-/* Global common subexpression elimination/Partial redundancy elimination
- and global constant/copy propagation for GNU compiler.
+/* Partial redundancy elimination / Hoisting for RTL.
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
- 2006, 2007 Free Software Foundation, Inc.
+ 2006, 2007, 2008, 2009, 2010, 2011 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, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, 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
- do rough calc of how many regs are needed in each block, and a rough
calc of how many regs are available in each class and use that to
throttle back the code in cases where RTX_COST is minimal.
- - a store to the same address as a load does not kill the load if the
- source of the store is also the destination of the load. Handling this
- allows more load motion, particularly out of loops.
- - ability to realloc sbitmap vectors would allow one initial computation
- of reg_set_in_block with only subsequent additions, rather than
- recomputing it for each pass
-
*/
/* References searched while implementing this.
#include "system.h"
#include "coretypes.h"
#include "tm.h"
+#include "diagnostic-core.h"
#include "toplev.h"
#include "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "flags.h"
-#include "real.h"
#include "insn-config.h"
#include "recog.h"
#include "basic-block.h"
#include "timevar.h"
#include "tree-pass.h"
#include "hashtab.h"
-
-/* Propagate flow information through back edges and thus enable PRE's
- moving loop invariant calculations out of loops.
-
- Originally this tended to create worse overall code, but several
- improvements during the development of PRE seem to have made following
- back edges generally a win.
-
- Note much of the loop invariant code motion done here would normally
- be done by loop.c, which has more heuristics for when to move invariants
- out of loops. At some point we might need to move some of those
- heuristics into gcse.c. */
+#include "df.h"
+#include "dbgcnt.h"
+#include "target.h"
+#include "gcse.h"
/* We support GCSE via Partial Redundancy Elimination. PRE optimizations
- are a superset of those done by GCSE.
-
- We perform the following steps:
-
- 1) Compute basic block information.
-
- 2) Compute table of places where registers are set.
-
- 3) Perform copy/constant propagation.
+ are a superset of those done by classic GCSE.
- 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.
-
- Two passes of copy/constant propagation are done because the first one
- enables more GCSE and the second one helps to clean up the copies that
- GCSE creates. This is needed more for PRE than for Classic because Classic
- GCSE will try to use an existing register containing the common
- subexpression rather than create a new one. This is harder to do for PRE
- because of the code motion (which Classic GCSE doesn't do).
+ Two passes of copy/constant propagation are done around PRE or hoisting
+ because the first one enables more GCSE and the second one helps to clean
+ up the copies that PRE and HOIST create. This is needed more for PRE than
+ for HOIST because code hoisting will try to use an existing register
+ containing the common subexpression rather than create a new one. This is
+ harder to do for PRE because of the code motion (which HOIST doesn't do).
Expressions we are interested in GCSE-ing are of the form
(set (pseudo-reg) (expression)).
Function want_to_gcse_p says what these are.
+ In addition, expressions in REG_EQUAL notes are candidates for GCSE-ing.
+ This allows PRE to hoist expressions that are expressed in multiple insns,
+ such as complex address calculations (e.g. for PIC code, or loads with a
+ high part and a low part).
+
PRE handles moving invariant expressions out of loops (by treating them as
partially redundant).
- Eventually it would be nice to replace cse.c/gcse.c with SSA (static single
- assignment) based GVN (global value numbering). L. T. Simpson's paper
- (Rice University) on value numbering is a useful reference for this.
-
**********************
We used to support multiple passes but there are diminishing returns in
It was found doing copy propagation between each pass enables further
substitutions.
+ This study was done before expressions in REG_EQUAL notes were added as
+ candidate expressions for optimization, and before the GIMPLE optimizers
+ were added. Probably, multiple passes is even less efficient now than
+ at the time when the study was conducted.
+
PRE is quite expensive in complicated functions because the DFA can take
- a while 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.
**********************
argue it is not. The number of iterations for the algorithm to converge
is typically 2-4 so I don't view it as that expensive (relatively speaking).
- PRE GCSE depends heavily on the second CSE pass to clean up the copies
+ PRE GCSE depends heavily on the second CPROP pass to clean up the copies
we create. To make an expression reach the place where it's redundant,
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
\f
/* GCSE global vars. */
-/* 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.
+struct target_gcse default_target_gcse;
+#if SWITCHABLE_TARGET
+struct target_gcse *this_target_gcse = &default_target_gcse;
+#endif
- * If we added any labels via edge splitting. */
-static int run_jump_opt_after_gcse;
+/* Set to non-zero if CSE should run after all GCSE optimizations are done. */
+int flag_rerun_cse_after_global_opts;
/* An obstack for our working variables. */
static struct obstack gcse_obstack;
struct expr
{
- /* The expression (SET_SRC for expressions, PATTERN for assignments). */
+ /* The expression. */
rtx expr;
/* Index in the available expression bitmaps. */
int bitmap_index;
The value is the newly created pseudo-reg to record a copy of the
expression in all the places that reach the redundant copy. */
rtx reaching_reg;
+ /* Maximum distance in instructions this expression can travel.
+ We avoid moving simple expressions for more than a few instructions
+ to keep register pressure under control.
+ A value of "0" removes restrictions on how far the expression can
+ travel. */
+ int max_distance;
};
/* Occurrence of an expression.
char copied_p;
};
-/* Expression and copy propagation hash tables.
+typedef struct occr *occr_t;
+DEF_VEC_P (occr_t);
+DEF_VEC_ALLOC_P (occr_t, heap);
+
+/* Expression hash tables.
Each hash table is an array of buckets.
??? It is known that if it were an array of entries, structure elements
`next_same_hash' and `bitmap_index' wouldn't be necessary. However, it is
[one could build a mapping table without holes afterwards though].
Someday I'll perform the computation and figure it out. */
-struct hash_table
+struct hash_table_d
{
/* The table itself.
This is an array of `expr_hash_table_size' elements. */
/* Number of hash table elements. */
unsigned int n_elems;
-
- /* Whether the table is expression of copy propagation one. */
- int set_p;
};
/* Expression hash table. */
-static struct hash_table expr_hash_table;
-
-/* Copy propagation hash table. */
-static struct hash_table set_hash_table;
-
-/* Mapping of uids to cuids.
- Only real insns get cuids. */
-static int *uid_cuid;
-
-/* Highest UID in UID_CUID. */
-static int max_uid;
-
-/* Get the cuid of an insn. */
-#ifdef ENABLE_CHECKING
-#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
-
-/* Number of cuids. */
-static int max_cuid;
-
-/* Mapping of cuids to insns. */
-static rtx *cuid_insn;
-
-/* Get insn from cuid. */
-#define CUID_INSN(CUID) (cuid_insn[CUID])
-
-/* Maximum register number in function prior to doing gcse + 1.
- Registers created during this pass have regno >= max_gcse_regno.
- This is named with "gcse" to not collide with global of same name. */
-static unsigned int max_gcse_regno;
-
-/* Table of registers that are modified.
-
- For each register, each element is a list of places where the pseudo-reg
- is set.
-
- For simplicity, GCSE is done on sets of pseudo-regs only. PRE GCSE only
- requires knowledge of which blocks kill which regs [and thus could use
- a bitmap instead of the lists `reg_set_table' uses].
-
- `reg_set_table' and could be turned into an array of bitmaps (num-bbs x
- num-regs) [however perhaps it may be useful to keep the data as is]. One
- advantage of recording things this way is that `reg_set_table' is fairly
- sparse with respect to pseudo regs but for hard regs could be fairly dense
- [relatively speaking]. And recording sets of pseudo-regs in lists speeds
- up functions like compute_transp since in the case of pseudo-regs we only
- need to iterate over the number of times a pseudo-reg is set, not over the
- number of basic blocks [clearly there is a bit of a slow down in the cases
- where a pseudo is set more than once in a block, however it is believed
- that the net effect is to speed things up]. This isn't done for hard-regs
- because recording call-clobbered hard-regs in `reg_set_table' at each
- function call can consume a fair bit of memory, and iterating over
- hard-regs stored this way in compute_transp will be more expensive. */
-
-typedef struct reg_set
-{
- /* The next setting of this register. */
- struct reg_set *next;
- /* The index of the block where it was set. */
- int bb_index;
-} reg_set;
-
-static reg_set **reg_set_table;
-
-/* Size of `reg_set_table'.
- The table starts out at max_gcse_regno + slop, and is enlarged as
- necessary. */
-static int reg_set_table_size;
-
-/* Amount to grow `reg_set_table' by when it's full. */
-#define REG_SET_TABLE_SLOP 100
+static struct hash_table_d expr_hash_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. (i.e., loads and stores to a single location).
+ Load motion tracks MEMs which aren't killed by 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
- no side effects so we can re-issue the setter value.
- Store Motion uses this structure as an expression table to track stores
- which look interesting, and might be moveable towards the exit block. */
+ no side effects so we can re-issue the setter value. */
struct ls_expr
{
rtx reaching_reg; /* Register to use when re-writing. */
};
-/* Array of implicit set patterns indexed by basic block index. */
-static rtx *implicit_sets;
-
/* Head of the list of load/store memory refs. */
static struct ls_expr * pre_ldst_mems = NULL;
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 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. */
-static sbitmap *reg_set_in_block;
-
/* Array, indexed by basic block number for a list of insns which modify
memory within that block. */
-static rtx * modify_mem_list;
+static VEC (rtx,heap) **modify_mem_list;
static bitmap modify_mem_list_set;
-/* This array parallels modify_mem_list, but is kept canonicalized. */
-static rtx * canon_modify_mem_list;
+typedef struct modify_pair_s
+{
+ rtx dest; /* A MEM. */
+ rtx dest_addr; /* The canonical address of `dest'. */
+} modify_pair;
+
+DEF_VEC_O(modify_pair);
+DEF_VEC_ALLOC_O(modify_pair,heap);
+
+/* This array parallels modify_mem_list, except that it stores MEMs
+ being set and their canonicalized memory addresses. */
+static VEC (modify_pair,heap) **canon_modify_mem_list;
/* Bitmap indexed by block numbers to record which blocks contain
function calls. */
static int gcse_subst_count;
/* Number of copy instructions created. */
static int gcse_create_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
+/* Doing code hoisting. */
+static bool doing_code_hoisting_p = false;
\f
/* For available exprs */
-static sbitmap *ae_kill, *ae_gen;
+static sbitmap *ae_kill;
\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 (void);
static void free_gcse_mem (void);
-static void alloc_reg_set_mem (int);
-static void free_reg_set_mem (void);
-static void record_one_set (int, rtx);
-static void record_set_info (rtx, 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 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_set (int, int);
-static int expr_equiv_p (rtx, rtx);
+static void hash_scan_insn (rtx, struct hash_table_d *);
+static void hash_scan_set (rtx, rtx, struct hash_table_d *);
+static void hash_scan_clobber (rtx, rtx, struct hash_table_d *);
+static void hash_scan_call (rtx, rtx, struct hash_table_d *);
+static int want_to_gcse_p (rtx, int *);
+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, int,
+ struct hash_table_d *);
+static unsigned int hash_expr (const_rtx, enum machine_mode, int *, int);
+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 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_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 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_transpout (void);
+static void record_last_set_info (rtx, const_rtx, void *);
+static void compute_hash_table (struct hash_table_d *);
+static void alloc_hash_table (struct hash_table_d *);
+static void free_hash_table (struct hash_table_d *);
+static void compute_hash_table_work (struct hash_table_d *);
+static void dump_hash_table (FILE *, const char *, struct hash_table_d *);
+static void compute_transp (const_rtx, int, sbitmap *);
static void compute_local_properties (sbitmap *, sbitmap *, sbitmap *,
- struct hash_table *);
-static void compute_cprop_data (void);
-static void find_used_regs (rtx *, void *);
-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 int cprop_insn (rtx, int);
-static int cprop (int);
-static void find_implicit_sets (void);
-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 int bypass_block (basic_block, rtx, rtx);
-static int bypass_conditional_jumps (void);
+ struct hash_table_d *);
+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 void alloc_pre_mem (int, int);
static void free_pre_mem (void);
-static void compute_pre_data (void);
+static struct edge_list *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);
static void pre_insert_copy_insn (struct expr *, rtx);
static void pre_insert_copies (void);
static int pre_delete (void);
-static int pre_gcse (void);
-static int one_pre_gcse_pass (int);
+static int pre_gcse (struct edge_list *);
+static int one_pre_gcse_pass (void);
static void add_label_notes (rtx, rtx);
static void alloc_code_hoist_mem (int, int);
static void free_code_hoist_mem (void);
static void compute_code_hoist_vbeinout (void);
static void compute_code_hoist_data (void);
-static int hoist_expr_reaches_here_p (basic_block, int, basic_block, char *);
-static void hoist_code (void);
+static int hoist_expr_reaches_here_p (basic_block, int, basic_block, char *,
+ int, int *);
+static int hoist_code (void);
static int one_code_hoisting_pass (void);
static rtx process_insert_insn (struct expr *);
static int pre_edge_insert (struct edge_list *, struct expr **);
basic_block, char *);
static struct ls_expr * ldst_entry (rtx);
static void free_ldst_entry (struct ls_expr *);
-static void free_ldst_mems (void);
+static void free_ld_motion_mems (void);
static void print_ldst_list (FILE *);
static struct ls_expr * find_rtx_in_ldst (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 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 void build_store_vectors (void);
-static void insert_insn_start_bb (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 delete_store (struct ls_expr *, basic_block);
-static void free_store_memory (void);
-static void store_motion (void);
-static void free_insn_expr_list_list (rtx *);
static void clear_modify_mem_tables (void);
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, bool, rtx*);
-static bool adjust_libcall_notes (rtx, rtx, rtx, rtx*);
-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. Return nonzero if a
- change is mode. */
-
-static int
-gcse_main (rtx f ATTRIBUTE_UNUSED)
-{
- int changed, pass;
- /* Bytes used at start of pass. */
- int initial_bytes_used;
- /* Maximum number of bytes used by a pass. */
- int max_pass_bytes;
- /* Point to release obstack data from for each pass. */
- char *gcse_obstack_bottom;
-
- /* 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;
-
- /* Assume that we do not need to run jump optimizations after gcse. */
- run_jump_opt_after_gcse = 0;
-
- /* Identify the basic block information for this function, including
- successors and predecessors. */
- max_gcse_regno = max_reg_num ();
-
- 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 <= NUM_FIXED_BLOCKS + 1
- || is_too_expensive (_("GCSE disabled")))
- return 0;
-
- gcc_obstack_init (&gcse_obstack);
- bytes_used = 0;
-
- /* We need alias. */
- init_alias_analysis ();
- /* 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.
-
- 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. */
-
- alloc_reg_set_mem (max_gcse_regno);
- compute_sets ();
-
- pass = 0;
- initial_bytes_used = bytes_used;
- max_pass_bytes = 0;
- gcse_obstack_bottom = gcse_alloc (1);
- changed = 1;
- while (changed && pass < MAX_GCSE_PASSES)
- {
- changed = 0;
- 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. */
- bytes_used = initial_bytes_used;
-
- /* Each pass may create new registers, so recalculate each time. */
- max_gcse_regno = max_reg_num ();
-
- alloc_gcse_mem ();
-
- /* Don't allow constant propagation to modify jumps
- during this pass. */
- timevar_push (TV_CPROP1);
- changed = one_cprop_pass (pass + 1, false, false);
- timevar_pop (TV_CPROP1);
-
- if (optimize_size)
- /* 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
- basic blocks. */
- if (changed)
- {
- free_modify_mem_tables ();
- modify_mem_list = gcalloc (last_basic_block, sizeof (rtx));
- canon_modify_mem_list = gcalloc (last_basic_block, sizeof (rtx));
- }
- free_reg_set_mem ();
- alloc_reg_set_mem (max_reg_num ());
- compute_sets ();
- run_jump_opt_after_gcse = 1;
- timevar_pop (TV_PRE);
- }
-
- if (max_pass_bytes < bytes_used)
- max_pass_bytes = bytes_used;
-
- /* Free up memory, then reallocate for code hoisting. We can
- not re-use the existing allocated memory because the tables
- will not have info for the insns or registers created by
- partial redundancy elimination. */
- free_gcse_mem ();
-
- /* 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 don't run the partial redundancy algorithms). */
- if (optimize_size)
- {
- timevar_push (TV_HOIST);
- max_gcse_regno = max_reg_num ();
- 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 (dump_file)
- {
- fprintf (dump_file, "\n");
- fflush (dump_file);
- }
-
- obstack_free (&gcse_obstack, gcse_obstack_bottom);
- pass++;
- }
-
- /* Do one last pass of copy propagation, including cprop into
- conditional jumps. */
-
- max_gcse_regno = max_reg_num ();
- alloc_gcse_mem ();
- /* This time, go ahead and allow cprop to alter jumps. */
- timevar_push (TV_CPROP2);
- one_cprop_pass (pass + 1, true, false);
- timevar_pop (TV_CPROP2);
- free_gcse_mem ();
-
- if (dump_file)
- {
- fprintf (dump_file, "GCSE of %s: %d basic blocks, ",
- current_function_name (), n_basic_blocks);
- 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 ();
+#define GNEW(T) ((T *) gmalloc (sizeof (T)))
+#define GCNEW(T) ((T *) gcalloc (1, sizeof (T)))
- /* We are finished with alias. */
- end_alias_analysis ();
- allocate_reg_info (max_reg_num (), FALSE, FALSE);
+#define GNEWVEC(T, N) ((T *) gmalloc (sizeof (T) * (N)))
+#define GCNEWVEC(T, N) ((T *) gcalloc ((N), sizeof (T)))
- if (!optimize_size && flag_gcse_sm)
- {
- timevar_push (TV_LSM);
- store_motion ();
- timevar_pop (TV_LSM);
- }
+#define GNEWVAR(T, S) ((T *) gmalloc ((S)))
+#define GCNEWVAR(T, S) ((T *) gcalloc (1, (S)))
- /* Record where pseudo-registers are set. */
- return run_jump_opt_after_gcse;
-}
+#define GOBNEW(T) ((T *) gcse_alloc (sizeof (T)))
+#define GOBNEWVAR(T, S) ((T *) gcse_alloc ((S)))
\f
/* Misc. utilities. */
-/* Nonzero for each mode that supports (set (reg) (reg)).
- This is trivially true for integer and floating point values.
- It may or may not be true for condition codes. */
-static char can_copy[(int) NUM_MACHINE_MODES];
+#define can_copy \
+ (this_target_gcse->x_can_copy)
+#define can_copy_init_p \
+ (this_target_gcse->x_can_copy_init_p)
/* Compute which modes support reg/reg copy operations. */
bool
can_copy_p (enum machine_mode mode)
{
- static bool can_copy_init_p = false;
-
if (! can_copy_init_p)
{
compute_can_copy ();
return xcalloc (nelem, elsize);
}
-/* Cover function to xrealloc.
- We don't record the additional size since we don't know it.
- It won't affect memory usage stats much anyway. */
-
-static void *
-grealloc (void *ptr, size_t size)
-{
- return xrealloc (ptr, size);
-}
-
/* Cover function to obstack_alloc. */
static void *
return obstack_alloc (&gcse_obstack, size);
}
-/* Allocate memory for the cuid mapping array,
- and reg/memory set tracking tables.
-
+/* Allocate memory for the reg/memory set tracking tables.
This is called at the start of each pass. */
static void
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.
- (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));
- 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));
- 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_ALLOC (NULL);
+ reg_set_bitmap = ALLOC_REG_SET (NULL);
- /* Allocate vars to track sets of regs, memory per block. */
- reg_set_in_block = sbitmap_vector_alloc (last_basic_block, max_gcse_regno);
/* Allocate array to keep a list of insns which modify memory in each
basic block. */
- modify_mem_list = gcalloc (last_basic_block, sizeof (rtx));
- canon_modify_mem_list = gcalloc (last_basic_block, sizeof (rtx));
+ modify_mem_list = GCNEWVEC (VEC (rtx,heap) *, last_basic_block);
+ canon_modify_mem_list = GCNEWVEC (VEC (modify_pair,heap) *,
+ last_basic_block);
modify_mem_list_set = BITMAP_ALLOC (NULL);
blocks_with_calls = BITMAP_ALLOC (NULL);
}
static void
free_gcse_mem (void)
{
- free (uid_cuid);
- free (cuid_insn);
+ FREE_REG_SET (reg_set_bitmap);
- BITMAP_FREE (reg_set_bitmap);
-
- sbitmap_vector_free (reg_set_in_block);
free_modify_mem_tables ();
BITMAP_FREE (modify_mem_list_set);
BITMAP_FREE (blocks_with_calls);
least once and expression would contain the same value if the computation
was moved to the beginning of the block.
- We call this routine for cprop, pre and code hoisting. They all compute
+ We call this routine for pre and code hoisting. They all compute
basically the same information and thus can easily share this code.
TRANSP, COMP, and ANTLOC are destination sbitmaps for recording local
properties. If NULL, then it is not necessary to compute or record that
particular property.
- TABLE controls which hash table to look at. If it is set hash table,
- additionally, TRANSP is computed as ~TRANSP, since this is really cprop's
- ABSALTERED. */
+ TABLE controls which hash table to look at. */
static void
compute_local_properties (sbitmap *transp, sbitmap *comp, sbitmap *antloc,
- struct hash_table *table)
+ struct hash_table_d *table)
{
unsigned int i;
/* Initialize any bitmaps that were passed in. */
if (transp)
{
- if (table->set_p)
- sbitmap_vector_zero (transp, last_basic_block);
- else
- sbitmap_vector_ones (transp, last_basic_block);
+ sbitmap_vector_ones (transp, last_basic_block);
}
if (comp)
We start by assuming all are transparent [none are killed], and
then reset the bits for those that are. */
if (transp)
- compute_transp (expr->expr, indx, transp, table->set_p);
+ compute_transp (expr->expr, indx, transp);
/* The occurrences recorded in antic_occr are exactly those that
we want to set to nonzero in ANTLOC. */
if (antloc)
for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
{
- SET_BIT (antloc[BLOCK_NUM (occr->insn)], indx);
+ SET_BIT (antloc[BLOCK_FOR_INSN (occr->insn)->index], indx);
/* While we're scanning the table, this is a good place to
initialize this. */
if (comp)
for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
{
- SET_BIT (comp[BLOCK_NUM (occr->insn)], indx);
+ SET_BIT (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
/* While we're scanning the table, this is a good place to
initialize this. */
}
}
\f
-/* Register set information.
-
- `reg_set_table' records where each register is set or otherwise
- modified. */
-
-static struct obstack reg_set_obstack;
-
-static void
-alloc_reg_set_mem (int n_regs)
-{
- reg_set_table_size = n_regs + REG_SET_TABLE_SLOP;
- reg_set_table = gcalloc (reg_set_table_size, sizeof (struct reg_set *));
-
- gcc_obstack_init (®_set_obstack);
-}
-
-static void
-free_reg_set_mem (void)
-{
- free (reg_set_table);
- obstack_free (®_set_obstack, NULL);
-}
-
-/* Record REGNO in the reg_set table. */
-
-static void
-record_one_set (int regno, rtx insn)
-{
- /* Allocate a new reg_set element and link it onto the list. */
- struct reg_set *new_reg_info;
-
- /* If the table isn't big enough, enlarge it. */
- if (regno >= reg_set_table_size)
- {
- int new_size = regno + REG_SET_TABLE_SLOP;
-
- reg_set_table = grealloc (reg_set_table,
- new_size * sizeof (struct reg_set *));
- memset (reg_set_table + reg_set_table_size, 0,
- (new_size - reg_set_table_size) * sizeof (struct reg_set *));
- reg_set_table_size = new_size;
- }
-
- new_reg_info = obstack_alloc (®_set_obstack, sizeof (struct reg_set));
- bytes_used += sizeof (struct reg_set);
- new_reg_info->bb_index = BLOCK_NUM (insn);
- new_reg_info->next = reg_set_table[regno];
- reg_set_table[regno] = new_reg_info;
-}
-
-/* Called from compute_sets via note_stores to handle one SET or CLOBBER in
- an insn. The DATA is really the instruction in which the SET is
- occurring. */
-
-static void
-record_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED, void *data)
-{
- rtx record_set_insn = (rtx) data;
-
- if (REG_P (dest) && REGNO (dest) >= FIRST_PSEUDO_REGISTER)
- record_one_set (REGNO (dest), record_set_insn);
-}
-
-/* Scan the function and record each set of each pseudo-register.
-
- This is called once, at the start of the gcse pass. See the comments for
- `reg_set_table' for further documentation. */
-
-static void
-compute_sets (void)
-{
- basic_block bb;
- rtx 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. */
struct reg_avail_info
static struct reg_avail_info *reg_avail_info;
static basic_block current_bb;
-
/* See whether X, the source of a set, is something we want to consider for
GCSE. */
static int
-want_to_gcse_p (rtx x)
+want_to_gcse_p (rtx x, int *max_distance_ptr)
{
#ifdef STACK_REGS
/* On register stack architectures, don't GCSE constants from the
x = avoid_constant_pool_reference (x);
#endif
+ /* GCSE'ing constants:
+
+ We do not specifically distinguish between constant and non-constant
+ expressions in PRE and Hoist. We use set_src_cost below to limit
+ the maximum distance simple expressions can travel.
+
+ Nevertheless, constants are much easier to GCSE, and, hence,
+ it is easy to overdo the optimizations. Usually, excessive PRE and
+ Hoisting of constant leads to increased register pressure.
+
+ RA can deal with this by rematerialing some of the constants.
+ Therefore, it is important that the back-end generates sets of constants
+ in a way that allows reload rematerialize them under high register
+ pressure, i.e., a pseudo register with REG_EQUAL to constant
+ is set only once. Failing to do so will result in IRA/reload
+ spilling such constants under high register pressure instead of
+ rematerializing them. */
+
switch (GET_CODE (x))
{
case REG:
case SUBREG:
+ case CALL:
+ return 0;
+
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_FIXED:
case CONST_VECTOR:
- case CALL:
- return 0;
+ if (!doing_code_hoisting_p)
+ /* Do not PRE constants. */
+ return 0;
+
+ /* FALLTHRU */
default:
- return can_assign_to_reg_p (x);
+ if (doing_code_hoisting_p)
+ /* PRE doesn't implement max_distance restriction. */
+ {
+ int cost;
+ int max_distance;
+
+ gcc_assert (!optimize_function_for_speed_p (cfun)
+ && optimize_function_for_size_p (cfun));
+ cost = set_src_cost (x, 0);
+
+ if (cost < COSTS_N_INSNS (GCSE_UNRESTRICTED_COST))
+ {
+ max_distance = (GCSE_COST_DISTANCE_RATIO * cost) / 10;
+ if (max_distance == 0)
+ return 0;
+
+ gcc_assert (max_distance > 0);
+ }
+ else
+ max_distance = 0;
+
+ if (max_distance_ptr)
+ *max_distance_ptr = max_distance;
+ }
+
+ return can_assign_to_reg_without_clobbers_p (x);
}
}
-/* Used internally by can_assign_to_reg_p. */
+/* Used internally by can_assign_to_reg_without_clobbers_p. */
static GTY(()) rtx test_insn;
-/* Return true if we can assign X to a pseudo register. */
+/* Return true if we can assign X to a pseudo register such that the
+ resulting insn does not result in clobbering a hard register as a
+ side-effect.
-static bool
-can_assign_to_reg_p (rtx x)
+ Additionally, if the target requires it, check that the resulting insn
+ can be copied. If it cannot, this means that X is special and probably
+ has hidden side-effects we don't want to mess with.
+
+ This function is typically used by code motion passes, to verify
+ that it is safe to insert an insn without worrying about clobbering
+ maybe live hard regs. */
+
+bool
+can_assign_to_reg_without_clobbers_p (rtx x)
{
int num_clobbers = 0;
int icode;
valid. */
PUT_MODE (SET_DEST (PATTERN (test_insn)), GET_MODE (x));
SET_SRC (PATTERN (test_insn)) = x;
- return ((icode = recog (PATTERN (test_insn), test_insn, &num_clobbers)) >= 0
- && (num_clobbers == 0 || ! added_clobbers_hard_reg_p (icode)));
+
+ icode = recog (PATTERN (test_insn), test_insn, &num_clobbers);
+ if (icode < 0)
+ return false;
+
+ if (num_clobbers > 0 && added_clobbers_hard_reg_p (icode))
+ return false;
+
+ if (targetm.cannot_copy_insn_p && targetm.cannot_copy_insn_p (test_insn))
+ return false;
+
+ return true;
}
/* Return nonzero if the operands of expression X are unchanged from the
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;
if (info->last_bb != current_bb)
return 1;
if (avail_p)
- return info->last_set < INSN_CUID (insn);
+ return info->last_set < DF_INSN_LUID (insn);
else
- return info->first_set >= INSN_CUID (insn);
+ return info->first_set >= DF_INSN_LUID (insn);
}
case MEM:
- if (load_killed_in_block_p (current_bb, INSN_CUID (insn),
+ if (load_killed_in_block_p (current_bb, DF_INSN_LUID (insn),
x, avail_p))
return 0;
else
case CONST:
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_FIXED:
case CONST_VECTOR:
case SYMBOL_REF:
case LABEL_REF:
return 1;
}
-/* Used for communication between mems_conflict_for_gcse_p and
- load_killed_in_block_p. Nonzero if mems_conflict_for_gcse_p finds a
- conflict between two memory references. */
-static int gcse_mems_conflict_p;
+/* Info passed from load_killed_in_block_p to mems_conflict_for_gcse_p. */
+
+struct mem_conflict_info
+{
+ /* A memory reference for a load instruction, mems_conflict_for_gcse_p will
+ see if a memory store conflicts with this memory load. */
+ const_rtx mem;
-/* Used for communication between mems_conflict_for_gcse_p and
- 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;
+ /* True if mems_conflict_for_gcse_p finds a conflict between two memory
+ references. */
+ bool conflict;
+};
-/* 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. */
+/* DEST is the output of an instruction. If it is a memory reference and
+ possibly conflicts with the load found in DATA, then communicate this
+ information back through DATA. */
static void
-mems_conflict_for_gcse_p (rtx dest, rtx setter ATTRIBUTE_UNUSED,
- void *data ATTRIBUTE_UNUSED)
+mems_conflict_for_gcse_p (rtx dest, const_rtx setter ATTRIBUTE_UNUSED,
+ void *data)
{
+ struct mem_conflict_info *mci = (struct mem_conflict_info *) data;
+
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
|| GET_CODE (dest) == STRICT_LOW_PART)
/* If we are setting a MEM in our list of specially recognized MEMs,
don't mark as killed this time. */
-
- if (expr_equiv_p (dest, gcse_mem_operand) && pre_ldst_mems != NULL)
+ if (pre_ldst_mems != NULL && expr_equiv_p (dest, mci->mem))
{
if (!find_rtx_in_ldst (dest))
- gcse_mems_conflict_p = 1;
+ mci->conflict = true;
return;
}
- if (true_dependence (dest, GET_MODE (dest), gcse_mem_operand,
- rtx_addr_varies_p))
- gcse_mems_conflict_p = 1;
+ if (true_dependence (dest, GET_MODE (dest), mci->mem))
+ mci->conflict = true;
}
/* Return nonzero if the expression in X (a memory reference) is killed
- in block BB before or after the insn with the CUID in UID_LIMIT.
+ in block BB before or after the insn with the LUID in UID_LIMIT.
AVAIL_P is nonzero for kills after UID_LIMIT, and zero for kills
before UID_LIMIT.
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];
+ VEC (rtx,heap) *list = modify_mem_list[bb->index];
+ rtx setter;
+ unsigned ix;
/* If this is a readonly then we aren't going to be changing it. */
if (MEM_READONLY_P (x))
return 0;
- while (list_entry)
+ FOR_EACH_VEC_ELT_REVERSE (rtx, list, ix, setter)
{
- rtx setter;
+ struct mem_conflict_info mci;
+
/* Ignore entries in the list that do not apply. */
if ((avail_p
- && INSN_CUID (XEXP (list_entry, 0)) < uid_limit)
+ && DF_INSN_LUID (setter) < uid_limit)
|| (! avail_p
- && INSN_CUID (XEXP (list_entry, 0)) > uid_limit))
- {
- list_entry = XEXP (list_entry, 1);
- continue;
- }
-
- setter = XEXP (list_entry, 0);
+ && DF_INSN_LUID (setter) > uid_limit))
+ continue;
/* If SETTER is a call everything is clobbered. Note that calls
to pure functions are never put on the list, so we need not
return 1;
/* SETTER must be an INSN of some kind that sets memory. Call
- note_stores to examine each hunk of memory that is modified.
-
- The note_stores interface is pretty limited, so we have to
- communicate via global variables. Yuk. */
- gcse_mem_operand = x;
- gcse_mems_conflict_p = 0;
- note_stores (PATTERN (setter), mems_conflict_for_gcse_p, NULL);
- if (gcse_mems_conflict_p)
+ note_stores to examine each hunk of memory that is modified. */
+ mci.mem = x;
+ mci.conflict = false;
+ note_stores (PATTERN (setter), mems_conflict_for_gcse_p, &mci);
+ if (mci.conflict)
return 1;
- list_entry = XEXP (list_entry, 1);
}
return 0;
}
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);
}
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_rtx (x, mode, do_not_record_p,
- NULL, /*have_reg_qty=*/false);
- return hash % hash_table_size;
-}
-
-/* Hash a set of register REGNO.
-
- Sets are hashed on the register that is set. This simplifies the PRE copy
- propagation code.
-
- ??? May need to make things more elaborate. Later, as necessary. */
-
-static unsigned int
-hash_set (int regno, int hash_table_size)
-{
- unsigned int hash;
-
- hash = regno;
+ hash = hash_rtx (x, mode, do_not_record_p, NULL, /*have_reg_qty=*/false);
return hash % hash_table_size;
}
/* 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)
{
return exp_equiv_p (x, y, 0, true);
}
It is only used if X is a CONST_INT.
ANTIC_P is nonzero if X is an anticipatable expression.
- AVAIL_P is nonzero if X is an available expression. */
+ AVAIL_P is nonzero if X is an available expression.
+
+ MAX_DISTANCE is the maximum distance in instructions this expression can
+ be moved. */
static void
insert_expr_in_table (rtx x, enum machine_mode mode, rtx insn, int antic_p,
- int avail_p, struct hash_table *table)
+ int avail_p, int max_distance, struct hash_table_d *table)
{
int found, do_not_record_p;
unsigned int hash;
if (! found)
{
- cur_expr = gcse_alloc (sizeof (struct expr));
+ cur_expr = GOBNEW (struct expr);
bytes_used += sizeof (struct expr);
if (table->table[hash] == NULL)
/* This is the first pattern that hashed to this index. */
cur_expr->next_same_hash = NULL;
cur_expr->antic_occr = NULL;
cur_expr->avail_occr = NULL;
+ gcc_assert (max_distance >= 0);
+ cur_expr->max_distance = max_distance;
}
+ else
+ gcc_assert (cur_expr->max_distance == max_distance);
/* Now record the occurrence(s). */
if (antic_p)
{
antic_occr = cur_expr->antic_occr;
- if (antic_occr && BLOCK_NUM (antic_occr->insn) != BLOCK_NUM (insn))
+ if (antic_occr
+ && BLOCK_FOR_INSN (antic_occr->insn) != BLOCK_FOR_INSN (insn))
antic_occr = NULL;
if (antic_occr)
else
{
/* First occurrence of this expression in this basic block. */
- antic_occr = gcse_alloc (sizeof (struct occr));
+ antic_occr = GOBNEW (struct occr);
bytes_used += sizeof (struct occr);
antic_occr->insn = insn;
antic_occr->next = cur_expr->antic_occr;
{
avail_occr = cur_expr->avail_occr;
- if (avail_occr && BLOCK_NUM (avail_occr->insn) == BLOCK_NUM (insn))
+ if (avail_occr
+ && BLOCK_FOR_INSN (avail_occr->insn) == BLOCK_FOR_INSN (insn))
{
/* Found another instance of the expression in the same basic block.
Prefer this occurrence to the currently recorded one. We want
else
{
/* First occurrence of this expression in this basic block. */
- avail_occr = gcse_alloc (sizeof (struct occr));
+ avail_occr = GOBNEW (struct occr);
bytes_used += sizeof (struct occr);
avail_occr->insn = insn;
avail_occr->next = cur_expr->avail_occr;
}
}
-/* Insert pattern X in INSN in the hash table.
- X is a SET of a reg to either another reg or a constant.
- If it is already present, record it as the last occurrence in INSN's
- basic block. */
+/* Scan SET present in INSN and add an entry to the hash TABLE. */
static void
-insert_set_in_table (rtx x, rtx insn, struct hash_table *table)
+hash_scan_set (rtx set, rtx insn, struct hash_table_d *table)
{
- int found;
- unsigned int hash;
- struct expr *cur_expr, *last_expr = NULL;
- struct occr *cur_occr;
-
- gcc_assert (GET_CODE (x) == SET && REG_P (SET_DEST (x)));
-
- hash = hash_set (REGNO (SET_DEST (x)), table->size);
+ rtx src = SET_SRC (set);
+ rtx dest = SET_DEST (set);
+ rtx note;
- cur_expr = table->table[hash];
- found = 0;
+ if (GET_CODE (src) == CALL)
+ hash_scan_call (src, insn, table);
- while (cur_expr && 0 == (found = expr_equiv_p (cur_expr->expr, x)))
+ else if (REG_P (dest))
{
- /* If the expression isn't found, save a pointer to the end of
- the list. */
- last_expr = cur_expr;
- cur_expr = cur_expr->next_same_hash;
- }
+ unsigned int regno = REGNO (dest);
+ int max_distance = 0;
- if (! found)
- {
- cur_expr = gcse_alloc (sizeof (struct expr));
- bytes_used += sizeof (struct expr);
- if (table->table[hash] == NULL)
- /* This is the first pattern that hashed to this index. */
- table->table[hash] = cur_expr;
- else
- /* Add EXPR to end of this hash chain. */
- last_expr->next_same_hash = cur_expr;
+ /* See if a REG_EQUAL note shows this equivalent to a simpler expression.
- /* Set the fields of the expr element.
- We must copy X because it can be modified when copy propagation is
- performed on its operands. */
- cur_expr->expr = copy_rtx (x);
- cur_expr->bitmap_index = table->n_elems++;
- cur_expr->next_same_hash = NULL;
- cur_expr->antic_occr = NULL;
- cur_expr->avail_occr = NULL;
- }
+ This allows us to do a single GCSE pass and still eliminate
+ redundant constants, addresses or other expressions that are
+ constructed with multiple instructions.
- /* Now record the occurrence. */
- cur_occr = cur_expr->avail_occr;
+ However, keep the original SRC if INSN is a simple reg-reg move.
+ In this case, there will almost always be a REG_EQUAL note on the
+ insn that sets SRC. By recording the REG_EQUAL value here as SRC
+ for INSN, we miss copy propagation opportunities and we perform the
+ same PRE GCSE operation repeatedly on the same REG_EQUAL value if we
+ do more than one PRE GCSE pass.
- if (cur_occr && BLOCK_NUM (cur_occr->insn) == BLOCK_NUM (insn))
- {
- /* 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);
-
- cur_occr->insn = insn;
- cur_occr->next = cur_expr->avail_occr;
- cur_occr->deleted_p = 0;
- cur_expr->avail_occr = cur_occr;
- }
-}
-
-/* Determine whether the rtx X should be treated as a constant for
- the purposes of GCSE's constant propagation. */
-
-static bool
-gcse_constant_p (rtx x)
-{
- /* Consider a COMPARE of two integers constant. */
- if (GET_CODE (x) == COMPARE
- && GET_CODE (XEXP (x, 0)) == CONST_INT
- && 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 (GET_CODE(x) == COMPARE
- && 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;
-
- return CONSTANT_P (x);
-}
-
-/* Scan pattern PAT of INSN and add an entry to the hash TABLE (set or
- expression one). */
-
-static void
-hash_scan_set (rtx pat, rtx insn, struct hash_table *table)
-{
- rtx src = SET_SRC (pat);
- rtx dest = SET_DEST (pat);
- rtx note;
-
- if (GET_CODE (src) == CALL)
- hash_scan_call (src, insn, table);
-
- else if (REG_P (dest))
- {
- unsigned int regno = REGNO (dest);
- rtx tmp;
-
- /* 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 that this does not impede profitable constant propagations. We
+ "look through" reg-reg sets in lookup_avail_set. */
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);
+ && REG_NOTE_KIND (note) == REG_EQUAL
+ && !REG_P (src)
+ && want_to_gcse_p (XEXP (note, 0), NULL))
+ src = XEXP (note, 0), set = gen_rtx_SET (VOIDmode, dest, src);
/* Only record sets of pseudo-regs in the hash table. */
- if (! table->set_p
- && regno >= FIRST_PSEUDO_REGISTER
+ if (regno >= FIRST_PSEUDO_REGISTER
/* 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)
+ do that easily for EH edges so disable GCSE on these for now. */
+ /* ??? We can now easily create new EH landing pads at the
+ gimple level, for splitting edges; there's no reason we
+ can't do the same thing at the rtl level. */
+ && !can_throw_internal (insn)
/* Is SET_SRC something we want to gcse? */
- && want_to_gcse_p (src)
+ && want_to_gcse_p (src, &max_distance)
/* Don't CSE a nop. */
- && ! set_noop_p (pat)
+ && ! set_noop_p (set)
/* Don't GCSE 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
{
/* 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
int avail_p = (oprs_available_p (src, insn)
&& ! JUMP_P (insn));
- insert_expr_in_table (src, GET_MODE (dest), insn, antic_p, avail_p, table);
+ insert_expr_in_table (src, GET_MODE (dest), insn, antic_p, avail_p,
+ max_distance, table);
}
-
- /* Record sets for constant/copy propagation. */
- else if (table->set_p
- && regno >= FIRST_PSEUDO_REGISTER
- && ((REG_P (src)
- && REGNO (src) >= FIRST_PSEUDO_REGISTER
- && can_copy_p (GET_MODE (dest))
- && REGNO (src) != regno)
- || gcse_constant_p (src))
- /* A copy is not available if its src or dest is subsequently
- 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))))
- 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
else if (flag_gcse_las && REG_P (src) && MEM_P (dest))
{
unsigned int regno = REGNO (src);
+ int max_distance = 0;
- /* Do not do this for constant/copy propagation. */
- if (! table->set_p
- /* Only record sets of pseudo-regs in the hash table. */
- && regno >= FIRST_PSEUDO_REGISTER
+ /* Only record sets of pseudo-regs in the hash table. */
+ if (regno >= FIRST_PSEUDO_REGISTER
/* 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)
+ do that easily for EH edges so disable GCSE on these for now. */
+ && !can_throw_internal (insn)
/* Is SET_DEST something we want to gcse? */
- && want_to_gcse_p (dest)
+ && want_to_gcse_p (dest, &max_distance)
/* Don't CSE a nop. */
- && ! set_noop_p (pat)
+ && ! set_noop_p (set)
/* Don't GCSE 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
/* Record the memory expression (DEST) in the hash table. */
insert_expr_in_table (dest, GET_MODE (dest), insn,
- antic_p, avail_p, table);
+ antic_p, avail_p, max_distance, table);
}
}
}
static void
hash_scan_clobber (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED,
- struct hash_table *table ATTRIBUTE_UNUSED)
+ struct hash_table_d *table ATTRIBUTE_UNUSED)
{
/* Currently nothing to do. */
}
static void
hash_scan_call (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED,
- struct hash_table *table ATTRIBUTE_UNUSED)
+ struct hash_table_d *table ATTRIBUTE_UNUSED)
{
/* Currently nothing to do. */
}
-/* Process INSN and add hash table entries as appropriate.
-
- Only available expressions that set a single pseudo-reg are recorded.
-
- Single sets in a PARALLEL could be handled, but it's an extra complication
- that isn't dealt with right now. The trick is handling the CLOBBERs that
- are also in the PARALLEL. Later.
-
- If SET_P is nonzero, this is for the assignment hash table,
- otherwise it is for the expression hash table.
- If IN_LIBCALL_BLOCK nonzero, we are in a libcall block, and should
- not record any expressions. */
+/* Process INSN and add hash table entries as appropriate. */
static void
-hash_scan_insn (rtx insn, struct hash_table *table, int in_libcall_block)
+hash_scan_insn (rtx insn, struct hash_table_d *table)
{
rtx pat = PATTERN (insn);
int i;
- if (in_libcall_block)
- return;
-
/* Pick out the sets of INSN and for other forms of instructions record
what's been modified. */
if (GET_CODE (pat) == SET)
hash_scan_set (pat, insn, table);
+
+ else if (GET_CODE (pat) == CLOBBER)
+ hash_scan_clobber (pat, insn, table);
+
+ else if (GET_CODE (pat) == CALL)
+ hash_scan_call (pat, insn, table);
+
else if (GET_CODE (pat) == PARALLEL)
for (i = 0; i < XVECLEN (pat, 0); i++)
{
else if (GET_CODE (x) == CALL)
hash_scan_call (x, insn, table);
}
-
- else if (GET_CODE (pat) == CLOBBER)
- hash_scan_clobber (pat, insn, table);
- else if (GET_CODE (pat) == CALL)
- hash_scan_call (pat, insn, table);
}
+/* Dump the hash table TABLE to file FILE under the name NAME. */
+
static void
-dump_hash_table (FILE *file, const char *name, struct hash_table *table)
+dump_hash_table (FILE *file, const char *name, struct hash_table_d *table)
{
int i;
/* Flattened out table, so it's printed in proper order. */
unsigned int *hash_val;
struct expr *expr;
- flat_table = xcalloc (table->n_elems, sizeof (struct expr *));
- hash_val = xmalloc (table->n_elems * sizeof (unsigned int));
+ flat_table = XCNEWVEC (struct expr *, table->n_elems);
+ hash_val = XNEWVEC (unsigned int, table->n_elems);
for (i = 0; i < (int) table->size; i++)
for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
if (flat_table[i] != 0)
{
expr = flat_table[i];
- fprintf (file, "Index %d (hash value %d)\n ",
- expr->bitmap_index, hash_val[i]);
+ fprintf (file, "Index %d (hash value %d; max distance %d)\n ",
+ expr->bitmap_index, hash_val[i], expr->max_distance);
print_rtl (file, expr->expr);
fprintf (file, "\n");
}
is set and is used to compute "availability".
last_bb records the block for which first_set and last_set are
- valid, as a quick test to invalidate them.
-
- reg_set_in_block records whether the register is set in the block
- and is used to compute "transparency". */
+ valid, as a quick test to invalidate them. */
static void
record_last_reg_set_info (rtx insn, int regno)
{
struct reg_avail_info *info = ®_avail_info[regno];
- int cuid = INSN_CUID (insn);
+ int luid = DF_INSN_LUID (insn);
- info->last_set = cuid;
+ info->last_set = luid;
if (info->last_bb != current_bb)
{
info->last_bb = current_bb;
- info->first_set = cuid;
- SET_BIT (reg_set_in_block[current_bb->index], regno);
+ info->first_set = luid;
}
}
-
/* Record all of the canonicalized MEMs of record_last_mem_set_info's insn.
Note we store a pair of elements in the list, so they have to be
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 x ATTRIBUTE_UNUSED,
void * v_insn)
{
rtx dest_addr, insn;
int bb;
+ modify_pair *pair;
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
dest_addr = get_addr (XEXP (dest, 0));
dest_addr = canon_rtx (dest_addr);
insn = (rtx) v_insn;
- bb = BLOCK_NUM (insn);
+ bb = BLOCK_FOR_INSN (insn)->index;
- canon_modify_mem_list[bb] =
- 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]);
+ pair = VEC_safe_push (modify_pair, heap, canon_modify_mem_list[bb], NULL);
+ pair->dest = dest;
+ pair->dest_addr = dest_addr;
}
/* Record memory modification information for INSN. We do not actually care
static void
record_last_mem_set_info (rtx insn)
{
- int bb = BLOCK_NUM (insn);
+ int bb = BLOCK_FOR_INSN (insn)->index;
/* load_killed_in_block_p will handle the case of calls clobbering
everything. */
- modify_mem_list[bb] = alloc_INSN_LIST (insn, modify_mem_list[bb]);
+ VEC_safe_push (rtx, heap, modify_mem_list[bb], insn);
bitmap_set_bit (modify_mem_list_set, bb);
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 (blocks_with_calls, 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;
record_last_mem_set_info (last_set_insn);
}
-/* Top level function to create an expression or assignment hash table.
+/* Top level function to create an expression hash table.
Expression entries are placed in the hash table if
- they are of the form (set (pseudo-reg) src),
- src is something we want to perform GCSE on,
- none of the operands are subsequently modified in the block
- Assignment entries are placed in the hash table if
- - they are of the form (set (pseudo-reg) src),
- - src is something we want to perform const/copy propagation on,
- - none of the operands or target are subsequently modified in the block
-
Currently src must be a pseudo-reg or a const_int.
TABLE is the table computed. */
static void
-compute_hash_table_work (struct hash_table *table)
+compute_hash_table_work (struct hash_table_d *table)
{
- unsigned int i;
-
- /* While we compute the hash table we also compute a bit array of which
- registers are set in which blocks.
- ??? This isn't needed during const/copy propagation, but it's cheap to
- compute. Later. */
- sbitmap_vector_zero (reg_set_in_block, last_basic_block);
+ int i;
/* re-Cache any INSN_LIST nodes we have allocated. */
clear_modify_mem_tables ();
/* 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));
+ reg_avail_info = GNEWVEC (struct reg_avail_info, max_reg_num ());
- for (i = 0; i < max_gcse_regno; ++i)
+ for (i = 0; i < max_reg_num (); ++i)
reg_avail_info[i].last_bb = NULL;
FOR_EACH_BB (current_bb)
{
rtx insn;
unsigned int regno;
- int in_libcall_block;
/* First pass over the instructions records information used to
- determine when registers and memory are first and last set.
- ??? hard-reg reg_set_in_block computation
- could be moved to compute_sets since they currently don't change. */
-
+ determine when registers and memory are first and last set. */
FOR_BB_INSNS (current_bb, insn)
{
- if (! INSN_P (insn))
+ if (!NONDEBUG_INSN_P (insn))
continue;
if (CALL_P (insn))
if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
record_last_reg_set_info (insn, regno);
- mark_call (insn);
+ if (! RTL_CONST_OR_PURE_CALL_P (insn))
+ record_last_mem_set_info (insn);
}
note_stores (PATTERN (insn), record_last_set_info, insn);
}
- /* Insert implicit sets in the hash table. */
- if (table->set_p
- && implicit_sets[current_bb->index] != NULL_RTX)
- hash_scan_set (implicit_sets[current_bb->index],
- BB_HEAD (current_bb), table);
-
/* The next pass builds the hash table. */
- in_libcall_block = 0;
FOR_BB_INSNS (current_bb, insn)
- if (INSN_P (insn))
- {
- if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
- in_libcall_block = 1;
- else if (table->set_p && find_reg_note (insn, REG_RETVAL, NULL_RTX))
- in_libcall_block = 0;
- hash_scan_insn (insn, table, in_libcall_block);
- if (!table->set_p && find_reg_note (insn, REG_RETVAL, NULL_RTX))
- in_libcall_block = 0;
- }
+ if (NONDEBUG_INSN_P (insn))
+ hash_scan_insn (insn, table);
}
free (reg_avail_info);
}
/* Allocate space for the set/expr hash TABLE.
- N_INSNS is the number of instructions in the function.
- It is used to determine the number of buckets to use.
- SET_P determines whether set or expression table will
- be created. */
+ It is used to determine the number of buckets to use. */
static void
-alloc_hash_table (int n_insns, struct hash_table *table, int set_p)
+alloc_hash_table (struct hash_table_d *table)
{
int n;
- table->size = n_insns / 4;
+ n = get_max_insn_count ();
+
+ table->size = n / 4;
if (table->size < 11)
table->size = 11;
??? Later take some measurements. */
table->size |= 1;
n = table->size * sizeof (struct expr *);
- table->table = gmalloc (n);
- table->set_p = set_p;
+ table->table = GNEWVAR (struct expr *, n);
}
/* Free things allocated by alloc_hash_table. */
static void
-free_hash_table (struct hash_table *table)
+free_hash_table (struct hash_table_d *table)
{
free (table->table);
}
-/* Compute the hash TABLE for doing copy/const propagation or
- expression hash table. */
+/* Compute the expression hash table TABLE. */
static void
-compute_hash_table (struct hash_table *table)
+compute_hash_table (struct hash_table_d *table)
{
/* Initialize count of number of entries in hash table. */
table->n_elems = 0;
\f
/* Expression tracking support. */
-/* Lookup REGNO in the set TABLE. The result is a pointer to the
- table entry, or NULL if not found. */
-
-static struct expr *
-lookup_set (unsigned int regno, struct hash_table *table)
-{
- unsigned int hash = hash_set (regno, table->size);
- struct expr *expr;
-
- expr = table->table[hash];
-
- while (expr && REGNO (SET_DEST (expr->expr)) != regno)
- expr = expr->next_same_hash;
-
- return expr;
-}
-
-/* Return the next entry for REGNO in list EXPR. */
-
-static struct expr *
-next_set (unsigned int regno, struct expr *expr)
-{
- do
- expr = expr->next_same_hash;
- while (expr && REGNO (SET_DEST (expr->expr)) != regno);
-
- return expr;
-}
-
-/* Like free_INSN_LIST_list or free_EXPR_LIST_list, except that the node
- types may be mixed. */
-
-static void
-free_insn_expr_list_list (rtx *listp)
-{
- rtx list, next;
-
- for (list = *listp; list ; list = next)
- {
- next = XEXP (list, 1);
- if (GET_CODE (list) == EXPR_LIST)
- free_EXPR_LIST_node (list);
- else
- free_INSN_LIST_node (list);
- }
-
- *listp = NULL;
-}
-
/* Clear canon_modify_mem_list and modify_mem_list tables. */
static void
clear_modify_mem_tables (void)
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);
+ VEC_free (rtx, heap, modify_mem_list[i]);
+ VEC_free (modify_pair, heap, canon_modify_mem_list[i]);
}
bitmap_clear (modify_mem_list_set);
bitmap_clear (blocks_with_calls);
modify_mem_list = 0;
canon_modify_mem_list = 0;
}
-
-/* Reset tables used to keep track of what's still available [since the
- start of the block]. */
-
-static void
-reset_opr_set_tables (void)
-{
- /* Maintain a bitmap of which regs have been set since beginning of
- the block. */
- CLEAR_REG_SET (reg_set_bitmap);
-
- /* Also keep a record of the last instruction to modify memory.
- For now this is very trivial, we only record whether any memory
- location has been modified. */
- clear_modify_mem_tables ();
-}
-
-/* Return nonzero if the operands of X are not set before INSN in
- INSN's basic block. */
-
-static int
-oprs_not_set_p (rtx x, rtx insn)
-{
- int i, j;
- enum rtx_code code;
- const char *fmt;
-
- if (x == 0)
- return 1;
-
- code = GET_CODE (x);
- switch (code)
- {
- case PC:
- case CC0:
- 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 1;
-
- case MEM:
- if (load_killed_in_block_p (BLOCK_FOR_INSN (insn),
- INSN_CUID (insn), x, 0))
- return 0;
- else
- return oprs_not_set_p (XEXP (x, 0), insn);
-
- case REG:
- return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
-
- default:
- break;
- }
-
- 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)
- return oprs_not_set_p (XEXP (x, i), insn);
-
- if (! oprs_not_set_p (XEXP (x, i), insn))
- return 0;
- }
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- if (! oprs_not_set_p (XVECEXP (x, i, j), insn))
- return 0;
- }
-
- return 1;
-}
-
-/* Mark things set by a CALL. */
-
-static void
-mark_call (rtx insn)
-{
- if (! CONST_OR_PURE_CALL_P (insn))
- record_last_mem_set_info (insn);
-}
-
-/* Mark things set by a SET. */
-
-static void
-mark_set (rtx pat, rtx insn)
-{
- rtx dest = SET_DEST (pat);
-
- while (GET_CODE (dest) == SUBREG
- || GET_CODE (dest) == ZERO_EXTRACT
- || GET_CODE (dest) == STRICT_LOW_PART)
- dest = XEXP (dest, 0);
-
- if (REG_P (dest))
- SET_REGNO_REG_SET (reg_set_bitmap, REGNO (dest));
- else if (MEM_P (dest))
- record_last_mem_set_info (insn);
-
- if (GET_CODE (SET_SRC (pat)) == CALL)
- mark_call (insn);
-}
-
-/* Record things set by a CLOBBER. */
-
-static void
-mark_clobber (rtx pat, rtx insn)
-{
- rtx clob = XEXP (pat, 0);
-
- while (GET_CODE (clob) == SUBREG || GET_CODE (clob) == STRICT_LOW_PART)
- clob = XEXP (clob, 0);
-
- if (REG_P (clob))
- SET_REGNO_REG_SET (reg_set_bitmap, REGNO (clob));
- else
- record_last_mem_set_info (insn);
-}
-
-/* Record things set by INSN.
- This data is used by oprs_not_set_p. */
-
-static void
-mark_oprs_set (rtx insn)
-{
- rtx pat = PATTERN (insn);
- int i;
-
- if (GET_CODE (pat) == SET)
- mark_set (pat, insn);
- else if (GET_CODE (pat) == PARALLEL)
- for (i = 0; i < XVECLEN (pat, 0); i++)
- {
- rtx x = XVECEXP (pat, 0, i);
-
- if (GET_CODE (x) == SET)
- mark_set (x, insn);
- else if (GET_CODE (x) == CLOBBER)
- mark_clobber (x, insn);
- else if (GET_CODE (x) == CALL)
- mark_call (insn);
- }
-
- else if (GET_CODE (pat) == CLOBBER)
- mark_clobber (pat, insn);
- else if (GET_CODE (pat) == CALL)
- mark_call (insn);
-}
-
\f
-/* Compute copy/constant propagation working variables. */
-
-/* Local properties of assignments. */
-static sbitmap *cprop_pavloc;
-static sbitmap *cprop_absaltered;
-
-/* Global properties of assignments (computed from the local properties). */
-static sbitmap *cprop_avin;
-static sbitmap *cprop_avout;
-
-/* Allocate vars used for copy/const propagation. N_BLOCKS is the number of
- basic blocks. N_SETS is the number of sets. */
-
-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);
-
- cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
- cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
-}
-
-/* Free vars used by copy/const propagation. */
-
-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);
-}
-
/* 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. */
+ element of X is modified, reset the INDX bit in BMAP. */
static void
-compute_transp (rtx x, int indx, sbitmap *bmap, int set_p)
+compute_transp (const_rtx x, int indx, sbitmap *bmap)
{
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
switch (code)
{
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[r->bb_index], 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[r->bb_index], indx);
- }
+ df_ref def;
+ for (def = DF_REG_DEF_CHAIN (REGNO (x));
+ def;
+ def = DF_REF_NEXT_REG (def))
+ RESET_BIT (bmap[DF_REF_BB (def)->index], indx);
}
return;
{
bitmap_iterator bi;
unsigned bb_index;
+ rtx x_addr;
+
+ x_addr = get_addr (XEXP (x, 0));
+ x_addr = canon_rtx (x_addr);
/* 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);
+ RESET_BIT (bmap[bb_index], indx);
}
- /* 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];
-
- while (list_entry)
- {
- rtx dest, dest_addr;
-
- /* LIST_ENTRY must be an INSN of some kind that sets memory.
- Examine each hunk of memory that is modified. */
+ /* 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)
+ {
+ VEC (modify_pair,heap) *list
+ = canon_modify_mem_list[bb_index];
+ modify_pair *pair;
+ unsigned ix;
- dest = XEXP (list_entry, 0);
- list_entry = XEXP (list_entry, 1);
- dest_addr = XEXP (list_entry, 0);
+ FOR_EACH_VEC_ELT_REVERSE (modify_pair, list, ix, pair)
+ {
+ rtx dest = pair->dest;
+ rtx dest_addr = pair->dest_addr;
- 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);
- }
- }
+ if (canon_true_dependence (dest, GET_MODE (dest),
+ dest_addr, x, x_addr))
+ RESET_BIT (bmap[bb_index], indx);
+ }
+ }
}
x = XEXP (x, 0);
case CONST:
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_FIXED:
case CONST_VECTOR:
case SYMBOL_REF:
case LABEL_REF:
goto repeat;
}
- compute_transp (XEXP (x, i), indx, bmap, set_p);
+ compute_transp (XEXP (x, i), indx, bmap);
}
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
- compute_transp (XVECEXP (x, i, j), indx, bmap, set_p);
+ compute_transp (XVECEXP (x, i, j), indx, bmap);
}
}
+\f
+/* Compute PRE+LCM working variables. */
-/* Top level routine to do the dataflow analysis needed by copy/const
- propagation. */
+/* Local properties of expressions. */
-static void
-compute_cprop_data (void)
-{
- 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. */
+/* Nonzero for expressions that are transparent in the block. */
+static sbitmap *transp;
+
+/* Nonzero for expressions that are computed (available) in the block. */
+static sbitmap *comp;
-/* Maximum number of register uses in an insn that we handle. */
-#define MAX_USES 8
+/* Nonzero for expressions that are locally anticipatable in the block. */
+static sbitmap *antloc;
+
+/* Nonzero for expressions where this block is an optimal computation
+ point. */
+static sbitmap *pre_optimal;
-/* 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];
+/* Nonzero for expressions which are redundant in a particular block. */
+static sbitmap *pre_redundant;
-/* Index into `reg_use_table' while building it. */
-static int reg_use_count;
+/* Nonzero for expressions which should be inserted on a specific edge. */
+static sbitmap *pre_insert_map;
-/* 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.
+/* Nonzero for expressions which should be deleted in a specific block. */
+static sbitmap *pre_delete_map;
- ??? If a register appears multiple times we will record it multiple times.
- This doesn't hurt anything but it will slow things down. */
+/* Allocate vars used for PRE analysis. */
static void
-find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
+alloc_pre_mem (int n_blocks, int n_exprs)
{
- int i, j;
- enum rtx_code code;
- const char *fmt;
- rtx x = *xptr;
+ transp = sbitmap_vector_alloc (n_blocks, n_exprs);
+ comp = sbitmap_vector_alloc (n_blocks, n_exprs);
+ antloc = sbitmap_vector_alloc (n_blocks, n_exprs);
- /* 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;
+ pre_optimal = NULL;
+ pre_redundant = NULL;
+ pre_insert_map = NULL;
+ pre_delete_map = NULL;
+ ae_kill = sbitmap_vector_alloc (n_blocks, n_exprs);
- code = GET_CODE (x);
- if (REG_P (x))
- {
- if (reg_use_count == MAX_USES)
- return;
+ /* pre_insert and pre_delete are allocated later. */
+}
- reg_use_table[reg_use_count].reg_rtx = x;
- reg_use_count++;
- }
+/* Free vars used for PRE analysis. */
- /* Recursively scan the operands of this expression. */
+static void
+free_pre_mem (void)
+{
+ sbitmap_vector_free (transp);
+ sbitmap_vector_free (comp);
- 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, 0);
- goto repeat;
- }
+ /* ANTLOC and AE_KILL are freed just after pre_lcm finishes. */
- 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);
- }
+ 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);
+
+ transp = comp = NULL;
+ pre_optimal = pre_redundant = pre_insert_map = pre_delete_map = NULL;
}
-/* Try to replace all non-SET_DEST occurrences of FROM in INSN with TO.
- Returns nonzero is successful. */
+/* Remove certain expressions from anticipatable and transparent
+ sets of basic blocks that have incoming abnormal edge.
+ For PRE remove potentially trapping expressions to avoid placing
+ them on abnormal edges. For hoisting remove memory references that
+ can be clobbered by calls. */
-static int
-try_replace_reg (rtx from, rtx to, rtx insn)
+static void
+prune_expressions (bool pre_p)
{
- rtx note = find_reg_equal_equiv_note (insn);
- rtx src = 0;
- int success = 0;
- rtx set = single_set (insn);
+ sbitmap prune_exprs;
+ struct expr *expr;
+ unsigned int ui;
+ basic_block bb;
- /* 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);
+ prune_exprs = sbitmap_alloc (expr_hash_table.n_elems);
+ sbitmap_zero (prune_exprs);
+ for (ui = 0; ui < expr_hash_table.size; ui++)
+ {
+ for (expr = expr_hash_table.table[ui]; expr; expr = expr->next_same_hash)
+ {
+ /* Note potentially trapping expressions. */
+ if (may_trap_p (expr->expr))
+ {
+ SET_BIT (prune_exprs, expr->bitmap_index);
+ continue;
+ }
- validate_replace_src_group (from, to, insn);
- if (num_changes_pending () && apply_change_group ())
- success = 1;
+ if (!pre_p && MEM_P (expr->expr))
+ /* Note memory references that can be clobbered by a call.
+ We do not split abnormal edges in hoisting, so would
+ a memory reference get hoisted along an abnormal edge,
+ it would be placed /before/ the call. Therefore, only
+ constant memory references can be hoisted along abnormal
+ edges. */
+ {
+ if (GET_CODE (XEXP (expr->expr, 0)) == SYMBOL_REF
+ && CONSTANT_POOL_ADDRESS_P (XEXP (expr->expr, 0)))
+ continue;
- /* Try to simplify SET_SRC if we have substituted a constant. */
- if (success && set && CONSTANT_P (to))
- {
- src = simplify_rtx (SET_SRC (set));
+ if (MEM_READONLY_P (expr->expr)
+ && !MEM_VOLATILE_P (expr->expr)
+ && MEM_NOTRAP_P (expr->expr))
+ /* Constant memory reference, e.g., a PIC address. */
+ continue;
- if (src)
- validate_change (insn, &SET_SRC (set), src, 0);
- }
+ /* ??? Optimally, we would use interprocedural alias
+ analysis to determine if this mem is actually killed
+ by this call. */
- /* 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));
+ SET_BIT (prune_exprs, expr->bitmap_index);
+ }
+ }
+ }
- if (!success && set && reg_mentioned_p (from, SET_SRC (set)))
+ FOR_EACH_BB (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);
-
- if (!rtx_equal_p (src, SET_SRC (set))
- && validate_change (insn, &SET_SRC (set), src, 0))
- success = 1;
-
- /* 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));
- }
+ edge e;
+ edge_iterator ei;
- /* 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);
+ /* If the current block is the destination of an abnormal edge, we
+ kill all trapping (for PRE) and memory (for hoist) 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 hoisting it may be necessary to check for set-and-jump
+ instructions here, not just for abnormal edges. The general problem
+ is that when an expression cannot not be placed right at the end of
+ a basic block we should account for any side-effects of a subsequent
+ jump instructions that could clobber the expression. It would
+ be best to implement this check along the lines of
+ hoist_expr_reaches_here_p where the target block is already known
+ and, hence, there's no need to conservatively prune expressions on
+ "intermediate" set-and-jump instructions. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if ((e->flags & EDGE_ABNORMAL)
+ && (pre_p || CALL_P (BB_END (e->src))))
+ {
+ sbitmap_difference (antloc[bb->index],
+ antloc[bb->index], prune_exprs);
+ sbitmap_difference (transp[bb->index],
+ transp[bb->index], prune_exprs);
+ break;
+ }
+ }
- return success;
+ sbitmap_free (prune_exprs);
}
-/* Find a set of REGNOs that are available on entry to INSN's block. Returns
- NULL no such set is found. */
-
-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;
-
- /* 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:
+/* It may be necessary to insert a large number of insns on edges to
+ make the existing occurrences of expressions fully redundant. This
+ routine examines the set of insertions and deletions and if the ratio
+ of insertions to deletions is too high for a particular expression, then
+ the expression is removed from the insertion/deletion sets.
- (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)
- {
- rtx src;
- struct expr *set = lookup_set (regno, &set_hash_table);
+ N_ELEMS is the number of elements in the hash table. */
- /* 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);
- }
+static void
+prune_insertions_deletions (int n_elems)
+{
+ sbitmap_iterator sbi;
+ sbitmap prune_exprs;
- /* If no available set was found we've reached the end of the
- (possibly empty) copy chain. */
- if (set == 0)
- break;
+ /* We always use I to iterate over blocks/edges and J to iterate over
+ expressions. */
+ unsigned int i, j;
- gcc_assert (GET_CODE (set->expr) == SET);
+ /* Counts for the number of times an expression needs to be inserted and
+ number of times an expression can be removed as a result. */
+ int *insertions = GCNEWVEC (int, n_elems);
+ int *deletions = GCNEWVEC (int, n_elems);
- src = SET_SRC (set->expr);
+ /* Set of expressions which require too many insertions relative to
+ the number of deletions achieved. We will prune these out of the
+ insertion/deletion sets. */
+ prune_exprs = sbitmap_alloc (n_elems);
+ sbitmap_zero (prune_exprs);
- /* 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).
+ /* Iterate over the edges counting the number of times each expression
+ needs to be inserted. */
+ for (i = 0; i < (unsigned) n_edges; i++)
+ {
+ EXECUTE_IF_SET_IN_SBITMAP (pre_insert_map[i], 0, j, sbi)
+ insertions[j]++;
+ }
- 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. */
+ /* Similarly for deletions, but those occur in blocks rather than on
+ edges. */
+ for (i = 0; i < (unsigned) last_basic_block; i++)
+ {
+ EXECUTE_IF_SET_IN_SBITMAP (pre_delete_map[i], 0, j, sbi)
+ deletions[j]++;
+ }
- if (gcse_constant_p (src) || oprs_not_set_p (src, insn))
- set1 = set;
+ /* Now that we have accurate counts, iterate over the elements in the
+ hash table and see if any need too many insertions relative to the
+ number of evaluations that can be removed. If so, mark them in
+ PRUNE_EXPRS. */
+ for (j = 0; j < (unsigned) n_elems; j++)
+ if (deletions[j]
+ && ((unsigned) insertions[j] / deletions[j]) > MAX_GCSE_INSERTION_RATIO)
+ SET_BIT (prune_exprs, j);
- /* 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;
+ /* Now prune PRE_INSERT_MAP and PRE_DELETE_MAP based on PRUNE_EXPRS. */
+ EXECUTE_IF_SET_IN_SBITMAP (prune_exprs, 0, j, sbi)
+ {
+ for (i = 0; i < (unsigned) n_edges; i++)
+ RESET_BIT (pre_insert_map[i], j);
- /* 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);
+ for (i = 0; i < (unsigned) last_basic_block; i++)
+ RESET_BIT (pre_delete_map[i], j);
}
- /* SET1 holds the last set that was available and anticipatable at
- INSN. */
- return set1;
+ sbitmap_free (prune_exprs);
+ free (insertions);
+ free (deletions);
}
-/* 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. */
+/* Top level routine to do the dataflow analysis needed by PRE. */
-static int
-cprop_jump (basic_block bb, rtx setcc, rtx jump, rtx from, rtx src)
+static struct edge_list *
+compute_pre_data (void)
{
- rtx new, set_src, note_src;
- rtx set = pc_set (jump);
- rtx note = find_reg_equal_equiv_note (jump);
+ struct edge_list *edge_list;
+ basic_block bb;
- if (note)
- {
- note_src = XEXP (note, 0);
- if (GET_CODE (note_src) == EXPR_LIST)
- note_src = NULL_RTX;
- }
- else note_src = NULL_RTX;
+ compute_local_properties (transp, comp, antloc, &expr_hash_table);
+ prune_expressions (true);
+ sbitmap_vector_zero (ae_kill, last_basic_block);
+
+ /* Compute ae_kill for each basic block using:
- /* Prefer REG_EQUAL notes except those containing EXPR_LISTs. */
- set_src = note_src ? note_src : SET_SRC (set);
+ ~(TRANSP | COMP)
+ */
- /* 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))
+ FOR_EACH_BB (bb)
{
- 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);
+ sbitmap_a_or_b (ae_kill[bb->index], transp[bb->index], comp[bb->index]);
+ sbitmap_not (ae_kill[bb->index], ae_kill[bb->index]);
}
- else
- setcc = NULL_RTX;
- new = simplify_replace_rtx (set_src, from, src);
+ 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;
- /* If no simplification can be made, then try the next register. */
- if (rtx_equal_p (new, SET_SRC (set)))
- return 0;
+ prune_insertions_deletions (expr_hash_table.n_elems);
- /* 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))
- {
- /* 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;
- }
+ return edge_list;
+}
+\f
+/* PRE utilities */
- /* Remove REG_EQUAL note after simplification. */
- if (note_src)
- remove_note (jump, note);
+/* Return nonzero if an occurrence of expression EXPR in OCCR_BB would reach
+ block BB.
- /* 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);
- }
+ VISITED is a pointer to a working buffer for tracking which BB's have
+ been visited. It is NULL for the top-level call.
-#ifdef HAVE_cc0
- /* Delete the cc0 setter. */
- if (setcc != NULL && CC0_P (SET_DEST (single_set (setcc))))
- delete_insn (setcc);
-#endif
+ 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. */
- run_jump_opt_after_gcse = 1;
+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;
- global_const_prop_count++;
- if (dump_file != NULL)
+ FOR_EACH_EDGE (pred, ei, bb->preds)
{
- 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);
+ basic_block pred_bb = pred->src;
- return 1;
-}
+ if (pred->src == ENTRY_BLOCK_PTR
+ /* Has predecessor has already been visited? */
+ || visited[pred_bb->index])
+ ;/* Nothing to do. */
-static bool
-constprop_register (rtx insn, rtx from, rtx to, bool alter_jumps)
-{
- rtx sset;
-
- /* 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;
- }
+ /* 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;
- /* Handle normal insns next. */
- if (NONJUMP_INSN_P (insn)
- && try_replace_reg (from, to, insn))
- return 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;
- /* 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.
+ /* 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;
+ }
+ }
- 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);
+ /* All paths have been checked. */
return 0;
}
-/* Perform constant and copy propagation on INSN.
- The result is nonzero if a change was made. */
+/* The wrapper for pre_expr_reaches_here_work that ensures that any
+ memory allocated for that function is returned. */
static int
-cprop_insn (rtx insn, int alter_jumps)
+pre_expr_reaches_here_p (basic_block occr_bb, struct expr *expr, basic_block bb)
{
- struct reg_use *reg_used;
- int changed = 0;
- rtx note;
-
- if (!INSN_P (insn))
- return 0;
-
- 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--)
- {
- unsigned int regno = REGNO (reg_used->reg_rtx);
- rtx pat, src;
- struct expr *set;
+ int rval;
+ char *visited = XCNEWVEC (char, last_basic_block);
- /* Ignore registers created by GCSE.
- We do this because ... */
- if (regno >= max_gcse_regno)
- continue;
+ rval = pre_expr_reaches_here_p_work (occr_bb, expr, bb, visited);
- /* 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;
+ free (visited);
+ return rval;
+}
+\f
+/* Generate RTL to copy an EXPR to its `reaching_reg' and return it. */
- /* 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;
+static rtx
+process_insert_insn (struct expr *expr)
+{
+ rtx reg = expr->reaching_reg;
+ /* Copy the expression to make sure we don't have any sharing issues. */
+ rtx exp = copy_rtx (expr->expr);
+ rtx pat;
- pat = set->expr;
- /* ??? We might be able to handle PARALLELs. Later. */
- gcc_assert (GET_CODE (pat) == SET);
+ start_sequence ();
- src = SET_SRC (pat);
+ /* 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);
- /* 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));
- }
+ /* Otherwise, make a new insn to compute this expression and make sure the
+ insn will be recognized (this also adds any needed CLOBBERs). */
+ else
+ {
+ rtx insn = emit_insn (gen_rtx_SET (VOIDmode, reg, exp));
- /* 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 (insn_invalid_p (insn))
+ gcc_unreachable ();
}
- return changed;
+ pat = get_insns ();
+ end_sequence ();
+
+ return pat;
}
-/* 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. */
+/* Add EXPR to the end of basic block BB.
+
+ This is used by both the PRE and code hoisting. */
static void
-local_cprop_find_used_regs (rtx *xptr, void *data)
+insert_insn_end_basic_block (struct expr *expr, basic_block bb)
{
- rtx x = *xptr;
-
- if (x == 0)
- return;
+ rtx insn = BB_END (bb);
+ rtx new_insn;
+ rtx reg = expr->reaching_reg;
+ int regno = REGNO (reg);
+ rtx pat, pat_end;
- switch (GET_CODE (x))
- {
- 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 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;
-
- default:
- break;
- }
+ pat = process_insert_insn (expr);
+ gcc_assert (pat && INSN_P (pat));
- find_used_regs (xptr, data);
-}
+ pat_end = pat;
+ while (NEXT_INSN (pat_end) != NULL_RTX)
+ pat_end = NEXT_INSN (pat_end);
-/* LIBCALL_SP is a zero-terminated array of insns at the end of a libcall;
- their REG_EQUAL notes need updating. */
+ /* 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. */
-static bool
-do_local_cprop (rtx x, rtx insn, bool alter_jumps, rtx *libcall_sp)
-{
- rtx newreg = NULL, newcnst = NULL;
-
- /* 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)))
+ if (JUMP_P (insn)
+ || (NONJUMP_INSN_P (insn)
+ && (!single_succ_p (bb)
+ || single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
{
- cselib_val *val = cselib_lookup (x, GET_MODE (x), 0);
- struct elt_loc_list *l;
-
- if (!val)
- return false;
- for (l = val->locs; l; l = l->next)
- {
- rtx this_rtx = l->loc;
- rtx note;
+#ifdef HAVE_cc0
+ rtx note;
+#endif
- /* Don't CSE non-constant values out of libcall blocks. */
- if (l->in_libcall && ! CONSTANT_P (this_rtx))
- continue;
+ /* 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_active_insn (insn);
- 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 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. */
- bool adjusted;
-
- adjusted = adjust_libcall_notes (x, newcnst, insn, libcall_sp);
- gcc_assert (adjusted);
-
- if (dump_file != NULL)
- {
- 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");
- }
- local_const_prop_count++;
- return true;
- }
- else if (newreg && newreg != x && try_replace_reg (x, newreg, 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
{
- 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;
+ 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);
}
- return false;
-}
-/* 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;
-
- while ((end = *libcall_sp++))
+ /* 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))
{
- rtx note = find_reg_equal_equiv_note (end);
+ /* Keeping in mind targets with 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 (! note)
- continue;
-
- 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);
- insn = end;
- }
- return true;
-}
+ /* 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));
-#define MAX_NESTED_LIBCALLS 9
+ /* If we found all the parameter loads, then we want to insert
+ before the first parameter load.
-/* 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. */
+ 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);
-static void
-local_cprop_pass (bool alter_jumps)
-{
- basic_block bb;
- rtx insn;
- struct reg_use *reg_used;
- rtx libcall_stack[MAX_NESTED_LIBCALLS + 1], *libcall_sp;
- bool changed = false;
+ new_insn = emit_insn_before_noloc (pat, insn, bb);
+ }
+ else
+ new_insn = emit_insn_after_noloc (pat, insn, bb);
- cselib_init (false);
- libcall_sp = &libcall_stack[MAX_NESTED_LIBCALLS];
- *libcall_sp = 0;
- FOR_EACH_BB (bb)
+ while (1)
{
- FOR_BB_INSNS (bb, insn)
- {
- if (INSN_P (insn))
- {
- rtx note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
-
- 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]);
+ if (INSN_P (pat))
+ add_label_notes (PATTERN (pat), new_insn);
+ if (pat == pat_end)
+ break;
+ pat = NEXT_INSN (pat);
}
- cselib_finish ();
+ gcse_create_count++;
- /* Global analysis may get into infinite loops for unreachable blocks. */
- if (changed && alter_jumps)
+ if (dump_file)
{
- delete_unreachable_blocks ();
- free_reg_set_mem ();
- alloc_reg_set_mem (max_reg_num ());
- compute_sets ();
+ 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);
}
}
-/* Forward propagate copies. This includes copies and constants. Return
- nonzero if a change was made. */
+/* Insert partially redundant expressions on edges in the CFG to make
+ the expressions fully redundant. */
static int
-cprop (int alter_jumps)
+pre_edge_insert (struct edge_list *edge_list, struct expr **index_map)
{
- int changed;
- basic_block bb;
- rtx insn;
-
- /* Note we start at block 1. */
- if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
- {
- if (dump_file != NULL)
- fprintf (dump_file, "\n");
- return 0;
- }
+ int e, i, j, num_edges, set_size, did_insert = 0;
+ sbitmap *inserted;
- changed = 0;
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb)
- {
- /* Reset tables used to keep track of what's still valid [since the
- start of the block]. */
- reset_opr_set_tables ();
+ /* Where PRE_INSERT_MAP is nonzero, we add the expression on that edge
+ if it reaches any of the deleted expressions. */
- FOR_BB_INSNS (bb, insn)
- if (INSN_P (insn))
- {
- changed |= cprop_insn (insn, alter_jumps);
+ 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);
- /* 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);
- }
- }
+ for (e = 0; e < num_edges; e++)
+ {
+ int indx;
+ basic_block bb = INDEX_EDGE_PRED_BB (edge_list, e);
- if (dump_file != NULL)
- fprintf (dump_file, "\n");
+ for (i = indx = 0; i < set_size; i++, indx += SBITMAP_ELT_BITS)
+ {
+ SBITMAP_ELT_TYPE insert = pre_insert_map[e]->elms[i];
- return changed;
-}
+ 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;
-/* Similar to get_condition, only the resulting condition must be
- valid at JUMP, instead of at EARLIEST.
+ /* Now look at each deleted occurrence of this expression. */
+ for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
+ {
+ if (! occr->deleted_p)
+ continue;
- 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. */
+ /* 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);
-rtx
-fis_get_condition (rtx jump)
-{
- return get_condition (jump, NULL, false, true);
-}
+ /* 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. */
-/* Check the comparison COND to see if we can safely form an implicit set from
- it. COND is either an EQ or NE comparison. */
+ if (eg->flags & EDGE_ABNORMAL)
+ insert_insn_end_basic_block (index_map[j], bb);
+ else
+ {
+ insn = process_insert_insn (index_map[j]);
+ insert_insn_on_edge (insn, eg);
+ }
-static bool
-implicit_set_cond_p (rtx cond)
-{
- enum machine_mode mode = GET_MODE (XEXP (cond, 0));
- rtx cst = XEXP (cond, 1);
+ if (dump_file)
+ {
+ fprintf (dump_file, "PRE: edge (%d,%d), ",
+ bb->index,
+ INDEX_EDGE_SUCC_BB (edge_list, e)->index);
+ fprintf (dump_file, "copy expression %d\n",
+ expr->bitmap_index);
+ }
- /* 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)
- {
- REAL_VALUE_TYPE d;
- REAL_VALUE_FROM_CONST_DOUBLE (d, cst);
- if (REAL_VALUES_EQUAL (d, dconst0))
- return 0;
+ update_ld_motion_stores (expr);
+ SET_BIT (inserted[e], j);
+ did_insert = 1;
+ gcse_create_count++;
+ }
+ }
+ }
}
- else
- return 0;
}
- return gcse_constant_p (cst);
+ sbitmap_vector_free (inserted);
+ return did_insert;
}
-/* 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. */
+/* 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
-find_implicit_sets (void)
+pre_insert_copy_insn (struct expr *expr, rtx insn)
{
- basic_block bb, dest;
- unsigned int count;
- rtx cond, new;
-
- 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));
+ 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 (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;
+ /* This block matches the logic in hash_scan_insn. */
+ switch (GET_CODE (pat))
+ {
+ case SET:
+ set = pat;
+ break;
- 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++;
- }
- }
- }
-
- if (dump_file)
- fprintf (dump_file, "Found %d implicit sets\n", count);
-}
-
-/* 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
-one_cprop_pass (int pass, bool cprop_jumps, bool bypass_jumps)
-{
- int changed = 0;
-
- 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);
+ 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)
+ {
+ /* 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;
+ }
+ }
+ }
- /* Free implicit_sets before peak usage. */
- free (implicit_sets);
- implicit_sets = NULL;
+ gcc_assert (first_set);
+ if (set == NULL_RTX)
+ set = first_set;
+ break;
- if (dump_file)
- dump_hash_table (dump_file, "SET", &set_hash_table);
- if (set_hash_table.n_elems > 0)
- {
- 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 ();
+ default:
+ gcc_unreachable ();
}
- free_hash_table (&set_hash_table);
-
- if (dump_file)
+ if (REG_P (SET_DEST (set)))
{
- 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);
+ 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);
+ }
+ else
+ {
+ new_insn = gen_move_insn (reg, old_reg);
+ new_insn = emit_insn_after (new_insn, insn);
+ }
}
- /* Global analysis may get into infinite loops for unreachable blocks. */
- if (changed && cprop_jumps)
- delete_unreachable_blocks ();
-
- return changed;
-}
-\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. */
-
-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 (;;)
+ else /* This is possible only in case of a store to memory. */
{
- rtx src;
- struct expr *set = lookup_set (regno, &set_hash_table);
-
- while (set)
- {
- if (TEST_BIT (cprop_avout[bb], set->bitmap_index))
- break;
- set = next_set (regno, set);
- }
-
- if (set == 0)
- break;
-
- gcc_assert (GET_CODE (set->expr) == SET);
-
- src = SET_SRC (set->expr);
- if (gcse_constant_p (src))
- result = set;
-
- if (! REG_P (src))
- break;
+ old_reg = SET_SRC (set);
+ new_insn = gen_move_insn (reg, old_reg);
- regno = REGNO (src);
+ /* 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);
}
- return result;
-}
+ gcse_create_count++;
-/* 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
-reg_killed_on_edge (rtx reg, edge e)
-{
- rtx insn;
-
- for (insn = e->insns.r; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && reg_set_p (reg, insn))
- return true;
-
- return false;
+ if (dump_file)
+ fprintf (dump_file,
+ "PRE: bb %d, insn %d, copy expression %d in insn %d to reg %d\n",
+ BLOCK_FOR_INSN (insn)->index, INSN_UID (new_insn), indx,
+ INSN_UID (insn), 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. */
+/* Copy available expressions that reach the redundant expression
+ to `reaching_reg'. */
-static int
-bypass_block (basic_block bb, rtx setcc, rtx jump)
+static void
+pre_insert_copies (void)
{
- rtx insn, note;
- edge e, edest;
- int i, change;
- int may_be_loop_header;
- unsigned removed_p;
- edge_iterator ei;
+ unsigned int i, added_copy;
+ struct expr *expr;
+ struct occr *occr;
+ struct occr *avail;
- insn = (setcc != NULL) ? setcc : jump;
+ /* For each available expression in the table, copy the result to
+ `reaching_reg' if the expression reaches a deleted one.
- /* 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);
+ ??? The current algorithm is rather brute force.
+ Need to do some profiling. */
- may_be_loop_header = false;
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (e->flags & EDGE_DFS_BACK)
+ for (i = 0; i < expr_hash_table.size; i++)
+ for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash)
{
- may_be_loop_header = true;
- break;
- }
-
- change = 0;
- for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
- {
- removed_p = 0;
-
- if (e->flags & EDGE_COMPLEX)
- {
- ei_next (&ei);
+ /* 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;
- }
- /* We can't redirect edges from new basic blocks. */
- if (e->src->index >= bypass_last_basic_block)
- {
- ei_next (&ei);
- continue;
- }
+ /* Set when we add a copy for that expression. */
+ added_copy = 0;
- /* 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;
- }
+ for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
+ {
+ if (! occr->deleted_p)
+ 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;
+ for (avail = expr->avail_occr; avail != NULL; avail = avail->next)
+ {
+ rtx insn = avail->insn;
- if (regno >= max_gcse_regno)
- continue;
+ /* No need to handle this one if handled already. */
+ if (avail->copied_p)
+ continue;
- set = find_bypass_set (regno, e->src->index);
+ /* Don't handle this one if it's a redundant one. */
+ if (INSN_DELETED_P (insn))
+ continue;
- if (! set)
- 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;
- /* Check the data flow is valid after edge insertions. */
- if (e->insns.r && reg_killed_on_edge (reg_used->reg_rtx, e))
- continue;
+ added_copy = 1;
+
+ /* Copy the result of avail to reaching_reg. */
+ pre_insert_copy_insn (expr, insn);
+ avail->copied_p = 1;
+ }
+ }
- src = SET_SRC (pc_set (jump));
+ if (added_copy)
+ update_ld_motion_stores (expr);
+ }
+}
- if (setcc != NULL)
- src = simplify_replace_rtx (src,
- SET_DEST (PATTERN (setcc)),
- SET_SRC (PATTERN (setcc)));
+/* Emit move from SRC to DEST noting the equivalence with expression computed
+ in INSN. */
- new = simplify_replace_rtx (src, reg_used->reg_rtx,
- SET_SRC (set->expr));
+static rtx
+gcse_emit_move_after (rtx dest, rtx src, rtx insn)
+{
+ rtx new_rtx;
+ rtx set = single_set (insn), set2;
+ rtx note;
+ rtx eqv;
- /* 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. */
+ /* This should never fail since we're creating a reg->reg copy
+ we've verified to be valid. */
- if (new == pc_rtx)
- {
- edest = FALLTHRU_EDGE (bb);
- dest = edest->insns.r ? NULL : edest->dest;
- }
- else if (GET_CODE (new) == LABEL_REF)
- {
- 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)
- {
- rtx pat = PATTERN (setcc);
- if (!CC0_P (SET_DEST (pat)))
- insert_insn_on_edge (copy_insn (pat), e);
- }
+ new_rtx = emit_insn_after (gen_move_insn (dest, src), insn);
- 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 change;
+ /* Note the equivalence for local CSE pass. */
+ set2 = single_set (new_rtx);
+ if (!set2 || !rtx_equal_p (SET_DEST (set2), dest))
+ return new_rtx;
+ if ((note = find_reg_equal_equiv_note (insn)))
+ eqv = XEXP (note, 0);
+ else
+ eqv = SET_SRC (set);
+
+ set_unique_reg_note (new_rtx, REG_EQUAL, copy_insn_1 (eqv));
+
+ return new_rtx;
}
-/* 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.
+/* 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.
- This function is now mis-named, because we also handle indirect jumps. */
+ Return nonzero if a change is made. */
static int
-bypass_conditional_jumps (void)
+pre_delete (void)
{
- basic_block bb;
+ unsigned int i;
int changed;
- rtx setcc;
- rtx insn;
- rtx dest;
+ struct expr *expr;
+ struct occr *occr;
- /* Note we start at block 1. */
- if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
- return 0;
+ changed = 0;
+ for (i = 0; i < expr_hash_table.size; i++)
+ for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash)
+ {
+ int indx = expr->bitmap_index;
- bypass_last_basic_block = last_basic_block;
- mark_dfs_back_edges ();
+ /* 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);
- 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;
-
- dest = SET_DEST (PATTERN (insn));
- if (REG_P (dest) || CC0_P (dest))
- setcc = insn;
- else
- break;
- }
- else if (JUMP_P (insn))
+ /* 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))
{
- 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;
- }
- }
+ /* 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_and_attrs (SET_DEST (set));
- /* 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_emit_move_after (SET_DEST (set), expr->reaching_reg, insn);
+ delete_insn (insn);
+ occr->deleted_p = 1;
+ 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
-/* Compute PRE+LCM working variables. */
-/* Local properties of expressions. */
-/* Nonzero for expressions that are transparent in the block. */
-static sbitmap *transp;
-
-/* 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;
-
-/* Nonzero for expressions that are computed (available) in the block. */
-static sbitmap *comp;
-
-/* Nonzero for expressions that are locally anticipatable in the block. */
-static sbitmap *antloc;
-
-/* Nonzero for expressions where this block is an optimal computation
- point. */
-static sbitmap *pre_optimal;
-
-/* Nonzero for expressions which are redundant in a particular block. */
-static sbitmap *pre_redundant;
-
-/* Nonzero for expressions which should be inserted on a specific edge. */
-static sbitmap *pre_insert_map;
-
-/* Nonzero for expressions which should be deleted in a specific block. */
-static sbitmap *pre_delete_map;
-
-/* 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. */
-}
-
-/* Free vars used for PRE analysis. */
-
-static void
-free_pre_mem (void)
-{
- sbitmap_vector_free (transp);
- sbitmap_vector_free (comp);
-
- /* ANTLOC and AE_KILL are freed just after pre_lcm finishes. */
-
- 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);
-
- transp = comp = NULL;
- pre_optimal = pre_redundant = pre_insert_map = pre_delete_map = NULL;
-}
-
-/* Top level routine to do the dataflow analysis needed by PRE. */
-
-static void
-compute_pre_data (void)
-{
- sbitmap trapping_expr;
- basic_block bb;
- unsigned int ui;
-
- 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++)
- {
- 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);
- }
-
- /* Compute ae_kill for each basic block using:
-
- ~(TRANSP | COMP)
- */
-
- FOR_EACH_BB (bb)
- {
- edge e;
- edge_iterator ei;
-
- /* 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)
- {
- sbitmap_difference (antloc[bb->index], antloc[bb->index], trapping_expr);
- sbitmap_difference (transp[bb->index], transp[bb->index], trapping_expr);
- break;
- }
-
- sbitmap_a_or_b (ae_kill[bb->index], transp[bb->index], comp[bb->index]);
- sbitmap_not (ae_kill[bb->index], ae_kill[bb->index]);
- }
-
- 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 */
-
-/* Return nonzero if an occurrence of expression EXPR in OCCR_BB would reach
- block BB.
-
- VISITED is a pointer to a working buffer for tracking which BB's have
- been visited. It is NULL for the top-level call.
-
- 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. */
-
-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;
-
- if (pred->src == ENTRY_BLOCK_PTR
- /* Has predecessor has already been visited? */
- || visited[pred_bb->index])
- ;/* Nothing to do. */
-
- /* 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;
-
- 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;
-
- /* 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;
- }
- }
-
- /* All paths have been checked. */
- return 0;
-}
-
-/* The wrapper for pre_expr_reaches_here_work that ensures that any
- memory allocated for that function is returned. */
-
-static int
-pre_expr_reaches_here_p (basic_block occr_bb, struct expr *expr, basic_block bb)
-{
- int rval;
- char *visited = XCNEWVEC (char, last_basic_block);
-
- rval = pre_expr_reaches_here_p_work (occr_bb, expr, bb, visited);
-
- free (visited);
- return rval;
-}
-\f
-
-/* 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 rtx
-process_insert_insn (struct expr *expr)
-{
- rtx reg = expr->reaching_reg;
- rtx exp = copy_rtx (expr->expr);
- rtx pat;
-
- start_sequence ();
-
- /* 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);
-
- /* 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
- {
- rtx insn = emit_insn (gen_rtx_SET (VOIDmode, reg, exp));
-
- if (insn_invalid_p (insn))
- gcc_unreachable ();
- }
-
-
- pat = get_insns ();
- end_sequence ();
-
- return pat;
-}
-
-/* Add EXPR to the end of basic block BB.
-
- This is used by both the PRE and code hoisting.
-
- 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 void
-insert_insn_end_bb (struct expr *expr, basic_block bb, int pre)
-{
- 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);
- 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)))
- {
-#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));
-
- /* 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
- {
- 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);
- }
-
- /* 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.
-
- 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 (!pre
- || TEST_BIT (antloc[bb->index], expr->bitmap_index)
- || TEST_BIT (transp[bb->index], expr->bitmap_index));
-
- /* 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));
-
- /* 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);
-
- new_insn = emit_insn_before_noloc (pat, insn);
- }
- else
- new_insn = emit_insn_after_noloc (pat, 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);
- }
-
- gcse_create_count++;
-
- 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);
- }
-}
-
-/* Insert partially redundant expressions on edges in the CFG to make
- the expressions fully redundant. */
-
-static int
-pre_edge_insert (struct edge_list *edge_list, struct expr **index_map)
-{
- int e, i, j, num_edges, set_size, did_insert = 0;
- sbitmap *inserted;
-
- /* Where PRE_INSERT_MAP is nonzero, we add the expression on that edge
- if it reaches any of the deleted expressions. */
-
- 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);
-
- for (e = 0; e < num_edges; e++)
- {
- int indx;
- basic_block bb = INDEX_EDGE_PRED_BB (edge_list, e);
-
- for (i = indx = 0; i < set_size; i++, indx += SBITMAP_ELT_BITS)
- {
- SBITMAP_ELT_TYPE insert = pre_insert_map[e]->elms[i];
-
- 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;
-
- /* Now look at each deleted occurrence of this expression. */
- for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
- {
- if (! occr->deleted_p)
- 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);
-
- /* 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 (eg->flags & 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);
- }
-
- 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);
- }
-
- update_ld_motion_stores (expr);
- SET_BIT (inserted[e], j);
- did_insert = 1;
- gcse_create_count++;
- }
- }
- }
- }
- }
-
- sbitmap_vector_free (inserted);
- return did_insert;
-}
-
-/* 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, first_set, new_insn;
- rtx old_reg;
- int i;
-
- /* This block matches the logic in hash_scan_insn. */
- switch (GET_CODE (pat))
- {
- case SET:
- set = pat;
- break;
-
- 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)
- {
- /* 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;
- }
- }
- }
-
- gcc_assert (first_set);
- if (set == NULL_RTX)
- set = first_set;
- break;
-
- default:
- gcc_unreachable ();
- }
-
- 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);
-
- /* 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);
-
- /* 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 (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);
-}
-
-/* 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 (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;
-}
-
-/* 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 = 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;
-
- /* 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 (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 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. */
-
-/* ??? 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 (! CALL_P (BB_END (bb)))
- continue;
-
- 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);
- }
- }
-}
-
-/* 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 (dump_file)
- fprintf (dump_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 (dump_file)
- fprintf (dump_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;
- edge_iterator ei;
- int visited_allocated_locally = 0;
-
-
- if (visited == NULL)
- {
- visited_allocated_locally = 1;
- visited = XCNEWVEC (char, last_basic_block);
- }
-
- FOR_EACH_EDGE (pred, ei, bb->preds)
- {
- basic_block pred_bb = pred->src;
-
- if (pred->src == ENTRY_BLOCK_PTR)
- break;
- else if (pred_bb == expr_bb)
- continue;
- else if (visited[pred_bb->index])
- continue;
-
- /* Does this predecessor generate this expression? */
- else if (TEST_BIT (comp[pred_bb->index], expr_index))
- break;
- else if (! TEST_BIT (transp[pred_bb->index], expr_index))
- break;
-
- /* Not killed. */
- else
- {
- visited[pred_bb->index] = 1;
- if (! hoist_expr_reaches_here_p (expr_bb, expr_index,
- pred_bb, visited))
- break;
- }
- }
- if (visited_allocated_locally)
- free (visited);
-
- return (pred == NULL);
-}
-\f
-/* Actually perform code hoisting. */
-
-static void
-hoist_code (void)
-{
- basic_block bb, dominated;
- basic_block *domby;
- unsigned int domby_len;
- unsigned int i,j;
- struct expr **index_map;
- struct expr *expr;
-
- sbitmap_vector_zero (hoist_exprs, last_basic_block);
-
- /* Compute a mapping from expression number (`bitmap_index') to
- hash table entry. */
-
- 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;
-
- /* Walk over each basic block looking for potentially hoistable
- expressions, nothing gets hoisted from the entry block. */
- FOR_EACH_BB (bb)
- {
- int found = 0;
- int insn_inserted_p;
-
- domby_len = get_dominated_by (CDI_DOMINATORS, bb, &domby);
- /* 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++)
- {
- int hoistable = 0;
-
- if (TEST_BIT (hoist_vbeout[bb->index], i)
- && TEST_BIT (transpout[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++)
- {
- dominated = domby[j];
- /* Ignore self dominance. */
- if (bb == dominated)
- continue;
- /* We've found a dominated block, now see if it computes
- the busy expression and whether or not moving that
- expression to the "beginning" of that block is safe. */
- if (!TEST_BIT (antloc[dominated->index], i))
- continue;
-
- /* Note if the expression would reach the dominated block
- unimpared if it was placed at the end of BB.
-
- Keep track of how many times this expression is hoistable
- from a dominated block into BB. */
- if (hoist_expr_reaches_here_p (bb, i, dominated, NULL))
- hoistable++;
- }
-
- /* If we found more than one hoistable occurrence of this
- expression, then note it in the bitmap of expressions to
- hoist. It makes no sense to hoist things which are computed
- in only one BB, and doing so tends to pessimize register
- allocation. One could increase this value to try harder
- to avoid any possible code expansion due to register
- allocation issues; however experiments have shown that
- the vast majority of hoistable expressions are only movable
- from two successors, so raising this threshold is likely
- to nullify any benefit we get from code hoisting. */
- if (hoistable > 1)
- {
- SET_BIT (hoist_exprs[bb->index], i);
- found = 1;
- }
- }
- }
- /* If we found nothing to hoist, then quit now. */
- if (! found)
- {
- free (domby);
- continue;
- }
-
- /* Loop over all the hoistable expressions. */
- for (i = 0; i < hoist_exprs[bb->index]->n_bits; i++)
- {
- /* We want to insert the expression into BB only once, so
- note when we've inserted it. */
- insn_inserted_p = 0;
-
- /* These tests should be the same as the tests above. */
- 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++)
- {
- dominated = domby[j];
- /* Ignore self dominance. */
- if (bb == dominated)
- continue;
-
- /* We've found a dominated block, now see if it computes
- the busy expression and whether or not moving that
- expression to the "beginning" of that block is safe. */
- if (!TEST_BIT (antloc[dominated->index], i))
- continue;
-
- /* The expression is computed in the dominated block and
- it would be safe to compute it at the start of the
- dominated block. Now we have to determine if the
- expression would reach the dominated block if it was
- placed at the end of BB. */
- if (hoist_expr_reaches_here_p (bb, i, dominated, NULL))
- {
- struct expr *expr = index_map[i];
- struct occr *occr = expr->antic_occr;
- rtx insn;
- rtx set;
-
- /* Find the right occurrence of this expression. */
- while (BLOCK_FOR_INSN (occr->insn) != dominated && occr)
- occr = occr->next;
-
- gcc_assert (occr);
- insn = occr->insn;
- set = single_set (insn);
- gcc_assert (set);
-
- /* 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;
- if (!insn_inserted_p)
- {
- insert_insn_end_bb (index_map[i], bb, 0);
- insn_inserted_p = 1;
- }
- }
- }
- }
- }
- free (domby);
- }
-
- free (index_map);
-}
-
-/* Top level routine to perform one code hoisting (aka unification) pass
-
- Return nonzero if a change was made. */
-
-static int
-one_code_hoisting_pass (void)
-{
- int changed = 0;
-
- alloc_hash_table (max_cuid, &expr_hash_table, 0);
- compute_hash_table (&expr_hash_table);
- if (dump_file)
- dump_hash_table (dump_file, "Code Hosting Expressions", &expr_hash_table);
-
- if (expr_hash_table.n_elems > 0)
- {
- alloc_code_hoist_mem (last_basic_block, expr_hash_table.n_elems);
- compute_code_hoist_data ();
- hoist_code ();
- free_code_hoist_mem ();
- }
-
- free_hash_table (&expr_hash_table);
-
- return changed;
-}
-\f
-/* Here we provide the things required to do store motion towards
- the exit. In order for this to be effective, gcse also needed to
- be taught how to move a load when it is kill only by a store to itself.
-
- int i;
- float a[10];
-
- void foo(float scale)
- {
- for (i=0; i<10; i++)
- a[i] *= scale;
- }
-
- 'i' is both loaded and stored to in the loop. Normally, gcse cannot move
- the load out since its live around the loop, and stored at the bottom
- of the loop.
-
- The 'Load Motion' referred to and implemented in this file is
- an enhancement to gcse which when using edge based lcm, recognizes
- this situation and allows gcse to move the load out of the loop.
-
- Once gcse has hoisted the load, store motion can then push this
- 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. */
-
-static struct ls_expr *
-ldst_entry (rtx x)
-{
- int do_not_record_p = 0;
- struct ls_expr * ptr;
- unsigned int hash;
- void **slot;
- struct ls_expr e;
-
- hash = hash_rtx (x, GET_MODE (x), &do_not_record_p,
- NULL, /*have_reg_qty=*/false);
-
- e.pattern = x;
- slot = htab_find_slot_with_hash (pre_ldst_table, &e, hash, INSERT);
- if (*slot)
- return (struct ls_expr *)*slot;
-
- ptr = XNEW (struct ls_expr);
-
- ptr->next = pre_ldst_mems;
- ptr->expr = NULL;
- ptr->pattern = x;
- ptr->pattern_regs = NULL_RTX;
- ptr->loads = NULL_RTX;
- ptr->stores = NULL_RTX;
- ptr->reaching_reg = NULL_RTX;
- ptr->invalid = 0;
- 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)
-{
- if (pre_ldst_table)
- htab_delete (pre_ldst_table);
- pre_ldst_table = NULL;
-
- 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 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;
-}
-
-/* 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;
-}
+/* Perform GCSE optimizations using PRE.
+ This is called by one_pre_gcse_pass after all the dataflow analysis
+ has been done.
-/* Return the next item in the list after the specified one. */
+ 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.
-static inline struct ls_expr *
-next_ls_expr (struct ls_expr * ptr)
-{
- return ptr->next;
-}
-\f
-/* Load Motion for loads which only kill themselves. */
+ ??? 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.
-/* 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. */
+ ??? 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
-simple_mem (rtx x)
-{
- if (! MEM_P (x))
- 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 (MEM_P (x) && 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;
- pre_ldst_table = htab_create (13, pre_ldst_expr_hash,
- pre_ldst_expr_eq, NULL);
-
- 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));
-
- /* 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);
- }
-
- /* 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 (! 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));
- }
- }
- }
-}
-
-/* Remove any references that have been either invalidated or are not in the
- expression list for pre gcse. */
-
-static void
-trim_ld_motion_mems (void)
+pre_gcse (struct edge_list *edge_list)
{
- struct ls_expr * * last = & pre_ldst_mems;
- struct ls_expr * ptr = pre_ldst_mems;
+ unsigned int i;
+ int did_insert, changed;
+ struct expr **index_map;
+ struct expr *expr;
- while (ptr != NULL)
- {
- struct expr * expr;
+ /* Compute a mapping from expression number (`bitmap_index') to
+ hash table entry. */
- /* 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;
+ 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; expr = expr->next_same_hash)
+ index_map[expr->bitmap_index] = expr;
- 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;
+ /* 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 */
- if (expr)
- {
- /* Set the expression field if we are keeping it. */
- ptr->expr = expr;
- last = & ptr->next;
- ptr = ptr->next;
- }
- else
- {
- *last = ptr->next;
- htab_remove_elt_with_hash (pre_ldst_table, ptr, ptr->hash_index);
- free_ldst_entry (ptr);
- ptr = * last;
- }
+ 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;
}
- /* Show the world what we've found. */
- if (dump_file && pre_ldst_mems != NULL)
- print_ldst_list (dump_file);
+ free (index_map);
+ return changed;
}
-/* 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. */
+/* Top level routine to perform one PRE GCSE pass.
-static void
-update_ld_motion_stores (struct expr * expr)
+ Return nonzero if a change was made. */
+
+static int
+one_pre_gcse_pass (void)
{
- struct ls_expr * mem_ptr;
+ int changed = 0;
- if ((mem_ptr = find_rtx_in_ldst (expr->expr)))
- {
- /* 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. */
+ gcse_subst_count = 0;
+ gcse_create_count = 0;
- /* 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;
+ /* Return if there's nothing to do, or it is too expensive. */
+ if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
+ || is_too_expensive (_("PRE disabled")))
+ return 0;
- 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;
+ /* We need alias. */
+ init_alias_analysis ();
- /* If we've already copied it, continue. */
- if (expr->reaching_reg == src)
- continue;
+ bytes_used = 0;
+ gcc_obstack_init (&gcse_obstack);
+ alloc_gcse_mem ();
- if (dump_file)
- {
- 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");
- }
+ alloc_hash_table (&expr_hash_table);
+ add_noreturn_fake_exit_edges ();
+ if (flag_gcse_lm)
+ compute_ld_motion_mems ();
- 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;
+ compute_hash_table (&expr_hash_table);
+ if (flag_gcse_lm)
+ trim_ld_motion_mems ();
+ if (dump_file)
+ dump_hash_table (dump_file, "Expression", &expr_hash_table);
- /* un-recognize this pattern since it's probably different now. */
- INSN_CODE (insn) = -1;
- gcse_create_count++;
- }
+ if (expr_hash_table.n_elems > 0)
+ {
+ struct edge_list *edge_list;
+ alloc_pre_mem (last_basic_block, expr_hash_table.n_elems);
+ edge_list = compute_pre_data ();
+ changed |= pre_gcse (edge_list);
+ free_edge_list (edge_list);
+ free_pre_mem ();
}
-}
-\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)
+ if (flag_gcse_lm)
+ free_ld_motion_mems ();
+ remove_fake_exit_edges ();
+ free_hash_table (&expr_hash_table);
-/* 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;
+ free_gcse_mem ();
+ obstack_free (&gcse_obstack, NULL);
-/* And current insn, for the same routine. */
-static rtx compute_store_table_current_insn;
+ /* We are finished with alias. */
+ end_alias_analysis ();
-/* Used in computing the reverse edge graph bit vectors. */
-static sbitmap * st_antloc;
+ if (dump_file)
+ {
+ fprintf (dump_file, "PRE GCSE of %s, %d basic blocks, %d bytes needed, ",
+ current_function_name (), n_basic_blocks, bytes_used);
+ fprintf (dump_file, "%d substs, %d insns created\n",
+ gcse_subst_count, gcse_create_count);
+ }
-/* Global holding the number of store expressions we are dealing with. */
-static int num_stores;
+ 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. */
-/* Checks to set if we need to mark a register set. Called from
- note_stores. */
+/* ??? 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 void
-reg_set_info (rtx dest, rtx setter ATTRIBUTE_UNUSED,
- void *data)
+add_label_notes (rtx x, rtx insn)
{
- sbitmap bb_reg = data;
+ enum rtx_code code = GET_CODE (x);
+ int i, j;
+ const char *fmt;
- if (GET_CODE (dest) == SUBREG)
- dest = SUBREG_REG (dest);
+ 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.
- if (REG_P (dest))
+ We no longer ignore such label references (see LABEL_REF handling in
+ mark_jump_label for additional information). */
+
+ /* 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));
+ add_reg_note (insn, REG_LABEL_OPERAND, XEXP (x, 0));
+
+ 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--)
{
- regvec[REGNO (dest)] = INSN_UID (compute_store_table_current_insn);
- if (bb_reg)
- SET_BIT (bb_reg, REGNO (dest));
+ 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);
}
}
-/* Clear any mark that says that this insn sets dest. Called from
- note_stores. */
+/* Code Hoisting variables and subroutines. */
-static void
-reg_clear_last_set (rtx dest, rtx setter ATTRIBUTE_UNUSED,
- void *data)
-{
- int *dead_vec = data;
+/* Very busy expressions. */
+static sbitmap *hoist_vbein;
+static sbitmap *hoist_vbeout;
- if (GET_CODE (dest) == SUBREG)
- dest = SUBREG_REG (dest);
+/* ??? 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 (REG_P (dest) &&
- dead_vec[REGNO (dest)] == INSN_UID (compute_store_table_current_insn))
- dead_vec[REGNO (dest)] = 0;
-}
+ It's unclear if tail merging could be run in parallel with
+ code hoisting. It would be nice. */
-/* Return zero if some of the registers in list X are killed
- due to set of registers in bitmap REGS_SET. */
+/* Allocate vars used for code hoisting analysis. */
-static bool
-store_ops_ok (rtx x, int *regs_set)
+static void
+alloc_code_hoist_mem (int n_blocks, int n_exprs)
{
- rtx reg;
-
- for (; x; x = XEXP (x, 1))
- {
- reg = XEXP (x, 0);
- if (regs_set[REGNO(reg)])
- return false;
- }
+ antloc = sbitmap_vector_alloc (n_blocks, n_exprs);
+ transp = sbitmap_vector_alloc (n_blocks, n_exprs);
+ comp = sbitmap_vector_alloc (n_blocks, n_exprs);
- return true;
+ hoist_vbein = sbitmap_vector_alloc (n_blocks, n_exprs);
+ hoist_vbeout = sbitmap_vector_alloc (n_blocks, n_exprs);
}
-/* Returns a list of registers mentioned in X. */
-static rtx
-extract_mentioned_regs (rtx x)
-{
- return extract_mentioned_regs_helper (x, NULL_RTX);
-}
+/* Free vars used for code hoisting analysis. */
-/* Helper for extract_mentioned_regs; ACCUM is used to accumulate used
- registers. */
-static rtx
-extract_mentioned_regs_helper (rtx x, rtx accum)
+static void
+free_code_hoist_mem (void)
{
- int i;
- enum rtx_code code;
- const char * fmt;
-
- /* Repeat is used to turn tail-recursion into iteration. */
- repeat:
+ sbitmap_vector_free (antloc);
+ sbitmap_vector_free (transp);
+ sbitmap_vector_free (comp);
- if (x == 0)
- return accum;
+ sbitmap_vector_free (hoist_vbein);
+ sbitmap_vector_free (hoist_vbeout);
- code = GET_CODE (x);
- switch (code)
- {
- case REG:
- return alloc_EXPR_LIST (0, x, accum);
+ free_dominance_info (CDI_DOMINATORS);
+}
- case MEM:
- x = XEXP (x, 0);
- goto repeat;
+/* Compute the very busy expressions at entry/exit from each block.
- case PRE_DEC:
- case PRE_INC:
- case POST_DEC:
- case POST_INC:
- /* We do not run this function with arguments having side effects. */
- gcc_unreachable ();
+ An expression is very busy if all paths from a given point
+ compute the expression. */
- 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
+compute_code_hoist_vbeinout (void)
+{
+ int changed, passes;
+ basic_block bb;
- default:
- break;
- }
+ sbitmap_vector_zero (hoist_vbeout, last_basic_block);
+ sbitmap_vector_zero (hoist_vbein, last_basic_block);
- i = GET_RTX_LENGTH (code) - 1;
- fmt = GET_RTX_FORMAT (code);
+ passes = 0;
+ changed = 1;
- for (; i >= 0; i--)
+ while (changed)
{
- if (fmt[i] == 'e')
+ changed = 0;
+
+ /* We scan the blocks in the reverse order to speed up
+ the convergence. */
+ FOR_EACH_BB_REVERSE (bb)
{
- 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 (bb->next_bb != EXIT_BLOCK_PTR)
{
- x = tem;
- goto repeat;
+ sbitmap_intersection_of_succs (hoist_vbeout[bb->index],
+ hoist_vbein, bb->index);
+
+ /* Include expressions in VBEout that are calculated
+ in BB and available at its end. */
+ sbitmap_a_or_b (hoist_vbeout[bb->index],
+ hoist_vbeout[bb->index], comp[bb->index]);
}
- accum = extract_mentioned_regs_helper (tem, accum);
+ changed |= sbitmap_a_or_b_and_c_cg (hoist_vbein[bb->index],
+ antloc[bb->index],
+ hoist_vbeout[bb->index],
+ transp[bb->index]);
}
- 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);
- }
+ passes++;
}
- 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:
+ if (dump_file)
+ {
+ fprintf (dump_file, "hoisting vbeinout computation: %d passes\n", passes);
- -- 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.
+ FOR_EACH_BB (bb)
+ {
+ fprintf (dump_file, "vbein (%d): ", bb->index);
+ dump_sbitmap_file (dump_file, hoist_vbein[bb->index]);
+ fprintf (dump_file, "vbeout(%d): ", bb->index);
+ dump_sbitmap_file (dump_file, hoist_vbeout[bb->index]);
+ }
+ }
+}
- 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.
- */
+/* Top level routine to do the dataflow analysis needed by code hoisting. */
static void
-find_moveable_store (rtx insn, int *regs_set_before, int *regs_set_after)
+compute_code_hoist_data (void)
{
- struct ls_expr * ptr;
- rtx dest, set, tmp;
- int check_anticipatable, check_available;
- basic_block bb = BLOCK_FOR_INSN (insn);
-
- set = single_set (insn);
- if (!set)
- return;
-
- dest = SET_DEST (set);
-
- if (! MEM_P (dest) || MEM_VOLATILE_P (dest)
- || GET_MODE (dest) == BLKmode)
- return;
-
- if (side_effects_p (dest))
- return;
+ compute_local_properties (transp, comp, antloc, &expr_hash_table);
+ prune_expressions (false);
+ compute_code_hoist_vbeinout ();
+ calculate_dominance_info (CDI_DOMINATORS);
+ if (dump_file)
+ fprintf (dump_file, "\n");
+}
- /* 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;
+/* Determine if the expression identified by EXPR_INDEX would
+ reach BB unimpared if it was placed at the end of EXPR_BB.
+ Stop the search if the expression would need to be moved more
+ than DISTANCE instructions.
- /* 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;
+ 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.
- /* 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;
+ Contrast this to reachability for PRE where an expression is
+ considered reachable if *any* path reaches instead of *all*
+ paths. */
- ptr = ldst_entry (dest);
- if (!ptr->pattern_regs)
- ptr->pattern_regs = extract_mentioned_regs (dest);
+static int
+hoist_expr_reaches_here_p (basic_block expr_bb, int expr_index, basic_block bb,
+ char *visited, int distance, int *bb_size)
+{
+ edge pred;
+ edge_iterator ei;
+ int visited_allocated_locally = 0;
- /* 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)
+ /* Terminate the search if distance, for which EXPR is allowed to move,
+ is exhausted. */
+ if (distance > 0)
{
- 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));
- }
+ distance -= bb_size[bb->index];
- /* 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;
+ if (distance <= 0)
+ return 0;
+ }
else
+ gcc_assert (distance == 0);
+
+ if (visited == NULL)
{
- tmp = XEXP (AVAIL_STORE_LIST (ptr), 0);
- if (BLOCK_FOR_INSN (tmp) != bb)
- check_available = 1;
+ visited_allocated_locally = 1;
+ visited = XCNEWVEC (char, last_basic_block);
}
- if (check_available)
+
+ FOR_EACH_EDGE (pred, ei, bb->preds)
{
- /* Check that we have already reached the insn at that the check
- failed last time. */
- if (LAST_AVAIL_CHECK_FAILURE (ptr))
+ basic_block pred_bb = pred->src;
+
+ if (pred->src == ENTRY_BLOCK_PTR)
+ break;
+ else if (pred_bb == expr_bb)
+ continue;
+ else if (visited[pred_bb->index])
+ continue;
+
+ else if (! TEST_BIT (transp[pred_bb->index], expr_index))
+ break;
+
+ /* Not killed. */
+ else
{
- for (tmp = BB_END (bb);
- tmp != insn && tmp != LAST_AVAIL_CHECK_FAILURE (ptr);
- tmp = PREV_INSN (tmp))
- continue;
- if (tmp == insn)
- check_available = 0;
+ visited[pred_bb->index] = 1;
+ if (! hoist_expr_reaches_here_p (expr_bb, expr_index, pred_bb,
+ visited, distance, bb_size))
+ break;
}
- 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));
+ if (visited_allocated_locally)
+ free (visited);
+
+ return (pred == NULL);
+}
+\f
+/* Find occurence in BB. */
+
+static struct occr *
+find_occr_in_bb (struct occr *occr, basic_block bb)
+{
+ /* Find the right occurrence of this expression. */
+ while (occr && BLOCK_FOR_INSN (occr->insn) != bb)
+ occr = occr->next;
+
+ return occr;
}
-/* Find available and anticipatable stores. */
+/* Actually perform code hoisting. */
static int
-compute_store_table (void)
+hoist_code (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;
-
- max_gcse_regno = max_reg_num ();
-
- 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);
-
- /* Find all the stores we care about. */
- FOR_EACH_BB (bb)
- {
- /* First compute the registers set in this block. */
- regvec = last_set_in;
+ basic_block bb, dominated;
+ VEC (basic_block, heap) *dom_tree_walk;
+ unsigned int dom_tree_walk_index;
+ VEC (basic_block, heap) *domby;
+ unsigned int i,j;
+ struct expr **index_map;
+ struct expr *expr;
+ int *to_bb_head;
+ int *bb_size;
+ int changed = 0;
- FOR_BB_INSNS (bb, insn)
- {
- if (! INSN_P (insn))
- continue;
+ /* Compute a mapping from expression number (`bitmap_index') to
+ hash table entry. */
- 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);
- }
- }
+ 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; expr = expr->next_same_hash)
+ index_map[expr->bitmap_index] = expr;
- pat = PATTERN (insn);
- compute_store_table_current_insn = insn;
- note_stores (pat, reg_set_info, reg_set_in_block[bb->index]);
- }
+ /* Calculate sizes of basic blocks and note how far
+ each instruction is from the start of its block. We then use this
+ data to restrict distance an expression can travel. */
+
+ to_bb_head = XCNEWVEC (int, get_max_uid ());
+ bb_size = XCNEWVEC (int, last_basic_block);
+
+ FOR_EACH_BB (bb)
+ {
+ rtx insn;
+ int to_head;
- /* Now find the stores. */
- memset (already_set, 0, sizeof (int) * max_gcse_regno);
- regvec = already_set;
+ to_head = 0;
FOR_BB_INSNS (bb, insn)
{
- if (! INSN_P (insn))
- continue;
+ /* Don't count debug instructions to avoid them affecting
+ decision choices. */
+ if (NONDEBUG_INSN_P (insn))
+ to_bb_head[INSN_UID (insn)] = to_head++;
+ }
- 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;
- }
+ bb_size[bb->index] = to_head;
+ }
- pat = PATTERN (insn);
- note_stores (pat, reg_set_info, NULL);
+ gcc_assert (EDGE_COUNT (ENTRY_BLOCK_PTR->succs) == 1
+ && (EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest
+ == ENTRY_BLOCK_PTR->next_bb));
- /* Now that we've marked regs, look for stores. */
- find_moveable_store (insn, already_set, last_set_in);
+ dom_tree_walk = get_all_dominated_blocks (CDI_DOMINATORS,
+ ENTRY_BLOCK_PTR->next_bb);
- /* 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))
- {
- 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;
- }
- }
+ /* Walk over each basic block looking for potentially hoistable
+ expressions, nothing gets hoisted from the entry block. */
+ FOR_EACH_VEC_ELT (basic_block, dom_tree_walk, dom_tree_walk_index, bb)
+ {
+ domby = get_dominated_to_depth (CDI_DOMINATORS, bb, MAX_HOIST_DEPTH);
-#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
+ if (VEC_length (basic_block, domby) == 0)
+ continue;
- /* Clear temporary marks. */
- for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
+ /* 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++)
{
- 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);
- }
- }
+ if (TEST_BIT (hoist_vbeout[bb->index], i))
+ {
+ /* Current expression. */
+ struct expr *expr = index_map[i];
+ /* Number of occurences of EXPR that can be hoisted to BB. */
+ int hoistable = 0;
+ /* Basic blocks that have occurences reachable from BB. */
+ bitmap_head _from_bbs, *from_bbs = &_from_bbs;
+ /* Occurences reachable from BB. */
+ VEC (occr_t, heap) *occrs_to_hoist = NULL;
+ /* We want to insert the expression into BB only once, so
+ note when we've inserted it. */
+ int insn_inserted_p;
+ occr_t occr;
+
+ bitmap_initialize (from_bbs, 0);
+
+ /* If an expression is computed in BB and is available at end of
+ BB, hoist all occurences dominated by BB to BB. */
+ if (TEST_BIT (comp[bb->index], i))
+ {
+ occr = find_occr_in_bb (expr->antic_occr, bb);
- /* 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;
- htab_remove_elt_with_hash (pre_ldst_table, ptr, ptr->hash_index);
- free_ldst_entry (ptr);
- }
- else
- prev_next_ptr_ptr = &ptr->next;
- }
+ if (occr)
+ {
+ /* An occurence might've been already deleted
+ while processing a dominator of BB. */
+ if (!occr->deleted_p)
+ {
+ gcc_assert (NONDEBUG_INSN_P (occr->insn));
+ hoistable++;
+ }
+ }
+ else
+ hoistable++;
+ }
- ret = enumerate_ldsts ();
+ /* We've found a potentially hoistable expression, now
+ we look at every block BB dominates to see if it
+ computes the expression. */
+ FOR_EACH_VEC_ELT (basic_block, domby, j, dominated)
+ {
+ int max_distance;
- if (dump_file)
- {
- fprintf (dump_file, "ST_avail and ST_antic (shown under loads..)\n");
- print_ldst_list (dump_file);
- }
+ /* Ignore self dominance. */
+ if (bb == dominated)
+ continue;
+ /* We've found a dominated block, now see if it computes
+ the busy expression and whether or not moving that
+ expression to the "beginning" of that block is safe. */
+ if (!TEST_BIT (antloc[dominated->index], i))
+ continue;
- free (last_set_in);
- free (already_set);
- return ret;
-}
+ occr = find_occr_in_bb (expr->antic_occr, dominated);
+ gcc_assert (occr);
-/* 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. */
+ /* An occurence might've been already deleted
+ while processing a dominator of BB. */
+ if (occr->deleted_p)
+ continue;
+ gcc_assert (NONDEBUG_INSN_P (occr->insn));
-static bool
-load_kills_store (rtx x, rtx store_pattern, int after)
-{
- if (after)
- return anti_dependence (x, store_pattern);
- else
- return true_dependence (store_pattern, GET_MODE (store_pattern), x,
- rtx_addr_varies_p);
-}
+ max_distance = expr->max_distance;
+ if (max_distance > 0)
+ /* Adjust MAX_DISTANCE to account for the fact that
+ OCCR won't have to travel all of DOMINATED, but
+ only part of it. */
+ max_distance += (bb_size[dominated->index]
+ - to_bb_head[INSN_UID (occr->insn)]);
-/* 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. */
+ /* Note if the expression would reach the dominated block
+ unimpared if it was placed at the end of BB.
-static bool
-find_loads (rtx x, rtx store_pattern, int after)
-{
- const char * fmt;
- int i, j;
- int ret = false;
+ Keep track of how many times this expression is hoistable
+ from a dominated block into BB. */
+ if (hoist_expr_reaches_here_p (bb, i, dominated, NULL,
+ max_distance, bb_size))
+ {
+ hoistable++;
+ VEC_safe_push (occr_t, heap,
+ occrs_to_hoist, occr);
+ bitmap_set_bit (from_bbs, dominated->index);
+ }
+ }
- if (!x)
- return false;
+ /* If we found more than one hoistable occurrence of this
+ expression, then note it in the vector of expressions to
+ hoist. It makes no sense to hoist things which are computed
+ in only one BB, and doing so tends to pessimize register
+ allocation. One could increase this value to try harder
+ to avoid any possible code expansion due to register
+ allocation issues; however experiments have shown that
+ the vast majority of hoistable expressions are only movable
+ from two successors, so raising this threshold is likely
+ to nullify any benefit we get from code hoisting. */
+ if (hoistable > 1 && dbg_cnt (hoist_insn))
+ {
+ /* If (hoistable != VEC_length), then there is
+ an occurence of EXPR in BB itself. Don't waste
+ time looking for LCA in this case. */
+ if ((unsigned) hoistable
+ == VEC_length (occr_t, occrs_to_hoist))
+ {
+ basic_block lca;
+
+ lca = nearest_common_dominator_for_set (CDI_DOMINATORS,
+ from_bbs);
+ if (lca != bb)
+ /* Punt, it's better to hoist these occurences to
+ LCA. */
+ VEC_free (occr_t, heap, occrs_to_hoist);
+ }
+ }
+ else
+ /* Punt, no point hoisting a single occurence. */
+ VEC_free (occr_t, heap, occrs_to_hoist);
- if (GET_CODE (x) == SET)
- x = SET_SRC (x);
+ insn_inserted_p = 0;
- if (MEM_P (x))
- {
- if (load_kills_store (x, store_pattern, after))
- return true;
+ /* Walk through occurences of I'th expressions we want
+ to hoist to BB and make the transformations. */
+ FOR_EACH_VEC_ELT (occr_t, occrs_to_hoist, j, occr)
+ {
+ rtx insn;
+ rtx set;
+
+ gcc_assert (!occr->deleted_p);
+
+ insn = occr->insn;
+ set = single_set (insn);
+ gcc_assert (set);
+
+ /* 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.
+
+ It is important to use new pseudos whenever we
+ emit a set. This will allow reload to use
+ rematerialization for such registers. */
+ if (!insn_inserted_p)
+ expr->reaching_reg
+ = gen_reg_rtx_and_attrs (SET_DEST (set));
+
+ gcse_emit_move_after (SET_DEST (set), expr->reaching_reg,
+ insn);
+ delete_insn (insn);
+ occr->deleted_p = 1;
+ changed = 1;
+ gcse_subst_count++;
+
+ if (!insn_inserted_p)
+ {
+ insert_insn_end_basic_block (expr, bb);
+ insn_inserted_p = 1;
+ }
+ }
+
+ VEC_free (occr_t, heap, occrs_to_hoist);
+ bitmap_clear (from_bbs);
+ }
+ }
+ VEC_free (basic_block, heap, domby);
}
- /* Recursively process the insn. */
- fmt = GET_RTX_FORMAT (GET_CODE (x));
+ VEC_free (basic_block, heap, dom_tree_walk);
+ free (bb_size);
+ free (to_bb_head);
+ free (index_map);
- 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 changed;
}
-static inline bool
-store_killed_in_pat (rtx x, rtx pat, int after)
-{
- if (GET_CODE (pat) == SET)
- {
- rtx dest = SET_DEST (pat);
+/* Top level routine to perform one code hoisting (aka unification) pass
- if (GET_CODE (dest) == ZERO_EXTRACT)
- dest = XEXP (dest, 0);
+ Return nonzero if a change was made. */
- /* 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;
- }
- }
- }
+static int
+one_code_hoisting_pass (void)
+{
+ int changed = 0;
+
+ gcse_subst_count = 0;
+ gcse_create_count = 0;
- if (find_loads (pat, x, after))
- return true;
+ /* Return if there's nothing to do, or it is too expensive. */
+ if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
+ || is_too_expensive (_("GCSE disabled")))
+ return 0;
- return false;
-}
+ doing_code_hoisting_p = 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 does. */
+ /* We need alias. */
+ init_alias_analysis ();
-static bool
-store_killed_in_insn (rtx x, rtx x_regs, rtx insn, int after)
-{
- rtx reg, base, note, pat;
+ bytes_used = 0;
+ gcc_obstack_init (&gcse_obstack);
+ alloc_gcse_mem ();
- if (!INSN_P (insn))
- return false;
+ alloc_hash_table (&expr_hash_table);
+ compute_hash_table (&expr_hash_table);
+ if (dump_file)
+ dump_hash_table (dump_file, "Code Hosting Expressions", &expr_hash_table);
- if (CALL_P (insn))
+ if (expr_hash_table.n_elems > 0)
{
- /* 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))
- {
- 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;
+ alloc_code_hoist_mem (last_basic_block, expr_hash_table.n_elems);
+ compute_code_hoist_data ();
+ changed = hoist_code ();
+ free_code_hoist_mem ();
}
- 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;
+ free_hash_table (&expr_hash_table);
+ free_gcse_mem ();
+ obstack_free (&gcse_obstack, NULL);
- 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;
+ /* We are finished with alias. */
+ end_alias_analysis ();
- /* 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);
+ if (dump_file)
+ {
+ fprintf (dump_file, "HOIST of %s, %d basic blocks, %d bytes needed, ",
+ current_function_name (), n_basic_blocks, bytes_used);
+ fprintf (dump_file, "%d substs, %d insns created\n",
+ gcse_subst_count, gcse_create_count);
+ }
- /* 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;
+ doing_code_hoisting_p = false;
- /* See if there are any aliased loads in the note. */
- return find_loads (note, x, after);
+ return changed;
}
+\f
+/* Here we provide the things required to do store motion towards the exit.
+ In order for this to be effective, gcse also needed to be taught how to
+ move a load when it is killed only by a store to itself.
-/* 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. */
+ int i;
+ float a[10];
-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;
+ void foo(float scale)
+ {
+ for (i=0; i<10; i++)
+ a[i] *= scale;
+ }
- 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;
- }
+ 'i' is both loaded and stored to in the loop. Normally, gcse cannot move
+ the load out since its live around the loop, and stored at the bottom
+ of the loop.
- /* 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;
- }
+ The 'Load Motion' referred to and implemented in this file is
+ an enhancement to gcse which when using edge based LCM, recognizes
+ this situation and allows gcse to move the load out of the loop.
- return false;
-}
+ Once gcse has hoisted the load, store motion can then push this
+ load towards the exit, and we end up with no loads or stores of 'i'
+ in the loop. */
-/* 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)
+static hashval_t
+pre_ldst_expr_hash (const void *p)
{
- rtx first = BB_HEAD (bb);
-
- if (!store_ops_ok (x_regs, regs_set_before))
- return true;
-
- for ( ; insn != PREV_INSN (first); insn = PREV_INSN (insn))
- if (store_killed_in_insn (x, x_regs, insn, true))
- return true;
-
- return false;
+ int do_not_record_p = 0;
+ const struct ls_expr *const x = (const struct ls_expr *) p;
+ return
+ hash_rtx (x->pattern, GET_MODE (x->pattern), &do_not_record_p, NULL, false);
}
-/* 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)
+static int
+pre_ldst_expr_eq (const void *p1, const void *p2)
{
- basic_block bb;
- int *regs_set_in_block;
- rtx insn, st;
- struct ls_expr * ptr;
- unsigned regno;
+ const struct ls_expr *const ptr1 = (const struct ls_expr *) p1,
+ *const ptr2 = (const struct ls_expr *) p2;
+ return expr_equiv_p (ptr1->pattern, ptr2->pattern);
+}
- /* 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);
+/* This will search the ldst list for a matching expression. If it
+ doesn't find one, we create one and initialize it. */
- st_antloc = sbitmap_vector_alloc (last_basic_block, num_stores);
- sbitmap_vector_zero (st_antloc, last_basic_block);
+static struct ls_expr *
+ldst_entry (rtx x)
+{
+ int do_not_record_p = 0;
+ struct ls_expr * ptr;
+ unsigned int hash;
+ void **slot;
+ struct ls_expr e;
- 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 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);
- }
+ hash = hash_rtx (x, GET_MODE (x), &do_not_record_p,
+ NULL, /*have_reg_qty=*/false);
- 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);
- }
- }
+ e.pattern = x;
+ slot = htab_find_slot_with_hash (pre_ldst_table, &e, hash, INSERT);
+ if (*slot)
+ return (struct ls_expr *)*slot;
- ae_kill = sbitmap_vector_alloc (last_basic_block, num_stores);
- sbitmap_vector_zero (ae_kill, last_basic_block);
+ ptr = XNEW (struct ls_expr);
- 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);
+ ptr->next = pre_ldst_mems;
+ ptr->expr = NULL;
+ ptr->pattern = x;
+ ptr->pattern_regs = NULL_RTX;
+ ptr->loads = NULL_RTX;
+ ptr->stores = NULL_RTX;
+ ptr->reaching_reg = NULL_RTX;
+ ptr->invalid = 0;
+ ptr->index = 0;
+ ptr->hash_index = hash;
+ pre_ldst_mems = ptr;
+ *slot = ptr;
- 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);
+ return ptr;
+}
- 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);
- }
- }
+/* Free up an individual ldst entry. */
- free (regs_set_in_block);
+static void
+free_ldst_entry (struct ls_expr * ptr)
+{
+ free_INSN_LIST_list (& ptr->loads);
+ free_INSN_LIST_list (& ptr->stores);
- if (dump_file)
- {
- 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);
- }
+ free (ptr);
}
-/* Insert an instruction at the beginning of a basic block, and update
- the BB_HEAD if needed. */
+/* Free up all memory associated with the ldst list. */
static void
-insert_insn_start_bb (rtx insn, basic_block bb)
+free_ld_motion_mems (void)
{
- /* Insert at start of successor block. */
- rtx prev = PREV_INSN (BB_HEAD (bb));
- rtx before = BB_HEAD (bb);
- while (before != 0)
+ if (pre_ldst_table)
+ htab_delete (pre_ldst_table);
+ pre_ldst_table = NULL;
+
+ while (pre_ldst_mems)
{
- if (! LABEL_P (before)
- && (! NOTE_P (before)
- || NOTE_LINE_NUMBER (before) != NOTE_INSN_BASIC_BLOCK))
- break;
- prev = before;
- if (prev == BB_END (bb))
- break;
- before = NEXT_INSN (before);
- }
+ struct ls_expr * tmp = pre_ldst_mems;
- insn = emit_insn_after_noloc (insn, prev);
+ pre_ldst_mems = pre_ldst_mems->next;
- 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");
+ free_ldst_entry (tmp);
}
+
+ pre_ldst_mems = NULL;
}
-/* 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. */
+/* Dump debugging info about the ldst list. */
-static int
-insert_store (struct ls_expr * expr, edge e)
+static void
+print_ldst_list (FILE * file)
{
- rtx reg, insn;
- basic_block bb;
- edge tmp;
- edge_iterator ei;
+ struct ls_expr * ptr;
- /* 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;
+ fprintf (file, "LDST list: \n");
- if (e->flags & EDGE_FAKE)
- return 0;
+ for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next)
+ {
+ fprintf (file, " Pattern (%3d): ", ptr->index);
- reg = expr->reaching_reg;
- insn = gen_move_insn (copy_rtx (expr->pattern), reg);
+ print_rtl (file, ptr->pattern);
- /* 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;
- }
+ fprintf (file, "\n Loads : ");
- /* 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_bb (insn, bb);
- return 0;
- }
+ if (ptr->loads)
+ print_rtl (file, ptr->loads);
+ else
+ fprintf (file, "(nil)");
- /* 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));
+ fprintf (file, "\n Stores : ");
- insert_insn_on_edge (insn, e);
+ if (ptr->stores)
+ print_rtl (file, ptr->stores);
+ else
+ fprintf (file, "(nil)");
- if (dump_file)
- {
- 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");
+ fprintf (file, "\n\n");
}
- return 1;
+ fprintf (file, "\n");
}
-/* 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. */
+/* Returns 1 if X is in the list of ldst only expressions. */
-static void
-remove_reachable_equiv_notes (basic_block bb, struct ls_expr *smexpr)
+static struct ls_expr *
+find_rtx_in_ldst (rtx x)
{
- edge_iterator *stack, ei;
- int sp;
- edge act;
- sbitmap visited = sbitmap_alloc (last_basic_block);
- rtx last, insn, note;
- rtx mem = smexpr->pattern;
-
- stack = XNEWVEC (edge_iterator, n_basic_blocks);
- sp = 0;
- ei = ei_start (bb->succs);
+ 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 (struct ls_expr *) *slot;
+}
+\f
+/* Load Motion for loads which only kill themselves. */
- sbitmap_zero (visited);
+/* Return true if x, a MEM, is a simple access with no 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. */
- 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;
+static int
+simple_mem (const_rtx x)
+{
+ if (MEM_VOLATILE_P (x))
+ return 0;
- 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);
+ if (GET_MODE (x) == BLKmode)
+ return 0;
- 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));
+ /* 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 (cfun->can_throw_non_call_exceptions && may_trap_p (x))
+ return 0;
- 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;
+ if (side_effects_p (x))
+ return 0;
- if (dump_file)
- fprintf (dump_file, "STORE_MOTION drop REG_EQUAL note at insn %d:\n",
- INSN_UID (insn));
- remove_note (insn, note);
- }
+ /* Do not consider function arguments passed on stack. */
+ if (reg_mentioned_p (stack_pointer_rtx, x))
+ return 0;
- if (!ei_end_p (ei))
- ei_next (&ei);
- act = (! ei_end_p (ei)) ? ei_edge (ei) : NULL;
+ if (flag_float_store && FLOAT_MODE_P (GET_MODE (x)))
+ return 0;
- 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 1;
}
-/* This routine will replace a store with a SET to a specified register. */
+/* 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
-replace_store_insn (rtx reg, rtx del, basic_block bb, struct ls_expr *smexpr)
+invalidate_any_buried_refs (rtx x)
{
- rtx insn, mem, note, set, ptr, pair;
-
- mem = smexpr->pattern;
- insn = gen_move_insn (reg, SET_SRC (single_set (del)));
- insn = emit_insn_after (insn, del);
+ const char * fmt;
+ int i, j;
+ struct ls_expr * ptr;
- if (dump_file)
+ /* Invalidate it in the list. */
+ if (MEM_P (x) && simple_mem (x))
{
- 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");
+ ptr = ldst_entry (x);
+ ptr->invalid = 1;
}
- 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);
+ /* Recursively process the insn. */
+ fmt = GET_RTX_FORMAT (GET_CODE (x));
- 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)
+ for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
{
- pair = XEXP (note, 0);
- note = find_reg_note (pair, REG_RETVAL, NULL_RTX);
- XEXP (note, 0) = insn;
+ 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));
}
-
- delete_insn (del);
-
- /* 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;
-
- 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);
}
-
-/* Delete a store, but copy the value that would have been stored into
- the reaching_reg for later storing. */
+/* 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
-delete_store (struct ls_expr * expr, basic_block bb)
+compute_ld_motion_mems (void)
{
- rtx reg, i, del;
-
- if (expr->reaching_reg == NULL_RTX)
- expr->reaching_reg = gen_reg_rtx (GET_MODE (expr->pattern));
+ struct ls_expr * ptr;
+ basic_block bb;
+ rtx insn;
- reg = expr->reaching_reg;
+ pre_ldst_mems = NULL;
+ pre_ldst_table
+ = htab_create (13, pre_ldst_expr_hash, pre_ldst_expr_eq, NULL);
- for (i = AVAIL_STORE_LIST (expr); i; i = XEXP (i, 1))
+ FOR_EACH_BB (bb)
{
- del = XEXP (i, 0);
- if (BLOCK_FOR_INSN (del) == bb)
+ FOR_BB_INSNS (bb, insn)
{
- /* We know there is only one since we deleted redundant
- ones during the available computation. */
- replace_store_insn (reg, del, bb, expr);
- break;
- }
- }
-}
-
-/* Free memory used by store motion. */
+ if (NONDEBUG_INSN_P (insn))
+ {
+ if (GET_CODE (PATTERN (insn)) == SET)
+ {
+ rtx src = SET_SRC (PATTERN (insn));
+ rtx dest = SET_DEST (PATTERN (insn));
-static void
-free_store_memory (void)
-{
- free_ldst_mems ();
+ /* 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 (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);
+ /* 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);
- ae_gen = ae_kill = transp = st_antloc = NULL;
- pre_insert_map = pre_delete_map = reg_set_in_block = NULL;
+ 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_without_clobbers_p (src))
+ ptr->stores = alloc_INSN_LIST (insn, ptr->stores);
+ else
+ ptr->invalid = 1;
+ }
+ }
+ else
+ invalidate_any_buried_refs (PATTERN (insn));
+ }
+ }
+ }
}
-/* Perform store motion. Much like gcse, except we move expressions the
- other way by looking at the flowgraph in reverse. */
+/* Remove any references that have been either invalidated or are not in the
+ expression list for pre gcse. */
static void
-store_motion (void)
+trim_ld_motion_mems (void)
{
- basic_block bb;
- int x;
- struct ls_expr * ptr;
- int update_flow = 0;
-
- if (dump_file)
- {
- fprintf (dump_file, "before store motion\n");
- print_rtl (dump_file, get_insns ());
- }
-
- init_alias_analysis ();
+ struct ls_expr * * last = & pre_ldst_mems;
+ struct ls_expr * ptr = pre_ldst_mems;
- /* Find all the available and anticipatable stores. */
- num_stores = compute_store_table ();
- if (num_stores == 0)
+ while (ptr != NULL)
{
- htab_delete (pre_ldst_table);
- pre_ldst_table = NULL;
- sbitmap_vector_free (reg_set_in_block);
- end_alias_analysis ();
- return;
- }
+ struct expr * expr;
- /* Now compute kill & transp vectors. */
- build_store_vectors ();
- add_noreturn_fake_exit_edges ();
- connect_infinite_loops_to_exit ();
+ /* 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;
- edge_list = pre_edge_rev_lcm (num_stores, transp, ae_gen,
- st_antloc, ae_kill, &pre_insert_map,
- &pre_delete_map);
+ 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;
- /* 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))
- {
- /* 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)
+ if (expr)
{
- 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;
+ /* Set the expression field if we are keeping it. */
+ ptr->expr = expr;
+ last = & ptr->next;
+ ptr = ptr->next;
+ }
+ else
+ {
+ *last = ptr->next;
+ htab_remove_elt_with_hash (pre_ldst_table, ptr, ptr->hash_index);
+ free_ldst_entry (ptr);
+ ptr = * last;
}
-
- /* 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);
-
- 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 (update_flow)
- commit_edge_insertions ();
-
- free_store_memory ();
- free_edge_list (edge_list);
- remove_fake_exit_edges ();
- end_alias_analysis ();
+ /* Show the world what we've found. */
+ if (dump_file && pre_ldst_mems != NULL)
+ print_ldst_list (dump_file);
}
-\f
-/* Entry point for jump bypassing optimization pass. */
+/* 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. */
-static int
-bypass_jumps (void)
+static void
+update_ld_motion_stores (struct expr * expr)
{
- 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;
-
- /* Identify the basic block information for this function, including
- successors and predecessors. */
- max_gcse_regno = max_reg_num ();
-
- 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 <= NUM_FIXED_BLOCKS + 1
- || is_too_expensive (_ ("jump bypassing disabled")))
- return 0;
+ struct ls_expr * mem_ptr;
- gcc_obstack_init (&gcse_obstack);
- bytes_used = 0;
+ if ((mem_ptr = find_rtx_in_ldst (expr->expr)))
+ {
+ /* 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 need alias. */
- init_alias_analysis ();
+ /* 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;
- /* 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 ( ; 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;
- 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. */
+ /* If we've already copied it, continue. */
+ if (expr->reaching_reg == src)
+ continue;
- alloc_reg_set_mem (max_gcse_regno);
- compute_sets ();
+ if (dump_file)
+ {
+ fprintf (dump_file, "PRE: store updated with reaching reg ");
+ print_rtl (dump_file, reg);
+ fprintf (dump_file, ":\n ");
+ print_inline_rtx (dump_file, insn, 8);
+ fprintf (dump_file, "\n");
+ }
- max_gcse_regno = max_reg_num ();
- alloc_gcse_mem ();
- changed = one_cprop_pass (MAX_GCSE_PASSES + 2, true, true);
- free_gcse_mem ();
+ copy = gen_move_insn (reg, copy_rtx (SET_SRC (pat)));
+ emit_insn_before (copy, insn);
+ SET_SRC (pat) = reg;
+ df_insn_rescan (insn);
- 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);
+ /* un-recognize this pattern since it's probably different now. */
+ INSN_CODE (insn) = -1;
+ gcse_create_count++;
+ }
}
-
- 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;
}
-
+\f
/* Return true if the graph is too expensive to optimize. PASS is the
optimization about to be performed. */
return true;
}
- /* If allocating memory for the cprop bitmap would take up too much
+ /* If allocating memory for the dataflow bitmaps would take up too much
storage it's better just to disable the optimization. */
if ((n_basic_blocks
* SBITMAP_SET_SIZE (max_reg_num ())
return false;
}
\f
+/* All the passes implemented in this file. Each pass has its
+ own gate and execute function, and at the end of the file a
+ pass definition for passes.c.
+
+ We do not construct an accurate cfg in functions which call
+ setjmp, so none of these passes runs if the function calls
+ setjmp.
+ FIXME: Should just handle setjmp via REG_SETJMP notes. */
+
static bool
-gate_handle_jump_bypass (void)
+gate_rtl_pre (void)
{
- return optimize > 0 && flag_gcse;
+ return optimize > 0 && flag_gcse
+ && !cfun->calls_setjmp
+ && optimize_function_for_speed_p (cfun)
+ && dbg_cnt (pre);
}
-/* Perform jump bypassing and control flow optimizations. */
static unsigned int
-rest_of_handle_jump_bypass (void)
+execute_rtl_pre (void)
{
- cleanup_cfg (CLEANUP_EXPENSIVE);
- reg_scan (get_insns (), max_reg_num ());
-
- if (bypass_jumps ())
- {
- rebuild_jump_labels (get_insns ());
- cleanup_cfg (CLEANUP_EXPENSIVE);
- delete_trivially_dead_insns (get_insns (), max_reg_num ());
- }
+ int changed;
+ delete_unreachable_blocks ();
+ df_analyze ();
+ changed = one_pre_gcse_pass ();
+ flag_rerun_cse_after_global_opts |= changed;
+ if (changed)
+ cleanup_cfg (0);
return 0;
}
-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 */
-};
-
-
static bool
-gate_handle_gcse (void)
+gate_rtl_hoist (void)
{
- return optimize > 0 && flag_gcse;
+ return optimize > 0 && flag_gcse
+ && !cfun->calls_setjmp
+ /* It does not make sense to run code hoisting unless we are optimizing
+ for code size -- it rarely makes programs faster, and can make then
+ bigger if we did PRE (when optimizing for space, we don't run PRE). */
+ && optimize_function_for_size_p (cfun)
+ && dbg_cnt (hoist);
}
-
static unsigned int
-rest_of_handle_gcse (void)
+execute_rtl_hoist (void)
{
- int save_csb, save_cfj;
- int tem2 = 0, tem;
-
- tem = gcse_main (get_insns ());
- rebuild_jump_labels (get_insns ());
- delete_trivially_dead_insns (get_insns (), max_reg_num ());
-
- 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);
- reg_scan (get_insns (), max_reg_num ());
- tem2 = cse_main (get_insns (), max_reg_num ());
- 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 ());
- delete_dead_jumptables ();
- cleanup_cfg (CLEANUP_EXPENSIVE);
- timevar_pop (TV_JUMP);
- }
-
- flag_cse_skip_blocks = save_csb;
- flag_cse_follow_jumps = save_cfj;
+ int changed;
+ delete_unreachable_blocks ();
+ df_analyze ();
+ changed = one_code_hoisting_pass ();
+ flag_rerun_cse_after_global_opts |= changed;
+ if (changed)
+ cleanup_cfg (0);
return 0;
}
-struct tree_opt_pass pass_gcse =
+struct rtl_opt_pass pass_rtl_pre =
{
- "gcse1", /* name */
- gate_handle_gcse, /* gate */
- rest_of_handle_gcse, /* execute */
+ {
+ RTL_PASS,
+ "rtl pre", /* name */
+ gate_rtl_pre, /* gate */
+ execute_rtl_pre, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
- TV_GCSE, /* tv_id */
- 0, /* properties_required */
+ TV_PRE, /* tv_id */
+ PROP_cfglayout, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func |
- TODO_verify_flow | TODO_ggc_collect, /* todo_flags_finish */
- 'G' /* letter */
+ TODO_df_finish | TODO_verify_rtl_sharing |
+ TODO_verify_flow | TODO_ggc_collect /* todo_flags_finish */
+ }
};
+struct rtl_opt_pass pass_rtl_hoist =
+{
+ {
+ RTL_PASS,
+ "hoist", /* name */
+ gate_rtl_hoist, /* gate */
+ execute_rtl_hoist, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_HOIST, /* tv_id */
+ PROP_cfglayout, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish | TODO_verify_rtl_sharing |
+ TODO_verify_flow | TODO_ggc_collect /* todo_flags_finish */
+ }
+};
#include "gt-gcse.h"
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