg (hoist_vbein[bb->index], antloc[bb->index],
- hoist_vbeout[bb->index], transp[bb->index]);
- if (bb->next_bb != EXIT_BLOCK_PTR)
- sbitmap_intersection_of_succs (hoist_vbeout[bb->index], hoist_vbein, bb->index);
- }
-
- passes++;
- }
-
- if (gcse_file)
- fprintf (gcse_file, "hoisting vbeinout computation: %d passes\n", passes);
-}
-
-/* Top level routine to do the dataflow analysis needed by code hoisting. */
-
-static void
-compute_code_hoist_data (void)
-{
- compute_local_properties (transp, comp, antloc, &expr_hash_table);
- compute_transpout ();
- compute_code_hoist_vbeinout ();
- calculate_dominance_info (CDI_DOMINATORS);
- if (gcse_file)
- fprintf (gcse_file, "\n");
-}
-
-/* Determine if the expression identified by EXPR_INDEX would
- reach BB unimpared if it was placed at the end of EXPR_BB.
-
- It's unclear exactly what Muchnick meant by "unimpared". It seems
- to me that the expression must either be computed or transparent in
- *every* block in the path(s) from EXPR_BB to BB. Any other definition
- would allow the expression to be hoisted out of loops, even if
- the expression wasn't a loop invariant.
-
- Contrast this to reachability for PRE where an expression is
- considered reachable if *any* path reaches instead of *all*
- paths. */
-
-static int
-hoist_expr_reaches_here_p (basic_block expr_bb, int expr_index, basic_block bb, char *visited)
-{
- edge pred;
- int visited_allocated_locally = 0;
-
-
- if (visited == NULL)
- {
- visited_allocated_locally = 1;
- visited = xcalloc (last_basic_block, 1);
- }
-
- for (pred = bb->pred; pred != NULL; pred = pred->pred_next)
+ FOR_EACH_EDGE (pred, ei, bb->preds)
{
basic_block pred_bb = pred->src;
hoist_code (void)
{
basic_block bb, dominated;
- basic_block *domby;
- unsigned int domby_len;
+ VEC (basic_block, heap) *domby;
unsigned int i,j;
struct expr **index_map;
struct expr *expr;
/* Compute a mapping from expression number (`bitmap_index') to
hash table entry. */
- index_map = xcalloc (expr_hash_table.n_elems, sizeof (struct expr *));
+ index_map = XCNEWVEC (struct expr *, expr_hash_table.n_elems);
for (i = 0; i < expr_hash_table.size; i++)
for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
index_map[expr->bitmap_index] = expr;
int found = 0;
int insn_inserted_p;
- domby_len = get_dominated_by (CDI_DOMINATORS, bb, &domby);
+ domby = get_dominated_by (CDI_DOMINATORS, bb);
/* Examine each expression that is very busy at the exit of this
block. These are the potentially hoistable expressions. */
for (i = 0; i < hoist_vbeout[bb->index]->n_bits; i++)
/* We've found a potentially hoistable expression, now
we look at every block BB dominates to see if it
computes the expression. */
- for (j = 0; j < domby_len; j++)
+ for (j = 0; VEC_iterate (basic_block, domby, j, dominated); j++)
{
- dominated = domby[j];
/* Ignore self dominance. */
if (bb == dominated)
continue;
/* If we found nothing to hoist, then quit now. */
if (! found)
{
- free (domby);
- continue;
+ VEC_free (basic_block, heap, domby);
+ continue;
}
/* Loop over all the hoistable expressions. */
insn_inserted_p = 0;
/* These tests should be the same as the tests above. */
- if (TEST_BIT (hoist_vbeout[bb->index], i))
+ if (TEST_BIT (hoist_exprs[bb->index], i))
{
/* We've found a potentially hoistable expression, now
we look at every block BB dominates to see if it
computes the expression. */
- for (j = 0; j < domby_len; j++)
+ for (j = 0; VEC_iterate (basic_block, domby, j, dominated); j++)
{
- dominated = domby[j];
/* Ignore self dominance. */
if (bb == dominated)
continue;
while (BLOCK_FOR_INSN (occr->insn) != dominated && occr)
occr = occr->next;
- /* Should never happen. */
- if (!occr)
- abort ();
-
+ gcc_assert (occr);
insn = occr->insn;
-
set = single_set (insn);
- if (! set)
- abort ();
+ gcc_assert (set);
/* Create a pseudo-reg to store the result of reaching
expressions into. Get the mode for the new pseudo
occr->deleted_p = 1;
if (!insn_inserted_p)
{
- insert_insn_end_bb (index_map[i], bb, 0);
+ insert_insn_end_basic_block (index_map[i], bb, 0);
insn_inserted_p = 1;
}
}
}
}
}
- free (domby);
+ VEC_free (basic_block, heap, domby);
}
free (index_map);
alloc_hash_table (max_cuid, &expr_hash_table, 0);
compute_hash_table (&expr_hash_table);
- if (gcse_file)
- dump_hash_table (gcse_file, "Code Hosting Expressions", &expr_hash_table);
+ if (dump_file)
+ dump_hash_table (dump_file, "Code Hosting Expressions", &expr_hash_table);
if (expr_hash_table.n_elems > 0)
{
load towards the exit, and we end up with no loads or stores of 'i'
in the loop. */
+static hashval_t
+pre_ldst_expr_hash (const void *p)
+{
+ int do_not_record_p = 0;
+ const struct ls_expr *x = p;
+ return hash_rtx (x->pattern, GET_MODE (x->pattern), &do_not_record_p, NULL, false);
+}
+
+static int
+pre_ldst_expr_eq (const void *p1, const void *p2)
+{
+ const struct ls_expr *ptr1 = p1, *ptr2 = p2;
+ return expr_equiv_p (ptr1->pattern, ptr2->pattern);
+}
+
/* This will search the ldst list for a matching expression. If it
doesn't find one, we create one and initialize it. */
int do_not_record_p = 0;
struct ls_expr * ptr;
unsigned int hash;
+ void **slot;
+ struct ls_expr e;
- hash = hash_expr_1 (x, GET_MODE (x), & do_not_record_p);
+ hash = hash_rtx (x, GET_MODE (x), &do_not_record_p,
+ NULL, /*have_reg_qty=*/false);
- for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next)
- if (ptr->hash_index == hash && expr_equiv_p (ptr->pattern, x))
- return ptr;
+ e.pattern = x;
+ slot = htab_find_slot_with_hash (pre_ldst_table, &e, hash, INSERT);
+ if (*slot)
+ return (struct ls_expr *)*slot;
- ptr = xmalloc (sizeof (struct ls_expr));
+ ptr = XNEW (struct ls_expr);
ptr->next = pre_ldst_mems;
ptr->expr = NULL;
ptr->index = 0;
ptr->hash_index = hash;
pre_ldst_mems = ptr;
+ *slot = ptr;
return ptr;
}
/* Free up an individual ldst entry. */
-static void
-free_ldst_entry (struct ls_expr * ptr)
-{
- free_INSN_LIST_list (& ptr->loads);
- free_INSN_LIST_list (& ptr->stores);
-
- free (ptr);
-}
-
-/* Free up all memory associated with the ldst list. */
-
-static void
-free_ldst_mems (void)
-{
- while (pre_ldst_mems)
- {
- struct ls_expr * tmp = pre_ldst_mems;
-
- pre_ldst_mems = pre_ldst_mems->next;
-
- free_ldst_entry (tmp);
- }
-
- pre_ldst_mems = NULL;
-}
-
-/* Dump debugging info about the ldst list. */
-
-static void
-print_ldst_list (FILE * file)
-{
- struct ls_expr * ptr;
-
- fprintf (file, "LDST list: \n");
-
- for (ptr = first_ls_expr(); ptr != NULL; ptr = next_ls_expr (ptr))
- {
- fprintf (file, " Pattern (%3d): ", ptr->index);
-
- print_rtl (file, ptr->pattern);
-
- fprintf (file, "\n Loads : ");
-
- if (ptr->loads)
- print_rtl (file, ptr->loads);
- else
- fprintf (file, "(nil)");
-
- fprintf (file, "\n Stores : ");
-
- if (ptr->stores)
- print_rtl (file, ptr->stores);
- else
- fprintf (file, "(nil)");
-
- fprintf (file, "\n\n");
- }
-
- fprintf (file, "\n");
-}
-
-/* Returns 1 if X is in the list of ldst only expressions. */
-
-static struct ls_expr *
-find_rtx_in_ldst (rtx x)
-{
- struct ls_expr * ptr;
-
- for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next)
- if (expr_equiv_p (ptr->pattern, x) && ! ptr->invalid)
- return ptr;
-
- return NULL;
-}
-
-/* Assign each element of the list of mems a monotonically increasing value. */
-
-static int
-enumerate_ldsts (void)
-{
- struct ls_expr * ptr;
- int n = 0;
-
- for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next)
- ptr->index = n++;
-
- return n;
-}
-
-/* Return first item in the list. */
-
-static inline struct ls_expr *
-first_ls_expr (void)
-{
- return pre_ldst_mems;
-}
-
-/* Return the next item in the list after the specified one. */
-
-static inline struct ls_expr *
-next_ls_expr (struct ls_expr * ptr)
-{
- return ptr->next;
-}
-\f
-/* Load Motion for loads which only kill themselves. */
-
-/* Return true if x is a simple MEM operation, with no registers or
- side effects. These are the types of loads we consider for the
- ld_motion list, otherwise we let the usual aliasing take care of it. */
-
-static int
-simple_mem (rtx x)
-{
- if (GET_CODE (x) != MEM)
- return 0;
-
- if (MEM_VOLATILE_P (x))
- return 0;
-
- if (GET_MODE (x) == BLKmode)
- return 0;
-
- /* If we are handling exceptions, we must be careful with memory references
- that may trap. If we are not, the behavior is undefined, so we may just
- continue. */
- if (flag_non_call_exceptions && may_trap_p (x))
- return 0;
-
- if (side_effects_p (x))
- return 0;
-
- /* Do not consider function arguments passed on stack. */
- if (reg_mentioned_p (stack_pointer_rtx, x))
- return 0;
-
- if (flag_float_store && FLOAT_MODE_P (GET_MODE (x)))
- return 0;
-
- return 1;
-}
-
-/* Make sure there isn't a buried reference in this pattern anywhere.
- If there is, invalidate the entry for it since we're not capable
- of fixing it up just yet.. We have to be sure we know about ALL
- loads since the aliasing code will allow all entries in the
- ld_motion list to not-alias itself. If we miss a load, we will get
- the wrong value since gcse might common it and we won't know to
- fix it up. */
-
-static void
-invalidate_any_buried_refs (rtx x)
-{
- const char * fmt;
- int i, j;
- struct ls_expr * ptr;
-
- /* Invalidate it in the list. */
- if (GET_CODE (x) == MEM && simple_mem (x))
- {
- ptr = ldst_entry (x);
- ptr->invalid = 1;
- }
-
- /* Recursively process the insn. */
- fmt = GET_RTX_FORMAT (GET_CODE (x));
-
- for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e')
- invalidate_any_buried_refs (XEXP (x, i));
- else if (fmt[i] == 'E')
- for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- invalidate_any_buried_refs (XVECEXP (x, i, j));
- }
-}
-
-/* Find all the 'simple' MEMs which are used in LOADs and STORES. Simple
- being defined as MEM loads and stores to symbols, with no side effects
- and no registers in the expression. For a MEM destination, we also
- check that the insn is still valid if we replace the destination with a
- REG, as is done in update_ld_motion_stores. If there are any uses/defs
- which don't match this criteria, they are invalidated and trimmed out
- later. */
-
-static void
-compute_ld_motion_mems (void)
-{
- struct ls_expr * ptr;
- basic_block bb;
- rtx insn;
-
- pre_ldst_mems = NULL;
-
- FOR_EACH_BB (bb)
- {
- for (insn = BB_HEAD (bb);
- insn && insn != NEXT_INSN (BB_END (bb));
- insn = NEXT_INSN (insn))
- {
- if (INSN_P (insn))
- {
- if (GET_CODE (PATTERN (insn)) == SET)
- {
- rtx src = SET_SRC (PATTERN (insn));
- rtx dest = SET_DEST (PATTERN (insn));
-
- /* Check for a simple LOAD... */
- if (GET_CODE (src) == MEM && simple_mem (src))
- {
- ptr = ldst_entry (src);
- if (GET_CODE (dest) == REG)
- ptr->loads = alloc_INSN_LIST (insn, ptr->loads);
- else
- ptr->invalid = 1;
- }
- else
- {
- /* Make sure there isn't a buried load somewhere. */
- invalidate_any_buried_refs (src);
- }
-
- /* Check for stores. Don't worry about aliased ones, they
- will block any movement we might do later. We only care
- about this exact pattern since those are the only
- circumstance that we will ignore the aliasing info. */
- if (GET_CODE (dest) == MEM && simple_mem (dest))
- {
- ptr = ldst_entry (dest);
+static void
+free_ldst_entry (struct ls_expr * ptr)
+{
+ free_INSN_LIST_list (& ptr->loads);
+ free_INSN_LIST_list (& ptr->stores);
- if (GET_CODE (src) != MEM
- && GET_CODE (src) != ASM_OPERANDS
- /* Check for REG manually since want_to_gcse_p
- returns 0 for all REGs. */
- && can_assign_to_reg_p (src))
- ptr->stores = alloc_INSN_LIST (insn, ptr->stores);
- else
- ptr->invalid = 1;
- }
- }
- else
- invalidate_any_buried_refs (PATTERN (insn));
- }
- }
- }
+ free (ptr);
}
-/* Remove any references that have been either invalidated or are not in the
- expression list for pre gcse. */
+/* Free up all memory associated with the ldst list. */
static void
-trim_ld_motion_mems (void)
+free_ldst_mems (void)
{
- struct ls_expr * * last = & pre_ldst_mems;
- struct ls_expr * ptr = pre_ldst_mems;
+ if (pre_ldst_table)
+ htab_delete (pre_ldst_table);
+ pre_ldst_table = NULL;
- while (ptr != NULL)
+ while (pre_ldst_mems)
{
- struct expr * expr;
-
- /* Delete if entry has been made invalid. */
- if (! ptr->invalid)
- {
- /* Delete if we cannot find this mem in the expression list. */
- unsigned int hash = ptr->hash_index % expr_hash_table.size;
+ struct ls_expr * tmp = pre_ldst_mems;
- for (expr = expr_hash_table.table[hash];
- expr != NULL;
- expr = expr->next_same_hash)
- if (expr_equiv_p (expr->expr, ptr->pattern))
- break;
- }
- else
- expr = (struct expr *) 0;
+ pre_ldst_mems = pre_ldst_mems->next;
- if (expr)
- {
- /* Set the expression field if we are keeping it. */
- ptr->expr = expr;
- last = & ptr->next;
- ptr = ptr->next;
- }
- else
- {
- *last = ptr->next;
- free_ldst_entry (ptr);
- ptr = * last;
- }
+ free_ldst_entry (tmp);
}
- /* Show the world what we've found. */
- if (gcse_file && pre_ldst_mems != NULL)
- print_ldst_list (gcse_file);
+ pre_ldst_mems = NULL;
}
-/* This routine will take an expression which we are replacing with
- a reaching register, and update any stores that are needed if
- that expression is in the ld_motion list. Stores are updated by
- copying their SRC to the reaching register, and then storing
- the reaching register into the store location. These keeps the
- correct value in the reaching register for the loads. */
+/* Dump debugging info about the ldst list. */
static void
-update_ld_motion_stores (struct expr * expr)
+print_ldst_list (FILE * file)
{
- struct ls_expr * mem_ptr;
+ struct ls_expr * ptr;
- if ((mem_ptr = find_rtx_in_ldst (expr->expr)))
+ fprintf (file, "LDST list: \n");
+
+ for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
{
- /* We can try to find just the REACHED stores, but is shouldn't
- matter to set the reaching reg everywhere... some might be
- dead and should be eliminated later. */
+ fprintf (file, " Pattern (%3d): ", ptr->index);
- /* We replace (set mem expr) with (set reg expr) (set mem reg)
- where reg is the reaching reg used in the load. We checked in
- compute_ld_motion_mems that we can replace (set mem expr) with
- (set reg expr) in that insn. */
- rtx list = mem_ptr->stores;
+ print_rtl (file, ptr->pattern);
- for ( ; list != NULL_RTX; list = XEXP (list, 1))
- {
- rtx insn = XEXP (list, 0);
- rtx pat = PATTERN (insn);
- rtx src = SET_SRC (pat);
- rtx reg = expr->reaching_reg;
- rtx copy, new;
+ fprintf (file, "\n Loads : ");
- /* If we've already copied it, continue. */
- if (expr->reaching_reg == src)
- continue;
+ if (ptr->loads)
+ print_rtl (file, ptr->loads);
+ else
+ fprintf (file, "(nil)");
- if (gcse_file)
- {
- fprintf (gcse_file, "PRE: store updated with reaching reg ");
- print_rtl (gcse_file, expr->reaching_reg);
- fprintf (gcse_file, ":\n ");
- print_inline_rtx (gcse_file, insn, 8);
- fprintf (gcse_file, "\n");
- }
+ fprintf (file, "\n Stores : ");
- copy = gen_move_insn ( reg, copy_rtx (SET_SRC (pat)));
- new = emit_insn_before (copy, insn);
- record_one_set (REGNO (reg), new);
- SET_SRC (pat) = reg;
+ if (ptr->stores)
+ print_rtl (file, ptr->stores);
+ else
+ fprintf (file, "(nil)");
- /* un-recognize this pattern since it's probably different now. */
- INSN_CODE (insn) = -1;
- gcse_create_count++;
- }
+ fprintf (file, "\n\n");
}
-}
-\f
-/* Store motion code. */
-
-#define ANTIC_STORE_LIST(x) ((x)->loads)
-#define AVAIL_STORE_LIST(x) ((x)->stores)
-#define LAST_AVAIL_CHECK_FAILURE(x) ((x)->reaching_reg)
-
-/* This is used to communicate the target bitvector we want to use in the
- reg_set_info routine when called via the note_stores mechanism. */
-static int * regvec;
-/* And current insn, for the same routine. */
-static rtx compute_store_table_current_insn;
+ fprintf (file, "\n");
+}
-/* Used in computing the reverse edge graph bit vectors. */
-static sbitmap * st_antloc;
+/* Returns 1 if X is in the list of ldst only expressions. */
-/* Global holding the number of store expressions we are dealing with. */
-static int num_stores;
+static struct ls_expr *
+find_rtx_in_ldst (rtx x)
+{
+ struct ls_expr e;
+ void **slot;
+ if (!pre_ldst_table)
+ return NULL;
+ e.pattern = x;
+ slot = htab_find_slot (pre_ldst_table, &e, NO_INSERT);
+ if (!slot || ((struct ls_expr *)*slot)->invalid)
+ return NULL;
+ return *slot;
+}
-/* Checks to set if we need to mark a register set. Called from
- note_stores. */
+/* Assign each element of the list of mems a monotonically increasing value. */
-static void
-reg_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED,
- void *data)
+static int
+enumerate_ldsts (void)
{
- sbitmap bb_reg = data;
+ struct ls_expr * ptr;
+ int n = 0;
- if (GET_CODE (dest) == SUBREG)
- dest = SUBREG_REG (dest);
+ for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next)
+ ptr->index = n++;
- if (GET_CODE (dest) == REG)
- {
- regvec[REGNO (dest)] = INSN_UID (compute_store_table_current_insn);
- if (bb_reg)
- SET_BIT (bb_reg, REGNO (dest));
- }
+ return n;
}
-/* Clear any mark that says that this insn sets dest. Called from
- note_stores. */
+/* Return first item in the list. */
-static void
-reg_clear_last_set (rtx dest, rtx setter ATTRIBUTE_UNUSED,
- void *data)
+static inline struct ls_expr *
+first_ls_expr (void)
{
- int *dead_vec = data;
+ return pre_ldst_mems;
+}
- if (GET_CODE (dest) == SUBREG)
- dest = SUBREG_REG (dest);
+/* Return the next item in the list after the specified one. */
- if (GET_CODE (dest) == REG &&
- dead_vec[REGNO (dest)] == INSN_UID (compute_store_table_current_insn))
- dead_vec[REGNO (dest)] = 0;
+static inline struct ls_expr *
+next_ls_expr (struct ls_expr * ptr)
+{
+ return ptr->next;
}
+\f
+/* Load Motion for loads which only kill themselves. */
-/* Return zero if some of the registers in list X are killed
- due to set of registers in bitmap REGS_SET. */
+/* Return true if x is a simple MEM operation, with no registers or
+ side effects. These are the types of loads we consider for the
+ ld_motion list, otherwise we let the usual aliasing take care of it. */
-static bool
-store_ops_ok (rtx x, int *regs_set)
+static int
+simple_mem (const_rtx x)
{
- rtx reg;
-
- for (; x; x = XEXP (x, 1))
- {
- reg = XEXP (x, 0);
- if (regs_set[REGNO(reg)])
- return false;
- }
+ if (! MEM_P (x))
+ return 0;
- return true;
-}
+ if (MEM_VOLATILE_P (x))
+ return 0;
-/* Returns a list of registers mentioned in X. */
-static rtx
-extract_mentioned_regs (rtx x)
-{
- return extract_mentioned_regs_helper (x, NULL_RTX);
-}
+ if (GET_MODE (x) == BLKmode)
+ return 0;
-/* Helper for extract_mentioned_regs; ACCUM is used to accumulate used
- registers. */
-static rtx
-extract_mentioned_regs_helper (rtx x, rtx accum)
-{
- int i;
- enum rtx_code code;
- const char * fmt;
+ /* If we are handling exceptions, we must be careful with memory references
+ that may trap. If we are not, the behavior is undefined, so we may just
+ continue. */
+ if (flag_non_call_exceptions && may_trap_p (x))
+ return 0;
- /* Repeat is used to turn tail-recursion into iteration. */
- repeat:
+ if (side_effects_p (x))
+ return 0;
- if (x == 0)
- return accum;
+ /* Do not consider function arguments passed on stack. */
+ if (reg_mentioned_p (stack_pointer_rtx, x))
+ return 0;
- code = GET_CODE (x);
- switch (code)
- {
- case REG:
- return alloc_EXPR_LIST (0, x, accum);
+ if (flag_float_store && FLOAT_MODE_P (GET_MODE (x)))
+ return 0;
- case MEM:
- x = XEXP (x, 0);
- goto repeat;
+ return 1;
+}
- case PRE_DEC:
- case PRE_INC:
- case POST_DEC:
- case POST_INC:
- /* We do not run this function with arguments having side effects. */
- abort ();
+/* Make sure there isn't a buried reference in this pattern anywhere.
+ If there is, invalidate the entry for it since we're not capable
+ of fixing it up just yet.. We have to be sure we know about ALL
+ loads since the aliasing code will allow all entries in the
+ ld_motion list to not-alias itself. If we miss a load, we will get
+ the wrong value since gcse might common it and we won't know to
+ fix it up. */
- case PC:
- case CC0: /*FIXME*/
- case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_VECTOR:
- case SYMBOL_REF:
- case LABEL_REF:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return accum;
+static void
+invalidate_any_buried_refs (rtx x)
+{
+ const char * fmt;
+ int i, j;
+ struct ls_expr * ptr;
- default:
- break;
+ /* Invalidate it in the list. */
+ if (MEM_P (x) && simple_mem (x))
+ {
+ ptr = ldst_entry (x);
+ ptr->invalid = 1;
}
- i = GET_RTX_LENGTH (code) - 1;
- fmt = GET_RTX_FORMAT (code);
+ /* Recursively process the insn. */
+ fmt = GET_RTX_FORMAT (GET_CODE (x));
- for (; i >= 0; i--)
+ for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
{
if (fmt[i] == 'e')
- {
- rtx tem = XEXP (x, i);
-
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration. */
- if (i == 0)
- {
- x = tem;
- goto repeat;
- }
-
- accum = extract_mentioned_regs_helper (tem, accum);
- }
+ invalidate_any_buried_refs (XEXP (x, i));
else if (fmt[i] == 'E')
- {
- int j;
-
- for (j = 0; j < XVECLEN (x, i); j++)
- accum = extract_mentioned_regs_helper (XVECEXP (x, i, j), accum);
- }
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ invalidate_any_buried_refs (XVECEXP (x, i, j));
}
-
- return accum;
}
-/* Determine whether INSN is MEM store pattern that we will consider moving.
- REGS_SET_BEFORE is bitmap of registers set before (and including) the
- current insn, REGS_SET_AFTER is bitmap of registers set after (and
- including) the insn in this basic block. We must be passing through BB from
- head to end, as we are using this fact to speed things up.
-
- The results are stored this way:
-
- -- the first anticipatable expression is added into ANTIC_STORE_LIST
- -- if the processed expression is not anticipatable, NULL_RTX is added
- there instead, so that we can use it as indicator that no further
- expression of this type may be anticipatable
- -- if the expression is available, it is added as head of AVAIL_STORE_LIST;
- consequently, all of them but this head are dead and may be deleted.
- -- if the expression is not available, the insn due to that it fails to be
- available is stored in reaching_reg.
-
- The things are complicated a bit by fact that there already may be stores
- to the same MEM from other blocks; also caller must take care of the
- necessary cleanup of the temporary markers after end of the basic block.
- */
+/* Find all the 'simple' MEMs which are used in LOADs and STORES. Simple
+ being defined as MEM loads and stores to symbols, with no side effects
+ and no registers in the expression. For a MEM destination, we also
+ check that the insn is still valid if we replace the destination with a
+ REG, as is done in update_ld_motion_stores. If there are any uses/defs
+ which don't match this criteria, they are invalidated and trimmed out
+ later. */
static void
-find_moveable_store (rtx insn, int *regs_set_before, int *regs_set_after)
+compute_ld_motion_mems (void)
{
struct ls_expr * ptr;
- rtx dest, set, tmp;
- int check_anticipatable, check_available;
- basic_block bb = BLOCK_FOR_INSN (insn);
+ basic_block bb;
+ rtx insn;
- set = single_set (insn);
- if (!set)
- return;
+ pre_ldst_mems = NULL;
+ pre_ldst_table = htab_create (13, pre_ldst_expr_hash,
+ pre_ldst_expr_eq, NULL);
- dest = SET_DEST (set);
+ FOR_EACH_BB (bb)
+ {
+ FOR_BB_INSNS (bb, insn)
+ {
+ if (INSN_P (insn))
+ {
+ if (GET_CODE (PATTERN (insn)) == SET)
+ {
+ rtx src = SET_SRC (PATTERN (insn));
+ rtx dest = SET_DEST (PATTERN (insn));
- if (GET_CODE (dest) != MEM || MEM_VOLATILE_P (dest)
- || GET_MODE (dest) == BLKmode)
- return;
+ /* Check for a simple LOAD... */
+ if (MEM_P (src) && simple_mem (src))
+ {
+ ptr = ldst_entry (src);
+ if (REG_P (dest))
+ ptr->loads = alloc_INSN_LIST (insn, ptr->loads);
+ else
+ ptr->invalid = 1;
+ }
+ else
+ {
+ /* Make sure there isn't a buried load somewhere. */
+ invalidate_any_buried_refs (src);
+ }
- if (side_effects_p (dest))
- return;
+ /* Check for stores. Don't worry about aliased ones, they
+ will block any movement we might do later. We only care
+ about this exact pattern since those are the only
+ circumstance that we will ignore the aliasing info. */
+ if (MEM_P (dest) && simple_mem (dest))
+ {
+ ptr = ldst_entry (dest);
- /* If we are handling exceptions, we must be careful with memory references
- that may trap. If we are not, the behavior is undefined, so we may just
- continue. */
- if (flag_non_call_exceptions && may_trap_p (dest))
- return;
+ if (! MEM_P (src)
+ && GET_CODE (src) != ASM_OPERANDS
+ /* Check for REG manually since want_to_gcse_p
+ returns 0 for all REGs. */
+ && can_assign_to_reg_p (src))
+ ptr->stores = alloc_INSN_LIST (insn, ptr->stores);
+ else
+ ptr->invalid = 1;
+ }
+ }
+ else
+ invalidate_any_buried_refs (PATTERN (insn));
+ }
+ }
+ }
+}
- ptr = ldst_entry (dest);
- if (!ptr->pattern_regs)
- ptr->pattern_regs = extract_mentioned_regs (dest);
+/* Remove any references that have been either invalidated or are not in the
+ expression list for pre gcse. */
- /* Do not check for anticipatability if we either found one anticipatable
- store already, or tested for one and found out that it was killed. */
- check_anticipatable = 0;
- if (!ANTIC_STORE_LIST (ptr))
- check_anticipatable = 1;
- else
- {
- tmp = XEXP (ANTIC_STORE_LIST (ptr), 0);
- if (tmp != NULL_RTX
- && BLOCK_FOR_INSN (tmp) != bb)
- check_anticipatable = 1;
- }
- if (check_anticipatable)
+static void
+trim_ld_motion_mems (void)
+{
+ struct ls_expr * * last = & pre_ldst_mems;
+ struct ls_expr * ptr = pre_ldst_mems;
+
+ while (ptr != NULL)
{
- if (store_killed_before (dest, ptr->pattern_regs, insn, bb, regs_set_before))
- tmp = NULL_RTX;
+ struct expr * expr;
+
+ /* Delete if entry has been made invalid. */
+ if (! ptr->invalid)
+ {
+ /* Delete if we cannot find this mem in the expression list. */
+ unsigned int hash = ptr->hash_index % expr_hash_table.size;
+
+ for (expr = expr_hash_table.table[hash];
+ expr != NULL;
+ expr = expr->next_same_hash)
+ if (expr_equiv_p (expr->expr, ptr->pattern))
+ break;
+ }
else
- tmp = insn;
- ANTIC_STORE_LIST (ptr) = alloc_INSN_LIST (tmp,
- ANTIC_STORE_LIST (ptr));
- }
+ expr = (struct expr *) 0;
- /* It is not necessary to check whether store is available if we did
- it successfully before; if we failed before, do not bother to check
- until we reach the insn that caused us to fail. */
- check_available = 0;
- if (!AVAIL_STORE_LIST (ptr))
- check_available = 1;
- else
- {
- tmp = XEXP (AVAIL_STORE_LIST (ptr), 0);
- if (BLOCK_FOR_INSN (tmp) != bb)
- check_available = 1;
- }
- if (check_available)
- {
- /* Check that we have already reached the insn at that the check
- failed last time. */
- if (LAST_AVAIL_CHECK_FAILURE (ptr))
+ if (expr)
{
- for (tmp = BB_END (bb);
- tmp != insn && tmp != LAST_AVAIL_CHECK_FAILURE (ptr);
- tmp = PREV_INSN (tmp))
- continue;
- if (tmp == insn)
- check_available = 0;
+ /* Set the expression field if we are keeping it. */
+ ptr->expr = expr;
+ last = & ptr->next;
+ ptr = ptr->next;
}
else
- check_available = store_killed_after (dest, ptr->pattern_regs, insn,
- bb, regs_set_after,
- &LAST_AVAIL_CHECK_FAILURE (ptr));
+ {
+ *last = ptr->next;
+ htab_remove_elt_with_hash (pre_ldst_table, ptr, ptr->hash_index);
+ free_ldst_entry (ptr);
+ ptr = * last;
+ }
}
- if (!check_available)
- AVAIL_STORE_LIST (ptr) = alloc_INSN_LIST (insn, AVAIL_STORE_LIST (ptr));
-}
-
-/* Find available and anticipatable stores. */
-static int
-compute_store_table (void)
-{
- int ret;
- basic_block bb;
- unsigned regno;
- rtx insn, pat, tmp;
- int *last_set_in, *already_set;
- struct ls_expr * ptr, **prev_next_ptr_ptr;
+ /* Show the world what we've found. */
+ if (dump_file && pre_ldst_mems != NULL)
+ print_ldst_list (dump_file);
+}
- max_gcse_regno = max_reg_num ();
+/* This routine will take an expression which we are replacing with
+ a reaching register, and update any stores that are needed if
+ that expression is in the ld_motion list. Stores are updated by
+ copying their SRC to the reaching register, and then storing
+ the reaching register into the store location. These keeps the
+ correct value in the reaching register for the loads. */
- reg_set_in_block = sbitmap_vector_alloc (last_basic_block,
- max_gcse_regno);
- sbitmap_vector_zero (reg_set_in_block, last_basic_block);
- pre_ldst_mems = 0;
- last_set_in = xcalloc (max_gcse_regno, sizeof (int));
- already_set = xmalloc (sizeof (int) * max_gcse_regno);
+static void
+update_ld_motion_stores (struct expr * expr)
+{
+ struct ls_expr * mem_ptr;
- /* Find all the stores we care about. */
- FOR_EACH_BB (bb)
+ if ((mem_ptr = find_rtx_in_ldst (expr->expr)))
{
- /* First compute the registers set in this block. */
- regvec = last_set_in;
+ /* We can try to find just the REACHED stores, but is shouldn't
+ matter to set the reaching reg everywhere... some might be
+ dead and should be eliminated later. */
+
+ /* We replace (set mem expr) with (set reg expr) (set mem reg)
+ where reg is the reaching reg used in the load. We checked in
+ compute_ld_motion_mems that we can replace (set mem expr) with
+ (set reg expr) in that insn. */
+ rtx list = mem_ptr->stores;
- for (insn = BB_HEAD (bb);
- insn != NEXT_INSN (BB_END (bb));
- insn = NEXT_INSN (insn))
+ for ( ; list != NULL_RTX; list = XEXP (list, 1))
{
- if (! INSN_P (insn))
+ rtx insn = XEXP (list, 0);
+ rtx pat = PATTERN (insn);
+ rtx src = SET_SRC (pat);
+ rtx reg = expr->reaching_reg;
+ rtx copy, new;
+
+ /* If we've already copied it, continue. */
+ if (expr->reaching_reg == src)
continue;
- if (GET_CODE (insn) == CALL_INSN)
+ if (dump_file)
{
- bool clobbers_all = false;
-#ifdef NON_SAVING_SETJMP
- if (NON_SAVING_SETJMP
- && find_reg_note (insn, REG_SETJMP, NULL_RTX))
- clobbers_all = true;
-#endif
-
- for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if (clobbers_all
- || TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
- {
- last_set_in[regno] = INSN_UID (insn);
- SET_BIT (reg_set_in_block[bb->index], regno);
- }
+ fprintf (dump_file, "PRE: store updated with reaching reg ");
+ print_rtl (dump_file, expr->reaching_reg);
+ fprintf (dump_file, ":\n ");
+ print_inline_rtx (dump_file, insn, 8);
+ fprintf (dump_file, "\n");
}
- pat = PATTERN (insn);
- compute_store_table_current_insn = insn;
- note_stores (pat, reg_set_info, reg_set_in_block[bb->index]);
- }
-
- /* Now find the stores. */
- memset (already_set, 0, sizeof (int) * max_gcse_regno);
- regvec = already_set;
- for (insn = BB_HEAD (bb);
- insn != NEXT_INSN (BB_END (bb));
- insn = NEXT_INSN (insn))
- {
- if (! INSN_P (insn))
- continue;
-
- if (GET_CODE (insn) == CALL_INSN)
- {
- bool clobbers_all = false;
-#ifdef NON_SAVING_SETJMP
- if (NON_SAVING_SETJMP
- && find_reg_note (insn, REG_SETJMP, NULL_RTX))
- clobbers_all = true;
-#endif
+ copy = gen_move_insn ( reg, copy_rtx (SET_SRC (pat)));
+ new = emit_insn_before (copy, insn);
+ record_one_set (REGNO (reg), new);
+ SET_SRC (pat) = reg;
+ df_insn_rescan (insn);
- for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if (clobbers_all
- || TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
- already_set[regno] = 1;
- }
+ /* un-recognize this pattern since it's probably different now. */
+ INSN_CODE (insn) = -1;
+ gcse_create_count++;
+ }
+ }
+}
+\f
+/* Store motion code. */
- pat = PATTERN (insn);
- note_stores (pat, reg_set_info, NULL);
+#define ANTIC_STORE_LIST(x) ((x)->loads)
+#define AVAIL_STORE_LIST(x) ((x)->stores)
+#define LAST_AVAIL_CHECK_FAILURE(x) ((x)->reaching_reg)
- /* Now that we've marked regs, look for stores. */
- find_moveable_store (insn, already_set, last_set_in);
+/* This is used to communicate the target bitvector we want to use in the
+ reg_set_info routine when called via the note_stores mechanism. */
+static int * regvec;
- /* Unmark regs that are no longer set. */
- compute_store_table_current_insn = insn;
- note_stores (pat, reg_clear_last_set, last_set_in);
- if (GET_CODE (insn) == CALL_INSN)
- {
- bool clobbers_all = false;
-#ifdef NON_SAVING_SETJMP
- if (NON_SAVING_SETJMP
- && find_reg_note (insn, REG_SETJMP, NULL_RTX))
- clobbers_all = true;
-#endif
+/* And current insn, for the same routine. */
+static rtx compute_store_table_current_insn;
- for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if ((clobbers_all
- || TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
- && last_set_in[regno] == INSN_UID (insn))
- last_set_in[regno] = 0;
- }
- }
+/* Used in computing the reverse edge graph bit vectors. */
+static sbitmap * st_antloc;
-#ifdef ENABLE_CHECKING
- /* last_set_in should now be all-zero. */
- for (regno = 0; regno < max_gcse_regno; regno++)
- if (last_set_in[regno] != 0)
- abort ();
-#endif
+/* Global holding the number of store expressions we are dealing with. */
+static int num_stores;
- /* Clear temporary marks. */
- for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
- {
- LAST_AVAIL_CHECK_FAILURE(ptr) = NULL_RTX;
- if (ANTIC_STORE_LIST (ptr)
- && (tmp = XEXP (ANTIC_STORE_LIST (ptr), 0)) == NULL_RTX)
- ANTIC_STORE_LIST (ptr) = XEXP (ANTIC_STORE_LIST (ptr), 1);
- }
- }
+/* Checks to set if we need to mark a register set. Called from
+ note_stores. */
- /* Remove the stores that are not available anywhere, as there will
- be no opportunity to optimize them. */
- for (ptr = pre_ldst_mems, prev_next_ptr_ptr = &pre_ldst_mems;
- ptr != NULL;
- ptr = *prev_next_ptr_ptr)
- {
- if (!AVAIL_STORE_LIST (ptr))
- {
- *prev_next_ptr_ptr = ptr->next;
- free_ldst_entry (ptr);
- }
- else
- prev_next_ptr_ptr = &ptr->next;
- }
+static void
+reg_set_info (rtx dest, const_rtx setter ATTRIBUTE_UNUSED,
+ void *data)
+{
+ sbitmap bb_reg = data;
- ret = enumerate_ldsts ();
+ if (GET_CODE (dest) == SUBREG)
+ dest = SUBREG_REG (dest);
- if (gcse_file)
+ if (REG_P (dest))
{
- fprintf (gcse_file, "ST_avail and ST_antic (shown under loads..)\n");
- print_ldst_list (gcse_file);
+ regvec[REGNO (dest)] = INSN_UID (compute_store_table_current_insn);
+ if (bb_reg)
+ SET_BIT (bb_reg, REGNO (dest));
}
-
- free (last_set_in);
- free (already_set);
- return ret;
}
-/* Check to see if the load X is aliased with STORE_PATTERN.
- AFTER is true if we are checking the case when STORE_PATTERN occurs
- after the X. */
+/* Clear any mark that says that this insn sets dest. Called from
+ note_stores. */
-static bool
-load_kills_store (rtx x, rtx store_pattern, int after)
+static void
+reg_clear_last_set (rtx dest, const_rtx setter ATTRIBUTE_UNUSED,
+ void *data)
{
- if (after)
- return anti_dependence (x, store_pattern);
- else
- return true_dependence (store_pattern, GET_MODE (store_pattern), x,
- rtx_addr_varies_p);
+ int *dead_vec = data;
+
+ if (GET_CODE (dest) == SUBREG)
+ dest = SUBREG_REG (dest);
+
+ if (REG_P (dest) &&
+ dead_vec[REGNO (dest)] == INSN_UID (compute_store_table_current_insn))
+ dead_vec[REGNO (dest)] = 0;
}
-/* Go through the entire insn X, looking for any loads which might alias
- STORE_PATTERN. Return true if found.
- AFTER is true if we are checking the case when STORE_PATTERN occurs
- after the insn X. */
+/* Return zero if some of the registers in list X are killed
+ due to set of registers in bitmap REGS_SET. */
static bool
-find_loads (rtx x, rtx store_pattern, int after)
+store_ops_ok (const_rtx x, int *regs_set)
{
- const char * fmt;
- int i, j;
- int ret = false;
-
- if (!x)
- return false;
+ const_rtx reg;
- if (GET_CODE (x) == SET)
- x = SET_SRC (x);
-
- if (GET_CODE (x) == MEM)
+ for (; x; x = XEXP (x, 1))
{
- if (load_kills_store (x, store_pattern, after))
- return true;
+ reg = XEXP (x, 0);
+ if (regs_set[REGNO(reg)])
+ return false;
}
- /* Recursively process the insn. */
- fmt = GET_RTX_FORMAT (GET_CODE (x));
-
- for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0 && !ret; i--)
- {
- if (fmt[i] == 'e')
- ret |= find_loads (XEXP (x, i), store_pattern, after);
- else if (fmt[i] == 'E')
- for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- ret |= find_loads (XVECEXP (x, i, j), store_pattern, after);
- }
- return ret;
+ return true;
}
-/* Check if INSN kills the store pattern X (is aliased with it).
- AFTER is true if we are checking the case when store X occurs
- after the insn. Return true if it it does. */
+/* Returns a list of registers mentioned in X. */
+static rtx
+extract_mentioned_regs (rtx x)
+{
+ return extract_mentioned_regs_helper (x, NULL_RTX);
+}
-static bool
-store_killed_in_insn (rtx x, rtx x_regs, rtx insn, int after)
+/* Helper for extract_mentioned_regs; ACCUM is used to accumulate used
+ registers. */
+static rtx
+extract_mentioned_regs_helper (rtx x, rtx accum)
{
- rtx reg, base, note;
+ int i;
+ enum rtx_code code;
+ const char * fmt;
- if (!INSN_P (insn))
- return false;
+ /* Repeat is used to turn tail-recursion into iteration. */
+ repeat:
+
+ if (x == 0)
+ return accum;
- if (GET_CODE (insn) == CALL_INSN)
+ code = GET_CODE (x);
+ switch (code)
{
- /* A normal or pure call might read from pattern,
- but a const call will not. */
- if (! CONST_OR_PURE_CALL_P (insn) || pure_call_p (insn))
- return true;
+ case REG:
+ return alloc_EXPR_LIST (0, x, accum);
- /* But even a const call reads its parameters. Check whether the
- base of some of registers used in mem is stack pointer. */
- for (reg = x_regs; reg; reg = XEXP (reg, 1))
- {
- base = find_base_term (XEXP (reg, 0));
- if (!base
- || (GET_CODE (base) == ADDRESS
- && GET_MODE (base) == Pmode
- && XEXP (base, 0) == stack_pointer_rtx))
- return true;
- }
+ case MEM:
+ x = XEXP (x, 0);
+ goto repeat;
- return false;
- }
+ case PRE_DEC:
+ case PRE_INC:
+ case PRE_MODIFY:
+ case POST_DEC:
+ case POST_INC:
+ case POST_MODIFY:
+ /* We do not run this function with arguments having side effects. */
+ gcc_unreachable ();
- if (GET_CODE (PATTERN (insn)) == SET)
- {
- rtx pat = PATTERN (insn);
- rtx dest = SET_DEST (pat);
+ case PC:
+ case CC0: /*FIXME*/
+ case CONST:
+ case CONST_INT:
+ case CONST_DOUBLE:
+ case CONST_FIXED:
+ case CONST_VECTOR:
+ case SYMBOL_REF:
+ case LABEL_REF:
+ case ADDR_VEC:
+ case ADDR_DIFF_VEC:
+ return accum;
+
+ default:
+ break;
+ }
- if (GET_CODE (dest) == SIGN_EXTRACT
- || GET_CODE (dest) == ZERO_EXTRACT)
- dest = XEXP (dest, 0);
+ i = GET_RTX_LENGTH (code) - 1;
+ fmt = GET_RTX_FORMAT (code);
- /* Check for memory stores to aliased objects. */
- if (GET_CODE (dest) == MEM
- && !expr_equiv_p (dest, x))
+ for (; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
{
- if (after)
- {
- if (output_dependence (dest, x))
- return true;
- }
- else
+ rtx tem = XEXP (x, i);
+
+ /* If we are about to do the last recursive call
+ needed at this level, change it into iteration. */
+ if (i == 0)
{
- if (output_dependence (x, dest))
- return true;
+ x = tem;
+ goto repeat;
}
- }
- if (find_loads (SET_SRC (pat), x, after))
- return true;
- }
- else if (find_loads (PATTERN (insn), x, after))
- return true;
-
- /* If this insn has a REG_EQUAL or REG_EQUIV note referencing a memory
- location aliased with X, then this insn kills X. */
- note = find_reg_equal_equiv_note (insn);
- if (! note)
- return false;
- note = XEXP (note, 0);
-
- /* However, if the note represents a must alias rather than a may
- alias relationship, then it does not kill X. */
- if (expr_equiv_p (note, x))
- return false;
-
- /* See if there are any aliased loads in the note. */
- return find_loads (note, x, after);
-}
-
-/* Returns true if the expression X is loaded or clobbered on or after INSN
- within basic block BB. REGS_SET_AFTER is bitmap of registers set in
- or after the insn. X_REGS is list of registers mentioned in X. If the store
- is killed, return the last insn in that it occurs in FAIL_INSN. */
-static bool
-store_killed_after (rtx x, rtx x_regs, rtx insn, basic_block bb,
- int *regs_set_after, rtx *fail_insn)
-{
- rtx last = BB_END (bb), act;
+ accum = extract_mentioned_regs_helper (tem, accum);
+ }
+ else if (fmt[i] == 'E')
+ {
+ int j;
- if (!store_ops_ok (x_regs, regs_set_after))
- {
- /* We do not know where it will happen. */
- if (fail_insn)
- *fail_insn = NULL_RTX;
- return true;
+ for (j = 0; j < XVECLEN (x, i); j++)
+ accum = extract_mentioned_regs_helper (XVECEXP (x, i, j), accum);
+ }
}
- /* Scan from the end, so that fail_insn is determined correctly. */
- for (act = last; act != PREV_INSN (insn); act = PREV_INSN (act))
- if (store_killed_in_insn (x, x_regs, act, false))
- {
- if (fail_insn)
- *fail_insn = act;
- return true;
- }
-
- return false;
+ return accum;
}
-/* Returns true if the expression X is loaded or clobbered on or before INSN
- within basic block BB. X_REGS is list of registers mentioned in X.
- REGS_SET_BEFORE is bitmap of registers set before or in this insn. */
-static bool
-store_killed_before (rtx x, rtx x_regs, rtx insn, basic_block bb,
- int *regs_set_before)
-{
- rtx first = BB_HEAD (bb);
+/* Determine whether INSN is MEM store pattern that we will consider moving.
+ REGS_SET_BEFORE is bitmap of registers set before (and including) the
+ current insn, REGS_SET_AFTER is bitmap of registers set after (and
+ including) the insn in this basic block. We must be passing through BB from
+ head to end, as we are using this fact to speed things up.
- if (!store_ops_ok (x_regs, regs_set_before))
- return true;
+ The results are stored this way:
- for ( ; insn != PREV_INSN (first); insn = PREV_INSN (insn))
- if (store_killed_in_insn (x, x_regs, insn, true))
- return true;
+ -- the first anticipatable expression is added into ANTIC_STORE_LIST
+ -- if the processed expression is not anticipatable, NULL_RTX is added
+ there instead, so that we can use it as indicator that no further
+ expression of this type may be anticipatable
+ -- if the expression is available, it is added as head of AVAIL_STORE_LIST;
+ consequently, all of them but this head are dead and may be deleted.
+ -- if the expression is not available, the insn due to that it fails to be
+ available is stored in reaching_reg.
- return false;
-}
+ The things are complicated a bit by fact that there already may be stores
+ to the same MEM from other blocks; also caller must take care of the
+ necessary cleanup of the temporary markers after end of the basic block.
+ */
-/* Fill in available, anticipatable, transparent and kill vectors in
- STORE_DATA, based on lists of available and anticipatable stores. */
static void
-build_store_vectors (void)
+find_moveable_store (rtx insn, int *regs_set_before, int *regs_set_after)
{
- basic_block bb;
- int *regs_set_in_block;
- rtx insn, st;
struct ls_expr * ptr;
- unsigned regno;
+ rtx dest, set, tmp;
+ int check_anticipatable, check_available;
+ basic_block bb = BLOCK_FOR_INSN (insn);
- /* Build the gen_vector. This is any store in the table which is not killed
- by aliasing later in its block. */
- ae_gen = sbitmap_vector_alloc (last_basic_block, num_stores);
- sbitmap_vector_zero (ae_gen, last_basic_block);
+ set = single_set (insn);
+ if (!set)
+ return;
- st_antloc = sbitmap_vector_alloc (last_basic_block, num_stores);
- sbitmap_vector_zero (st_antloc, last_basic_block);
+ dest = SET_DEST (set);
- for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
- {
- for (st = AVAIL_STORE_LIST (ptr); st != NULL; st = XEXP (st, 1))
- {
- insn = XEXP (st, 0);
- bb = BLOCK_FOR_INSN (insn);
+ if (! MEM_P (dest) || MEM_VOLATILE_P (dest)
+ || GET_MODE (dest) == BLKmode)
+ return;
- /* If we've already seen an available expression in this block,
- we can delete this one (It occurs earlier in the block). We'll
- copy the SRC expression to an unused register in case there
- are any side effects. */
- if (TEST_BIT (ae_gen[bb->index], ptr->index))
- {
- rtx r = gen_reg_rtx (GET_MODE (ptr->pattern));
- if (gcse_file)
- fprintf (gcse_file, "Removing redundant store:\n");
- replace_store_insn (r, XEXP (st, 0), bb, ptr);
- continue;
- }
- SET_BIT (ae_gen[bb->index], ptr->index);
- }
+ if (side_effects_p (dest))
+ return;
- for (st = ANTIC_STORE_LIST (ptr); st != NULL; st = XEXP (st, 1))
- {
- insn = XEXP (st, 0);
- bb = BLOCK_FOR_INSN (insn);
- SET_BIT (st_antloc[bb->index], ptr->index);
- }
- }
+ /* If we are handling exceptions, we must be careful with memory references
+ that may trap. If we are not, the behavior is undefined, so we may just
+ continue. */
+ if (flag_non_call_exceptions && may_trap_p (dest))
+ return;
- ae_kill = sbitmap_vector_alloc (last_basic_block, num_stores);
- sbitmap_vector_zero (ae_kill, last_basic_block);
+ /* Even if the destination cannot trap, the source may. In this case we'd
+ need to handle updating the REG_EH_REGION note. */
+ if (find_reg_note (insn, REG_EH_REGION, NULL_RTX))
+ return;
- transp = sbitmap_vector_alloc (last_basic_block, num_stores);
- sbitmap_vector_zero (transp, last_basic_block);
- regs_set_in_block = xmalloc (sizeof (int) * max_gcse_regno);
+ /* Make sure that the SET_SRC of this store insns can be assigned to
+ a register, or we will fail later on in replace_store_insn, which
+ assumes that we can do this. But sometimes the target machine has
+ oddities like MEM read-modify-write instruction. See for example
+ PR24257. */
+ if (!can_assign_to_reg_p (SET_SRC (set)))
+ return;
- FOR_EACH_BB (bb)
- {
- for (regno = 0; regno < max_gcse_regno; regno++)
- regs_set_in_block[regno] = TEST_BIT (reg_set_in_block[bb->index], regno);
+ ptr = ldst_entry (dest);
+ if (!ptr->pattern_regs)
+ ptr->pattern_regs = extract_mentioned_regs (dest);
- for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
- {
- if (store_killed_after (ptr->pattern, ptr->pattern_regs, BB_HEAD (bb),
- bb, regs_set_in_block, NULL))
- {
- /* It should not be necessary to consider the expression
- killed if it is both anticipatable and available. */
- if (!TEST_BIT (st_antloc[bb->index], ptr->index)
- || !TEST_BIT (ae_gen[bb->index], ptr->index))
- SET_BIT (ae_kill[bb->index], ptr->index);
- }
- else
- SET_BIT (transp[bb->index], ptr->index);
- }
+ /* Do not check for anticipatability if we either found one anticipatable
+ store already, or tested for one and found out that it was killed. */
+ check_anticipatable = 0;
+ if (!ANTIC_STORE_LIST (ptr))
+ check_anticipatable = 1;
+ else
+ {
+ tmp = XEXP (ANTIC_STORE_LIST (ptr), 0);
+ if (tmp != NULL_RTX
+ && BLOCK_FOR_INSN (tmp) != bb)
+ check_anticipatable = 1;
}
-
- free (regs_set_in_block);
-
- if (gcse_file)
+ if (check_anticipatable)
{
- dump_sbitmap_vector (gcse_file, "st_antloc", "", st_antloc, last_basic_block);
- dump_sbitmap_vector (gcse_file, "st_kill", "", ae_kill, last_basic_block);
- dump_sbitmap_vector (gcse_file, "Transpt", "", transp, last_basic_block);
- dump_sbitmap_vector (gcse_file, "st_avloc", "", ae_gen, last_basic_block);
+ if (store_killed_before (dest, ptr->pattern_regs, insn, bb, regs_set_before))
+ tmp = NULL_RTX;
+ else
+ tmp = insn;
+ ANTIC_STORE_LIST (ptr) = alloc_INSN_LIST (tmp,
+ ANTIC_STORE_LIST (ptr));
}
-}
-
-/* Insert an instruction at the beginning of a basic block, and update
- the BB_HEAD if needed. */
-static void
-insert_insn_start_bb (rtx insn, basic_block bb)
-{
- /* Insert at start of successor block. */
- rtx prev = PREV_INSN (BB_HEAD (bb));
- rtx before = BB_HEAD (bb);
- while (before != 0)
+ /* It is not necessary to check whether store is available if we did
+ it successfully before; if we failed before, do not bother to check
+ until we reach the insn that caused us to fail. */
+ check_available = 0;
+ if (!AVAIL_STORE_LIST (ptr))
+ check_available = 1;
+ else
{
- if (GET_CODE (before) != CODE_LABEL
- && (GET_CODE (before) != NOTE
- || NOTE_LINE_NUMBER (before) != NOTE_INSN_BASIC_BLOCK))
- break;
- prev = before;
- if (prev == BB_END (bb))
- break;
- before = NEXT_INSN (before);
+ tmp = XEXP (AVAIL_STORE_LIST (ptr), 0);
+ if (BLOCK_FOR_INSN (tmp) != bb)
+ check_available = 1;
}
-
- insn = emit_insn_after (insn, prev);
-
- if (gcse_file)
+ if (check_available)
{
- fprintf (gcse_file, "STORE_MOTION insert store at start of BB %d:\n",
- bb->index);
- print_inline_rtx (gcse_file, insn, 6);
- fprintf (gcse_file, "\n");
+ /* Check that we have already reached the insn at that the check
+ failed last time. */
+ if (LAST_AVAIL_CHECK_FAILURE (ptr))
+ {
+ for (tmp = BB_END (bb);
+ tmp != insn && tmp != LAST_AVAIL_CHECK_FAILURE (ptr);
+ tmp = PREV_INSN (tmp))
+ continue;
+ if (tmp == insn)
+ check_available = 0;
+ }
+ else
+ check_available = store_killed_after (dest, ptr->pattern_regs, insn,
+ bb, regs_set_after,
+ &LAST_AVAIL_CHECK_FAILURE (ptr));
}
+ if (!check_available)
+ AVAIL_STORE_LIST (ptr) = alloc_INSN_LIST (insn, AVAIL_STORE_LIST (ptr));
}
-/* This routine will insert a store on an edge. EXPR is the ldst entry for
- the memory reference, and E is the edge to insert it on. Returns nonzero
- if an edge insertion was performed. */
+/* Find available and anticipatable stores. */
static int
-insert_store (struct ls_expr * expr, edge e)
+compute_store_table (void)
{
- rtx reg, insn;
+ int ret;
basic_block bb;
- edge tmp;
-
- /* We did all the deleted before this insert, so if we didn't delete a
- store, then we haven't set the reaching reg yet either. */
- if (expr->reaching_reg == NULL_RTX)
- return 0;
-
- if (e->flags & EDGE_FAKE)
- return 0;
-
- reg = expr->reaching_reg;
- insn = gen_move_insn (copy_rtx (expr->pattern), reg);
+ unsigned regno;
+ rtx insn, pat, tmp;
+ int *last_set_in, *already_set;
+ struct ls_expr * ptr, **prev_next_ptr_ptr;
- /* If we are inserting this expression on ALL predecessor edges of a BB,
- insert it at the start of the BB, and reset the insert bits on the other
- edges so we don't try to insert it on the other edges. */
- bb = e->dest;
- for (tmp = e->dest->pred; tmp ; tmp = tmp->pred_next)
- if (!(tmp->flags & EDGE_FAKE))
- {
- int index = EDGE_INDEX (edge_list, tmp->src, tmp->dest);
- if (index == EDGE_INDEX_NO_EDGE)
- abort ();
- if (! TEST_BIT (pre_insert_map[index], expr->index))
- break;
- }
+ max_gcse_regno = max_reg_num ();
- /* If tmp is NULL, we found an insertion on every edge, blank the
- insertion vector for these edges, and insert at the start of the BB. */
- if (!tmp && bb != EXIT_BLOCK_PTR)
- {
- for (tmp = e->dest->pred; tmp ; tmp = tmp->pred_next)
- {
- int index = EDGE_INDEX (edge_list, tmp->src, tmp->dest);
- RESET_BIT (pre_insert_map[index], expr->index);
- }
- insert_insn_start_bb (insn, bb);
- return 0;
- }
+ reg_set_in_block = sbitmap_vector_alloc (last_basic_block,
+ max_gcse_regno);
+ sbitmap_vector_zero (reg_set_in_block, last_basic_block);
+ pre_ldst_mems = 0;
+ pre_ldst_table = htab_create (13, pre_ldst_expr_hash,
+ pre_ldst_expr_eq, NULL);
+ last_set_in = XCNEWVEC (int, max_gcse_regno);
+ already_set = XNEWVEC (int, max_gcse_regno);
- /* We can't insert on this edge, so we'll insert at the head of the
- successors block. See Morgan, sec 10.5. */
- if ((e->flags & EDGE_ABNORMAL) == EDGE_ABNORMAL)
+ /* Find all the stores we care about. */
+ FOR_EACH_BB (bb)
{
- insert_insn_start_bb (insn, bb);
- return 0;
- }
+ /* First compute the registers set in this block. */
+ regvec = last_set_in;
- insert_insn_on_edge (insn, e);
+ FOR_BB_INSNS (bb, insn)
+ {
+ if (! INSN_P (insn))
+ continue;
- if (gcse_file)
- {
- fprintf (gcse_file, "STORE_MOTION insert insn on edge (%d, %d):\n",
- e->src->index, e->dest->index);
- print_inline_rtx (gcse_file, insn, 6);
- fprintf (gcse_file, "\n");
- }
+ if (CALL_P (insn))
+ {
+ for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
+ if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
+ {
+ last_set_in[regno] = INSN_UID (insn);
+ SET_BIT (reg_set_in_block[bb->index], regno);
+ }
+ }
- return 1;
-}
+ pat = PATTERN (insn);
+ compute_store_table_current_insn = insn;
+ note_stores (pat, reg_set_info, reg_set_in_block[bb->index]);
+ }
-/* Remove any REG_EQUAL or REG_EQUIV notes containing a reference to the
- memory location in SMEXPR set in basic block BB.
+ /* Now find the stores. */
+ memset (already_set, 0, sizeof (int) * max_gcse_regno);
+ regvec = already_set;
+ FOR_BB_INSNS (bb, insn)
+ {
+ if (! INSN_P (insn))
+ continue;
- This could be rather expensive. */
+ if (CALL_P (insn))
+ {
+ for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
+ if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
+ already_set[regno] = 1;
+ }
-static void
-remove_reachable_equiv_notes (basic_block bb, struct ls_expr *smexpr)
-{
- edge *stack = xmalloc (sizeof (edge) * n_basic_blocks), act;
- sbitmap visited = sbitmap_alloc (last_basic_block);
- int stack_top = 0;
- rtx last, insn, note;
- rtx mem = smexpr->pattern;
+ pat = PATTERN (insn);
+ note_stores (pat, reg_set_info, NULL);
- sbitmap_zero (visited);
- act = bb->succ;
+ /* Now that we've marked regs, look for stores. */
+ find_moveable_store (insn, already_set, last_set_in);
- while (1)
- {
- if (!act)
- {
- if (!stack_top)
+ /* Unmark regs that are no longer set. */
+ compute_store_table_current_insn = insn;
+ note_stores (pat, reg_clear_last_set, last_set_in);
+ if (CALL_P (insn))
{
- free (stack);
- sbitmap_free (visited);
- return;
+ for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
+ if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno)
+ && last_set_in[regno] == INSN_UID (insn))
+ last_set_in[regno] = 0;
}
- act = stack[--stack_top];
}
- bb = act->dest;
-
- if (bb == EXIT_BLOCK_PTR
- || TEST_BIT (visited, bb->index)
- || TEST_BIT (ae_kill[bb->index], smexpr->index))
+
+#ifdef ENABLE_CHECKING
+ /* last_set_in should now be all-zero. */
+ for (regno = 0; regno < max_gcse_regno; regno++)
+ gcc_assert (!last_set_in[regno]);
+#endif
+
+ /* Clear temporary marks. */
+ for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
{
- act = act->succ_next;
- continue;
+ LAST_AVAIL_CHECK_FAILURE(ptr) = NULL_RTX;
+ if (ANTIC_STORE_LIST (ptr)
+ && (tmp = XEXP (ANTIC_STORE_LIST (ptr), 0)) == NULL_RTX)
+ ANTIC_STORE_LIST (ptr) = XEXP (ANTIC_STORE_LIST (ptr), 1);
}
- SET_BIT (visited, bb->index);
+ }
- if (TEST_BIT (st_antloc[bb->index], smexpr->index))
+ /* Remove the stores that are not available anywhere, as there will
+ be no opportunity to optimize them. */
+ for (ptr = pre_ldst_mems, prev_next_ptr_ptr = &pre_ldst_mems;
+ ptr != NULL;
+ ptr = *prev_next_ptr_ptr)
+ {
+ if (!AVAIL_STORE_LIST (ptr))
{
- for (last = ANTIC_STORE_LIST (smexpr);
- BLOCK_FOR_INSN (XEXP (last, 0)) != bb;
- last = XEXP (last, 1))
- continue;
- last = XEXP (last, 0);
+ *prev_next_ptr_ptr = ptr->next;
+ htab_remove_elt_with_hash (pre_ldst_table, ptr, ptr->hash_index);
+ free_ldst_entry (ptr);
}
else
- last = NEXT_INSN (BB_END (bb));
-
- for (insn = BB_HEAD (bb); insn != last; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- {
- note = find_reg_equal_equiv_note (insn);
- if (!note || !expr_equiv_p (XEXP (note, 0), mem))
- continue;
+ prev_next_ptr_ptr = &ptr->next;
+ }
- if (gcse_file)
- fprintf (gcse_file, "STORE_MOTION drop REG_EQUAL note at insn %d:\n",
- INSN_UID (insn));
- remove_note (insn, note);
- }
- act = act->succ_next;
- if (bb->succ)
- {
- if (act)
- stack[stack_top++] = act;
- act = bb->succ;
- }
+ ret = enumerate_ldsts ();
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "ST_avail and ST_antic (shown under loads..)\n");
+ print_ldst_list (dump_file);
}
+
+ free (last_set_in);
+ free (already_set);
+ return ret;
}
-/* This routine will replace a store with a SET to a specified register. */
+/* Check to see if the load X is aliased with STORE_PATTERN.
+ AFTER is true if we are checking the case when STORE_PATTERN occurs
+ after the X. */
-static void
-replace_store_insn (rtx reg, rtx del, basic_block bb, struct ls_expr *smexpr)
+static bool
+load_kills_store (const_rtx x, const_rtx store_pattern, int after)
{
- rtx insn, mem, note, set, ptr;
+ if (after)
+ return anti_dependence (x, store_pattern);
+ else
+ return true_dependence (store_pattern, GET_MODE (store_pattern), x,
+ rtx_addr_varies_p);
+}
- mem = smexpr->pattern;
- insn = gen_move_insn (reg, SET_SRC (single_set (del)));
- insn = emit_insn_after (insn, del);
+/* Go through the entire insn X, looking for any loads which might alias
+ STORE_PATTERN. Return true if found.
+ AFTER is true if we are checking the case when STORE_PATTERN occurs
+ after the insn X. */
+
+static bool
+find_loads (const_rtx x, const_rtx store_pattern, int after)
+{
+ const char * fmt;
+ int i, j;
+ int ret = false;
+
+ if (!x)
+ return false;
+
+ if (GET_CODE (x) == SET)
+ x = SET_SRC (x);
- if (gcse_file)
+ if (MEM_P (x))
{
- fprintf (gcse_file,
- "STORE_MOTION delete insn in BB %d:\n ", bb->index);
- print_inline_rtx (gcse_file, del, 6);
- fprintf (gcse_file, "\nSTORE MOTION replaced with insn:\n ");
- print_inline_rtx (gcse_file, insn, 6);
- fprintf (gcse_file, "\n");
+ if (load_kills_store (x, store_pattern, after))
+ return true;
}
- for (ptr = ANTIC_STORE_LIST (smexpr); ptr; ptr = XEXP (ptr, 1))
- if (XEXP (ptr, 0) == del)
- {
- XEXP (ptr, 0) = insn;
- break;
- }
- delete_insn (del);
+ /* Recursively process the insn. */
+ fmt = GET_RTX_FORMAT (GET_CODE (x));
- /* Now we must handle REG_EQUAL notes whose contents is equal to the mem;
- they are no longer accurate provided that they are reached by this
- definition, so drop them. */
- for (; insn != NEXT_INSN (BB_END (bb)); insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- {
- set = single_set (insn);
- if (!set)
- continue;
- if (expr_equiv_p (SET_DEST (set), mem))
- return;
- note = find_reg_equal_equiv_note (insn);
- if (!note || !expr_equiv_p (XEXP (note, 0), mem))
- continue;
+ for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0 && !ret; i--)
+ {
+ if (fmt[i] == 'e')
+ ret |= find_loads (XEXP (x, i), store_pattern, after);
+ else if (fmt[i] == 'E')
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ ret |= find_loads (XVECEXP (x, i, j), store_pattern, after);
+ }
+ return ret;
+}
+
+static inline bool
+store_killed_in_pat (const_rtx x, const_rtx pat, int after)
+{
+ if (GET_CODE (pat) == SET)
+ {
+ rtx dest = SET_DEST (pat);
+
+ if (GET_CODE (dest) == ZERO_EXTRACT)
+ dest = XEXP (dest, 0);
+
+ /* Check for memory stores to aliased objects. */
+ if (MEM_P (dest)
+ && !expr_equiv_p (dest, x))
+ {
+ if (after)
+ {
+ if (output_dependence (dest, x))
+ return true;
+ }
+ else
+ {
+ if (output_dependence (x, dest))
+ return true;
+ }
+ }
+ }
- if (gcse_file)
- fprintf (gcse_file, "STORE_MOTION drop REG_EQUAL note at insn %d:\n",
- INSN_UID (insn));
- remove_note (insn, note);
- }
- remove_reachable_equiv_notes (bb, smexpr);
-}
+ if (find_loads (pat, x, after))
+ return true;
+ return false;
+}
-/* Delete a store, but copy the value that would have been stored into
- the reaching_reg for later storing. */
+/* Check if INSN kills the store pattern X (is aliased with it).
+ AFTER is true if we are checking the case when store X occurs
+ after the insn. Return true if it does. */
-static void
-delete_store (struct ls_expr * expr, basic_block bb)
+static bool
+store_killed_in_insn (const_rtx x, const_rtx x_regs, const_rtx insn, int after)
{
- rtx reg, i, del;
+ const_rtx reg, base, note, pat;
- if (expr->reaching_reg == NULL_RTX)
- expr->reaching_reg = gen_reg_rtx (GET_MODE (expr->pattern));
-
- reg = expr->reaching_reg;
+ if (!INSN_P (insn))
+ return false;
- for (i = AVAIL_STORE_LIST (expr); i; i = XEXP (i, 1))
+ if (CALL_P (insn))
{
- del = XEXP (i, 0);
- if (BLOCK_FOR_INSN (del) == bb)
+ /* A normal or pure call might read from pattern,
+ but a const call will not. */
+ if (! CONST_OR_PURE_CALL_P (insn) || pure_call_p (insn))
+ return true;
+
+ /* But even a const call reads its parameters. Check whether the
+ base of some of registers used in mem is stack pointer. */
+ for (reg = x_regs; reg; reg = XEXP (reg, 1))
{
- /* We know there is only one since we deleted redundant
- ones during the available computation. */
- replace_store_insn (reg, del, bb, expr);
- break;
+ base = find_base_term (XEXP (reg, 0));
+ if (!base
+ || (GET_CODE (base) == ADDRESS
+ && GET_MODE (base) == Pmode
+ && XEXP (base, 0) == stack_pointer_rtx))
+ return true;
}
+
+ return false;
}
-}
-/* Free memory used by store motion. */
+ pat = PATTERN (insn);
+ if (GET_CODE (pat) == SET)
+ {
+ if (store_killed_in_pat (x, pat, after))
+ return true;
+ }
+ else if (GET_CODE (pat) == PARALLEL)
+ {
+ int i;
-static void
-free_store_memory (void)
-{
- free_ldst_mems ();
+ for (i = 0; i < XVECLEN (pat, 0); i++)
+ if (store_killed_in_pat (x, XVECEXP (pat, 0, i), after))
+ return true;
+ }
+ else if (find_loads (PATTERN (insn), x, after))
+ return true;
- if (ae_gen)
- sbitmap_vector_free (ae_gen);
- if (ae_kill)
- sbitmap_vector_free (ae_kill);
- if (transp)
- sbitmap_vector_free (transp);
- if (st_antloc)
- sbitmap_vector_free (st_antloc);
- if (pre_insert_map)
- sbitmap_vector_free (pre_insert_map);
- if (pre_delete_map)
- sbitmap_vector_free (pre_delete_map);
- if (reg_set_in_block)
- sbitmap_vector_free (reg_set_in_block);
+ /* If this insn has a REG_EQUAL or REG_EQUIV note referencing a memory
+ location aliased with X, then this insn kills X. */
+ note = find_reg_equal_equiv_note (insn);
+ if (! note)
+ return false;
+ note = XEXP (note, 0);
- ae_gen = ae_kill = transp = st_antloc = NULL;
- pre_insert_map = pre_delete_map = reg_set_in_block = NULL;
+ /* However, if the note represents a must alias rather than a may
+ alias relationship, then it does not kill X. */
+ if (expr_equiv_p (note, x))
+ return false;
+
+ /* See if there are any aliased loads in the note. */
+ return find_loads (note, x, after);
}
-/* Perform store motion. Much like gcse, except we move expressions the
- other way by looking at the flowgraph in reverse. */
+/* Returns true if the expression X is loaded or clobbered on or after INSN
+ within basic block BB. REGS_SET_AFTER is bitmap of registers set in
+ or after the insn. X_REGS is list of registers mentioned in X. If the store
+ is killed, return the last insn in that it occurs in FAIL_INSN. */
-static void
-store_motion (void)
+static bool
+store_killed_after (const_rtx x, const_rtx x_regs, const_rtx insn, const_basic_block bb,
+ int *regs_set_after, rtx *fail_insn)
{
- basic_block bb;
- int x;
- struct ls_expr * ptr;
- int update_flow = 0;
-
- if (gcse_file)
- {
- fprintf (gcse_file, "before store motion\n");
- print_rtl (gcse_file, get_insns ());
- }
-
- init_alias_analysis ();
+ rtx last = BB_END (bb), act;
- /* Find all the available and anticipatable stores. */
- num_stores = compute_store_table ();
- if (num_stores == 0)
+ if (!store_ops_ok (x_regs, regs_set_after))
{
- sbitmap_vector_free (reg_set_in_block);
- end_alias_analysis ();
- return;
+ /* We do not know where it will happen. */
+ if (fail_insn)
+ *fail_insn = NULL_RTX;
+ return true;
}
- /* Now compute kill & transp vectors. */
- build_store_vectors ();
- add_noreturn_fake_exit_edges ();
- connect_infinite_loops_to_exit ();
+ /* Scan from the end, so that fail_insn is determined correctly. */
+ for (act = last; act != PREV_INSN (insn); act = PREV_INSN (act))
+ if (store_killed_in_insn (x, x_regs, act, false))
+ {
+ if (fail_insn)
+ *fail_insn = act;
+ return true;
+ }
- edge_list = pre_edge_rev_lcm (gcse_file, num_stores, transp, ae_gen,
- st_antloc, ae_kill, &pre_insert_map,
- &pre_delete_map);
+ return false;
+}
- /* Now we want to insert the new stores which are going to be needed. */
- for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
- {
- FOR_EACH_BB (bb)
- if (TEST_BIT (pre_delete_map[bb->index], ptr->index))
- delete_store (ptr, bb);
+/* Returns true if the expression X is loaded or clobbered on or before INSN
+ within basic block BB. X_REGS is list of registers mentioned in X.
+ REGS_SET_BEFORE is bitmap of registers set before or in this insn. */
+static bool
+store_killed_before (const_rtx x, const_rtx x_regs, const_rtx insn, const_basic_block bb,
+ int *regs_set_before)
+{
+ rtx first = BB_HEAD (bb);
- for (x = 0; x < NUM_EDGES (edge_list); x++)
- if (TEST_BIT (pre_insert_map[x], ptr->index))
- update_flow |= insert_store (ptr, INDEX_EDGE (edge_list, x));
- }
+ if (!store_ops_ok (x_regs, regs_set_before))
+ return true;
- if (update_flow)
- commit_edge_insertions ();
+ for ( ; insn != PREV_INSN (first); insn = PREV_INSN (insn))
+ if (store_killed_in_insn (x, x_regs, insn, true))
+ return true;
- free_store_memory ();
- free_edge_list (edge_list);
- remove_fake_edges ();
- end_alias_analysis ();
+ return false;
}
-\f
-/* Entry point for jump bypassing optimization pass. */
-
-int
-bypass_jumps (FILE *file)
+/* Fill in available, anticipatable, transparent and kill vectors in
+ STORE_DATA, based on lists of available and anticipatable stores. */
+static void
+build_store_vectors (void)
{
- int changed;
-
- /* We do not construct an accurate cfg in functions which call
- setjmp, so just punt to be safe. */
- if (current_function_calls_setjmp)
- return 0;
+ basic_block bb;
+ int *regs_set_in_block;
+ rtx insn, st;
+ struct ls_expr * ptr;
+ unsigned regno;
- /* For calling dump_foo fns from gdb. */
- debug_stderr = stderr;
- gcse_file = file;
+ /* Build the gen_vector. This is any store in the table which is not killed
+ by aliasing later in its block. */
+ ae_gen = sbitmap_vector_alloc (last_basic_block, num_stores);
+ sbitmap_vector_zero (ae_gen, last_basic_block);
- /* Identify the basic block information for this function, including
- successors and predecessors. */
- max_gcse_regno = max_reg_num ();
+ st_antloc = sbitmap_vector_alloc (last_basic_block, num_stores);
+ sbitmap_vector_zero (st_antloc, last_basic_block);
- if (file)
- dump_flow_info (file);
+ for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
+ {
+ for (st = AVAIL_STORE_LIST (ptr); st != NULL; st = XEXP (st, 1))
+ {
+ insn = XEXP (st, 0);
+ bb = BLOCK_FOR_INSN (insn);
- /* Return if there's nothing to do, or it is too expensive. */
- if (n_basic_blocks <= 1 || is_too_expensive (_ ("jump bypassing disabled")))
- return 0;
+ /* If we've already seen an available expression in this block,
+ we can delete this one (It occurs earlier in the block). We'll
+ copy the SRC expression to an unused register in case there
+ are any side effects. */
+ if (TEST_BIT (ae_gen[bb->index], ptr->index))
+ {
+ rtx r = gen_reg_rtx (GET_MODE (ptr->pattern));
+ if (dump_file)
+ fprintf (dump_file, "Removing redundant store:\n");
+ replace_store_insn (r, XEXP (st, 0), bb, ptr);
+ continue;
+ }
+ SET_BIT (ae_gen[bb->index], ptr->index);
+ }
- gcc_obstack_init (&gcse_obstack);
- bytes_used = 0;
+ for (st = ANTIC_STORE_LIST (ptr); st != NULL; st = XEXP (st, 1))
+ {
+ insn = XEXP (st, 0);
+ bb = BLOCK_FOR_INSN (insn);
+ SET_BIT (st_antloc[bb->index], ptr->index);
+ }
+ }
- /* We need alias. */
- init_alias_analysis ();
+ ae_kill = sbitmap_vector_alloc (last_basic_block, num_stores);
+ sbitmap_vector_zero (ae_kill, last_basic_block);
- /* Record where pseudo-registers are set. This data is kept accurate
- during each pass. ??? We could also record hard-reg information here
- [since it's unchanging], however it is currently done during hash table
- computation.
+ transp = sbitmap_vector_alloc (last_basic_block, num_stores);
+ sbitmap_vector_zero (transp, last_basic_block);
+ regs_set_in_block = XNEWVEC (int, max_gcse_regno);
- It may be tempting to compute MEM set information here too, but MEM sets
- will be subject to code motion one day and thus we need to compute
- information about memory sets when we build the hash tables. */
+ FOR_EACH_BB (bb)
+ {
+ for (regno = 0; regno < max_gcse_regno; regno++)
+ regs_set_in_block[regno] = TEST_BIT (reg_set_in_block[bb->index], regno);
- alloc_reg_set_mem (max_gcse_regno);
- compute_sets (get_insns ());
+ for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
+ {
+ if (store_killed_after (ptr->pattern, ptr->pattern_regs, BB_HEAD (bb),
+ bb, regs_set_in_block, NULL))
+ {
+ /* It should not be necessary to consider the expression
+ killed if it is both anticipatable and available. */
+ if (!TEST_BIT (st_antloc[bb->index], ptr->index)
+ || !TEST_BIT (ae_gen[bb->index], ptr->index))
+ SET_BIT (ae_kill[bb->index], ptr->index);
+ }
+ else
+ SET_BIT (transp[bb->index], ptr->index);
+ }
+ }
- max_gcse_regno = max_reg_num ();
- alloc_gcse_mem (get_insns ());
- changed = one_cprop_pass (1, 1, 1);
- free_gcse_mem ();
+ free (regs_set_in_block);
- if (file)
+ if (dump_file)
{
- fprintf (file, "BYPASS of %s: %d basic blocks, ",
- current_function_name (), n_basic_blocks);
- fprintf (file, "%d bytes\n\n", bytes_used);
+ dump_sbitmap_vector (dump_file, "st_antloc", "", st_antloc, last_basic_block);
+ dump_sbitmap_vector (dump_file, "st_kill", "", ae_kill, last_basic_block);
+ dump_sbitmap_vector (dump_file, "Transpt", "", transp, last_basic_block);
+ dump_sbitmap_vector (dump_file, "st_avloc", "", ae_gen, last_basic_block);
}
-
- obstack_free (&gcse_obstack, NULL);
- free_reg_set_mem ();
-
- /* We are finished with alias. */
- end_alias_analysis ();
- allocate_reg_info (max_reg_num (), FALSE, FALSE);
-
- return changed;
}
-/* Return true if the graph is too expensive to optimize. PASS is the
- optimization about to be performed. */
+/* Insert an instruction at the beginning of a basic block, and update
+ the BB_HEAD if needed. */
-static bool
-is_too_expensive (const char *pass)
+static void
+insert_insn_start_basic_block (rtx insn, basic_block bb)
{
- /* Trying to perform global optimizations on flow graphs which have
- a high connectivity will take a long time and is unlikely to be
- particularly useful.
-
- In normal circumstances a cfg should have about twice as many
- edges as blocks. But we do not want to punish small functions
- which have a couple switch statements. Rather than simply
- threshold the number of blocks, uses something with a more
- graceful degradation. */
- if (n_edges > 20000 + n_basic_blocks * 4)
+ /* Insert at start of successor block. */
+ rtx prev = PREV_INSN (BB_HEAD (bb));
+ rtx before = BB_HEAD (bb);
+ while (before != 0)
{
- if (warn_disabled_optimization)
- warning ("%s: %d basic blocks and %d edges/basic block",
- pass, n_basic_blocks, n_edges / n_basic_blocks);
-
- return true;
+ if (! LABEL_P (before)
+ && !NOTE_INSN_BASIC_BLOCK_P (before))
+ break;
+ prev = before;
+ if (prev == BB_END (bb))
+ break;
+ before = NEXT_INSN (before);
}
- /* If allocating memory for the cprop bitmap would take up too much
- storage it's better just to disable the optimization. */
- if ((n_basic_blocks
- * SBITMAP_SET_SIZE (max_reg_num ())
- * sizeof (SBITMAP_ELT_TYPE)) > MAX_GCSE_MEMORY)
- {
- if (warn_disabled_optimization)
- warning ("%s: %d basic blocks and %d registers",
- pass, n_basic_blocks, max_reg_num ());
+ insn = emit_insn_after_noloc (insn, prev, bb);
- return true;
+ if (dump_file)
+ {
+ fprintf (dump_file, "STORE_MOTION insert store at start of BB %d:\n",
+ bb->index);
+ print_inline_rtx (dump_file, insn, 6);
+ fprintf (dump_file, "\n");
}
-
- return false;
}
-/* The following code implements gcse after reload, the purpose of this
- pass is to cleanup redundant loads generated by reload and other
- optimizations that come after gcse. It searches for simple inter-block
- redundancies and tries to eliminate them by adding moves and loads
- in cold places. */
-
-/* The following structure holds the information about the occurrences of
- the redundant instructions. */
-struct unoccr
-{
- struct unoccr *next;
- edge pred;
- rtx insn;
-};
-
-static bool reg_used_on_edge (rtx, edge);
-static rtx reg_set_between_after_reload_p (rtx, rtx, rtx);
-static rtx reg_used_between_after_reload_p (rtx, rtx, rtx);
-static rtx get_avail_load_store_reg (rtx);
-static bool is_jump_table_basic_block (basic_block);
-static bool bb_has_well_behaved_predecessors (basic_block);
-static struct occr* get_bb_avail_insn (basic_block, struct occr *);
-static void hash_scan_set_after_reload (rtx, rtx, struct hash_table *);
-static void compute_hash_table_after_reload (struct hash_table *);
-static void eliminate_partially_redundant_loads (basic_block,
- rtx,
- struct expr *);
-static void gcse_after_reload (void);
-static struct occr* get_bb_avail_insn (basic_block, struct occr *);
-void gcse_after_reload_main (rtx, FILE *);
-
-
-/* Check if register REG is used in any insn waiting to be inserted on E.
- Assumes no such insn can be a CALL_INSN; if so call reg_used_between_p
- with PREV(insn),NEXT(insn) instead of calling
- reg_overlap_mentioned_p. */
+/* This routine will insert a store on an edge. EXPR is the ldst entry for
+ the memory reference, and E is the edge to insert it on. Returns nonzero
+ if an edge insertion was performed. */
-static bool
-reg_used_on_edge (rtx reg, edge e)
+static int
+insert_store (struct ls_expr * expr, edge e)
{
- rtx insn;
+ rtx reg, insn;
+ basic_block bb;
+ edge tmp;
+ edge_iterator ei;
- for (insn = e->insns; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && reg_overlap_mentioned_p (reg, PATTERN (insn)))
- return true;
+ /* We did all the deleted before this insert, so if we didn't delete a
+ store, then we haven't set the reaching reg yet either. */
+ if (expr->reaching_reg == NULL_RTX)
+ return 0;
- return false;
-}
+ if (e->flags & EDGE_FAKE)
+ return 0;
-/* Return the insn that sets register REG or clobbers it in between
- FROM_INSN and TO_INSN (exclusive of those two).
- Just like reg_set_between but for hard registers and not pseudos. */
+ reg = expr->reaching_reg;
+ insn = gen_move_insn (copy_rtx (expr->pattern), reg);
-static rtx
-reg_set_between_after_reload_p (rtx reg, rtx from_insn, rtx to_insn)
-{
- rtx insn;
- int regno;
+ /* If we are inserting this expression on ALL predecessor edges of a BB,
+ insert it at the start of the BB, and reset the insert bits on the other
+ edges so we don't try to insert it on the other edges. */
+ bb = e->dest;
+ FOR_EACH_EDGE (tmp, ei, e->dest->preds)
+ if (!(tmp->flags & EDGE_FAKE))
+ {
+ int index = EDGE_INDEX (edge_list, tmp->src, tmp->dest);
+
+ gcc_assert (index != EDGE_INDEX_NO_EDGE);
+ if (! TEST_BIT (pre_insert_map[index], expr->index))
+ break;
+ }
- if (GET_CODE (reg) != REG)
- abort ();
- regno = REGNO (reg);
+ /* If tmp is NULL, we found an insertion on every edge, blank the
+ insertion vector for these edges, and insert at the start of the BB. */
+ if (!tmp && bb != EXIT_BLOCK_PTR)
+ {
+ FOR_EACH_EDGE (tmp, ei, e->dest->preds)
+ {
+ int index = EDGE_INDEX (edge_list, tmp->src, tmp->dest);
+ RESET_BIT (pre_insert_map[index], expr->index);
+ }
+ insert_insn_start_basic_block (insn, bb);
+ return 0;
+ }
- /* We are called after register allocation. */
- if (regno >= FIRST_PSEUDO_REGISTER)
- abort ();
+ /* We can't put stores in the front of blocks pointed to by abnormal
+ edges since that may put a store where one didn't used to be. */
+ gcc_assert (!(e->flags & EDGE_ABNORMAL));
- if (from_insn == to_insn)
- return NULL_RTX;
+ insert_insn_on_edge (insn, e);
- for (insn = NEXT_INSN (from_insn);
- insn != to_insn;
- insn = NEXT_INSN (insn))
+ if (dump_file)
{
- if (INSN_P (insn))
- {
- if (FIND_REG_INC_NOTE (insn, reg)
- || (GET_CODE (insn) == CALL_INSN
- && call_used_regs[regno])
- || find_reg_fusage (insn, CLOBBER, reg))
- return insn;
- }
- if (set_of (reg, insn) != NULL_RTX)
- return insn;
+ fprintf (dump_file, "STORE_MOTION insert insn on edge (%d, %d):\n",
+ e->src->index, e->dest->index);
+ print_inline_rtx (dump_file, insn, 6);
+ fprintf (dump_file, "\n");
}
- return NULL_RTX;
+
+ return 1;
}
-/* Return the insn that uses register REG in between FROM_INSN and TO_INSN
- (exclusive of those two). Similar to reg_used_between but for hard
- registers and not pseudos. */
+/* Remove any REG_EQUAL or REG_EQUIV notes containing a reference to the
+ memory location in SMEXPR set in basic block BB.
+
+ This could be rather expensive. */
-static rtx
-reg_used_between_after_reload_p (rtx reg, rtx from_insn, rtx to_insn)
+static void
+remove_reachable_equiv_notes (basic_block bb, struct ls_expr *smexpr)
{
- rtx insn;
- int regno;
+ edge_iterator *stack, ei;
+ int sp;
+ edge act;
+ sbitmap visited = sbitmap_alloc (last_basic_block);
+ rtx last, insn, note;
+ rtx mem = smexpr->pattern;
- if (GET_CODE (reg) != REG)
- return to_insn;
- regno = REGNO (reg);
+ stack = XNEWVEC (edge_iterator, n_basic_blocks);
+ sp = 0;
+ ei = ei_start (bb->succs);
- /* We are called after register allocation. */
- if (regno >= FIRST_PSEUDO_REGISTER)
- abort ();
- if (from_insn == to_insn)
- return NULL_RTX;
+ sbitmap_zero (visited);
- for (insn = NEXT_INSN (from_insn);
- insn != to_insn;
- insn = NEXT_INSN (insn))
- if (INSN_P (insn)
- && (reg_overlap_mentioned_p (reg, PATTERN (insn))
- || (GET_CODE (insn) == CALL_INSN
- && call_used_regs[regno])
- || find_reg_fusage (insn, USE, reg)
- || find_reg_fusage (insn, CLOBBER, reg)))
- return insn;
- return NULL_RTX;
-}
+ act = (EDGE_COUNT (ei_container (ei)) > 0 ? EDGE_I (ei_container (ei), 0) : NULL);
+ while (1)
+ {
+ if (!act)
+ {
+ if (!sp)
+ {
+ free (stack);
+ sbitmap_free (visited);
+ return;
+ }
+ act = ei_edge (stack[--sp]);
+ }
+ bb = act->dest;
+
+ if (bb == EXIT_BLOCK_PTR
+ || TEST_BIT (visited, bb->index))
+ {
+ if (!ei_end_p (ei))
+ ei_next (&ei);
+ act = (! ei_end_p (ei)) ? ei_edge (ei) : NULL;
+ continue;
+ }
+ SET_BIT (visited, bb->index);
-/* Return the loaded/stored register of a load/store instruction. */
+ if (TEST_BIT (st_antloc[bb->index], smexpr->index))
+ {
+ for (last = ANTIC_STORE_LIST (smexpr);
+ BLOCK_FOR_INSN (XEXP (last, 0)) != bb;
+ last = XEXP (last, 1))
+ continue;
+ last = XEXP (last, 0);
+ }
+ else
+ last = NEXT_INSN (BB_END (bb));
-static rtx
-get_avail_load_store_reg (rtx insn)
-{
- if (GET_CODE (SET_DEST (PATTERN (insn))) == REG) /* A load. */
- return SET_DEST(PATTERN(insn));
- if (GET_CODE (SET_SRC (PATTERN (insn))) == REG) /* A store. */
- return SET_SRC (PATTERN (insn));
- abort ();
-}
+ for (insn = BB_HEAD (bb); insn != last; insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ {
+ note = find_reg_equal_equiv_note (insn);
+ if (!note || !expr_equiv_p (XEXP (note, 0), mem))
+ continue;
-/* Don't handle ABNORMAL edges or jump tables. */
+ if (dump_file)
+ fprintf (dump_file, "STORE_MOTION drop REG_EQUAL note at insn %d:\n",
+ INSN_UID (insn));
+ remove_note (insn, note);
+ }
-static bool
-is_jump_table_basic_block (basic_block bb)
-{
- rtx insn = BB_END (bb);
+ if (!ei_end_p (ei))
+ ei_next (&ei);
+ act = (! ei_end_p (ei)) ? ei_edge (ei) : NULL;
- if (GET_CODE (insn) == JUMP_INSN &&
- (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
- return true;
- return false;
+ if (EDGE_COUNT (bb->succs) > 0)
+ {
+ if (act)
+ stack[sp++] = ei;
+ ei = ei_start (bb->succs);
+ act = (EDGE_COUNT (ei_container (ei)) > 0 ? EDGE_I (ei_container (ei), 0) : NULL);
+ }
+ }
}
-/* Return nonzero if the predecessors of BB are "well behaved". */
+/* This routine will replace a store with a SET to a specified register. */
-static bool
-bb_has_well_behaved_predecessors (basic_block bb)
+static void
+replace_store_insn (rtx reg, rtx del, basic_block bb, struct ls_expr *smexpr)
{
- edge pred;
+ rtx insn, mem, note, set, ptr, pair;
- if (! bb->pred)
- return false;
- for (pred = bb->pred; pred != NULL; pred = pred->pred_next)
- if (((pred->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (pred))
- || is_jump_table_basic_block (pred->src))
- return false;
- return true;
-}
+ mem = smexpr->pattern;
+ insn = gen_move_insn (reg, SET_SRC (single_set (del)));
+
+ for (ptr = ANTIC_STORE_LIST (smexpr); ptr; ptr = XEXP (ptr, 1))
+ if (XEXP (ptr, 0) == del)
+ {
+ XEXP (ptr, 0) = insn;
+ break;
+ }
+ /* Move the notes from the deleted insn to its replacement, and patch
+ up the LIBCALL notes. */
+ REG_NOTES (insn) = REG_NOTES (del);
+
+ note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
+ if (note)
+ {
+ pair = XEXP (note, 0);
+ note = find_reg_note (pair, REG_LIBCALL, NULL_RTX);
+ XEXP (note, 0) = insn;
+ }
+ note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
+ if (note)
+ {
+ pair = XEXP (note, 0);
+ note = find_reg_note (pair, REG_RETVAL, NULL_RTX);
+ XEXP (note, 0) = insn;
+ }
-/* Search for the occurrences of expression in BB. */
+ /* Emit the insn AFTER all the notes are transferred.
+ This is cheaper since we avoid df rescanning for the note change. */
+ insn = emit_insn_after (insn, del);
-static struct occr*
-get_bb_avail_insn (basic_block bb, struct occr *occr)
-{
- for (; occr != NULL; occr = occr->next)
- if (BLOCK_FOR_INSN (occr->insn)->index == bb->index)
- return occr;
- return NULL;
-}
+ if (dump_file)
+ {
+ fprintf (dump_file,
+ "STORE_MOTION delete insn in BB %d:\n ", bb->index);
+ print_inline_rtx (dump_file, del, 6);
+ fprintf (dump_file, "\nSTORE MOTION replaced with insn:\n ");
+ print_inline_rtx (dump_file, insn, 6);
+ fprintf (dump_file, "\n");
+ }
-/* Perform partial GCSE pass after reload, try to eliminate redundant loads
- created by the reload pass. We try to look for a full or partial
- redundant loads fed by one or more loads/stores in predecessor BBs,
- and try adding loads to make them fully redundant. We also check if
- it's worth adding loads to be able to delete the redundant load.
+ delete_insn (del);
- Algorithm:
- 1. Build available expressions hash table:
- For each load/store instruction, if the loaded/stored memory didn't
- change until the end of the basic block add this memory expression to
- the hash table.
- 2. Perform Redundancy elimination:
- For each load instruction do the following:
- perform partial redundancy elimination, check if it's worth adding
- loads to make the load fully redundant. If so add loads and
- register copies and delete the load.
+ /* Now we must handle REG_EQUAL notes whose contents is equal to the mem;
+ they are no longer accurate provided that they are reached by this
+ definition, so drop them. */
+ for (; insn != NEXT_INSN (BB_END (bb)); insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ {
+ set = single_set (insn);
+ if (!set)
+ continue;
+ if (expr_equiv_p (SET_DEST (set), mem))
+ return;
+ note = find_reg_equal_equiv_note (insn);
+ if (!note || !expr_equiv_p (XEXP (note, 0), mem))
+ continue;
- Future enhancement:
- if loaded register is used/defined between load and some store,
- look for some other free register between load and all its stores,
- and replace load with a copy from this register to the loaded
- register. */
+ if (dump_file)
+ fprintf (dump_file, "STORE_MOTION drop REG_EQUAL note at insn %d:\n",
+ INSN_UID (insn));
+ remove_note (insn, note);
+ }
+ remove_reachable_equiv_notes (bb, smexpr);
+}
-/* This handles the case where several stores feed a partially redundant
- load. It checks if the redundancy elimination is possible and if it's
- worth it. */
+/* Delete a store, but copy the value that would have been stored into
+ the reaching_reg for later storing. */
static void
-eliminate_partially_redundant_loads (basic_block bb, rtx insn,
- struct expr *expr)
+delete_store (struct ls_expr * expr, basic_block bb)
{
- edge pred;
- rtx avail_insn = NULL_RTX;
- rtx avail_reg;
- rtx dest, pat;
- struct occr *a_occr;
- struct unoccr *occr, *avail_occrs = NULL;
- struct unoccr *unoccr, *unavail_occrs = NULL;
- int npred_ok = 0;
- gcov_type ok_count = 0; /* Redundant load execution count. */
- gcov_type critical_count = 0; /* Execution count of critical edges. */
-
- /* The execution count of the loads to be added to make the
- load fully redundant. */
- gcov_type not_ok_count = 0;
- basic_block pred_bb;
+ rtx reg, i, del;
- pat = PATTERN (insn);
- dest = SET_DEST (pat);
- /* Check that the loaded register is not used, set, or killed from the
- beginning of the block. */
- if (reg_used_between_after_reload_p (dest,
- PREV_INSN (BB_HEAD (bb)), insn)
- || reg_set_between_after_reload_p (dest,
- PREV_INSN (BB_HEAD (bb)), insn))
- return;
+ if (expr->reaching_reg == NULL_RTX)
+ expr->reaching_reg = gen_reg_rtx (GET_MODE (expr->pattern));
- /* Check potential for replacing load with copy for predecessors. */
- for (pred = bb->pred; pred; pred = pred->pred_next)
- {
- rtx next_pred_bb_end;
+ reg = expr->reaching_reg;
- avail_insn = NULL_RTX;
- pred_bb = pred->src;
- next_pred_bb_end = NEXT_INSN (BB_END (pred_bb));
- for (a_occr = get_bb_avail_insn (pred_bb, expr->avail_occr); a_occr;
- a_occr = get_bb_avail_insn (pred_bb, a_occr->next))
- {
- /* Check if the loaded register is not used. */
- avail_insn = a_occr->insn;
- if (! (avail_reg = get_avail_load_store_reg (avail_insn)))
- abort ();
- /* Make sure we can generate a move from register avail_reg to
- dest. */
- extract_insn (gen_move_insn (copy_rtx (dest),
- copy_rtx (avail_reg)));
- if (! constrain_operands (1)
- || reg_killed_on_edge (avail_reg, pred)
- || reg_used_on_edge (dest, pred))
- {
- avail_insn = NULL;
- continue;
- }
- if (! reg_set_between_after_reload_p (avail_reg, avail_insn,
- next_pred_bb_end))
- /* AVAIL_INSN remains non-null. */
- break;
- else
- avail_insn = NULL;
- }
- if (avail_insn != NULL_RTX)
- {
- npred_ok++;
- ok_count += pred->count;
- if (EDGE_CRITICAL_P (pred))
- critical_count += pred->count;
- occr = gmalloc (sizeof (struct unoccr));
- occr->insn = avail_insn;
- occr->pred = pred;
- occr->next = avail_occrs;
- avail_occrs = occr;
- }
- else
+ for (i = AVAIL_STORE_LIST (expr); i; i = XEXP (i, 1))
+ {
+ del = XEXP (i, 0);
+ if (BLOCK_FOR_INSN (del) == bb)
{
- not_ok_count += pred->count;
- if (EDGE_CRITICAL_P (pred))
- critical_count += pred->count;
- unoccr = gmalloc (sizeof (struct unoccr));
- unoccr->insn = NULL_RTX;
- unoccr->pred = pred;
- unoccr->next = unavail_occrs;
- unavail_occrs = unoccr;
+ /* We know there is only one since we deleted redundant
+ ones during the available computation. */
+ replace_store_insn (reg, del, bb, expr);
+ break;
}
}
+}
- if (npred_ok == 0 /* No load can be replaced by copy. */
- || (optimize_size && npred_ok > 1)) /* Prevent exploding the code. */
- return;
-
- /* Check if it's worth applying the partial redundancy elimination. */
- if (ok_count < GCSE_AFTER_RELOAD_PARTIAL_FRACTION * not_ok_count)
- return;
-
- if (ok_count < GCSE_AFTER_RELOAD_CRITICAL_FRACTION * critical_count)
- return;
-
- /* Generate moves to the loaded register from where
- the memory is available. */
- for (occr = avail_occrs; occr; occr = occr->next)
- {
- avail_insn = occr->insn;
- pred = occr->pred;
- /* Set avail_reg to be the register having the value of the
- memory. */
- avail_reg = get_avail_load_store_reg (avail_insn);
- if (! avail_reg)
- abort ();
-
- insert_insn_on_edge (gen_move_insn (copy_rtx (dest),
- copy_rtx (avail_reg)),
- pred);
-
- if (gcse_file)
- fprintf (gcse_file,
- "GCSE AFTER reload generating move from %d to %d on \
- edge from %d to %d\n",
- REGNO (avail_reg),
- REGNO (dest),
- pred->src->index,
- pred->dest->index);
- }
+/* Free memory used by store motion. */
- /* Regenerate loads where the memory is unavailable. */
- for (unoccr = unavail_occrs; unoccr; unoccr = unoccr->next)
- {
- pred = unoccr->pred;
- insert_insn_on_edge (copy_insn (PATTERN (insn)), pred);
-
- if (gcse_file)
- fprintf (gcse_file,
- "GCSE AFTER reload: generating on edge from %d to %d\
- a copy of load:\n",
- pred->src->index,
- pred->dest->index);
- }
+static void
+free_store_memory (void)
+{
+ free_ldst_mems ();
- /* Delete the insn if it is not available in this block and mark it
- for deletion if it is available. If insn is available it may help
- discover additional redundancies, so mark it for later deletion.*/
- for (a_occr = get_bb_avail_insn (bb, expr->avail_occr);
- a_occr && (a_occr->insn != insn);
- a_occr = get_bb_avail_insn (bb, a_occr->next));
+ if (ae_gen)
+ sbitmap_vector_free (ae_gen);
+ if (ae_kill)
+ sbitmap_vector_free (ae_kill);
+ if (transp)
+ sbitmap_vector_free (transp);
+ if (st_antloc)
+ sbitmap_vector_free (st_antloc);
+ if (pre_insert_map)
+ sbitmap_vector_free (pre_insert_map);
+ if (pre_delete_map)
+ sbitmap_vector_free (pre_delete_map);
+ if (reg_set_in_block)
+ sbitmap_vector_free (reg_set_in_block);
- if (!a_occr)
- delete_insn (insn);
- else
- a_occr->deleted_p = 1;
+ ae_gen = ae_kill = transp = st_antloc = NULL;
+ pre_insert_map = pre_delete_map = reg_set_in_block = NULL;
}
-/* Performing the redundancy elimination as described before. */
+/* Perform store motion. Much like gcse, except we move expressions the
+ other way by looking at the flowgraph in reverse. */
static void
-gcse_after_reload (void)
+store_motion (void)
{
- unsigned int i;
- rtx insn;
basic_block bb;
- struct expr *expr;
- struct occr *occr;
-
- /* Note we start at block 1. */
-
- if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
- return;
+ int x;
+ struct ls_expr * ptr;
+ int update_flow = 0;
- FOR_BB_BETWEEN (bb,
- ENTRY_BLOCK_PTR->next_bb->next_bb,
- EXIT_BLOCK_PTR,
- next_bb)
+ if (dump_file)
{
- if (! bb_has_well_behaved_predecessors (bb))
- continue;
-
- /* Do not try this optimization on cold basic blocks. */
- if (probably_cold_bb_p (bb))
- continue;
-
- reset_opr_set_tables ();
-
- for (insn = BB_HEAD (bb);
- insn != NULL
- && insn != NEXT_INSN (BB_END (bb));
- insn = NEXT_INSN (insn))
- {
- /* Is it a load - of the form (set (reg) (mem))? */
- if (GET_CODE (insn) == INSN
- && GET_CODE (PATTERN (insn)) == SET
- && GET_CODE (SET_DEST (PATTERN (insn))) == REG
- && GET_CODE (SET_SRC (PATTERN (insn))) == MEM)
- {
- rtx pat = PATTERN (insn);
- rtx src = SET_SRC (pat);
- struct expr *expr;
-
- if (general_operand (src, GET_MODE (src))
- /* Is the expression recorded? */
- && (expr = lookup_expr (src, &expr_hash_table)) != NULL
- /* Are the operands unchanged since the start of the
- block? */
- && oprs_not_set_p (src, insn)
- && ! MEM_VOLATILE_P (src)
- && GET_MODE (src) != BLKmode
- && !(flag_non_call_exceptions && may_trap_p (src))
- && !side_effects_p (src))
- {
- /* We now have a load (insn) and an available memory at
- its BB start (expr). Try to remove the loads if it is
- redundant. */
- eliminate_partially_redundant_loads (bb, insn, expr);
- }
- }
-
- /* Keep track of everything modified by this insn. */
- if (INSN_P (insn))
- mark_oprs_set (insn);
- }
+ fprintf (dump_file, "before store motion\n");
+ print_rtl (dump_file, get_insns ());
}
- commit_edge_insertions ();
+ init_alias_analysis ();
- /* Go over the expression hash table and delete insns that were
- marked for later deletion. */
- for (i = 0; i < expr_hash_table.size; i++)
+ /* Find all the available and anticipatable stores. */
+ num_stores = compute_store_table ();
+ if (num_stores == 0)
{
- for (expr = expr_hash_table.table[i];
- expr != NULL;
- expr = expr->next_same_hash)
- for (occr = expr->avail_occr; occr; occr = occr->next)
- if (occr->deleted_p)
- delete_insn (occr->insn);
+ htab_delete (pre_ldst_table);
+ pre_ldst_table = NULL;
+ sbitmap_vector_free (reg_set_in_block);
+ end_alias_analysis ();
+ return;
}
-}
-/* Scan pattern PAT of INSN and add an entry to the hash TABLE.
- After reload we are interested in loads/stores only. */
-
-static void
-hash_scan_set_after_reload (rtx pat, rtx insn, struct hash_table *table)
-{
- rtx src = SET_SRC (pat);
- rtx dest = SET_DEST (pat);
+ /* Now compute kill & transp vectors. */
+ build_store_vectors ();
+ add_noreturn_fake_exit_edges ();
+ connect_infinite_loops_to_exit ();
- if (GET_CODE (src) != MEM && GET_CODE (dest) != MEM)
- return;
+ edge_list = pre_edge_rev_lcm (num_stores, transp, ae_gen,
+ st_antloc, ae_kill, &pre_insert_map,
+ &pre_delete_map);
- if (GET_CODE (dest) == REG)
- {
- if (/* Don't GCSE something if we can't do a reg/reg copy. */
- can_copy_p (GET_MODE (dest))
- /* GCSE commonly inserts instruction after the insn. We can't
- do that easily for EH_REGION notes so disable GCSE on these
- for now. */
- && ! find_reg_note (insn, REG_EH_REGION, NULL_RTX)
- /* Is SET_SRC something we want to gcse? */
- && general_operand (src, GET_MODE (src))
- /* Don't CSE a nop. */
- && ! set_noop_p (pat)
- && ! JUMP_P (insn))
- {
- /* An expression is not available if its operands are
- subsequently modified, including this insn. */
- if (oprs_available_p (src, insn))
- insert_expr_in_table (src, GET_MODE (dest), insn, 0, 1, table);
- }
- }
- else if ((GET_CODE (src) == REG))
+ /* Now we want to insert the new stores which are going to be needed. */
+ for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
{
- /* Only record sets of pseudo-regs in the hash table. */
- if (/* Don't GCSE something if we can't do a reg/reg copy. */
- can_copy_p (GET_MODE (src))
- /* GCSE commonly inserts instruction after the insn. We can't
- do that easily for EH_REGION notes so disable GCSE on these
- for now. */
- && ! find_reg_note (insn, REG_EH_REGION, NULL_RTX)
- /* Is SET_DEST something we want to gcse? */
- && general_operand (dest, GET_MODE (dest))
- /* Don't CSE a nop. */
- && ! set_noop_p (pat)
- &&! JUMP_P (insn)
- && ! (flag_float_store && FLOAT_MODE_P (GET_MODE (dest)))
- /* Check if the memory expression is killed after insn. */
- && ! load_killed_in_block_p (BLOCK_FOR_INSN (insn),
- INSN_CUID (insn) + 1,
- dest,
- 1)
- && oprs_unchanged_p (XEXP (dest, 0), insn, 1))
+ /* If any of the edges we have above are abnormal, we can't move this
+ store. */
+ for (x = NUM_EDGES (edge_list) - 1; x >= 0; x--)
+ if (TEST_BIT (pre_insert_map[x], ptr->index)
+ && (INDEX_EDGE (edge_list, x)->flags & EDGE_ABNORMAL))
+ break;
+
+ if (x >= 0)
{
- insert_expr_in_table (dest, GET_MODE (dest), insn, 0, 1, table);
+ if (dump_file != NULL)
+ fprintf (dump_file,
+ "Can't replace store %d: abnormal edge from %d to %d\n",
+ ptr->index, INDEX_EDGE (edge_list, x)->src->index,
+ INDEX_EDGE (edge_list, x)->dest->index);
+ continue;
}
- }
-}
+
+ /* Now we want to insert the new stores which are going to be needed. */
+ FOR_EACH_BB (bb)
+ if (TEST_BIT (pre_delete_map[bb->index], ptr->index))
+ delete_store (ptr, bb);
-/* Create hash table of memory expressions available at end of basic
- blocks. */
+ for (x = 0; x < NUM_EDGES (edge_list); x++)
+ if (TEST_BIT (pre_insert_map[x], ptr->index))
+ update_flow |= insert_store (ptr, INDEX_EDGE (edge_list, x));
+ }
-static void
-compute_hash_table_after_reload (struct hash_table *table)
-{
- unsigned int i;
+ if (update_flow)
+ commit_edge_insertions ();
- table->set_p = 0;
+ free_store_memory ();
+ free_edge_list (edge_list);
+ remove_fake_exit_edges ();
+ end_alias_analysis ();
+}
- /* Initialize count of number of entries in hash table. */
- table->n_elems = 0;
- memset ((char *) table->table, 0,
- table->size * sizeof (struct expr *));
+\f
+/* Entry point for jump bypassing optimization pass. */
- /* While we compute the hash table we also compute a bit array of which
- registers are set in which blocks. */
- sbitmap_vector_zero (reg_set_in_block, last_basic_block);
+static int
+bypass_jumps (void)
+{
+ int changed;
- /* Re-cache any INSN_LIST nodes we have allocated. */
- clear_modify_mem_tables ();
+ /* We do not construct an accurate cfg in functions which call
+ setjmp, so just punt to be safe. */
+ if (current_function_calls_setjmp)
+ return 0;
- /* Some working arrays used to track first and last set in each block. */
- reg_avail_info = gmalloc (max_gcse_regno * sizeof (struct reg_avail_info));
+ /* Identify the basic block information for this function, including
+ successors and predecessors. */
+ max_gcse_regno = max_reg_num ();
- for (i = 0; i < max_gcse_regno; ++i)
- reg_avail_info[i].last_bb = NULL;
+ if (dump_file)
+ dump_flow_info (dump_file, dump_flags);
- FOR_EACH_BB (current_bb)
- {
- rtx insn;
- unsigned int regno;
+ /* Return if there's nothing to do, or it is too expensive. */
+ if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
+ || is_too_expensive (_ ("jump bypassing disabled")))
+ return 0;
- /* First pass over the instructions records information used to
- determine when registers and memory are first and last set. */
- for (insn = BB_HEAD (current_bb);
- insn && insn != NEXT_INSN (BB_END (current_bb));
- insn = NEXT_INSN (insn))
- {
- if (! INSN_P (insn))
- continue;
+ gcc_obstack_init (&gcse_obstack);
+ bytes_used = 0;
- if (GET_CODE (insn) == CALL_INSN)
- {
- bool clobbers_all = false;
+ /* We need alias. */
+ init_alias_analysis ();
-#ifdef NON_SAVING_SETJMP
- if (NON_SAVING_SETJMP
- && find_reg_note (insn, REG_SETJMP, NULL_RTX))
- clobbers_all = true;
-#endif
+ /* Record where pseudo-registers are set. This data is kept accurate
+ during each pass. ??? We could also record hard-reg information here
+ [since it's unchanging], however it is currently done during hash table
+ computation.
- for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if (clobbers_all
- || TEST_HARD_REG_BIT (regs_invalidated_by_call,
- regno))
- record_last_reg_set_info (insn, regno);
+ It may be tempting to compute MEM set information here too, but MEM sets
+ will be subject to code motion one day and thus we need to compute
+ information about memory sets when we build the hash tables. */
- mark_call (insn);
- }
+ alloc_reg_set_mem (max_gcse_regno);
+ compute_sets ();
- note_stores (PATTERN (insn), record_last_set_info, insn);
+ max_gcse_regno = max_reg_num ();
+ alloc_gcse_mem ();
+ changed = one_cprop_pass (MAX_GCSE_PASSES + 2, true, true);
+ free_gcse_mem ();
- if (GET_CODE (PATTERN (insn)) == SET)
- {
- rtx src, dest;
+ if (dump_file)
+ {
+ fprintf (dump_file, "BYPASS of %s: %d basic blocks, ",
+ current_function_name (), n_basic_blocks);
+ fprintf (dump_file, "%d bytes\n\n", bytes_used);
+ }
- src = SET_SRC (PATTERN (insn));
- dest = SET_DEST (PATTERN (insn));
- if (GET_CODE (src) == MEM && auto_inc_p (XEXP (src, 0)))
- {
- regno = REGNO (XEXP (XEXP (src, 0), 0));
- record_last_reg_set_info (insn, regno);
- }
- if (GET_CODE (dest) == MEM && auto_inc_p (XEXP (dest, 0)))
- {
- regno = REGNO (XEXP (XEXP (dest, 0), 0));
- record_last_reg_set_info (insn, regno);
- }
- }
- }
+ obstack_free (&gcse_obstack, NULL);
+ free_reg_set_mem ();
- /* The next pass builds the hash table. */
- for (insn = BB_HEAD (current_bb);
- insn && insn != NEXT_INSN (BB_END (current_bb));
- insn = NEXT_INSN (insn))
- if (INSN_P (insn) && GET_CODE (PATTERN (insn)) == SET)
- if (! find_reg_note (insn, REG_LIBCALL, NULL_RTX))
- hash_scan_set_after_reload (PATTERN (insn), insn, table);
- }
+ /* We are finished with alias. */
+ end_alias_analysis ();
- free (reg_avail_info);
- reg_avail_info = NULL;
+ return changed;
}
+/* Return true if the graph is too expensive to optimize. PASS is the
+ optimization about to be performed. */
-/* Main entry point of the GCSE after reload - clean some redundant loads
- due to spilling. */
-
-void
-gcse_after_reload_main (rtx f, FILE* file)
+static bool
+is_too_expensive (const char *pass)
{
- gcse_subst_count = 0;
- gcse_create_count = 0;
+ /* Trying to perform global optimizations on flow graphs which have
+ a high connectivity will take a long time and is unlikely to be
+ particularly useful.
- gcse_file = file;
+ In normal circumstances a cfg should have about twice as many
+ edges as blocks. But we do not want to punish small functions
+ which have a couple switch statements. Rather than simply
+ threshold the number of blocks, uses something with a more
+ graceful degradation. */
+ if (n_edges > 20000 + n_basic_blocks * 4)
+ {
+ warning (OPT_Wdisabled_optimization,
+ "%s: %d basic blocks and %d edges/basic block",
+ pass, n_basic_blocks, n_edges / n_basic_blocks);
- gcc_obstack_init (&gcse_obstack);
- bytes_used = 0;
+ return true;
+ }
- /* We need alias. */
- init_alias_analysis ();
+ /* If allocating memory for the cprop bitmap would take up too much
+ storage it's better just to disable the optimization. */
+ if ((n_basic_blocks
+ * SBITMAP_SET_SIZE (max_reg_num ())
+ * sizeof (SBITMAP_ELT_TYPE)) > MAX_GCSE_MEMORY)
+ {
+ warning (OPT_Wdisabled_optimization,
+ "%s: %d basic blocks and %d registers",
+ pass, n_basic_blocks, max_reg_num ());
- max_gcse_regno = max_reg_num ();
+ return true;
+ }
- alloc_reg_set_mem (max_gcse_regno);
- alloc_gcse_mem (f);
- alloc_hash_table (max_cuid, &expr_hash_table, 0);
- compute_hash_table_after_reload (&expr_hash_table);
+ return false;
+}
+\f
+static bool
+gate_handle_jump_bypass (void)
+{
+ return optimize > 0 && flag_gcse;
+}
- if (gcse_file)
- dump_hash_table (gcse_file, "Expression", &expr_hash_table);
+/* Perform jump bypassing and control flow optimizations. */
+static unsigned int
+rest_of_handle_jump_bypass (void)
+{
+ delete_unreachable_blocks ();
+ if (bypass_jumps ())
+ {
+ delete_trivially_dead_insns (get_insns (), max_reg_num ());
+ rebuild_jump_labels (get_insns ());
+ cleanup_cfg (0);
+ }
+ return 0;
+}
- if (expr_hash_table.n_elems > 0)
- gcse_after_reload ();
+struct tree_opt_pass pass_jump_bypass =
+{
+ "bypass", /* name */
+ gate_handle_jump_bypass, /* gate */
+ rest_of_handle_jump_bypass, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_BYPASS, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_dump_func |
+ TODO_ggc_collect | TODO_verify_flow, /* todo_flags_finish */
+ 'G' /* letter */
+};
- free_hash_table (&expr_hash_table);
- free_gcse_mem ();
- free_reg_set_mem ();
+static bool
+gate_handle_gcse (void)
+{
+ return optimize > 0 && flag_gcse;
+}
- /* We are finished with alias. */
- end_alias_analysis ();
- obstack_free (&gcse_obstack, NULL);
+static unsigned int
+rest_of_handle_gcse (void)
+{
+ int save_csb, save_cfj;
+ int tem2 = 0, tem;
+ tem = gcse_main (get_insns ());
+ delete_trivially_dead_insns (get_insns (), max_reg_num ());
+ rebuild_jump_labels (get_insns ());
+ save_csb = flag_cse_skip_blocks;
+ save_cfj = flag_cse_follow_jumps;
+ flag_cse_skip_blocks = flag_cse_follow_jumps = 0;
+
+ /* If -fexpensive-optimizations, re-run CSE to clean up things done
+ by gcse. */
+ if (flag_expensive_optimizations)
+ {
+ timevar_push (TV_CSE);
+ tem2 = cse_main (get_insns (), max_reg_num ());
+ df_finish_pass (false);
+ purge_all_dead_edges ();
+ delete_trivially_dead_insns (get_insns (), max_reg_num ());
+ timevar_pop (TV_CSE);
+ cse_not_expected = !flag_rerun_cse_after_loop;
+ }
+
+ /* If gcse or cse altered any jumps, rerun jump optimizations to clean
+ things up. */
+ if (tem || tem2)
+ {
+ timevar_push (TV_JUMP);
+ rebuild_jump_labels (get_insns ());
+ cleanup_cfg (0);
+ timevar_pop (TV_JUMP);
+ }
+
+ flag_cse_skip_blocks = save_csb;
+ flag_cse_follow_jumps = save_cfj;
+ return 0;
}
+struct tree_opt_pass pass_gcse =
+{
+ "gcse1", /* name */
+ gate_handle_gcse, /* gate */
+ rest_of_handle_gcse, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_GCSE, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish | TODO_verify_rtl_sharing |
+ TODO_dump_func |
+ TODO_verify_flow | TODO_ggc_collect, /* todo_flags_finish */
+ 'G' /* letter */
+};
+
+
#include "gt-gcse.h"
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