/* Rewrite a program in Normal form into SSA.
- Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008
+ Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
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)
+the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "hard-reg-set.h"
#include "basic-block.h"
#include "output.h"
-#include "errors.h"
#include "expr.h"
#include "function.h"
#include "diagnostic.h"
#include "cfgloop.h"
#include "domwalk.h"
#include "ggc.h"
+#include "params.h"
+#include "vecprim.h"
/* This file builds the SSA form for a function as described in:
R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently
state after completing rewriting of a block and its dominator
children. Its elements have the following properties:
- - An SSA_NAME indicates that the current definition of the
- underlying variable should be set to the given SSA_NAME.
+ - An SSA_NAME (N) indicates that the current definition of the
+ underlying variable should be set to the given SSA_NAME. If the
+ symbol associated with the SSA_NAME is not a GIMPLE register, the
+ next slot in the stack must be a _DECL node (SYM). In this case,
+ the name N in the previous slot is the current reaching
+ definition for SYM.
- A _DECL node indicates that the underlying variable has no
current definition.
- - A NULL node is used to mark the last node associated with the
- current block.
-
- - A NULL node at the top entry is used to mark the last node
+ - A NULL node at the top entry is used to mark the last slot
associated with the current block. */
-static VEC(tree_on_heap) *block_defs_stack;
-
-/* Basic block vectors used in this file ought to be allocated in the heap. */
-DEF_VEC_MALLOC_P(int);
+static VEC(tree,heap) *block_defs_stack;
/* Set of existing SSA names being replaced by update_ssa. */
static sbitmap old_ssa_names;
the operations done on them are presence tests. */
static sbitmap new_ssa_names;
-/* Set of virtual SSA names to be updated. Since virtuals are always
- in FUD chain form, these names are not used as a mapping mechanism
- like OLD_SSA_NAMES and NEW_SSA_NAMES. Instead, the names in this
- set are used by ssa_names_to_replace to inform its caller which
- names are going to be updated. */
-static bitmap old_virtual_ssa_names;
-
/* Symbols whose SSA form needs to be updated or created for the first
time. */
static bitmap syms_to_rename;
+/* Subset of SYMS_TO_RENAME. Contains all the GIMPLE register symbols
+ that have been marked for renaming. */
+static bitmap regs_to_rename;
+
+/* Subset of SYMS_TO_RENAME. Contains all the memory symbols
+ that have been marked for renaming. */
+static bitmap mem_syms_to_rename;
+
/* Set of SSA names that have been marked to be released after they
were registered in the replacement table. They will be finally
released after we finish updating the SSA web. */
static bitmap names_to_release;
+/* For each block, the PHI nodes that need to be rewritten are stored into
+ these vectors. */
+typedef VEC(tree, heap) *tree_vec;
+DEF_VEC_P (tree_vec);
+DEF_VEC_ALLOC_P (tree_vec, heap);
+
+static VEC(tree_vec, heap) *phis_to_rewrite;
+
+/* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */
+static bitmap blocks_with_phis_to_rewrite;
+
/* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need
to grow as the callers to register_new_name_mapping will typically
create new names on the fly. FIXME. Currently set to 1/3 to avoid
/* true if update_ssa needs to update virtual operands. */
static bool need_to_update_vops_p = false;
-/* true if update_ssa is replacing existing SSA names. */
-static bool need_to_replace_names_p = false;
+/* Statistics kept by update_ssa to use in the virtual mapping
+ heuristic. If the number of virtual mappings is beyond certain
+ threshold, the updater will switch from using the mappings into
+ renaming the virtual symbols from scratch. In some cases, the
+ large number of name mappings for virtual names causes significant
+ slowdowns in the PHI insertion code. */
+struct update_ssa_stats_d
+{
+ unsigned num_virtual_mappings;
+ unsigned num_total_mappings;
+ bitmap virtual_symbols;
+ unsigned num_virtual_symbols;
+};
+static struct update_ssa_stats_d update_ssa_stats;
/* Global data to attach to the main dominator walk structure. */
struct mark_def_sites_global_data
/* Information stored for SSA names. */
struct ssa_name_info
{
+ /* The current reaching definition replacing this SSA name. */
+ tree current_def;
+
/* This field indicates whether or not the variable may need PHI nodes.
See the enum's definition for more detailed information about the
states. */
ENUM_BITFIELD (need_phi_state) need_phi_state : 2;
- /* The actual definition of the ssa name. */
- tree current_def;
+ /* Age of this record (so that info_for_ssa_name table can be cleared
+ quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields
+ are assumed to be null. */
+ unsigned age;
};
+/* The information associated with names. */
+typedef struct ssa_name_info *ssa_name_info_p;
+DEF_VEC_P (ssa_name_info_p);
+DEF_VEC_ALLOC_P (ssa_name_info_p, heap);
+
+static VEC(ssa_name_info_p, heap) *info_for_ssa_name;
+static unsigned current_info_for_ssa_name_age;
+
+/* The set of blocks affected by update_ssa. */
+static bitmap blocks_to_update;
/* The main entry point to the SSA renamer (rewrite_blocks) may be
called several times to do different, but related, tasks.
processed from those that only need to have their defs processed.
Statements that define new SSA names only need to have their defs
registered, but they don't need to have their uses renamed. */
-#define REGISTER_DEFS_IN_THIS_STMT(T) (T)->common.unsigned_flag
-
+#define REGISTER_DEFS_IN_THIS_STMT(T) (T)->base.unsigned_flag
+
+
+/* Prototypes for debugging functions. */
+extern void dump_tree_ssa (FILE *);
+extern void debug_tree_ssa (void);
+extern void debug_def_blocks (void);
+extern void dump_tree_ssa_stats (FILE *);
+extern void debug_tree_ssa_stats (void);
+extern void dump_update_ssa (FILE *);
+extern void debug_update_ssa (void);
+extern void dump_names_replaced_by (FILE *, tree);
+extern void debug_names_replaced_by (tree);
+extern void dump_def_blocks (FILE *);
+extern void debug_def_blocks (void);
+extern void dump_defs_stack (FILE *, int);
+extern void debug_defs_stack (int);
+extern void dump_currdefs (FILE *);
+extern void debug_currdefs (void);
/* Get the information associated with NAME. */
-static inline struct ssa_name_info *
+static inline ssa_name_info_p
get_ssa_name_ann (tree name)
{
- if (!SSA_NAME_AUX (name))
- SSA_NAME_AUX (name) = xcalloc (1, sizeof (struct ssa_name_info));
+ unsigned ver = SSA_NAME_VERSION (name);
+ unsigned len = VEC_length (ssa_name_info_p, info_for_ssa_name);
+ struct ssa_name_info *info;
+
+ if (ver >= len)
+ {
+ unsigned new_len = num_ssa_names;
+
+ VEC_reserve (ssa_name_info_p, heap, info_for_ssa_name, new_len);
+ while (len++ < new_len)
+ {
+ struct ssa_name_info *info = XCNEW (struct ssa_name_info);
+ info->age = current_info_for_ssa_name_age;
+ VEC_quick_push (ssa_name_info_p, info_for_ssa_name, info);
+ }
+ }
+
+ info = VEC_index (ssa_name_info_p, info_for_ssa_name, ver);
+ if (info->age < current_info_for_ssa_name_age)
+ {
+ info->need_phi_state = 0;
+ info->current_def = NULL_TREE;
+ info->age = current_info_for_ssa_name_age;
+ }
- return SSA_NAME_AUX (name);
+ return info;
}
-/* Gets phi_state field for VAR. */
+/* Clears info for SSA names. */
+
+static void
+clear_ssa_name_info (void)
+{
+ current_info_for_ssa_name_age++;
+}
+
+
+/* Get phi_state field for VAR. */
static inline enum need_phi_state
get_phi_state (tree var)
/* Return the current definition for VAR. */
-static inline tree
+tree
get_current_def (tree var)
{
if (TREE_CODE (var) == SSA_NAME)
/* Sets current definition of VAR to DEF. */
-static inline void
+void
set_current_def (tree var, tree def)
{
if (TREE_CODE (var) == SSA_NAME)
}
-/* Compute global livein information given the set of blockx where
+/* Compute global livein information given the set of blocks where
an object is locally live at the start of the block (LIVEIN)
and the set of blocks where the object is defined (DEF_BLOCKS).
= (basic_block *) xmalloc (sizeof (basic_block) * (last_basic_block + 1));
EXECUTE_IF_SET_IN_BITMAP (livein, 0, i, bi)
- {
- *tos++ = BASIC_BLOCK (i);
- }
+ *tos++ = BASIC_BLOCK (i);
/* Iterate until the worklist is empty. */
while (tos != worklist)
}
+/* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for
+ all statements in basic block BB. */
+
+static void
+initialize_flags_in_bb (basic_block bb)
+{
+ tree phi, stmt;
+ block_stmt_iterator bsi;
+
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ {
+ REWRITE_THIS_STMT (phi) = 0;
+ REGISTER_DEFS_IN_THIS_STMT (phi) = 0;
+ }
+
+ for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ {
+ stmt = bsi_stmt (bsi);
+ /* We are going to use the operand cache API, such as
+ SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand
+ cache for each statement should be up-to-date. */
+ gcc_assert (!stmt_modified_p (stmt));
+ REWRITE_THIS_STMT (stmt) = 0;
+ REGISTER_DEFS_IN_THIS_STMT (stmt) = 0;
+ }
+}
+
+/* Mark block BB as interesting for update_ssa. */
+
+static void
+mark_block_for_update (basic_block bb)
+{
+ gcc_assert (blocks_to_update != NULL);
+ if (bitmap_bit_p (blocks_to_update, bb->index))
+ return;
+ bitmap_set_bit (blocks_to_update, bb->index);
+ initialize_flags_in_bb (bb);
+}
+
/* Return the set of blocks where variable VAR is defined and the blocks
where VAR is live on entry (livein). If no entry is found in
DEF_BLOCKS, a new one is created and returned. */
slot = htab_find_slot (def_blocks, (void *) &db, INSERT);
if (*slot == NULL)
{
- db_p = xmalloc (sizeof (*db_p));
+ db_p = XNEW (struct def_blocks_d);
db_p->var = var;
db_p->def_blocks = BITMAP_ALLOC (NULL);
db_p->phi_blocks = BITMAP_ALLOC (NULL);
static inline bool
symbol_marked_for_renaming (tree sym)
{
- gcc_assert (DECL_P (sym));
- return bitmap_bit_p (syms_to_rename, var_ann (sym)->uid);
+ return bitmap_bit_p (syms_to_rename, DECL_UID (sym));
}
static inline bool
is_old_name (tree name)
{
- if (!need_to_replace_names_p)
- return false;
-
- return TEST_BIT (old_ssa_names, SSA_NAME_VERSION (name));
+ unsigned ver = SSA_NAME_VERSION (name);
+ return ver < new_ssa_names->n_bits && TEST_BIT (old_ssa_names, ver);
}
static inline bool
is_new_name (tree name)
{
- if (!need_to_replace_names_p)
- return false;
-
- return TEST_BIT (new_ssa_names, SSA_NAME_VERSION (name));
+ unsigned ver = SSA_NAME_VERSION (name);
+ return ver < new_ssa_names->n_bits && TEST_BIT (new_ssa_names, ver);
}
slot = htab_find_slot (repl_tbl, (void *) &m, INSERT);
if (*slot == NULL)
{
- mp = xmalloc (sizeof (*mp));
+ mp = XNEW (struct repl_map_d);
mp->name = new;
mp->set = BITMAP_ALLOC (NULL);
*slot = (void *) mp;
{
timevar_push (TV_TREE_SSA_INCREMENTAL);
- /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our
- caller may have created new names since the set was created. */
- if (new_ssa_names->n_bits <= num_ssa_names - 1)
- {
- unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR;
- new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0);
- old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0);
- }
+ /* OLD and NEW must be different SSA names for the same symbol. */
+ gcc_assert (new != old && SSA_NAME_VAR (new) == SSA_NAME_VAR (old));
- /* We don't need to keep replacement mappings for virtual names.
- Since these names are kept in FUD-chain form, we need to traverse
- the CFG from ENTRY to repair FUD chains. */
+ /* If this mapping is for virtual names, we will need to update
+ virtual operands. If this is a mapping for .MEM, then we gather
+ the symbols associated with each name. */
if (!is_gimple_reg (new))
{
tree sym;
- gcc_assert (!is_gimple_reg (old));
-
- if (DECL_P (old))
- sym = new;
- else
- {
- sym = SSA_NAME_VAR (old);
- bitmap_set_bit (old_virtual_ssa_names, SSA_NAME_VERSION (old));
- }
-
- mark_sym_for_renaming (sym);
need_to_update_vops_p = true;
- timevar_pop (TV_TREE_SSA_INCREMENTAL);
+ update_ssa_stats.num_virtual_mappings++;
+ update_ssa_stats.num_virtual_symbols++;
- return;
+ /* Keep counts of virtual mappings and symbols to use in the
+ virtual mapping heuristic. If we have large numbers of
+ virtual mappings for a relatively low number of symbols, it
+ will make more sense to rename the symbols from scratch.
+ Otherwise, the insertion of PHI nodes for each of the old
+ names in these mappings will be very slow. */
+ sym = SSA_NAME_VAR (new);
+ bitmap_set_bit (update_ssa_stats.virtual_symbols, DECL_UID (sym));
}
- /* Assume that OLD and NEW are different GIMPLE register names. */
- gcc_assert (new != old && is_gimple_reg (old));
+ /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our
+ caller may have created new names since the set was created. */
+ if (new_ssa_names->n_bits <= num_ssa_names - 1)
+ {
+ unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR;
+ new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0);
+ old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0);
+ }
/* Update the REPL_TBL table. */
add_to_repl_tbl (new, old);
SET_BIT (new_ssa_names, SSA_NAME_VERSION (new));
SET_BIT (old_ssa_names, SSA_NAME_VERSION (old));
- /* Indicate that we are going to be replacing existing names. */
- need_to_replace_names_p = true;
+ /* Update mapping counter to use in the virtual mapping heuristic. */
+ update_ssa_stats.num_total_mappings++;
timevar_pop (TV_TREE_SSA_INCREMENTAL);
}
for every variable in the function. For every statement S in block
BB:
- 1- Variables defined by S in DEF_OPS(S) are marked in the bitmap
+ 1- Variables defined by S in the DEFS of S are marked in the bitmap
WALK_DATA->GLOBAL_DATA->KILLS.
2- If S uses a variable VAR and there is no preceding kill of VAR,
- then it is marked in marked in the LIVEIN_BLOCKS bitmap
- associated with VAR.
+ then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR.
This information is used to determine which variables are live
across block boundaries to reduce the number of PHI nodes
we create. */
static void
-mark_def_sites (struct dom_walk_data *walk_data,
- basic_block bb,
+mark_def_sites (struct dom_walk_data *walk_data, basic_block bb,
block_stmt_iterator bsi)
{
- struct mark_def_sites_global_data *gd = walk_data->global_data;
- bitmap kills = gd->kills;
+ struct mark_def_sites_global_data *gd;
+ bitmap kills;
tree stmt, def;
use_operand_p use_p;
- def_operand_p def_p;
ssa_op_iter iter;
stmt = bsi_stmt (bsi);
update_stmt_if_modified (stmt);
+ gd = (struct mark_def_sites_global_data *) walk_data->global_data;
+ kills = gd->kills;
+
+ gcc_assert (blocks_to_update == NULL);
REGISTER_DEFS_IN_THIS_STMT (stmt) = 0;
REWRITE_THIS_STMT (stmt) = 0;
/* If a variable is used before being set, then the variable is live
across a block boundary, so mark it live-on-entry to BB. */
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter,
- SSA_OP_USE | SSA_OP_VUSE | SSA_OP_VMUSTDEFKILL)
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
{
tree sym = USE_FROM_PTR (use_p);
gcc_assert (DECL_P (sym));
- if (!bitmap_bit_p (kills, var_ann (sym)->uid))
+ if (!bitmap_bit_p (kills, DECL_UID (sym)))
set_livein_block (sym, bb);
REWRITE_THIS_STMT (stmt) = 1;
}
- /* Note that virtual definitions are irrelevant for computing KILLS
- because a V_MAY_DEF does not constitute a killing definition of the
- variable. However, the operand of a virtual definitions is a use
- of the variable, so it may cause the variable to be considered
- live-on-entry. */
- FOR_EACH_SSA_MAYDEF_OPERAND (def_p, use_p, stmt, iter)
- {
- tree sym = USE_FROM_PTR (use_p);
- gcc_assert (DECL_P (sym));
- set_livein_block (sym, bb);
- set_def_block (sym, bb, false);
- REGISTER_DEFS_IN_THIS_STMT (stmt) = 1;
- REWRITE_THIS_STMT (stmt) = 1;
- }
-
- /* Now process the defs and must-defs made by this statement. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF | SSA_OP_VMUSTDEF)
+ /* Now process the defs. Mark BB as the definition block and add
+ each def to the set of killed symbols. */
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
{
gcc_assert (DECL_P (def));
set_def_block (def, bb, false);
- bitmap_set_bit (kills, var_ann (def)->uid);
+ bitmap_set_bit (kills, DECL_UID (def));
REGISTER_DEFS_IN_THIS_STMT (stmt) = 1;
}
SET_BIT (gd->interesting_blocks, bb->index);
}
+/* Structure used by prune_unused_phi_nodes to record bounds of the intervals
+ in the dfs numbering of the dominance tree. */
-/* Given a set of blocks with variable definitions (DEF_BLOCKS),
- return a bitmap with all the blocks in the iterated dominance
- frontier of the blocks in DEF_BLOCKS. DFS contains dominance
- frontier information as returned by compute_dominance_frontiers.
-
- The resulting set of blocks are the potential sites where PHI nodes
- are needed. The caller is responsible from freeing the memory
- allocated for the return value. */
+struct dom_dfsnum
+{
+ /* Basic block whose index this entry corresponds to. */
+ unsigned bb_index;
+
+ /* The dfs number of this node. */
+ unsigned dfs_num;
+};
+
+/* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback
+ for qsort. */
+
+static int
+cmp_dfsnum (const void *a, const void *b)
+{
+ const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a;
+ const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b;
+
+ return (int) da->dfs_num - (int) db->dfs_num;
+}
+
+/* Among the intervals starting at the N points specified in DEFS, find
+ the one that contains S, and return its bb_index. */
+
+static unsigned
+find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s)
+{
+ unsigned f = 0, t = n, m;
+
+ while (t > f + 1)
+ {
+ m = (f + t) / 2;
+ if (defs[m].dfs_num <= s)
+ f = m;
+ else
+ t = m;
+ }
-static bitmap
-find_idf (bitmap def_blocks, bitmap *dfs)
+ return defs[f].bb_index;
+}
+
+/* Clean bits from PHIS for phi nodes whose value cannot be used in USES.
+ KILLS is a bitmap of blocks where the value is defined before any use. */
+
+static void
+prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses)
{
+ VEC(int, heap) *worklist;
bitmap_iterator bi;
- unsigned bb_index;
- VEC(int) *work_stack;
- bitmap phi_insertion_points;
-
- work_stack = VEC_alloc (int, n_basic_blocks);
- phi_insertion_points = BITMAP_ALLOC (NULL);
-
- /* Seed the work list with all the blocks in DEF_BLOCKS. */
- EXECUTE_IF_SET_IN_BITMAP (def_blocks, 0, bb_index, bi)
- /* We use VEC_quick_push here for speed. This is safe because we
- know that the number of definition blocks is no greater than
- the number of basic blocks, which is the initial capacity of
- WORK_STACK. */
- VEC_quick_push (int, work_stack, bb_index);
-
- /* Pop a block off the worklist, add every block that appears in
- the original block's DF that we have not already processed to
- the worklist. Iterate until the worklist is empty. Blocks
- which are added to the worklist are potential sites for
- PHI nodes. */
- while (VEC_length (int, work_stack) > 0)
- {
- bb_index = VEC_pop (int, work_stack);
-
- /* Since the registration of NEW -> OLD name mappings is done
- separately from the call to update_ssa, when updating the SSA
- form, the basic blocks where new and/or old names are defined
- may have disappeared by CFG cleanup calls. In this case,
- we may pull a non-existing block from the work stack. */
- gcc_assert (bb_index < (unsigned) last_basic_block);
-
- EXECUTE_IF_AND_COMPL_IN_BITMAP (dfs[bb_index], phi_insertion_points,
- 0, bb_index, bi)
+ unsigned i, b, p, u, top;
+ bitmap live_phis;
+ basic_block def_bb, use_bb;
+ edge e;
+ edge_iterator ei;
+ bitmap to_remove;
+ struct dom_dfsnum *defs;
+ unsigned n_defs, adef;
+
+ if (bitmap_empty_p (uses))
+ {
+ bitmap_clear (phis);
+ return;
+ }
+
+ /* The phi must dominate a use, or an argument of a live phi. Also, we
+ do not create any phi nodes in def blocks, unless they are also livein. */
+ to_remove = BITMAP_ALLOC (NULL);
+ bitmap_and_compl (to_remove, kills, uses);
+ bitmap_and_compl_into (phis, to_remove);
+ if (bitmap_empty_p (phis))
+ {
+ BITMAP_FREE (to_remove);
+ return;
+ }
+
+ /* We want to remove the unnecessary phi nodes, but we do not want to compute
+ liveness information, as that may be linear in the size of CFG, and if
+ there are lot of different variables to rewrite, this may lead to quadratic
+ behavior.
+
+ Instead, we basically emulate standard dce. We put all uses to worklist,
+ then for each of them find the nearest def that dominates them. If this
+ def is a phi node, we mark it live, and if it was not live before, we
+ add the predecessors of its basic block to the worklist.
+
+ To quickly locate the nearest def that dominates use, we use dfs numbering
+ of the dominance tree (that is already available in order to speed up
+ queries). For each def, we have the interval given by the dfs number on
+ entry to and on exit from the corresponding subtree in the dominance tree.
+ The nearest dominator for a given use is the smallest of these intervals
+ that contains entry and exit dfs numbers for the basic block with the use.
+ If we store the bounds for all the uses to an array and sort it, we can
+ locate the nearest dominating def in logarithmic time by binary search.*/
+ bitmap_ior (to_remove, kills, phis);
+ n_defs = bitmap_count_bits (to_remove);
+ defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1);
+ defs[0].bb_index = 1;
+ defs[0].dfs_num = 0;
+ adef = 1;
+ EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi)
+ {
+ def_bb = BASIC_BLOCK (i);
+ defs[adef].bb_index = i;
+ defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb);
+ defs[adef + 1].bb_index = i;
+ defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb);
+ adef += 2;
+ }
+ BITMAP_FREE (to_remove);
+ gcc_assert (adef == 2 * n_defs + 1);
+ qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum);
+ gcc_assert (defs[0].bb_index == 1);
+
+ /* Now each DEFS entry contains the number of the basic block to that the
+ dfs number corresponds. Change them to the number of basic block that
+ corresponds to the interval following the dfs number. Also, for the
+ dfs_out numbers, increase the dfs number by one (so that it corresponds
+ to the start of the following interval, not to the end of the current
+ one). We use WORKLIST as a stack. */
+ worklist = VEC_alloc (int, heap, n_defs + 1);
+ VEC_quick_push (int, worklist, 1);
+ top = 1;
+ n_defs = 1;
+ for (i = 1; i < adef; i++)
+ {
+ b = defs[i].bb_index;
+ if (b == top)
+ {
+ /* This is a closing element. Interval corresponding to the top
+ of the stack after removing it follows. */
+ VEC_pop (int, worklist);
+ top = VEC_index (int, worklist, VEC_length (int, worklist) - 1);
+ defs[n_defs].bb_index = top;
+ defs[n_defs].dfs_num = defs[i].dfs_num + 1;
+ }
+ else
{
- /* Use a safe push because if there is a definition of VAR
- in every basic block, then WORK_STACK may eventually have
- more than N_BASIC_BLOCK entries. */
- VEC_safe_push (int, work_stack, bb_index);
- bitmap_set_bit (phi_insertion_points, bb_index);
+ /* Opening element. Nothing to do, just push it to the stack and move
+ it to the correct position. */
+ defs[n_defs].bb_index = defs[i].bb_index;
+ defs[n_defs].dfs_num = defs[i].dfs_num;
+ VEC_quick_push (int, worklist, b);
+ top = b;
}
+
+ /* If this interval starts at the same point as the previous one, cancel
+ the previous one. */
+ if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num)
+ defs[n_defs - 1].bb_index = defs[n_defs].bb_index;
+ else
+ n_defs++;
+ }
+ VEC_pop (int, worklist);
+ gcc_assert (VEC_empty (int, worklist));
+
+ /* Now process the uses. */
+ live_phis = BITMAP_ALLOC (NULL);
+ EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi)
+ {
+ VEC_safe_push (int, heap, worklist, i);
}
- VEC_free (int, work_stack);
+ while (!VEC_empty (int, worklist))
+ {
+ b = VEC_pop (int, worklist);
+ if (b == ENTRY_BLOCK)
+ continue;
- return phi_insertion_points;
-}
+ /* If there is a phi node in USE_BB, it is made live. Otherwise,
+ find the def that dominates the immediate dominator of USE_BB
+ (the kill in USE_BB does not dominate the use). */
+ if (bitmap_bit_p (phis, b))
+ p = b;
+ else
+ {
+ use_bb = get_immediate_dominator (CDI_DOMINATORS, BASIC_BLOCK (b));
+ p = find_dfsnum_interval (defs, n_defs,
+ bb_dom_dfs_in (CDI_DOMINATORS, use_bb));
+ if (!bitmap_bit_p (phis, p))
+ continue;
+ }
+
+ /* If the phi node is already live, there is nothing to do. */
+ if (bitmap_bit_p (live_phis, p))
+ continue;
+
+ /* Mark the phi as live, and add the new uses to the worklist. */
+ bitmap_set_bit (live_phis, p);
+ def_bb = BASIC_BLOCK (p);
+ FOR_EACH_EDGE (e, ei, def_bb->preds)
+ {
+ u = e->src->index;
+ if (bitmap_bit_p (uses, u))
+ continue;
+
+ /* In case there is a kill directly in the use block, do not record
+ the use (this is also necessary for correctness, as we assume that
+ uses dominated by a def directly in their block have been filtered
+ out before). */
+ if (bitmap_bit_p (kills, u))
+ continue;
+ bitmap_set_bit (uses, u);
+ VEC_safe_push (int, heap, worklist, u);
+ }
+ }
+
+ VEC_free (int, heap, worklist);
+ bitmap_copy (phis, live_phis);
+ BITMAP_FREE (live_phis);
+ free (defs);
+}
/* Return the set of blocks where variable VAR is defined and the blocks
where VAR is live on entry (livein). Return NULL, if no entry is
static inline tree
get_default_def_for (tree sym)
{
- tree ddef = default_def (sym);
+ tree ddef = gimple_default_def (cfun, sym);
if (ddef == NULL_TREE)
{
}
+/* Marks phi node PHI in basic block BB for rewrite. */
+
+static void
+mark_phi_for_rewrite (basic_block bb, tree phi)
+{
+ tree_vec phis;
+ unsigned i, idx = bb->index;
+
+ if (REWRITE_THIS_STMT (phi))
+ return;
+
+ REWRITE_THIS_STMT (phi) = 1;
+
+ if (!blocks_with_phis_to_rewrite)
+ return;
+
+ bitmap_set_bit (blocks_with_phis_to_rewrite, idx);
+ VEC_reserve (tree_vec, heap, phis_to_rewrite, last_basic_block + 1);
+ for (i = VEC_length (tree_vec, phis_to_rewrite); i <= idx; i++)
+ VEC_quick_push (tree_vec, phis_to_rewrite, NULL);
+
+ phis = VEC_index (tree_vec, phis_to_rewrite, idx);
+ if (!phis)
+ phis = VEC_alloc (tree, heap, 10);
+
+ VEC_safe_push (tree, heap, phis, phi);
+ VEC_replace (tree_vec, phis_to_rewrite, idx, phis);
+}
+
+
/* Insert PHI nodes for variable VAR using the iterated dominance
frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this
- function assumes that the caller is incrementally updating the SSA
- form, in which case (1) VAR is assumed to be an SSA name, (2) a new
- SSA name is created for VAR's symbol, and, (3) all the arguments
- for the newly created PHI node are set to VAR.
+ function assumes that the caller is incrementally updating the
+ existing SSA form, in which case VAR may be an SSA name instead of
+ a symbol.
PHI_INSERTION_POINTS is updated to reflect nodes that already had a
PHI node for VAR. On exit, only the nodes that received a PHI node
/* Remove the blocks where we already have PHI nodes for VAR. */
bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks);
- /* Now compute global livein for this variable. Note this modifies
- def_map->livein_blocks. */
- compute_global_livein (def_map->livein_blocks, def_map->def_blocks);
+ /* Remove obviously useless phi nodes. */
+ prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks,
+ def_map->livein_blocks);
/* And insert the PHI nodes. */
- EXECUTE_IF_AND_IN_BITMAP (phi_insertion_points, def_map->livein_blocks,
- 0, bb_index, bi)
+ EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi)
{
bb = BASIC_BLOCK (bb_index);
- phi = create_phi_node (var, bb);
+ if (update_p)
+ mark_block_for_update (bb);
+
+ phi = NULL_TREE;
if (TREE_CODE (var) == SSA_NAME)
{
+ /* If we are rewriting SSA names, create the LHS of the PHI
+ node by duplicating VAR. This is useful in the case of
+ pointers, to also duplicate pointer attributes (alias
+ information, in particular). */
edge_iterator ei;
+ tree new_lhs;
- /* FIXME. After removing rewrite_ssa_into_ssa, change this
- if() to gcc_assert(). */
- if (update_p)
- {
- /* If we are rewriting SSA names, create the LHS of the
- PHI node by duplicating VAR. This is useful in the
- case of pointers, to also duplicate pointer
- attributes (alias information, in particular). */
- tree new_lhs = duplicate_ssa_name (var, phi);
- SET_PHI_RESULT (phi, new_lhs);
- add_new_name_mapping (new_lhs, var);
- }
+ gcc_assert (update_p);
+ phi = create_phi_node (var, bb);
+
+ new_lhs = duplicate_ssa_name (var, phi);
+ SET_PHI_RESULT (phi, new_lhs);
+ add_new_name_mapping (new_lhs, var);
/* Add VAR to every argument slot of PHI. We need VAR in
every argument so that rewrite_update_phi_arguments knows
FOR_EACH_EDGE (e, ei, bb->preds)
add_phi_arg (phi, var, e);
}
+ else
+ {
+ gcc_assert (DECL_P (var));
+ phi = create_phi_node (var, bb);
+ }
/* Mark this PHI node as interesting for update_ssa. */
REGISTER_DEFS_IN_THIS_STMT (phi) = 1;
- REWRITE_THIS_STMT (phi) = 1;
- }
-}
-
-
-/* Helper for insert_phi_nodes. If VAR needs PHI nodes, insert them
- at the dominance frontier (DFS) of blocks defining VAR. */
-
-static inline void
-insert_phi_nodes_1 (tree var, bitmap *dfs)
-{
- struct def_blocks_d *def_map;
- bitmap idf;
-
- def_map = find_def_blocks_for (var);
- if (def_map == NULL)
- return;
-
- if (get_phi_state (var) != NEED_PHI_STATE_NO)
- {
- idf = find_idf (def_map->def_blocks, dfs);
- insert_phi_nodes_for (var, idf, false);
- BITMAP_FREE (idf);
+ mark_phi_for_rewrite (bb, phi);
}
}
/* Insert PHI nodes at the dominance frontier of blocks with variable
definitions. DFS contains the dominance frontier information for
- the flowgraph. PHI nodes will only be inserted at the dominance
- frontier of definition blocks for variables whose NEED_PHI_STATE
- annotation is marked as ``maybe'' or ``unknown'' (computed by
- mark_def_sites). If NAMES_TO_RENAME is not NULL, do the same but
- for ssa name rewriting. */
+ the flowgraph. */
static void
-insert_phi_nodes (bitmap *dfs, bitmap names_to_rename)
+insert_phi_nodes (bitmap *dfs)
{
- unsigned i;
+ referenced_var_iterator rvi;
+ tree var;
timevar_push (TV_TREE_INSERT_PHI_NODES);
-
- if (names_to_rename)
+
+ FOR_EACH_REFERENCED_VAR (var, rvi)
{
- bitmap_iterator bi;
+ struct def_blocks_d *def_map;
+ bitmap idf;
- EXECUTE_IF_SET_IN_BITMAP (names_to_rename, 0, i, bi)
- if (ssa_name (i))
- insert_phi_nodes_1 (ssa_name (i), dfs);
- }
- else
- {
- for (i = 0; i < num_referenced_vars; i++)
- insert_phi_nodes_1 (referenced_var (i), dfs);
+ def_map = find_def_blocks_for (var);
+ if (def_map == NULL)
+ continue;
+
+ if (get_phi_state (var) != NEED_PHI_STATE_NO)
+ {
+ idf = compute_idf (def_map->def_blocks, dfs);
+ insert_phi_nodes_for (var, idf, false);
+ BITMAP_FREE (idf);
+ }
}
timevar_pop (TV_TREE_INSERT_PHI_NODES);
}
-/* Register DEF (an SSA_NAME) to be a new definition for its underlying
- variable (SSA_NAME_VAR (DEF)) and push VAR's current reaching definition
- into the stack pointed by BLOCK_DEFS_P. */
+/* Push SYM's current reaching definition into BLOCK_DEFS_STACK and
+ register DEF (an SSA_NAME) to be a new definition for SYM. */
-void
-register_new_def (tree def, VEC (tree_on_heap) **block_defs_p)
+static void
+register_new_def (tree def, tree sym)
{
- tree var = SSA_NAME_VAR (def);
tree currdef;
/* If this variable is set in a single basic block and all uses are
This is the same test to prune the set of variables which may
need PHI nodes. So we just use that information since it's already
computed and available for us to use. */
- if (get_phi_state (var) == NEED_PHI_STATE_NO)
+ if (get_phi_state (sym) == NEED_PHI_STATE_NO)
{
- set_current_def (var, def);
+ set_current_def (sym, def);
return;
}
- currdef = get_current_def (var);
+ currdef = get_current_def (sym);
+
+ /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose
+ SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM
+ in the stack so that we know which symbol is being defined by
+ this SSA name when we unwind the stack. */
+ if (currdef && !is_gimple_reg (sym))
+ VEC_safe_push (tree, heap, block_defs_stack, sym);
- /* Push the current reaching definition into *BLOCK_DEFS_P. This stack is
- later used by the dominator tree callbacks to restore the reaching
- definitions for all the variables defined in the block after a recursive
- visit to all its immediately dominated blocks. If there is no current
- reaching definition, then just record the underlying _DECL node. */
- VEC_safe_push (tree_on_heap, *block_defs_p, currdef ? currdef : var);
+ /* Push the current reaching definition into BLOCK_DEFS_STACK. This
+ stack is later used by the dominator tree callbacks to restore
+ the reaching definitions for all the variables defined in the
+ block after a recursive visit to all its immediately dominated
+ blocks. If there is no current reaching definition, then just
+ record the underlying _DECL node. */
+ VEC_safe_push (tree, heap, block_defs_stack, currdef ? currdef : sym);
- /* Set the current reaching definition for VAR to be DEF. */
- set_current_def (var, def);
+ /* Set the current reaching definition for SYM to be DEF. */
+ set_current_def (sym, def);
}
fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index);
/* Mark the unwind point for this block. */
- VEC_safe_push (tree_on_heap, block_defs_stack, NULL_TREE);
+ VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE);
/* Step 1. Register new definitions for every PHI node in the block.
Conceptually, all the PHI nodes are executed in parallel and each PHI
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
{
tree result = PHI_RESULT (phi);
- register_new_def (result, &block_defs_stack);
+ gcc_assert (is_gimple_reg (result));
+ register_new_def (result, SSA_NAME_VAR (result));
}
}
/* Return the current definition for variable VAR. If none is found,
- create a new SSA name to act as the zeroth definition for VAR. If VAR
- is call clobbered and there exists a more recent definition of
- GLOBAL_VAR, return the definition for GLOBAL_VAR. This means that VAR
- has been clobbered by a function call since its last assignment. */
+ create a new SSA name to act as the zeroth definition for VAR. */
static tree
get_reaching_def (tree var)
{
- tree currdef_var, avar;
+ tree currdef;
/* Lookup the current reaching definition for VAR. */
- currdef_var = get_current_def (var);
+ currdef = get_current_def (var);
/* If there is no reaching definition for VAR, create and register a
default definition for it (if needed). */
- if (currdef_var == NULL_TREE)
+ if (currdef == NULL_TREE)
{
- avar = DECL_P (var) ? var : SSA_NAME_VAR (var);
- currdef_var = get_default_def_for (avar);
- set_current_def (var, currdef_var);
+ tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var);
+ currdef = get_default_def_for (sym);
+ set_current_def (var, currdef);
}
/* Return the current reaching definition for VAR, or the default
definition, if we had to create one. */
- return currdef_var;
+ return currdef;
}
static void
rewrite_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
- basic_block bb ATTRIBUTE_UNUSED,
- block_stmt_iterator si)
+ basic_block bb ATTRIBUTE_UNUSED, block_stmt_iterator si)
{
tree stmt;
use_operand_p use_p;
/* If mark_def_sites decided that we don't need to rewrite this
statement, ignore it. */
+ gcc_assert (blocks_to_update == NULL);
if (!REWRITE_THIS_STMT (stmt) && !REGISTER_DEFS_IN_THIS_STMT (stmt))
return;
fprintf (dump_file, "\n");
}
- /* Step 1. Rewrite USES and VUSES in the statement. */
+ /* Step 1. Rewrite USES in the statement. */
if (REWRITE_THIS_STMT (stmt))
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter,
- SSA_OP_ALL_USES|SSA_OP_ALL_KILLS)
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
{
tree var = USE_FROM_PTR (use_p);
gcc_assert (DECL_P (var));
SET_USE (use_p, get_reaching_def (var));
}
- /* Step 2. Register the statement's DEF and VDEF operands. */
+ /* Step 2. Register the statement's DEF operands. */
if (REGISTER_DEFS_IN_THIS_STMT (stmt))
- FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS)
+ FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
{
tree var = DEF_FROM_PTR (def_p);
gcc_assert (DECL_P (var));
SET_DEF (def_p, make_ssa_name (var, stmt));
- register_new_def (DEF_FROM_PTR (def_p), &block_defs_stack);
+ register_new_def (DEF_FROM_PTR (def_p), var);
}
}
}
-/* Called after visiting basic block BB. Restore CURRDEFS to its
- original value. */
+/* Called after visiting all the statements in basic block BB and all
+ of its dominator children. Restore CURRDEFS to its original value. */
static void
rewrite_finalize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
basic_block bb ATTRIBUTE_UNUSED)
{
/* Restore CURRDEFS to its original state. */
- while (VEC_length (tree_on_heap, block_defs_stack) > 0)
+ while (VEC_length (tree, block_defs_stack) > 0)
{
- tree tmp = VEC_pop (tree_on_heap, block_defs_stack);
+ tree tmp = VEC_pop (tree, block_defs_stack);
tree saved_def, var;
if (tmp == NULL_TREE)
break;
- /* If we recorded an SSA_NAME, then make the SSA_NAME the current
- definition of its underlying variable. If we recorded anything
- else, it must have been an _DECL node and its current reaching
- definition must have been NULL. */
if (TREE_CODE (tmp) == SSA_NAME)
{
+ /* If we recorded an SSA_NAME, then make the SSA_NAME the
+ current definition of its underlying variable. Note that
+ if the SSA_NAME is not for a GIMPLE register, the symbol
+ being defined is stored in the next slot in the stack.
+ This mechanism is needed because an SSA name for a
+ non-register symbol may be the definition for more than
+ one symbol (e.g., SFTs, aliased variables, etc). */
saved_def = tmp;
var = SSA_NAME_VAR (saved_def);
+ if (!is_gimple_reg (var))
+ var = VEC_pop (tree, block_defs_stack);
}
else
{
+ /* If we recorded anything else, it must have been a _DECL
+ node and its current reaching definition must have been
+ NULL. */
saved_def = NULL;
var = tmp;
}
}
-/* Dump SSA information to FILE. */
+/* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */
void
-dump_tree_ssa (FILE *file)
+dump_decl_set (FILE *file, bitmap set)
{
- basic_block bb;
- const char *funcname
- = lang_hooks.decl_printable_name (current_function_decl, 2);
+ if (set)
+ {
+ bitmap_iterator bi;
+ unsigned i;
- fprintf (file, "SSA information for %s\n\n", funcname);
+ fprintf (file, "{ ");
- FOR_EACH_BB (bb)
- {
- dump_bb (bb, file, 0);
- fputs (" ", file);
- print_generic_stmt (file, phi_nodes (bb), dump_flags);
- fputs ("\n\n", file);
+ EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
+ {
+ print_generic_expr (file, referenced_var (i), 0);
+ fprintf (file, " ");
+ }
+
+ fprintf (file, "}\n");
}
+ else
+ fprintf (file, "NIL\n");
}
-/* Dump SSA information to stderr. */
+/* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */
void
-debug_tree_ssa (void)
+debug_decl_set (bitmap set)
{
- dump_tree_ssa (stderr);
+ dump_decl_set (stderr, set);
}
-/* Dump statistics for the hash table HTAB. */
+/* Dump the renaming stack (block_defs_stack) to FILE. Traverse the
+ stack up to a maximum of N levels. If N is -1, the whole stack is
+ dumped. New levels are created when the dominator tree traversal
+ used for renaming enters a new sub-tree. */
-static void
-htab_statistics (FILE *file, htab_t htab)
+void
+dump_defs_stack (FILE *file, int n)
{
- fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n",
- (long) htab_size (htab),
- (long) htab_elements (htab),
- htab_collisions (htab));
-}
+ int i, j;
+ fprintf (file, "\n\nRenaming stack");
+ if (n > 0)
+ fprintf (file, " (up to %d levels)", n);
+ fprintf (file, "\n\n");
-/* Dump SSA statistics on FILE. */
-
-void
-dump_tree_ssa_stats (FILE *file)
-{
- fprintf (file, "\nHash table statistics:\n");
+ i = 1;
+ fprintf (file, "Level %d (current level)\n", i);
+ for (j = (int) VEC_length (tree, block_defs_stack) - 1; j >= 0; j--)
+ {
+ tree name, var;
+
+ name = VEC_index (tree, block_defs_stack, j);
+ if (name == NULL_TREE)
+ {
+ i++;
+ if (n > 0 && i > n)
+ break;
+ fprintf (file, "\nLevel %d\n", i);
+ continue;
+ }
- fprintf (file, " def_blocks: ");
- htab_statistics (file, def_blocks);
+ if (DECL_P (name))
+ {
+ var = name;
+ name = NULL_TREE;
+ }
+ else
+ {
+ var = SSA_NAME_VAR (name);
+ if (!is_gimple_reg (var))
+ {
+ j--;
+ var = VEC_index (tree, block_defs_stack, j);
+ }
+ }
- fprintf (file, "\n");
+ fprintf (file, " Previous CURRDEF (");
+ print_generic_expr (file, var, 0);
+ fprintf (file, ") = ");
+ if (name)
+ print_generic_expr (file, name, 0);
+ else
+ fprintf (file, "<NIL>");
+ fprintf (file, "\n");
+ }
+}
+
+
+/* Dump the renaming stack (block_defs_stack) to stderr. Traverse the
+ stack up to a maximum of N levels. If N is -1, the whole stack is
+ dumped. New levels are created when the dominator tree traversal
+ used for renaming enters a new sub-tree. */
+
+void
+debug_defs_stack (int n)
+{
+ dump_defs_stack (stderr, n);
+}
+
+
+/* Dump the current reaching definition of every symbol to FILE. */
+
+void
+dump_currdefs (FILE *file)
+{
+ referenced_var_iterator i;
+ tree var;
+
+ fprintf (file, "\n\nCurrent reaching definitions\n\n");
+ FOR_EACH_REFERENCED_VAR (var, i)
+ if (syms_to_rename == NULL || bitmap_bit_p (syms_to_rename, DECL_UID (var)))
+ {
+ fprintf (file, "CURRDEF (");
+ print_generic_expr (file, var, 0);
+ fprintf (file, ") = ");
+ if (get_current_def (var))
+ print_generic_expr (file, get_current_def (var), 0);
+ else
+ fprintf (file, "<NIL>");
+ fprintf (file, "\n");
+ }
+}
+
+
+/* Dump the current reaching definition of every symbol to stderr. */
+
+void
+debug_currdefs (void)
+{
+ dump_currdefs (stderr);
+}
+
+
+/* Dump SSA information to FILE. */
+
+void
+dump_tree_ssa (FILE *file)
+{
+ const char *funcname
+ = lang_hooks.decl_printable_name (current_function_decl, 2);
+
+ fprintf (file, "SSA renaming information for %s\n\n", funcname);
+
+ dump_def_blocks (file);
+ dump_defs_stack (file, -1);
+ dump_currdefs (file);
+ dump_tree_ssa_stats (file);
+}
+
+
+/* Dump SSA information to stderr. */
+
+void
+debug_tree_ssa (void)
+{
+ dump_tree_ssa (stderr);
+}
+
+
+/* Dump statistics for the hash table HTAB. */
+
+static void
+htab_statistics (FILE *file, htab_t htab)
+{
+ fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n",
+ (long) htab_size (htab),
+ (long) htab_elements (htab),
+ htab_collisions (htab));
+}
+
+
+/* Dump SSA statistics on FILE. */
+
+void
+dump_tree_ssa_stats (FILE *file)
+{
+ if (def_blocks || repl_tbl)
+ fprintf (file, "\nHash table statistics:\n");
+
+ if (def_blocks)
+ {
+ fprintf (file, " def_blocks: ");
+ htab_statistics (file, def_blocks);
+ }
+
+ if (repl_tbl)
+ {
+ fprintf (file, " repl_tbl: ");
+ htab_statistics (file, repl_tbl);
+ }
+
+ if (def_blocks || repl_tbl)
+ fprintf (file, "\n");
}
static void
def_blocks_free (void *p)
{
- struct def_blocks_d *entry = p;
+ struct def_blocks_d *entry = (struct def_blocks_d *) p;
BITMAP_FREE (entry->def_blocks);
BITMAP_FREE (entry->phi_blocks);
BITMAP_FREE (entry->livein_blocks);
/* Callback for htab_traverse to dump the DEF_BLOCKS hash table. */
static int
-debug_def_blocks_r (void **slot, void *data ATTRIBUTE_UNUSED)
+debug_def_blocks_r (void **slot, void *data)
{
+ FILE *file = (FILE *) data;
struct def_blocks_d *db_p = (struct def_blocks_d *) *slot;
- fprintf (stderr, "VAR: ");
- print_generic_expr (stderr, db_p->var, dump_flags);
- bitmap_print (stderr, db_p->def_blocks, ", DEF_BLOCKS: { ", "}");
- bitmap_print (stderr, db_p->livein_blocks, ", LIVEIN_BLOCKS: { ", "}\n");
+ fprintf (file, "VAR: ");
+ print_generic_expr (file, db_p->var, dump_flags);
+ bitmap_print (file, db_p->def_blocks, ", DEF_BLOCKS: { ", "}");
+ bitmap_print (file, db_p->livein_blocks, ", LIVEIN_BLOCKS: { ", "}");
+ bitmap_print (file, db_p->phi_blocks, ", PHI_BLOCKS: { ", "}\n");
return 1;
}
+/* Dump the DEF_BLOCKS hash table on FILE. */
+
+void
+dump_def_blocks (FILE *file)
+{
+ fprintf (file, "\n\nDefinition and live-in blocks:\n\n");
+ if (def_blocks)
+ htab_traverse (def_blocks, debug_def_blocks_r, file);
+}
+
+
/* Dump the DEF_BLOCKS hash table on stderr. */
void
debug_def_blocks (void)
{
- htab_traverse (def_blocks, debug_def_blocks_r, NULL);
+ dump_def_blocks (stderr);
}
{
tree currdef = get_current_def (old_name);
- /* Push the current reaching definition into *BLOCK_DEFS_P.
+ /* Push the current reaching definition into BLOCK_DEFS_STACK.
This stack is later used by the dominator tree callbacks to
restore the reaching definitions for all the variables
defined in the block after a recursive visit to all its
immediately dominated blocks. */
- VEC_safe_push (tree_on_heap, block_defs_stack, currdef);
- VEC_safe_push (tree_on_heap, block_defs_stack, old_name);
+ VEC_reserve (tree, heap, block_defs_stack, 2);
+ VEC_quick_push (tree, block_defs_stack, currdef);
+ VEC_quick_push (tree, block_defs_stack, old_name);
/* Set the current reaching definition for OLD_NAME to be
NEW_NAME. */
bb->index);
/* Mark the unwind point for this block. */
- VEC_safe_push (tree_on_heap, block_defs_stack, NULL_TREE);
+ VEC_safe_push (tree, heap, block_defs_stack, NULL_TREE);
+
+ if (!bitmap_bit_p (blocks_to_update, bb->index))
+ return;
/* Mark the LHS if any of the arguments flows through an abnormal
edge. */
register_new_update_single (lhs, lhs_sym);
else
{
+
/* If LHS is a new name, register a new definition for all
the names replaced by LHS. */
if (is_new_name (lhs))
}
-/* Replace the operand pointed by USE_P with USE's current reaching
- definition. */
-
-static inline void
-replace_use (use_operand_p use_p, tree use)
-{
- tree rdef = get_reaching_def (use);
- if (rdef != use)
- SET_USE (use_p, rdef);
-}
-
-
/* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore
the current reaching definition of every name re-written in BB to
the original reaching definition before visiting BB. This
rewrite_update_fini_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
basic_block bb ATTRIBUTE_UNUSED)
{
- while (VEC_length (tree_on_heap, block_defs_stack) > 0)
+ while (VEC_length (tree, block_defs_stack) > 0)
{
- tree var = VEC_pop (tree_on_heap, block_defs_stack);
+ tree var = VEC_pop (tree, block_defs_stack);
tree saved_def;
/* NULL indicates the unwind stop point for this block (see
if (var == NULL)
return;
- saved_def = VEC_pop (tree_on_heap, block_defs_stack);
+ saved_def = VEC_pop (tree, block_defs_stack);
set_current_def (var, saved_def);
}
}
+/* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or
+ it is a symbol marked for renaming, replace it with USE_P's current
+ reaching definition. */
+
+static inline void
+maybe_replace_use (use_operand_p use_p)
+{
+ tree rdef = NULL_TREE;
+ tree use = USE_FROM_PTR (use_p);
+ tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use);
+
+ if (symbol_marked_for_renaming (sym))
+ rdef = get_reaching_def (sym);
+ else if (is_old_name (use))
+ rdef = get_reaching_def (use);
+
+ if (rdef && rdef != use)
+ SET_USE (use_p, rdef);
+}
+
+
+/* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES
+ or OLD_SSA_NAMES, or if it is a symbol marked for renaming,
+ register it as the current definition for the names replaced by
+ DEF_P. */
+
+static inline void
+maybe_register_def (def_operand_p def_p, tree stmt)
+{
+ tree def = DEF_FROM_PTR (def_p);
+ tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def);
+
+ /* If DEF is a naked symbol that needs renaming, create a new
+ name for it. */
+ if (symbol_marked_for_renaming (sym))
+ {
+ if (DECL_P (def))
+ {
+ def = make_ssa_name (def, stmt);
+ SET_DEF (def_p, def);
+ }
+
+ register_new_update_single (def, sym);
+ }
+ else
+ {
+ /* If DEF is a new name, register it as a new definition
+ for all the names replaced by DEF. */
+ if (is_new_name (def))
+ register_new_update_set (def, names_replaced_by (def));
+
+ /* If DEF is an old name, register DEF as a new
+ definition for itself. */
+ if (is_old_name (def))
+ register_new_update_single (def, def);
+ }
+}
+
+
/* Update every variable used in the statement pointed-to by SI. The
statement is assumed to be in SSA form already. Names in
OLD_SSA_NAMES used by SI will be updated to their current reaching
stmt = bsi_stmt (si);
ann = stmt_ann (stmt);
+ gcc_assert (bitmap_bit_p (blocks_to_update, bb->index));
+
/* Only update marked statements. */
if (!REWRITE_THIS_STMT (stmt) && !REGISTER_DEFS_IN_THIS_STMT (stmt))
return;
if (REWRITE_THIS_STMT (stmt))
{
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
- {
- tree use = USE_FROM_PTR (use_p);
- tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use);
-
- if (symbol_marked_for_renaming (sym))
- replace_use (use_p, sym);
- else if (is_old_name (use))
- replace_use (use_p, use);
- }
+ maybe_replace_use (use_p);
if (need_to_update_vops_p)
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter,
- SSA_OP_VIRTUAL_USES | SSA_OP_VIRTUAL_KILLS)
- {
- tree use = USE_FROM_PTR (use_p);
- tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use);
-
- if (symbol_marked_for_renaming (sym))
- replace_use (use_p, sym);
- }
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_VIRTUAL_USES)
+ maybe_replace_use (use_p);
}
/* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES.
if (REGISTER_DEFS_IN_THIS_STMT (stmt))
{
FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
- {
- tree def = DEF_FROM_PTR (def_p);
- tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def);
-
- /* If DEF is a naked symbol that needs renaming, create a
- new name for it. */
- if (symbol_marked_for_renaming (sym))
- {
- if (DECL_P (def))
- {
- def = make_ssa_name (def, stmt);
- SET_DEF (def_p, def);
- }
-
- register_new_update_single (def, sym);
- }
- else
- {
- /* If DEF is a new name, register it as a new definition
- for all the names replaced by DEF. */
- if (is_new_name (def))
- register_new_update_set (def, names_replaced_by (def));
-
- /* If DEF is an old name, register DEF as a new
- definition for itself. */
- if (is_old_name (def))
- register_new_update_single (def, def);
- }
- }
+ maybe_register_def (def_p, stmt);
if (need_to_update_vops_p)
FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_VIRTUAL_DEFS)
- {
- tree def = DEF_FROM_PTR (def_p);
- tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def);
-
- if (symbol_marked_for_renaming (sym))
- {
- if (DECL_P (def))
- {
- def = make_ssa_name (def, stmt);
- SET_DEF (def_p, def);
- }
-
- register_new_update_single (def, sym);
- }
- }
+ maybe_register_def (def_p, stmt);
}
}
{
edge e;
edge_iterator ei;
+ unsigned i;
FOR_EACH_EDGE (e, ei, bb->succs)
{
tree phi;
+ tree_vec phis;
- for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
+ if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index))
+ continue;
+
+ phis = VEC_index (tree_vec, phis_to_rewrite, e->dest->index);
+ for (i = 0; VEC_iterate (tree, phis, i, phi); i++)
{
- tree arg;
+ tree arg, lhs_sym;
use_operand_p arg_p;
- /* Skip PHI nodes that are not marked for rewrite. */
- if (!REWRITE_THIS_STMT (phi))
- continue;
+ gcc_assert (REWRITE_THIS_STMT (phi));
arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e);
arg = USE_FROM_PTR (arg_p);
if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME)
continue;
+ lhs_sym = SSA_NAME_VAR (PHI_RESULT (phi));
+
if (arg == NULL_TREE)
{
/* When updating a PHI node for a recently introduced
symbol we may find NULL arguments. That's why we
take the symbol from the LHS of the PHI node. */
- replace_use (arg_p, SSA_NAME_VAR (PHI_RESULT (phi)));
+ SET_USE (arg_p, get_reaching_def (lhs_sym));
}
else
{
tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg);
if (symbol_marked_for_renaming (sym))
- replace_use (arg_p, sym);
+ SET_USE (arg_p, get_reaching_def (sym));
else if (is_old_name (arg))
- replace_use (arg_p, arg);
+ SET_USE (arg_p, get_reaching_def (arg));
}
if (e->flags & EDGE_ABNORMAL)
walk_data.dom_direction = CDI_DOMINATORS;
walk_data.interesting_blocks = blocks;
- if (what == REWRITE_UPDATE)
- walk_data.before_dom_children_before_stmts = rewrite_update_init_block;
- else
+ if (what == REWRITE_ALL)
walk_data.before_dom_children_before_stmts = rewrite_initialize_block;
+ else
+ walk_data.before_dom_children_before_stmts = rewrite_update_init_block;
if (what == REWRITE_ALL)
walk_data.before_dom_children_walk_stmts = rewrite_stmt;
else
gcc_unreachable ();
- block_defs_stack = VEC_alloc (tree_on_heap, 10);
+ block_defs_stack = VEC_alloc (tree, heap, 10);
/* Initialize the dominator walker. */
init_walk_dominator_tree (&walk_data);
if (def_blocks)
dump_tree_ssa_stats (dump_file);
}
-
- if (def_blocks)
- {
- htab_delete (def_blocks);
- def_blocks = NULL;
- }
- VEC_free (tree_on_heap, block_defs_stack);
- block_defs_stack = NULL;
+ VEC_free (tree, heap, block_defs_stack);
timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS);
}
mark_def_sites_initialize_block (struct dom_walk_data *walk_data,
basic_block bb ATTRIBUTE_UNUSED)
{
- struct mark_def_sites_global_data *gd = walk_data->global_data;
- bitmap kills = gd->kills;
- bitmap_clear (kills);
+ struct mark_def_sites_global_data *gd;
+ gd = (struct mark_def_sites_global_data *) walk_data->global_data;
+ bitmap_clear (gd->kills);
}
static void
mark_def_site_blocks (sbitmap interesting_blocks)
{
- size_t i;
struct dom_walk_data walk_data;
struct mark_def_sites_global_data mark_def_sites_global_data;
- /* Allocate memory for the DEF_BLOCKS hash table. */
- def_blocks = htab_create (VARRAY_ACTIVE_SIZE (referenced_vars),
- def_blocks_hash, def_blocks_eq, def_blocks_free);
-
- for (i = 0; i < num_referenced_vars; i++)
- set_current_def (referenced_var (i), NULL_TREE);
-
/* Setup callbacks for the generic dominator tree walker to find and
mark definition sites. */
walk_data.walk_stmts_backward = false;
}
+/* Initialize internal data needed during renaming. */
+
+static void
+init_ssa_renamer (void)
+{
+ tree var;
+ referenced_var_iterator rvi;
+
+ cfun->gimple_df->in_ssa_p = false;
+
+ /* Allocate memory for the DEF_BLOCKS hash table. */
+ gcc_assert (def_blocks == NULL);
+ def_blocks = htab_create (num_referenced_vars, def_blocks_hash,
+ def_blocks_eq, def_blocks_free);
+
+ FOR_EACH_REFERENCED_VAR(var, rvi)
+ set_current_def (var, NULL_TREE);
+}
+
+
+/* Deallocate internal data structures used by the renamer. */
+
+static void
+fini_ssa_renamer (void)
+{
+ if (def_blocks)
+ {
+ htab_delete (def_blocks);
+ def_blocks = NULL;
+ }
+
+ cfun->gimple_df->in_ssa_p = true;
+}
+
+
/* Main entry point into the SSA builder. The renaming process
proceeds in four main phases:
4- Rename all the blocks (rewrite_blocks) and statements in the program.
- Steps 3 and 5 are done using the dominator tree walker
+ Steps 3 and 4 are done using the dominator tree walker
(walk_dominator_tree). */
-static void
+static unsigned int
rewrite_into_ssa (void)
{
bitmap *dfs;
/* Initialize operand data structures. */
init_ssa_operands ();
+ /* Initialize internal data needed by the renamer. */
+ init_ssa_renamer ();
+
/* Initialize the set of interesting blocks. The callback
mark_def_sites will add to this set those blocks that the renamer
should process. */
sbitmap_zero (interesting_blocks);
/* Initialize dominance frontier. */
- dfs = (bitmap *) xmalloc (last_basic_block * sizeof (bitmap *));
+ dfs = XNEWVEC (bitmap, last_basic_block);
FOR_EACH_BB (bb)
dfs[bb->index] = BITMAP_ALLOC (NULL);
mark_def_site_blocks (interesting_blocks);
/* 3- Insert PHI nodes at dominance frontiers of definition blocks. */
- insert_phi_nodes (dfs, NULL);
+ insert_phi_nodes (dfs);
/* 4- Rename all the blocks. */
rewrite_blocks (ENTRY_BLOCK_PTR, REWRITE_ALL, interesting_blocks);
free (dfs);
sbitmap_free (interesting_blocks);
+ fini_ssa_renamer ();
+
timevar_pop (TV_TREE_SSA_OTHER);
+ return 0;
}
-struct tree_opt_pass pass_build_ssa =
+struct gimple_opt_pass pass_build_ssa =
{
+ {
+ GIMPLE_PASS,
"ssa", /* name */
NULL, /* gate */
rewrite_into_ssa, /* execute */
PROP_ssa, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func | TODO_verify_ssa, /* todo_flags_finish */
- 0 /* letter */
+ TODO_dump_func
+ | TODO_verify_ssa
+ | TODO_remove_unused_locals /* todo_flags_finish */
+ }
};
renamer. BLOCKS is the set of blocks that need updating. */
static void
-mark_def_interesting (tree var, tree stmt, basic_block bb, bitmap blocks,
- bool insert_phi_p)
+mark_def_interesting (tree var, tree stmt, basic_block bb, bool insert_phi_p)
{
+ gcc_assert (bitmap_bit_p (blocks_to_update, bb->index));
REGISTER_DEFS_IN_THIS_STMT (stmt) = 1;
- bitmap_set_bit (blocks, bb->index);
if (insert_phi_p)
{
bool is_phi_p = TREE_CODE (stmt) == PHI_NODE;
-#if defined ENABLE_CHECKING
- /* If VAR is a virtual, then it had better be a symbol.
- Virtuals are in FUD-chain form, so we are interested in the
- definition and use sites of the symbol, not the individual
- SSA names. */
- if (!is_gimple_reg (var))
- gcc_assert (DECL_P (var));
-#endif
-
set_def_block (var, bb, is_phi_p);
/* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition
/* Mark the use of VAR at STMT and BB as interesting for the
renamer. INSERT_PHI_P is true if we are going to insert new PHI
- nodes. BLOCKS is the set of blocks that need updating. */
+ nodes. */
static inline void
-mark_use_interesting (tree var, tree stmt, basic_block bb, bitmap blocks,
- bool insert_phi_p)
+mark_use_interesting (tree var, tree stmt, basic_block bb, bool insert_phi_p)
{
- REWRITE_THIS_STMT (stmt) = 1;
- bitmap_set_bit (blocks, bb->index);
+ basic_block def_bb = bb_for_stmt (stmt);
+
+ mark_block_for_update (def_bb);
+ mark_block_for_update (bb);
+
+ if (TREE_CODE (stmt) == PHI_NODE)
+ mark_phi_for_rewrite (def_bb, stmt);
+ else
+ REWRITE_THIS_STMT (stmt) = 1;
/* If VAR has not been defined in BB, then it is live-on-entry
to BB. Note that we cannot just use the block holding VAR's
replace it). */
if (insert_phi_p)
{
- struct def_blocks_d *db_p;
-
-#if defined ENABLE_CHECKING
- /* If VAR is a virtual, then it had better be a symbol.
- Virtuals are in FUD-chain form, so we are interested in the
- definition and use sites of the symbol, not the individual
- SSA names. */
- if (!is_gimple_reg (var))
- gcc_assert (DECL_P (var));
-#endif
-
- db_p = get_def_blocks_for (var);
+ struct def_blocks_d *db_p = get_def_blocks_for (var);
if (!bitmap_bit_p (db_p->def_blocks, bb->index))
set_livein_block (var, bb);
}
}
-/* If any of the arguments of PHI is in OLD_SSA_NAMES, mark PHI to
- be rewritten. BB is the block where PHI resides, BLOCKS is the
- region to be renamed and INSERT_PHI_P is true if the updating
- process should insert new PHI nodes. */
-
-static void
-prepare_phi_args_for_update (tree phi, basic_block bb, bitmap blocks,
- bool insert_phi_p)
-{
- int i;
-
- for (i = 0; i < PHI_NUM_ARGS (phi); i++)
- {
- tree arg = PHI_ARG_DEF (phi, i);
-
- if (TREE_CODE (arg) == SSA_NAME && is_old_name (arg))
- {
- /* Mark this use of ARG interesting for the renamer. Notice
- that we explicitly call mark_use_interesting with
- INSERT_PHI_P == false.
-
- This is to avoid marking ARG as live-in in this block BB.
- If we were to mark ARG live-in to BB, then ARG would be
- considered live-in through ALL incoming edges to BB which
- is not what we want. Since we are updating the SSA form
- for ARG, we don't really know what other names of ARG are
- coming in through other edges into BB.
-
- If we considered ARG live-in at BB, then the PHI
- placement algorithm may try to insert PHI nodes in blocks
- that are not only unnecessary but also the renamer would
- not know how to fill in. */
- mark_use_interesting (arg, phi, bb, blocks, false);
-
- /* As discussed above, we only want to mark ARG live-in
- through the edge corresponding to its slot inside the PHI
- argument list. So, we look for the block BB1 where ARG is
- flowing through. If BB1 does not contain a definition of
- ARG, then consider ARG live-in at BB1. */
- if (insert_phi_p)
- {
- edge e = PHI_ARG_EDGE (phi, i);
- basic_block bb1 = e->src;
- struct def_blocks_d *db = get_def_blocks_for (arg);
-
- if (!bitmap_bit_p (db->def_blocks, bb1->index))
- set_livein_block (arg, bb1);
- }
- }
- }
-}
-
-
/* Do a dominator walk starting at BB processing statements that
- reference variables in OLD_SSA_NAMES and NEW_SSA_NAMES.
-
- 1- Mark in BLOCKS the defining block of every name N in
- NEW_SSA_NAMES.
+ reference symbols in SYMS_TO_RENAME. This is very similar to
+ mark_def_sites, but the scan handles statements whose operands may
+ already be SSA names.
- 2- Mark in BLOCKS the defining block of every name O in
- OLD_SSA_NAMES.
+ If INSERT_PHI_P is true, mark those uses as live in the
+ corresponding block. This is later used by the PHI placement
+ algorithm to make PHI pruning decisions.
- 3- For every statement or PHI node that uses a name O in
- OLD_SSA_NAMES. If INSERT_PHI_P is true, mark those uses as live
- in the corresponding block. This is later used by the PHI
- placement algorithm to make PHI pruning decisions.
-
- If VISIT_DOM_P is true, all the dominator children of BB are also
- visited.
-
- FIXME. This process is slower than necessary. Once we have
- immediate uses merged in, we should be able to just visit the
- immediate uses of all the names that we are about to replace,
- instead of visiting the whole block. */
+ FIXME. Most of this would be unnecessary if we could associate a
+ symbol to all the SSA names that reference it. But that
+ sounds like it would be expensive to maintain. Still, it
+ would be interesting to see if it makes better sense to do
+ that. */
static void
-prepare_block_for_update (basic_block bb, bool insert_phi_p,
- bitmap blocks, bool visit_dom_p)
+prepare_block_for_update (basic_block bb, bool insert_phi_p)
{
basic_block son;
block_stmt_iterator si;
tree phi;
+ edge e;
+ edge_iterator ei;
+
+ mark_block_for_update (bb);
/* Process PHI nodes marking interesting those that define or use
- the names that we are interested in. */
+ the symbols that we are interested in. */
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
{
tree lhs_sym, lhs = PHI_RESULT (phi);
- REWRITE_THIS_STMT (phi) = 0;
- REGISTER_DEFS_IN_THIS_STMT (phi) = 0;
-
- /* Ignore virtual PHIs if we are not updating virtual operands.
- Note that even if NEED_TO_REPLACE_NAMES_P is false, we need
- to process real PHIs because we may be rewriting GIMPLE regs
- into SSA for the first time. Therefore, we cannot do a
- similar shortcut for real PHIs. */
- if (!need_to_update_vops_p && !is_gimple_reg (lhs))
- continue;
-
lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs);
- if (symbol_marked_for_renaming (lhs_sym))
- {
- /* If the LHS is a virtual symbol marked for renaming, then
- we don't need to scan the argument list. Since virtual
- operands are in FUD-chain form, all the arguments of this
- PHI must be the same symbol as the LHS. So, we just need
- to mark this site as both an interesting use and an
- interesting def for the symbol. */
- mark_use_interesting (lhs_sym, phi, bb, blocks, insert_phi_p);
- mark_def_interesting (lhs_sym, phi, bb, blocks, insert_phi_p);
- }
- else if (need_to_replace_names_p)
+ if (!symbol_marked_for_renaming (lhs_sym))
+ continue;
+ mark_def_interesting (lhs_sym, phi, bb, insert_phi_p);
+
+ /* Mark the uses in phi nodes as interesting. It would be more correct
+ to process the arguments of the phi nodes of the successor edges of
+ BB at the end of prepare_block_for_update, however, that turns out
+ to be significantly more expensive. Doing it here is conservatively
+ correct -- it may only cause us to believe a value to be live in a
+ block that also contains its definition, and thus insert a few more
+ phi nodes for it. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
{
- /* If the LHS is in OLD_SSA_NAMES or NEW_SSA_NAMES, this is
- a definition site for it. */
- if (is_old_name (lhs) || is_new_name (lhs))
- mark_def_interesting (lhs, phi, bb, blocks, insert_phi_p);
-
- prepare_phi_args_for_update (phi, bb, blocks, insert_phi_p);
+ mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p);
}
}
stmt = bsi_stmt (si);
- REWRITE_THIS_STMT (stmt) = 0;
- REGISTER_DEFS_IN_THIS_STMT (stmt) = 0;
-
- /* Note, even if NEED_TO_REPLACE_NAMES_P is false, we need to
- scan real uses and defs, as we may be renaming a GIMPLE
- register for the first time. */
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_USE)
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES)
{
tree use = USE_FROM_PTR (use_p);
tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use);
- if (symbol_marked_for_renaming (sym) || is_old_name (use))
- mark_use_interesting (use, stmt, bb, blocks, insert_phi_p);
- }
-
- FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_DEF)
- {
- tree def = DEF_FROM_PTR (def_p);
- tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def);
-
- if (symbol_marked_for_renaming (sym)
- || is_new_name (def)
- || is_old_name (def))
- mark_def_interesting (def, stmt, bb, blocks, insert_phi_p);
+ if (symbol_marked_for_renaming (sym))
+ mark_use_interesting (sym, stmt, bb, insert_phi_p);
}
- /* If we don't need to update virtual operands, continue to the
- next statement. */
- if (!need_to_update_vops_p)
- continue;
-
- /* For every interesting N_i = V_MAY_DEF <N_j> and
- N_i = V_MUST_DEF <N_j>, mark the statement as interesting.
- Notice that N_j may in fact be a naked symbol (if this
- statement is the result of basic block duplication). The
- rename process will later fill in the appropriate reaching
- definition for the symbol. */
- FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_VIRTUAL_DEFS)
+ FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_ALL_DEFS)
{
tree def = DEF_FROM_PTR (def_p);
tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def);
-
- if (symbol_marked_for_renaming (sym))
- {
- mark_use_interesting (sym, stmt, bb, blocks, insert_phi_p);
- mark_def_interesting (sym, stmt, bb, blocks, insert_phi_p);
- }
- }
-
- /* Similarly, for V_USE <N_i>. */
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_VUSE)
- {
- tree use = USE_FROM_PTR (use_p);
- tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use);
-
if (symbol_marked_for_renaming (sym))
- mark_use_interesting (sym, stmt, bb, blocks, insert_phi_p);
+ mark_def_interesting (sym, stmt, bb, insert_phi_p);
}
}
/* Now visit all the blocks dominated by BB. */
- if (visit_dom_p)
- for (son = first_dom_son (CDI_DOMINATORS, bb);
- son;
- son = next_dom_son (CDI_DOMINATORS, son))
- prepare_block_for_update (son, insert_phi_p, blocks, true);
+ for (son = first_dom_son (CDI_DOMINATORS, bb);
+ son;
+ son = next_dom_son (CDI_DOMINATORS, son))
+ prepare_block_for_update (son, insert_phi_p);
}
-/* Helper for prepare_def_sites. Mark the definition site for NAME as
- interesting. BLOCKS and INSERT_PHI_P are as in prepare_def_sites. */
+/* Helper for prepare_names_to_update. Mark all the use sites for
+ NAME as interesting. BLOCKS and INSERT_PHI_P are as in
+ prepare_names_to_update. */
static void
-prepare_def_site_for (tree name, bitmap blocks, bool insert_phi_p)
+prepare_use_sites_for (tree name, bool insert_phi_p)
{
- tree stmt;
- basic_block bb;
-
- gcc_assert (name && is_gimple_reg (name));
- gcc_assert (names_to_release == NULL
- || !bitmap_bit_p (names_to_release, SSA_NAME_VERSION (name)));
+ use_operand_p use_p;
+ imm_use_iterator iter;
+
+ FOR_EACH_IMM_USE_FAST (use_p, iter, name)
+ {
+ tree stmt = USE_STMT (use_p);
+ basic_block bb = bb_for_stmt (stmt);
+
+ if (TREE_CODE (stmt) == PHI_NODE)
+ {
+ int ix = PHI_ARG_INDEX_FROM_USE (use_p);
+ edge e = PHI_ARG_EDGE (stmt, ix);
+ mark_use_interesting (name, stmt, e->src, insert_phi_p);
+ }
+ else
+ {
+ /* For regular statements, mark this as an interesting use
+ for NAME. */
+ mark_use_interesting (name, stmt, bb, insert_phi_p);
+ }
+ }
+}
+
+
+/* Helper for prepare_names_to_update. Mark the definition site for
+ NAME as interesting. BLOCKS and INSERT_PHI_P are as in
+ prepare_names_to_update. */
+
+static void
+prepare_def_site_for (tree name, bool insert_phi_p)
+{
+ tree stmt;
+ basic_block bb;
+
+ gcc_assert (names_to_release == NULL
+ || !bitmap_bit_p (names_to_release, SSA_NAME_VERSION (name)));
stmt = SSA_NAME_DEF_STMT (name);
bb = bb_for_stmt (stmt);
if (bb)
{
gcc_assert (bb->index < last_basic_block);
- mark_def_interesting (name, stmt, bb, blocks, insert_phi_p);
+ mark_block_for_update (bb);
+ mark_def_interesting (name, stmt, bb, insert_phi_p);
}
}
-/* Mark definition sites of names in NEW_SSA_NAMES and OLD_SSA_NAMES.
- Add each definition block to BLOCKS. INSERT_PHI_P is true if the
- caller wants to insert PHI nodes for newly created names. */
+/* Mark definition and use sites of names in NEW_SSA_NAMES and
+ OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert
+ PHI nodes for newly created names. */
static void
-prepare_def_sites (bitmap blocks, bool insert_phi_p)
+prepare_names_to_update (bool insert_phi_p)
{
- unsigned i;
+ unsigned i = 0;
bitmap_iterator bi;
+ sbitmap_iterator sbi;
/* If a name N from NEW_SSA_NAMES is also marked to be released,
remove it from NEW_SSA_NAMES so that we don't try to visit its
EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi)
RESET_BIT (new_ssa_names, i);
+ /* First process names in NEW_SSA_NAMES. Otherwise, uses of old
+ names may be considered to be live-in on blocks that contain
+ definitions for their replacements. */
+ EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi)
+ prepare_def_site_for (ssa_name (i), insert_phi_p);
+
/* If an old name is in NAMES_TO_RELEASE, we cannot remove it from
OLD_SSA_NAMES, but we have to ignore its definition site. */
- EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i,
- if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i))
- prepare_def_site_for (ssa_name (i), blocks, insert_phi_p));
-
- EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i,
- prepare_def_site_for (ssa_name (i), blocks, insert_phi_p));
+ EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi)
+ {
+ if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i))
+ prepare_def_site_for (ssa_name (i), insert_phi_p);
+ prepare_use_sites_for (ssa_name (i), insert_phi_p);
+ }
}
}
-/* Dump the SSA name replacement table to FILE. */
+/* Dump SSA update information to FILE. */
void
-dump_repl_tbl (FILE *file)
+dump_update_ssa (FILE *file)
{
- unsigned i;
+ unsigned i = 0;
bitmap_iterator bi;
if (!need_ssa_update_p ())
if (new_ssa_names && sbitmap_first_set_bit (new_ssa_names) >= 0)
{
+ sbitmap_iterator sbi;
+
fprintf (file, "\nSSA replacement table\n");
fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces "
"O_1, ..., O_j\n\n");
- EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i,
- dump_names_replaced_by (file, ssa_name (i)));
+ EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi)
+ dump_names_replaced_by (file, ssa_name (i));
+
+ fprintf (file, "\n");
+ fprintf (file, "Number of virtual NEW -> OLD mappings: %7u\n",
+ update_ssa_stats.num_virtual_mappings);
+ fprintf (file, "Number of real NEW -> OLD mappings: %7u\n",
+ update_ssa_stats.num_total_mappings
+ - update_ssa_stats.num_virtual_mappings);
+ fprintf (file, "Number of total NEW -> OLD mappings: %7u\n",
+ update_ssa_stats.num_total_mappings);
+
+ fprintf (file, "\nNumber of virtual symbols: %u\n",
+ update_ssa_stats.num_virtual_symbols);
}
if (syms_to_rename && !bitmap_empty_p (syms_to_rename))
{
fprintf (file, "\n\nSymbols to be put in SSA form\n\n");
- EXECUTE_IF_SET_IN_BITMAP (syms_to_rename, 0, i, bi)
- {
- print_generic_expr (file, referenced_var (i), 0);
- fprintf (file, " ");
- }
- }
-
- if (old_virtual_ssa_names && !bitmap_empty_p (old_virtual_ssa_names))
- {
- fprintf (file, "\n\nVirtual SSA names to be updated\n\n");
- EXECUTE_IF_SET_IN_BITMAP (old_virtual_ssa_names, 0, i, bi)
- {
- print_generic_expr (file, ssa_name (i), 0);
- fprintf (file, " ");
- }
+ dump_decl_set (file, syms_to_rename);
}
if (names_to_release && !bitmap_empty_p (names_to_release))
}
-/* Dump the SSA name replacement table to stderr. */
+/* Dump SSA update information to stderr. */
void
-debug_repl_tbl (void)
+debug_update_ssa (void)
{
- dump_repl_tbl (stderr);
+ dump_update_ssa (stderr);
}
static void
init_update_ssa (void)
{
- /* Reserve 1/3 more than the current number of names. The calls to
+ /* Reserve more space than the current number of names. The calls to
add_new_name_mapping are typically done after creating new SSA
names, so we'll need to reallocate these arrays. */
old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR);
repl_tbl = htab_create (20, repl_map_hash, repl_map_eq, repl_map_free);
need_to_initialize_update_ssa_p = false;
need_to_update_vops_p = false;
- need_to_replace_names_p = false;
syms_to_rename = BITMAP_ALLOC (NULL);
- old_virtual_ssa_names = BITMAP_ALLOC (NULL);
+ regs_to_rename = BITMAP_ALLOC (NULL);
+ mem_syms_to_rename = BITMAP_ALLOC (NULL);
names_to_release = NULL;
+ memset (&update_ssa_stats, 0, sizeof (update_ssa_stats));
+ update_ssa_stats.virtual_symbols = BITMAP_ALLOC (NULL);
}
/* Deallocate data structures used for incremental SSA updates. */
-static void
+void
delete_update_ssa (void)
{
unsigned i;
need_to_initialize_update_ssa_p = true;
need_to_update_vops_p = false;
- need_to_replace_names_p = false;
BITMAP_FREE (syms_to_rename);
- BITMAP_FREE (old_virtual_ssa_names);
+ BITMAP_FREE (regs_to_rename);
+ BITMAP_FREE (mem_syms_to_rename);
+ BITMAP_FREE (update_ssa_stats.virtual_symbols);
if (names_to_release)
{
BITMAP_FREE (names_to_release);
}
- for (i = 1; i < num_ssa_names; i++)
- {
- tree n = ssa_name (i);
+ clear_ssa_name_info ();
- if (n)
- {
- free (SSA_NAME_AUX (n));
- SSA_NAME_AUX (n) = NULL;
- }
- }
+ fini_ssa_renamer ();
+
+ if (blocks_with_phis_to_rewrite)
+ EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi)
+ {
+ tree_vec phis = VEC_index (tree_vec, phis_to_rewrite, i);
- /* Unmark all the names we may have protected from being released in
- insert_updated_phi_nodes_for. */
- unmark_all_for_rewrite ();
+ VEC_free (tree, heap, phis);
+ VEC_replace (tree_vec, phis_to_rewrite, i, NULL);
+ }
+
+ BITMAP_FREE (blocks_with_phis_to_rewrite);
+ BITMAP_FREE (blocks_to_update);
}
if (need_to_initialize_update_ssa_p)
init_update_ssa ();
- bitmap_set_bit (syms_to_rename, var_ann (sym)->uid);
+ bitmap_set_bit (syms_to_rename, DECL_UID (sym));
if (!is_gimple_reg (sym))
- need_to_update_vops_p = true;
+ {
+ need_to_update_vops_p = true;
+ if (memory_partition (sym))
+ bitmap_set_bit (syms_to_rename, DECL_UID (memory_partition (sym)));
+ }
}
bitmap_iterator bi;
unsigned i;
+ if (set == NULL || bitmap_empty_p (set))
+ return;
+
if (need_to_initialize_update_ssa_p)
init_update_ssa ();
- bitmap_ior_into (syms_to_rename, set);
-
EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
- if (!is_gimple_reg (referenced_var (i)))
- {
- need_to_update_vops_p = true;
- break;
- }
+ mark_sym_for_renaming (referenced_var (i));
}
return syms_to_rename || old_ssa_names || new_ssa_names;
}
+/* Return true if SSA name mappings have been registered for SSA updating. */
+
+bool
+name_mappings_registered_p (void)
+{
+ return repl_tbl && htab_elements (repl_tbl) > 0;
+}
/* Return true if name N has been registered in the replacement table. */
bitmap
ssa_names_to_replace (void)
{
- unsigned i;
+ unsigned i = 0;
bitmap ret;
+ sbitmap_iterator sbi;
ret = BITMAP_ALLOC (NULL);
- EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i,
- bitmap_set_bit (ret, i));
-
- bitmap_ior_into (ret, old_virtual_ssa_names);
+ EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi)
+ bitmap_set_bit (ret, i);
return ret;
}
- If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI
nodes inside the region affected by the block that defines VAR
and the blocks that define all its replacements. All these
- definition blocks have been gathered by prepare_block_for_update
- and they are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS.
+ definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS.
First, we compute the entry point to the region (ENTRY). This is
given by the nearest common dominator to all the definition
return;
/* Compute the initial iterated dominance frontier. */
- idf = find_idf (db->def_blocks, dfs);
+ idf = compute_idf (db->def_blocks, dfs);
pruned_idf = BITMAP_ALLOC (NULL);
if (TREE_CODE (var) == SSA_NAME)
common dominator of all the definition blocks. */
entry = nearest_common_dominator_for_set (CDI_DOMINATORS,
db->def_blocks);
-
if (entry != ENTRY_BLOCK_PTR)
EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi)
if (BASIC_BLOCK (i) != entry
for the first time, so we need to compute the full IDF for
it. */
bitmap_copy (pruned_idf, idf);
-
- /* There may already be PHI nodes for VAR in the flowgraph.
- Some of them are no longer necessary. PRUNED_IDF is
- the set of blocks that need PHI nodes for VAR and
- DB.PHI_BLOCKS is the set of blocks that already contain a PHI
- node for VAR. Therefore, the set DB.PHI_BLOCKS - PRUNED_IDF
- gives us the set of blocks that contain PHI nodes which are
- no longer needed. */
- if (!bitmap_empty_p (db->phi_blocks) && !bitmap_empty_p (pruned_idf))
- EXECUTE_IF_AND_COMPL_IN_BITMAP (db->phi_blocks, pruned_idf, 0, i, bi)
- {
- tree phi, prev;
- unsigned ver;
-
- phi = find_phi_node_for (BASIC_BLOCK (i), var, &prev);
-
- /* Protect the name on PHI's LHS from being released into
- the SSA name free list. Since we have still not
- updated the SSA form of the program, there may be
- instances of PHI's LHS in the IL. */
- ver = SSA_NAME_VERSION (PHI_RESULT (phi));
- mark_for_rewrite (PHI_RESULT (phi));
- release_ssa_name_after_update_ssa (PHI_RESULT (phi));
- remove_phi_node (phi, prev);
- }
}
if (!bitmap_empty_p (pruned_idf))
are included in the region to be updated. The feeding blocks
are important to guarantee that the PHI arguments are renamed
properly. */
+
+ /* FIXME, this is not needed if we are updating symbols. We are
+ already starting at the ENTRY block anyway. */
bitmap_ior_into (blocks, pruned_idf);
EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi)
{
}
+/* Heuristic to determine whether SSA name mappings for virtual names
+ should be discarded and their symbols rewritten from scratch. When
+ there is a large number of mappings for virtual names, the
+ insertion of PHI nodes for the old names in the mappings takes
+ considerable more time than if we inserted PHI nodes for the
+ symbols instead.
+
+ Currently the heuristic takes these stats into account:
+
+ - Number of mappings for virtual SSA names.
+ - Number of distinct virtual symbols involved in those mappings.
+
+ If the number of virtual mappings is much larger than the number of
+ virtual symbols, then it will be faster to compute PHI insertion
+ spots for the symbols. Even if this involves traversing the whole
+ CFG, which is what happens when symbols are renamed from scratch. */
+
+static bool
+switch_virtuals_to_full_rewrite_p (void)
+{
+ if (update_ssa_stats.num_virtual_mappings < (unsigned) MIN_VIRTUAL_MAPPINGS)
+ return false;
+
+ if (update_ssa_stats.num_virtual_mappings
+ > (unsigned) VIRTUAL_MAPPINGS_TO_SYMS_RATIO
+ * update_ssa_stats.num_virtual_symbols)
+ return true;
+
+ return false;
+}
+
+
+/* Remove every virtual mapping and mark all the affected virtual
+ symbols for renaming. */
+
+static void
+switch_virtuals_to_full_rewrite (void)
+{
+ unsigned i = 0;
+ sbitmap_iterator sbi;
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "\nEnabled virtual name mapping heuristic.\n");
+ fprintf (dump_file, "\tNumber of virtual mappings: %7u\n",
+ update_ssa_stats.num_virtual_mappings);
+ fprintf (dump_file, "\tNumber of unique virtual symbols: %7u\n",
+ update_ssa_stats.num_virtual_symbols);
+ fprintf (dump_file, "Updating FUD-chains from top of CFG will be "
+ "faster than processing\nthe name mappings.\n\n");
+ }
+
+ /* Remove all virtual names from NEW_SSA_NAMES and OLD_SSA_NAMES.
+ Note that it is not really necessary to remove the mappings from
+ REPL_TBL, that would only waste time. */
+ EXECUTE_IF_SET_IN_SBITMAP (new_ssa_names, 0, i, sbi)
+ if (!is_gimple_reg (ssa_name (i)))
+ RESET_BIT (new_ssa_names, i);
+
+ EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi)
+ if (!is_gimple_reg (ssa_name (i)))
+ RESET_BIT (old_ssa_names, i);
+
+ mark_set_for_renaming (update_ssa_stats.virtual_symbols);
+}
+
+
/* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of
existing SSA names (OLD_SSA_NAMES), update the SSA form so that:
void
update_ssa (unsigned update_flags)
{
- bitmap *dfs, blocks;
basic_block bb, start_bb;
bitmap_iterator bi;
- unsigned i;
+ unsigned i = 0;
sbitmap tmp;
bool insert_phi_p;
+ sbitmap_iterator sbi;
if (!need_ssa_update_p ())
return;
timevar_push (TV_TREE_SSA_INCREMENTAL);
+ blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL);
+ if (!phis_to_rewrite)
+ phis_to_rewrite = VEC_alloc (tree_vec, heap, last_basic_block);
+ blocks_to_update = BITMAP_ALLOC (NULL);
+
/* Ensure that the dominance information is up-to-date. */
calculate_dominance_info (CDI_DOMINATORS);
|| update_flags == TODO_update_ssa_only_virtuals);
/* If we only need to update virtuals, remove all the mappings for
- real names before proceeding. */
+ real names before proceeding. The caller is responsible for
+ having dealt with the name mappings before calling update_ssa. */
if (update_flags == TODO_update_ssa_only_virtuals)
{
sbitmap_zero (old_ssa_names);
sbitmap_zero (new_ssa_names);
htab_empty (repl_tbl);
- need_to_replace_names_p = false;
}
- if (update_flags == TODO_update_ssa
- || update_flags == TODO_update_ssa_full_phi
- || update_flags == TODO_update_ssa_only_virtuals)
- insert_phi_p = true;
- else
- insert_phi_p = false;
+ insert_phi_p = (update_flags != TODO_update_ssa_no_phi);
if (insert_phi_p)
{
- /* If the caller requested PHI nodes to be added, compute
- dominance frontiers and initialize live-in information data
- structures (DEF_BLOCKS). */
- dfs = (bitmap *) xmalloc (last_basic_block * sizeof (bitmap *));
- FOR_EACH_BB (bb)
- dfs[bb->index] = BITMAP_ALLOC (NULL);
- compute_dominance_frontiers (dfs);
+ /* If the caller requested PHI nodes to be added, initialize
+ live-in information data structures (DEF_BLOCKS). */
/* For each SSA name N, the DEF_BLOCKS table describes where the
name is defined, which blocks have PHI nodes for N, and which
}
else
{
- dfs = NULL;
def_blocks = NULL;
}
- blocks = BITMAP_ALLOC (NULL);
+ /* Heuristic to avoid massive slow downs when the replacement
+ mappings include lots of virtual names. */
+ if (insert_phi_p && switch_virtuals_to_full_rewrite_p ())
+ switch_virtuals_to_full_rewrite ();
- /* Determine the CFG region that we are going to update. First add
- all the blocks that define each of the names in NEW_SSA_NAMES
- and OLD_SSA_NAMES. */
- prepare_def_sites (blocks, insert_phi_p);
+ /* If there are symbols to rename, identify those symbols that are
+ GIMPLE registers into the set REGS_TO_RENAME and those that are
+ memory symbols into the set MEM_SYMS_TO_RENAME. */
+ if (!bitmap_empty_p (syms_to_rename))
+ {
+ unsigned i;
+ bitmap_iterator bi;
+
+ EXECUTE_IF_SET_IN_BITMAP (syms_to_rename, 0, i, bi)
+ {
+ tree sym = referenced_var (i);
+ if (is_gimple_reg (sym))
+ bitmap_set_bit (regs_to_rename, i);
+ else
+ {
+ /* Memory partitioning information may have been
+ computed after the symbol was marked for renaming,
+ if SYM is inside a partition also mark the partition
+ for renaming. */
+ tree mpt = memory_partition (sym);
+ if (mpt)
+ bitmap_set_bit (syms_to_rename, DECL_UID (mpt));
+ }
+ }
+
+ /* Memory symbols are those not in REGS_TO_RENAME. */
+ bitmap_and_compl (mem_syms_to_rename, syms_to_rename, regs_to_rename);
+ }
- /* Next, determine the nearest common dominator START_BB for all the
- blocks in the region. */
- if (!bitmap_empty_p (syms_to_rename) || bitmap_empty_p (blocks))
+ /* If there are names defined in the replacement table, prepare
+ definition and use sites for all the names in NEW_SSA_NAMES and
+ OLD_SSA_NAMES. */
+ if (sbitmap_first_set_bit (new_ssa_names) >= 0)
{
- /* If the region to update is seemingly empty, or if we have to
- rename some symbols from scratch, we need to start the
- process at the root of the CFG.
+ prepare_names_to_update (insert_phi_p);
- FIXME, it should be possible to determine the nearest block
- that had a definition for each of the symbols that are marked
- for updating. For now this seems more work than it's worth. */
+ /* If all the names in NEW_SSA_NAMES had been marked for
+ removal, and there are no symbols to rename, then there's
+ nothing else to do. */
+ if (sbitmap_first_set_bit (new_ssa_names) < 0
+ && bitmap_empty_p (syms_to_rename))
+ goto done;
+ }
+
+ /* Next, determine the block at which to start the renaming process. */
+ if (!bitmap_empty_p (syms_to_rename))
+ {
+ /* If we have to rename some symbols from scratch, we need to
+ start the process at the root of the CFG. FIXME, it should
+ be possible to determine the nearest block that had a
+ definition for each of the symbols that are marked for
+ updating. For now this seems more work than it's worth. */
start_bb = ENTRY_BLOCK_PTR;
+
+ /* Traverse the CFG looking for existing definitions and uses of
+ symbols in SYMS_TO_RENAME. Mark interesting blocks and
+ statements and set local live-in information for the PHI
+ placement heuristics. */
+ prepare_block_for_update (start_bb, insert_phi_p);
}
else
- start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, blocks);
-
- /* Traverse all the blocks dominated by START_BB. Mark interesting
- blocks and statements and set local live-in information for the
- PHI placement heuristics. */
- prepare_block_for_update (start_bb, insert_phi_p, blocks, true);
-
- /* If are going to insert PHI nodes, blocks in the dominance
- frontier of START_BB may be affected. Note that we don't need to
- visit the dominator children of blocks in the dominance frontier
- of START_BB. None of the changes inside this region can affect
- blocks on the outside. */
- if (insert_phi_p && start_bb->index >= 0)
- EXECUTE_IF_SET_IN_BITMAP (dfs[start_bb->index], 0, i, bi)
- prepare_block_for_update (BASIC_BLOCK (i), insert_phi_p,
- blocks, false);
+ {
+ /* Otherwise, the entry block to the region is the nearest
+ common dominator for the blocks in BLOCKS. */
+ start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS,
+ blocks_to_update);
+ }
/* If requested, insert PHI nodes at the iterated dominance frontier
- of every block making new definitions for names in OLD_SSA_NAMES
+ of every block, creating new definitions for names in OLD_SSA_NAMES
and for symbols in SYMS_TO_RENAME. */
if (insert_phi_p)
{
+ bitmap *dfs;
+
+ /* If the caller requested PHI nodes to be added, compute
+ dominance frontiers. */
+ dfs = XNEWVEC (bitmap, last_basic_block);
+ FOR_EACH_BB (bb)
+ dfs[bb->index] = BITMAP_ALLOC (NULL);
+ compute_dominance_frontiers (dfs);
+
if (sbitmap_first_set_bit (old_ssa_names) >= 0)
{
- /* insert_update_phi_nodes_for will call
- add_new_name_mapping when inserting new PHI nodes, so the
- set OLD_SSA_NAMES will grow while we are traversing it
- (but it will not gain any new members). Copy
- OLD_SSA_NAMES to a temporary for traversal. */
+ sbitmap_iterator sbi;
+
+ /* insert_update_phi_nodes_for will call add_new_name_mapping
+ when inserting new PHI nodes, so the set OLD_SSA_NAMES
+ will grow while we are traversing it (but it will not
+ gain any new members). Copy OLD_SSA_NAMES to a temporary
+ for traversal. */
sbitmap tmp = sbitmap_alloc (old_ssa_names->n_bits);
sbitmap_copy (tmp, old_ssa_names);
- EXECUTE_IF_SET_IN_SBITMAP (tmp, 0, i,
- insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks,
- update_flags));
+ EXECUTE_IF_SET_IN_SBITMAP (tmp, 0, i, sbi)
+ insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update,
+ update_flags);
sbitmap_free (tmp);
}
EXECUTE_IF_SET_IN_BITMAP (syms_to_rename, 0, i, bi)
- insert_updated_phi_nodes_for (referenced_var (i), dfs, blocks,
+ insert_updated_phi_nodes_for (referenced_var (i), dfs, blocks_to_update,
update_flags);
+ FOR_EACH_BB (bb)
+ BITMAP_FREE (dfs[bb->index]);
+ free (dfs);
+
/* Insertion of PHI nodes may have added blocks to the region.
We need to re-compute START_BB to include the newly added
blocks. */
if (start_bb != ENTRY_BLOCK_PTR)
- start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, blocks);
+ start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS,
+ blocks_to_update);
}
/* Reset the current definition for name and symbol before renaming
the sub-graph. */
- if (update_flags == TODO_update_ssa_full_phi)
- {
- /* If we are not prunning the IDF for new PHI nodes, set the
- current name of every GIMPLE register to NULL. This way, PHI
- arguments coming from edges with uninitialized values will be
- renamed to use the symbol's default definition. */
- EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i,
- set_current_def (ssa_name (i), NULL_TREE));
- }
- else
- {
- /* Otherwise, set each old name to be its current reaching
- definition. */
- EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i,
- set_current_def (ssa_name (i), NULL_TREE));
- }
+ EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi)
+ set_current_def (ssa_name (i), NULL_TREE);
EXECUTE_IF_SET_IN_BITMAP (syms_to_rename, 0, i, bi)
set_current_def (referenced_var (i), NULL_TREE);
/* Now start the renaming process at START_BB. */
tmp = sbitmap_alloc (last_basic_block);
sbitmap_zero (tmp);
- EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
+ EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi)
SET_BIT (tmp, i);
rewrite_blocks (start_bb, REWRITE_UPDATE, tmp);
int c;
unsigned i;
- dump_repl_tbl (dump_file);
+ dump_update_ssa (dump_file);
fprintf (dump_file, "Incremental SSA update started at block: %d\n\n",
start_bb->index);
c = 0;
- EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
+ EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi)
c++;
fprintf (dump_file, "Number of blocks in CFG: %d\n", last_basic_block);
fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n\n",
if (dump_flags & TDF_DETAILS)
{
fprintf (dump_file, "Affected blocks: ");
- EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
+ EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi)
fprintf (dump_file, "%u ", i);
fprintf (dump_file, "\n");
}
}
/* Free allocated memory. */
- if (insert_phi_p)
- {
- FOR_EACH_BB (bb)
- BITMAP_FREE (dfs[bb->index]);
- free (dfs);
- }
-
- BITMAP_FREE (blocks);
+done:
delete_update_ssa ();
timevar_pop (TV_TREE_SSA_INCREMENTAL);
}
-
-
-/*---------------------------------------------------------------------------
- Functions to fix a program in invalid SSA form into valid SSA
- form. The main entry point here is rewrite_ssa_into_ssa.
----------------------------------------------------------------------------*/
-
-/* Called after visiting basic block BB. Restore CURRDEFS to its
- original value. */
-
-static void
-ssa_rewrite_finalize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
- basic_block bb ATTRIBUTE_UNUSED)
-{
-
- /* Step 5. Restore the current reaching definition for each variable
- referenced in the block (in reverse order). */
- while (VEC_length (tree_on_heap, block_defs_stack) > 0)
- {
- tree var = VEC_pop (tree_on_heap, block_defs_stack);
- tree saved_def;
-
- if (var == NULL)
- break;
-
- saved_def = VEC_pop (tree_on_heap, block_defs_stack);
- set_current_def (var, saved_def);
- }
-}
-
-
-/* Register DEF (an SSA_NAME) to be a new definition for the original
- ssa name VAR and push VAR's current reaching definition
- into the stack pointed by BLOCK_DEFS_P. */
-
-static void
-ssa_register_new_def (tree var, tree def)
-{
- tree currdef;
-
- /* If this variable is set in a single basic block and all uses are
- dominated by the set(s) in that single basic block, then there is
- nothing to do. TODO we should not be called at all, and just
- keep the original name. */
- if (get_phi_state (var) == NEED_PHI_STATE_NO)
- {
- set_current_def (var, def);
- return;
- }
-
- currdef = get_current_def (var);
-
- /* Push the current reaching definition into *BLOCK_DEFS_P. This stack is
- later used by the dominator tree callbacks to restore the reaching
- definitions for all the variables defined in the block after a recursive
- visit to all its immediately dominated blocks. */
- VEC_safe_push (tree_on_heap, block_defs_stack, currdef);
- VEC_safe_push (tree_on_heap, block_defs_stack, var);
-
- /* Set the current reaching definition for VAR to be DEF. */
- set_current_def (var, def);
-}
-
-
-/* Same as rewrite_stmt, for rewriting ssa names. */
-
-static void
-ssa_rewrite_stmt (struct dom_walk_data *walk_data,
- basic_block bb ATTRIBUTE_UNUSED,
- block_stmt_iterator si)
-{
- stmt_ann_t ann;
- tree stmt, var;
- ssa_op_iter iter;
- use_operand_p use_p;
- def_operand_p def_p;
- sbitmap names_to_rename = walk_data->global_data;
-
- stmt = bsi_stmt (si);
- ann = stmt_ann (stmt);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Renaming statement ");
- print_generic_stmt (dump_file, stmt, TDF_SLIM);
- fprintf (dump_file, "\n");
- }
-
- /* We have just scanned the code for operands. No statement should
- be modified. */
- gcc_assert (!ann->modified);
-
- /* Step 1. Rewrite USES and VUSES in the statement. */
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES | SSA_OP_ALL_KILLS)
- {
- if (TEST_BIT (names_to_rename, SSA_NAME_VERSION (USE_FROM_PTR (use_p))))
- SET_USE (use_p, get_reaching_def (USE_FROM_PTR (use_p)));
- }
-
- /* Step 2. Register the statement's DEF and VDEF operands. */
- FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS)
- {
- var = DEF_FROM_PTR (def_p);
-
- if (!TEST_BIT (names_to_rename, SSA_NAME_VERSION (var)))
- continue;
-
- SET_DEF (def_p, duplicate_ssa_name (var, stmt));
- ssa_register_new_def (var, DEF_FROM_PTR (def_p));
- }
-}
-
-
-/* Ditto, for ssa name rewriting. */
-
-static void
-ssa_rewrite_phi_arguments (struct dom_walk_data *walk_data, basic_block bb)
-{
- edge e;
- sbitmap names_to_rename = walk_data->global_data;
- use_operand_p op;
- edge_iterator ei;
-
- FOR_EACH_EDGE (e, ei, bb->succs)
- {
- tree phi;
-
- if (e->dest == EXIT_BLOCK_PTR)
- continue;
-
- for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
- {
- op = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e);
- if (TREE_CODE (USE_FROM_PTR (op)) != SSA_NAME)
- continue;
-
- if (!TEST_BIT (names_to_rename, SSA_NAME_VERSION (USE_FROM_PTR (op))))
- continue;
-
- SET_USE (op, get_reaching_def (USE_FROM_PTR (op)));
- if (e->flags & EDGE_ABNORMAL)
- SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (op)) = 1;
- }
- }
-}
-
-/* Ditto, for rewriting ssa names. */
-
-static void
-ssa_rewrite_initialize_block (struct dom_walk_data *walk_data, basic_block bb)
-{
- tree phi, new_name;
- sbitmap names_to_rename = walk_data->global_data;
- edge e;
- bool abnormal_phi;
- edge_iterator ei;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index);
-
- /* Mark the unwind point for this block. */
- VEC_safe_push (tree_on_heap, block_defs_stack, NULL_TREE);
-
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (e->flags & EDGE_ABNORMAL)
- break;
- abnormal_phi = (e != NULL);
-
- /* Step 1. Register new definitions for every PHI node in the block.
- Conceptually, all the PHI nodes are executed in parallel and each PHI
- node introduces a new version for the associated variable. */
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
- {
- tree result = PHI_RESULT (phi);
-
- if (TEST_BIT (names_to_rename, SSA_NAME_VERSION (result)))
- {
- new_name = duplicate_ssa_name (result, phi);
- SET_PHI_RESULT (phi, new_name);
-
- if (abnormal_phi)
- SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = 1;
- ssa_register_new_def (result, new_name);
- }
- }
-}
-
-
-/* Same as mark_def_sites, but works over SSA names. */
-
-static void
-ssa_mark_def_sites (struct dom_walk_data *walk_data,
- basic_block bb,
- block_stmt_iterator bsi)
-{
- struct mark_def_sites_global_data *gd = walk_data->global_data;
- bitmap kills = gd->kills;
- size_t uid, def_uid;
- tree stmt, use, def;
- ssa_op_iter iter;
-
- /* Mark all the blocks that have definitions for each variable in the
- names_to_rename bitmap. */
- stmt = bsi_stmt (bsi);
- update_stmt_if_modified (stmt);
-
- /* If a variable is used before being set, then the variable is live
- across a block boundary, so mark it live-on-entry to BB. */
- FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_ALL_USES | SSA_OP_ALL_KILLS)
- {
- uid = SSA_NAME_VERSION (use);
-
- if (TEST_BIT (gd->names_to_rename, uid)
- && !bitmap_bit_p (kills, uid))
- set_livein_block (use, bb);
- }
-
- /* Now process the definition made by this statement. Mark the
- variables in KILLS. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
- {
- def_uid = SSA_NAME_VERSION (def);
-
- if (TEST_BIT (gd->names_to_rename, def_uid))
- {
- set_def_block (def, bb, false);
- bitmap_set_bit (kills, def_uid);
- }
- }
-}
-
-
-/* Block initialization routine for mark_def_sites. Clear the
- KILLS bitmap at the start of each block. */
-
-static void
-ssa_mark_def_sites_initialize_block (struct dom_walk_data *walk_data,
- basic_block bb)
-{
- struct mark_def_sites_global_data *gd = walk_data->global_data;
- bitmap kills = gd->kills;
- tree phi, def;
- unsigned def_uid;
-
- bitmap_clear (kills);
-
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
- {
- def = PHI_RESULT (phi);
- def_uid = SSA_NAME_VERSION (def);
-
- if (!TEST_BIT (gd->names_to_rename, def_uid))
- continue;
-
- set_def_block (def, bb, true);
- bitmap_set_bit (kills, def_uid);
- }
-}
-
-/* Marks ssa names used as arguments of phis at the end of BB. */
-
-static void
-ssa_mark_phi_uses (struct dom_walk_data *walk_data, basic_block bb)
-{
- struct mark_def_sites_global_data *gd = walk_data->global_data;
- bitmap kills = gd->kills;
- edge e;
- tree phi, use;
- unsigned uid;
- edge_iterator ei;
-
- FOR_EACH_EDGE (e, ei, bb->succs)
- {
- if (e->dest == EXIT_BLOCK_PTR)
- continue;
-
- for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
- {
- use = PHI_ARG_DEF_FROM_EDGE (phi, e);
- if (TREE_CODE (use) != SSA_NAME)
- continue;
-
- uid = SSA_NAME_VERSION (use);
-
- if (TEST_BIT (gd->names_to_rename, uid)
- && !bitmap_bit_p (kills, uid))
- set_livein_block (use, bb);
- }
- }
-}
-
-
-/* The marked ssa names may have more than one definition;
- add PHI nodes and rewrite them to fix this. */
-
-void
-rewrite_ssa_into_ssa (void)
-{
- bitmap *dfs;
- basic_block bb;
- struct dom_walk_data walk_data;
- struct mark_def_sites_global_data mark_def_sites_global_data;
- unsigned i;
- sbitmap snames_to_rename;
- bitmap to_rename;
- bitmap_iterator bi;
-
- if (!any_marked_for_rewrite_p ())
- return;
- to_rename = marked_ssa_names ();
-
- timevar_push (TV_TREE_SSA_OTHER);
-
- /* Allocate memory for the DEF_BLOCKS hash table. */
- def_blocks = htab_create (num_ssa_names,
- def_blocks_hash, def_blocks_eq, def_blocks_free);
-
- /* Initialize dominance frontier and immediate dominator bitmaps.
- Also count the number of predecessors for each block. Doing so
- can save significant time during PHI insertion for large graphs. */
- dfs = (bitmap *) xmalloc (last_basic_block * sizeof (bitmap *));
- FOR_EACH_BB (bb)
- dfs[bb->index] = BITMAP_ALLOC (NULL);
-
- /* Ensure that the dominance information is OK. */
- calculate_dominance_info (CDI_DOMINATORS);
-
- /* Compute dominance frontiers. */
- compute_dominance_frontiers (dfs);
-
- /* Setup callbacks for the generic dominator tree walker to find and
- mark definition sites. */
- walk_data.walk_stmts_backward = false;
- walk_data.dom_direction = CDI_DOMINATORS;
- walk_data.interesting_blocks = NULL;
- walk_data.initialize_block_local_data = NULL;
- walk_data.before_dom_children_before_stmts
- = ssa_mark_def_sites_initialize_block;
- walk_data.before_dom_children_walk_stmts = ssa_mark_def_sites;
- walk_data.before_dom_children_after_stmts = ssa_mark_phi_uses;
- walk_data.after_dom_children_before_stmts = NULL;
- walk_data.after_dom_children_walk_stmts = NULL;
- walk_data.after_dom_children_after_stmts = NULL;
-
- snames_to_rename = sbitmap_alloc (num_ssa_names);
- sbitmap_zero (snames_to_rename);
- EXECUTE_IF_SET_IN_BITMAP (to_rename, 0, i, bi)
- {
- SET_BIT (snames_to_rename, i);
- set_current_def (ssa_name (i), NULL_TREE);
- }
-
- mark_def_sites_global_data.kills = BITMAP_ALLOC (NULL);
- mark_def_sites_global_data.names_to_rename = snames_to_rename;
- walk_data.global_data = &mark_def_sites_global_data;
-
- block_defs_stack = VEC_alloc (tree_on_heap, 10);
-
- /* We do not have any local data. */
- walk_data.block_local_data_size = 0;
-
- /* Initialize the dominator walker. */
- init_walk_dominator_tree (&walk_data);
-
- /* Recursively walk the dominator tree. */
- walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
-
- /* Finalize the dominator walker. */
- fini_walk_dominator_tree (&walk_data);
-
- /* We no longer need this bitmap, clear and free it. */
- BITMAP_FREE (mark_def_sites_global_data.kills);
-
- /* Insert PHI nodes at dominance frontiers of definition blocks. */
- insert_phi_nodes (dfs, to_rename);
-
- /* Rewrite all the basic blocks in the program. */
- timevar_push (TV_TREE_SSA_REWRITE_BLOCKS);
-
- /* Setup callbacks for the generic dominator tree walker. */
- walk_data.walk_stmts_backward = false;
- walk_data.dom_direction = CDI_DOMINATORS;
- walk_data.interesting_blocks = NULL;
- walk_data.initialize_block_local_data = NULL;
- walk_data.before_dom_children_before_stmts = ssa_rewrite_initialize_block;
- walk_data.before_dom_children_walk_stmts = ssa_rewrite_stmt;
- walk_data.before_dom_children_after_stmts = ssa_rewrite_phi_arguments;
- walk_data.after_dom_children_before_stmts = NULL;
- walk_data.after_dom_children_walk_stmts = NULL;
- walk_data.after_dom_children_after_stmts = ssa_rewrite_finalize_block;
- walk_data.global_data = snames_to_rename;
- walk_data.block_local_data_size = 0;
-
- /* Initialize the dominator walker. */
- init_walk_dominator_tree (&walk_data);
-
- /* Recursively walk the dominator tree rewriting each statement in
- each basic block. */
- walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
-
- /* Finalize the dominator walker. */
- fini_walk_dominator_tree (&walk_data);
-
- unmark_all_for_rewrite ();
-
- EXECUTE_IF_SET_IN_BITMAP (to_rename, 0, i, bi)
- {
- /* Free SSA_NAME_AUX. We don't have to zero it because
- release_ssa_name will. */
- if (SSA_NAME_AUX (ssa_name (i)))
- free (SSA_NAME_AUX (ssa_name (i)));
-
- release_ssa_name (ssa_name (i));
- }
-
- sbitmap_free (snames_to_rename);
-
- timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS);
-
- /* Debugging dumps. */
- if (dump_file && (dump_flags & TDF_STATS))
- {
- dump_dfa_stats (dump_file);
- dump_tree_ssa_stats (dump_file);
- }
-
- /* Free allocated memory. */
- FOR_EACH_BB (bb)
- BITMAP_FREE (dfs[bb->index]);
- free (dfs);
-
- htab_delete (def_blocks);
-
-#ifdef ENABLE_CHECKING
- for (i = 1; i < num_ssa_names; i++)
- {
- tree name = ssa_name (i);
- if (!name)
- continue;
-
- gcc_assert (SSA_NAME_AUX (name) == NULL);
- }
-#endif
-
- BITMAP_FREE (to_rename);
-
- VEC_free (tree_on_heap, block_defs_stack);
- block_defs_stack = NULL;
- timevar_pop (TV_TREE_SSA_OTHER);
-}
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