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Diffstat (limited to 'gcc-4.2.1-5666.3/gcc/tree-into-ssa.c')
| -rw-r--r-- | gcc-4.2.1-5666.3/gcc/tree-into-ssa.c | 3157 |
1 files changed, 0 insertions, 3157 deletions
diff --git a/gcc-4.2.1-5666.3/gcc/tree-into-ssa.c b/gcc-4.2.1-5666.3/gcc/tree-into-ssa.c deleted file mode 100644 index 14a50b62c..000000000 --- a/gcc-4.2.1-5666.3/gcc/tree-into-ssa.c +++ /dev/null @@ -1,3157 +0,0 @@ -/* Rewrite a program in Normal form into SSA. - Copyright (C) 2001, 2002, 2003, 2004, 2005 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) -any later version. - -GCC is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -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, 51 Franklin Street, Fifth Floor, -Boston, MA 02110-1301, USA. */ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "tm.h" -#include "tree.h" -#include "flags.h" -#include "rtl.h" -#include "tm_p.h" -#include "langhooks.h" -#include "hard-reg-set.h" -#include "basic-block.h" -#include "output.h" -#include "expr.h" -#include "function.h" -#include "diagnostic.h" -#include "bitmap.h" -#include "tree-flow.h" -#include "tree-gimple.h" -#include "tree-inline.h" -#include "varray.h" -#include "timevar.h" -#include "hashtab.h" -#include "tree-dump.h" -#include "tree-pass.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 - Computing Static Single Assignment Form and the Control Dependence - Graph. ACM Transactions on Programming Languages and Systems, - 13(4):451-490, October 1991. */ - -/* True if the code is in ssa form. */ -bool in_ssa_p; - -/* Structure to map a variable VAR to the set of blocks that contain - definitions for VAR. */ -struct def_blocks_d -{ - /* The variable. */ - tree var; - - /* Blocks that contain definitions of VAR. Bit I will be set if the - Ith block contains a definition of VAR. */ - bitmap def_blocks; - - /* Blocks that contain a PHI node for VAR. */ - bitmap phi_blocks; - - /* Blocks where VAR is live-on-entry. Similar semantics as - DEF_BLOCKS. */ - bitmap livein_blocks; -}; - - -/* Each entry in DEF_BLOCKS contains an element of type STRUCT - DEF_BLOCKS_D, mapping a variable VAR to a bitmap describing all the - basic blocks where VAR is defined (assigned a new value). It also - contains a bitmap of all the blocks where VAR is live-on-entry - (i.e., there is a use of VAR in block B without a preceding - definition in B). The live-on-entry information is used when - computing PHI pruning heuristics. */ -static htab_t def_blocks; - -/* Stack of trees used to restore the global currdefs to its original - 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. - - - 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 - associated with the current block. */ -static VEC(tree,heap) *block_defs_stack; - -/* Set of existing SSA names being replaced by update_ssa. */ -static sbitmap old_ssa_names; - -/* Set of new SSA names being added by update_ssa. Note that both - NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of - the operations done on them are presence tests. */ -static sbitmap new_ssa_names; - -/* Symbols whose SSA form needs to be updated or created for the first - time. */ -static bitmap 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 - frequent reallocations but still need to find a reasonable growth - strategy. */ -#define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) - -/* Tuple used to represent replacement mappings. */ -struct repl_map_d -{ - tree name; - bitmap set; -}; - -/* NEW -> OLD_SET replacement table. If we are replacing several - existing SSA names O_1, O_2, ..., O_j with a new name N_i, - then REPL_TBL[N_i] = { O_1, O_2, ..., O_j }. */ -static htab_t repl_tbl; - -/* true if register_new_name_mapping needs to initialize the data - structures needed by update_ssa. */ -static bool need_to_initialize_update_ssa_p = true; - -/* true if update_ssa needs to update virtual operands. */ -static bool need_to_update_vops_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 -{ - /* This bitmap contains the variables which are set before they - are used in a basic block. */ - bitmap kills; - - /* Bitmap of names to rename. */ - sbitmap names_to_rename; - - /* Set of blocks that mark_def_sites deems interesting for the - renamer to process. */ - sbitmap interesting_blocks; -}; - - -/* Information stored for SSA names. */ -struct ssa_name_info -{ - /* The actual definition of the 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; - - /* Age of this record (so that info_for_ssa_name table can be cleared - quicky); 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. - Initially, we need it to rename the whole program into SSA form. - At other times, we may need it to only rename into SSA newly - exposed symbols. Finally, we can also call it to incrementally fix - an already built SSA web. */ -enum rewrite_mode { - /* Convert the whole function into SSA form. */ - REWRITE_ALL, - - /* Incrementally update the SSA web by replacing existing SSA - names with new ones. See update_ssa for details. */ - REWRITE_UPDATE -}; - - -/* Use TREE_VISITED to keep track of which statements we want to - rename. When renaming a subset of the variables, not all - statements will be processed. This is decided in mark_def_sites. */ -#define REWRITE_THIS_STMT(T) TREE_VISITED (T) - -/* Use the unsigned flag to keep track of which statements we want to - visit when marking new definition sites. This is slightly - different than REWRITE_THIS_STMT: it's used by update_ssa to - distinguish statements that need to have both uses and defs - 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 - - -/* 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); -void dump_update_ssa (FILE *); -void debug_update_ssa (void); -void dump_names_replaced_by (FILE *, tree); -void debug_names_replaced_by (tree); - -/* Get the information associated with NAME. */ - -static inline struct ssa_name_info * -get_ssa_name_ann (tree name) -{ - 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 info; -} - -/* Clears info for ssa names. */ - -static void -clear_ssa_name_info (void) -{ - current_info_for_ssa_name_age++; -} - -/* Gets phi_state field for VAR. */ - -static inline enum need_phi_state -get_phi_state (tree var) -{ - if (TREE_CODE (var) == SSA_NAME) - return get_ssa_name_ann (var)->need_phi_state; - else - return var_ann (var)->need_phi_state; -} - - -/* Sets phi_state field for VAR to STATE. */ - -static inline void -set_phi_state (tree var, enum need_phi_state state) -{ - if (TREE_CODE (var) == SSA_NAME) - get_ssa_name_ann (var)->need_phi_state = state; - else - var_ann (var)->need_phi_state = state; -} - - -/* Return the current definition for VAR. */ - -tree -get_current_def (tree var) -{ - if (TREE_CODE (var) == SSA_NAME) - return get_ssa_name_ann (var)->current_def; - else - return var_ann (var)->current_def; -} - - -/* Sets current definition of VAR to DEF. */ - -void -set_current_def (tree var, tree def) -{ - if (TREE_CODE (var) == SSA_NAME) - get_ssa_name_ann (var)->current_def = def; - else - var_ann (var)->current_def = def; -} - - -/* Compute global livein information given the set of blockx 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). - - Note: This routine augments the existing local livein information - to include global livein (i.e., it modifies the underlying bitmap - for LIVEIN). */ - -void -compute_global_livein (bitmap livein, bitmap def_blocks) -{ - basic_block bb, *worklist, *tos; - unsigned i; - bitmap_iterator bi; - - tos = worklist - = (basic_block *) xmalloc (sizeof (basic_block) * (last_basic_block + 1)); - - EXECUTE_IF_SET_IN_BITMAP (livein, 0, i, bi) - { - *tos++ = BASIC_BLOCK (i); - } - - /* Iterate until the worklist is empty. */ - while (tos != worklist) - { - edge e; - edge_iterator ei; - - /* Pull a block off the worklist. */ - bb = *--tos; - - /* For each predecessor block. */ - FOR_EACH_EDGE (e, ei, bb->preds) - { - basic_block pred = e->src; - int pred_index = pred->index; - - /* None of this is necessary for the entry block. */ - if (pred != ENTRY_BLOCK_PTR - && ! bitmap_bit_p (livein, pred_index) - && ! bitmap_bit_p (def_blocks, pred_index)) - { - *tos++ = pred; - bitmap_set_bit (livein, pred_index); - } - } - } - - free (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. */ - -static inline struct def_blocks_d * -get_def_blocks_for (tree var) -{ - struct def_blocks_d db, *db_p; - void **slot; - - db.var = var; - slot = htab_find_slot (def_blocks, (void *) &db, INSERT); - if (*slot == NULL) - { - 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); - db_p->livein_blocks = BITMAP_ALLOC (NULL); - *slot = (void *) db_p; - } - else - db_p = (struct def_blocks_d *) *slot; - - return db_p; -} - - -/* Mark block BB as the definition site for variable VAR. PHI_P is true if - VAR is defined by a PHI node. */ - -static void -set_def_block (tree var, basic_block bb, bool phi_p) -{ - struct def_blocks_d *db_p; - enum need_phi_state state; - - state = get_phi_state (var); - db_p = get_def_blocks_for (var); - - /* Set the bit corresponding to the block where VAR is defined. */ - bitmap_set_bit (db_p->def_blocks, bb->index); - if (phi_p) - bitmap_set_bit (db_p->phi_blocks, bb->index); - - /* Keep track of whether or not we may need to insert PHI nodes. - - If we are in the UNKNOWN state, then this is the first definition - of VAR. Additionally, we have not seen any uses of VAR yet, so - we do not need a PHI node for this variable at this time (i.e., - transition to NEED_PHI_STATE_NO). - - If we are in any other state, then we either have multiple definitions - of this variable occurring in different blocks or we saw a use of the - variable which was not dominated by the block containing the - definition(s). In this case we may need a PHI node, so enter - state NEED_PHI_STATE_MAYBE. */ - if (state == NEED_PHI_STATE_UNKNOWN) - set_phi_state (var, NEED_PHI_STATE_NO); - else - set_phi_state (var, NEED_PHI_STATE_MAYBE); -} - - -/* Mark block BB as having VAR live at the entry to BB. */ - -static void -set_livein_block (tree var, basic_block bb) -{ - struct def_blocks_d *db_p; - enum need_phi_state state = get_phi_state (var); - - db_p = get_def_blocks_for (var); - - /* Set the bit corresponding to the block where VAR is live in. */ - bitmap_set_bit (db_p->livein_blocks, bb->index); - - /* Keep track of whether or not we may need to insert PHI nodes. - - If we reach here in NEED_PHI_STATE_NO, see if this use is dominated - by the single block containing the definition(s) of this variable. If - it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to - NEED_PHI_STATE_MAYBE. */ - if (state == NEED_PHI_STATE_NO) - { - int def_block_index = bitmap_first_set_bit (db_p->def_blocks); - - if (def_block_index == -1 - || ! dominated_by_p (CDI_DOMINATORS, bb, - BASIC_BLOCK (def_block_index))) - set_phi_state (var, NEED_PHI_STATE_MAYBE); - } - else - set_phi_state (var, NEED_PHI_STATE_MAYBE); -} - - -/* Return true if symbol SYM is marked for renaming. */ - -static inline bool -symbol_marked_for_renaming (tree sym) -{ - gcc_assert (DECL_P (sym)); - return bitmap_bit_p (syms_to_rename, DECL_UID (sym)); -} - - -/* Return true if NAME is in OLD_SSA_NAMES. */ - -static inline bool -is_old_name (tree name) -{ - unsigned ver = SSA_NAME_VERSION (name); - return ver < new_ssa_names->n_bits && TEST_BIT (old_ssa_names, ver); -} - - -/* Return true if NAME is in NEW_SSA_NAMES. */ - -static inline bool -is_new_name (tree name) -{ - unsigned ver = SSA_NAME_VERSION (name); - return ver < new_ssa_names->n_bits && TEST_BIT (new_ssa_names, ver); -} - - -/* Hashing and equality functions for REPL_TBL. */ - -static hashval_t -repl_map_hash (const void *p) -{ - return htab_hash_pointer ((const void *)((const struct repl_map_d *)p)->name); -} - -static int -repl_map_eq (const void *p1, const void *p2) -{ - return ((const struct repl_map_d *)p1)->name - == ((const struct repl_map_d *)p2)->name; -} - -static void -repl_map_free (void *p) -{ - BITMAP_FREE (((struct repl_map_d *)p)->set); - free (p); -} - - -/* Return the names replaced by NEW (i.e., REPL_TBL[NEW].SET). */ - -static inline bitmap -names_replaced_by (tree new) -{ - struct repl_map_d m; - void **slot; - - m.name = new; - slot = htab_find_slot (repl_tbl, (void *) &m, NO_INSERT); - - /* If N was not registered in the replacement table, return NULL. */ - if (slot == NULL || *slot == NULL) - return NULL; - - return ((struct repl_map_d *) *slot)->set; -} - - -/* Add OLD to REPL_TBL[NEW].SET. */ - -static inline void -add_to_repl_tbl (tree new, tree old) -{ - struct repl_map_d m, *mp; - void **slot; - - m.name = new; - slot = htab_find_slot (repl_tbl, (void *) &m, INSERT); - if (*slot == NULL) - { - mp = XNEW (struct repl_map_d); - mp->name = new; - mp->set = BITMAP_ALLOC (NULL); - *slot = (void *) mp; - } - else - mp = (struct repl_map_d *) *slot; - - bitmap_set_bit (mp->set, SSA_NAME_VERSION (old)); -} - - -/* Add a new mapping NEW -> OLD REPL_TBL. Every entry N_i in REPL_TBL - represents the set of names O_1 ... O_j replaced by N_i. This is - used by update_ssa and its helpers to introduce new SSA names in an - already formed SSA web. */ - -static void -add_new_name_mapping (tree new, tree old) -{ - timevar_push (TV_TREE_SSA_INCREMENTAL); - - /* 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 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); - } - - /* If this mapping is for virtual names, we will need to update - virtual operands. */ - if (!is_gimple_reg (new)) - { - tree sym; - size_t uid; - - need_to_update_vops_p = true; - - /* 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); - uid = DECL_UID (sym); - update_ssa_stats.num_virtual_mappings++; - if (!bitmap_bit_p (update_ssa_stats.virtual_symbols, uid)) - { - bitmap_set_bit (update_ssa_stats.virtual_symbols, uid); - update_ssa_stats.num_virtual_symbols++; - } - } - - /* Update the REPL_TBL table. */ - add_to_repl_tbl (new, old); - - /* If OLD had already been registered as a new name, then all the - names that OLD replaces should also be replaced by NEW. */ - if (is_new_name (old)) - bitmap_ior_into (names_replaced_by (new), names_replaced_by (old)); - - /* Register NEW and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, - respectively. */ - SET_BIT (new_ssa_names, SSA_NAME_VERSION (new)); - SET_BIT (old_ssa_names, SSA_NAME_VERSION (old)); - - /* Update mapping counter to use in the virtual mapping heuristic. */ - update_ssa_stats.num_total_mappings++; - - timevar_pop (TV_TREE_SSA_INCREMENTAL); -} - - -/* Call back for walk_dominator_tree used to collect definition sites - for every variable in the function. For every statement S in block - BB: - - 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 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, - block_stmt_iterator bsi) -{ - struct mark_def_sites_global_data *gd = - (struct mark_def_sites_global_data *) walk_data->global_data; - bitmap kills = gd->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); - - 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_VMUSTKILL) - { - tree sym = USE_FROM_PTR (use_p); - gcc_assert (DECL_P (sym)); - 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) - { - gcc_assert (DECL_P (def)); - set_def_block (def, bb, false); - bitmap_set_bit (kills, DECL_UID (def)); - REGISTER_DEFS_IN_THIS_STMT (stmt) = 1; - } - - /* If we found the statement interesting then also mark the block BB - as interesting. */ - if (REWRITE_THIS_STMT (stmt) || REGISTER_DEFS_IN_THIS_STMT (stmt)) - 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. */ - -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 *da = a; - const struct dom_dfsnum *db = 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; - } - - 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 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 - { - /* 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); - } - - while (!VEC_empty (int, worklist)) - { - b = VEC_pop (int, worklist); - if (b == ENTRY_BLOCK) - continue; - - /* 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); -} - -/* 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. */ - -static bitmap -find_idf (bitmap def_blocks, bitmap *dfs) -{ - bitmap_iterator bi; - unsigned bb_index; - VEC(int,heap) *work_stack; - bitmap phi_insertion_points; - - work_stack = VEC_alloc (int, heap, 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) - { - /* 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, heap, work_stack, bb_index); - bitmap_set_bit (phi_insertion_points, bb_index); - } - } - - VEC_free (int, heap, work_stack); - - return phi_insertion_points; -} - - -/* 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 - found in DEF_BLOCKS. */ - -static inline struct def_blocks_d * -find_def_blocks_for (tree var) -{ - struct def_blocks_d dm; - dm.var = var; - return (struct def_blocks_d *) htab_find (def_blocks, &dm); -} - - -/* Retrieve or create a default definition for symbol SYM. */ - -static inline tree -get_default_def_for (tree sym) -{ - tree ddef = default_def (sym); - - if (ddef == NULL_TREE) - { - ddef = make_ssa_name (sym, build_empty_stmt ()); - set_default_def (sym, ddef); - } - - return ddef; -} - - -/* 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. - - 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 - for VAR will be present in PHI_INSERTION_POINTS. */ - -static void -insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) -{ - unsigned bb_index; - edge e; - tree phi; - basic_block bb; - bitmap_iterator bi; - struct def_blocks_d *def_map; - - def_map = find_def_blocks_for (var); - gcc_assert (def_map); - - /* Remove the blocks where we already have PHI nodes for VAR. */ - bitmap_and_compl_into (phi_insertion_points, def_map->phi_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_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) - { - bb = BASIC_BLOCK (bb_index); - if (update_p) - mark_block_for_update (bb); - - if (update_p && 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; - - 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 - which name is this PHI node replacing. If VAR is a - symbol marked for renaming, this is not necessary, the - renamer will use the symbol on the LHS to get its - reaching definition. */ - FOR_EACH_EDGE (e, ei, bb->preds) - add_phi_arg (phi, var, e); - } - else - { - tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); - phi = create_phi_node (sym, bb); - } - - /* Mark this PHI node as interesting for update_ssa. */ - REGISTER_DEFS_IN_THIS_STMT (phi) = 1; - 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). */ - -static void -insert_phi_nodes (bitmap *dfs) -{ - referenced_var_iterator rvi; - tree var; - - timevar_push (TV_TREE_INSERT_PHI_NODES); - - FOR_EACH_REFERENCED_VAR (var, rvi) - { - struct def_blocks_d *def_map; - bitmap idf; - - def_map = find_def_blocks_for (var); - if (def_map == NULL) - continue; - - 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); - } - } - - 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 to by BLOCK_DEFS_P. */ - -void -register_new_def (tree def, VEC(tree,heap) **block_defs_p) -{ - tree var = SSA_NAME_VAR (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 - no reason to record anything for this variable in the block local - definition stacks. Doing so just wastes time and memory. - - 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) - { - 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. If there is no current - reaching definition, then just record the underlying _DECL node. */ - VEC_safe_push (tree, heap, *block_defs_p, currdef ? currdef : var); - - /* Set the current reaching definition for VAR to be DEF. */ - set_current_def (var, def); -} - - -/* Perform a depth-first traversal of the dominator tree looking for - variables to rename. BB is the block where to start searching. - Renaming is a five step process: - - 1- Every definition made by PHI nodes at the start of the blocks is - registered as the current definition for the corresponding variable. - - 2- Every statement in BB is rewritten. USE and VUSE operands are - rewritten with their corresponding reaching definition. DEF and - VDEF targets are registered as new definitions. - - 3- All the PHI nodes in successor blocks of BB are visited. The - argument corresponding to BB is replaced with its current reaching - definition. - - 4- Recursively rewrite every dominator child block of BB. - - 5- Restore (in reverse order) the current reaching definition for every - new definition introduced in this block. This is done so that when - we return from the recursive call, all the current reaching - definitions are restored to the names that were valid in the - dominator parent of BB. */ - -/* SSA Rewriting Step 1. Initialization, create a block local stack - of reaching definitions for new SSA names produced in this block - (BLOCK_DEFS). Register new definitions for every PHI node in the - block. */ - -static void -rewrite_initialize_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, - basic_block bb) -{ - tree phi; - - 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, 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 - node introduces a new version for the associated variable. */ - for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) - { - tree result = PHI_RESULT (phi); - register_new_def (result, &block_defs_stack); - } -} - - -/* 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. */ - -static tree -get_reaching_def (tree var) -{ - tree currdef_var, avar; - - /* Lookup the current reaching definition for VAR. */ - currdef_var = 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) - { - avar = DECL_P (var) ? var : SSA_NAME_VAR (var); - currdef_var = get_default_def_for (avar); - set_current_def (var, currdef_var); - } - - /* Return the current reaching definition for VAR, or the default - definition, if we had to create one. */ - return currdef_var; -} - - -/* SSA Rewriting Step 2. Rewrite every variable used in each statement in - the block with its immediate reaching definitions. Update the current - definition of a variable when a new real or virtual definition is found. */ - -static void -rewrite_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, - basic_block bb ATTRIBUTE_UNUSED, - block_stmt_iterator si) -{ - tree stmt; - use_operand_p use_p; - def_operand_p def_p; - ssa_op_iter iter; - - stmt = bsi_stmt (si); - - /* 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; - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Renaming statement "); - print_generic_stmt (dump_file, stmt, TDF_SLIM); - fprintf (dump_file, "\n"); - } - - /* Step 1. Rewrite USES and VUSES 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) - { - 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. */ - if (REGISTER_DEFS_IN_THIS_STMT (stmt)) - FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) - { - 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); - } -} - - -/* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for - PHI nodes. For every PHI node found, add a new argument containing the - current reaching definition for the variable and the edge through which - that definition is reaching the PHI node. */ - -static void -rewrite_add_phi_arguments (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, - basic_block bb) -{ - edge e; - edge_iterator ei; - - FOR_EACH_EDGE (e, ei, bb->succs) - { - tree phi; - - for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi)) - { - tree currdef; - currdef = get_reaching_def (SSA_NAME_VAR (PHI_RESULT (phi))); - add_phi_arg (phi, currdef, e); - } - } -} - - -/* Called after visiting basic block BB. 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, block_defs_stack) > 0) - { - 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) - { - saved_def = tmp; - var = SSA_NAME_VAR (saved_def); - } - else - { - saved_def = NULL; - var = tmp; - } - - set_current_def (var, saved_def); - } -} - - -/* Dump SSA information to FILE. */ - -void -dump_tree_ssa (FILE *file) -{ - basic_block bb; - const char *funcname - = lang_hooks.decl_printable_name (current_function_decl, 2); - - fprintf (file, "SSA information for %s\n\n", funcname); - - FOR_EACH_BB (bb) - { - dump_bb (bb, file, 0); - fputs (" ", file); - print_generic_stmt (file, phi_nodes (bb), dump_flags); - fputs ("\n\n", 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) -{ - fprintf (file, "\nHash table statistics:\n"); - - fprintf (file, " def_blocks: "); - htab_statistics (file, def_blocks); - - fprintf (file, "\n"); -} - - -/* Dump SSA statistics on stderr. */ - -void -debug_tree_ssa_stats (void) -{ - dump_tree_ssa_stats (stderr); -} - - -/* Hashing and equality functions for DEF_BLOCKS. */ - -static hashval_t -def_blocks_hash (const void *p) -{ - return htab_hash_pointer - ((const void *)((const struct def_blocks_d *)p)->var); -} - -static int -def_blocks_eq (const void *p1, const void *p2) -{ - return ((const struct def_blocks_d *)p1)->var - == ((const struct def_blocks_d *)p2)->var; -} - - -/* Free memory allocated by one entry in DEF_BLOCKS. */ - -static void -def_blocks_free (void *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); - free (entry); -} - - -/* Callback for htab_traverse to dump the DEF_BLOCKS hash table. */ - -static int -debug_def_blocks_r (void **slot, void *data ATTRIBUTE_UNUSED) -{ - 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"); - - return 1; -} - - -/* Dump the DEF_BLOCKS hash table on stderr. */ - -void -debug_def_blocks (void) -{ - htab_traverse (def_blocks, debug_def_blocks_r, NULL); -} - - -/* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ - -static inline void -register_new_update_single (tree new_name, tree old_name) -{ - tree currdef = get_current_def (old_name); - - /* 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_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. */ - set_current_def (old_name, new_name); -} - - -/* Register NEW_NAME to be the new reaching definition for all the - names in OLD_NAMES. Used by the incremental SSA update routines to - replace old SSA names with new ones. */ - -static inline void -register_new_update_set (tree new_name, bitmap old_names) -{ - bitmap_iterator bi; - unsigned i; - - EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) - register_new_update_single (new_name, ssa_name (i)); -} - - -/* Initialization of block data structures for the incremental SSA - update pass. Create a block local stack of reaching definitions - for new SSA names produced in this block (BLOCK_DEFS). Register - new definitions for every PHI node in the block. */ - -static void -rewrite_update_init_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, - basic_block bb) -{ - edge e; - edge_iterator ei; - tree phi; - bool is_abnormal_phi; - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "\n\nRegistering new PHI nodes in block #%d\n\n", - bb->index); - - /* Mark the unwind point for this block. */ - 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. */ - is_abnormal_phi = false; - FOR_EACH_EDGE (e, ei, bb->preds) - if (e->flags & EDGE_ABNORMAL) - { - is_abnormal_phi = true; - break; - } - - /* If any of the PHI nodes is a replacement for a name in - OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then - register it as a new definition for its corresponding name. Also - register definitions for names whose underlying symbols are - marked for renaming. */ - - for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) - { - tree lhs, lhs_sym; - - if (!REGISTER_DEFS_IN_THIS_STMT (phi)) - continue; - - lhs = PHI_RESULT (phi); - lhs_sym = SSA_NAME_VAR (lhs); - - if (symbol_marked_for_renaming (lhs_sym)) - 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)) - register_new_update_set (lhs, names_replaced_by (lhs)); - - /* If LHS is an OLD name, register it as a new definition - for itself. */ - if (is_old_name (lhs)) - register_new_update_single (lhs, lhs); - } - - if (is_abnormal_phi) - SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; - } -} - - -/* 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 - unwinding must be done in the opposite order to what is done in - register_new_update_set. */ - -static void -rewrite_update_fini_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, - basic_block bb ATTRIBUTE_UNUSED) -{ - while (VEC_length (tree, block_defs_stack) > 0) - { - tree var = VEC_pop (tree, block_defs_stack); - tree saved_def; - - /* NULL indicates the unwind stop point for this block (see - rewrite_update_init_block). */ - if (var == NULL) - return; - - 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 - definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI - will be registered as a new definition for their corresponding name - in OLD_SSA_NAMES. */ - -static void -rewrite_update_stmt (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, - basic_block bb ATTRIBUTE_UNUSED, - block_stmt_iterator si) -{ - stmt_ann_t ann; - tree stmt; - use_operand_p use_p; - def_operand_p def_p; - ssa_op_iter iter; - - 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 (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Updating SSA information for statement "); - print_generic_stmt (dump_file, stmt, TDF_SLIM); - fprintf (dump_file, "\n"); - } - - /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying - symbol is marked for renaming. */ - if (REWRITE_THIS_STMT (stmt)) - { - FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_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) - maybe_replace_use (use_p); - } - - /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. - Also register definitions for names whose underlying symbol is - marked for renaming. */ - if (REGISTER_DEFS_IN_THIS_STMT (stmt)) - { - FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_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) - maybe_register_def (def_p, stmt); - } -} - - -/* Replace the operand pointed to 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); -} - - -/* Visit all the successor blocks of BB looking for PHI nodes. For - every PHI node found, check if any of its arguments is in - OLD_SSA_NAMES. If so, and if the argument has a current reaching - definition, replace it. */ - -static void -rewrite_update_phi_arguments (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED, - basic_block bb) -{ - edge e; - edge_iterator ei; - unsigned i; - - FOR_EACH_EDGE (e, ei, bb->succs) - { - tree phi; - tree_vec phis; - - 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; - use_operand_p arg_p; - - 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; - - 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))); - } - else - { - tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); - - if (symbol_marked_for_renaming (sym)) - replace_use (arg_p, sym); - else if (is_old_name (arg)) - replace_use (arg_p, arg); - } - - if (e->flags & EDGE_ABNORMAL) - SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; - } - } -} - - -/* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA - form. - - ENTRY indicates the block where to start. Every block dominated by - ENTRY will be rewritten. - - WHAT indicates what actions will be taken by the renamer (see enum - rewrite_mode). - - BLOCKS are the set of interesting blocks for the dominator walker - to process. If this set is NULL, then all the nodes dominated - by ENTRY are walked. Otherwise, blocks dominated by ENTRY that - are not present in BLOCKS are ignored. */ - -static void -rewrite_blocks (basic_block entry, enum rewrite_mode what, sbitmap blocks) -{ - struct dom_walk_data walk_data; - - /* Rewrite all the basic blocks in the program. */ - timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); - - /* Setup callbacks for the generic dominator tree walker. */ - memset (&walk_data, 0, sizeof (walk_data)); - - 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 - walk_data.before_dom_children_before_stmts = rewrite_initialize_block; - - if (what == REWRITE_ALL) - walk_data.before_dom_children_walk_stmts = rewrite_stmt; - else if (what == REWRITE_UPDATE) - walk_data.before_dom_children_walk_stmts = rewrite_update_stmt; - else - gcc_unreachable (); - - if (what == REWRITE_ALL) - walk_data.before_dom_children_after_stmts = rewrite_add_phi_arguments; - else if (what == REWRITE_UPDATE) - walk_data.before_dom_children_after_stmts = rewrite_update_phi_arguments; - else - gcc_unreachable (); - - if (what == REWRITE_ALL) - walk_data.after_dom_children_after_stmts = rewrite_finalize_block; - else if (what == REWRITE_UPDATE) - walk_data.after_dom_children_after_stmts = rewrite_update_fini_block; - else - gcc_unreachable (); - - block_defs_stack = VEC_alloc (tree, heap, 10); - - /* 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); - - /* Finalize the dominator walker. */ - fini_walk_dominator_tree (&walk_data); - - /* Debugging dumps. */ - if (dump_file && (dump_flags & TDF_STATS)) - { - dump_dfa_stats (dump_file); - if (def_blocks) - dump_tree_ssa_stats (dump_file); - } - - if (def_blocks) - { - htab_delete (def_blocks); - def_blocks = NULL; - } - - VEC_free (tree, heap, block_defs_stack); - - timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); -} - - -/* Block initialization routine for mark_def_sites. Clear the - KILLS bitmap at the start of each block. */ - -static void -mark_def_sites_initialize_block (struct dom_walk_data *walk_data, - basic_block bb ATTRIBUTE_UNUSED) -{ - struct mark_def_sites_global_data *gd = - (struct mark_def_sites_global_data *) walk_data->global_data; - bitmap kills = gd->kills; - bitmap_clear (kills); -} - - -/* Mark the definition site blocks for each variable, so that we know - where the variable is actually live. - - INTERESTING_BLOCKS will be filled in with all the blocks that - should be processed by the renamer. It is assumed to be - initialized and zeroed by the caller. */ - -static void -mark_def_site_blocks (sbitmap interesting_blocks) -{ - struct dom_walk_data walk_data; - struct mark_def_sites_global_data mark_def_sites_global_data; - referenced_var_iterator rvi; - tree var; - - /* Allocate memory for the DEF_BLOCKS hash table. */ - 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); - - /* 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.initialize_block_local_data = NULL; - walk_data.before_dom_children_before_stmts = mark_def_sites_initialize_block; - walk_data.before_dom_children_walk_stmts = mark_def_sites; - walk_data.before_dom_children_after_stmts = NULL; - walk_data.after_dom_children_before_stmts = NULL; - walk_data.after_dom_children_walk_stmts = NULL; - walk_data.after_dom_children_after_stmts = NULL; - walk_data.interesting_blocks = NULL; - - /* Notice that this bitmap is indexed using variable UIDs, so it must be - large enough to accommodate all the variables referenced in the - function, not just the ones we are renaming. */ - mark_def_sites_global_data.kills = BITMAP_ALLOC (NULL); - - /* Create the set of interesting blocks that will be filled by - mark_def_sites. */ - mark_def_sites_global_data.interesting_blocks = interesting_blocks; - walk_data.global_data = &mark_def_sites_global_data; - - /* 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); -} - - -/* Main entry point into the SSA builder. The renaming process - proceeds in four main phases: - - 1- Compute dominance frontier and immediate dominators, needed to - insert PHI nodes and rename the function in dominator tree - order. - - 2- Find and mark all the blocks that define variables - (mark_def_site_blocks). - - 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). - - 4- Rename all the blocks (rewrite_blocks) and statements in the program. - - Steps 3 and 4 are done using the dominator tree walker - (walk_dominator_tree). */ - -static unsigned int -rewrite_into_ssa (void) -{ - bitmap *dfs; - basic_block bb; - sbitmap interesting_blocks; - - timevar_push (TV_TREE_SSA_OTHER); - - /* Initialize operand data structures. */ - init_ssa_operands (); - - /* Initialize the set of interesting blocks. The callback - mark_def_sites will add to this set those blocks that the renamer - should process. */ - interesting_blocks = sbitmap_alloc (last_basic_block); - sbitmap_zero (interesting_blocks); - - /* Initialize dominance frontier. */ - dfs = (bitmap *) xmalloc (last_basic_block * sizeof (bitmap)); - FOR_EACH_BB (bb) - dfs[bb->index] = BITMAP_ALLOC (NULL); - - /* 1- Compute dominance frontiers. */ - calculate_dominance_info (CDI_DOMINATORS); - compute_dominance_frontiers (dfs); - - /* 2- Find and mark definition sites. */ - mark_def_site_blocks (interesting_blocks); - - /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ - insert_phi_nodes (dfs); - - /* 4- Rename all the blocks. */ - rewrite_blocks (ENTRY_BLOCK_PTR, REWRITE_ALL, interesting_blocks); - - /* Free allocated memory. */ - FOR_EACH_BB (bb) - BITMAP_FREE (dfs[bb->index]); - free (dfs); - sbitmap_free (interesting_blocks); - - timevar_pop (TV_TREE_SSA_OTHER); - in_ssa_p = true; - return 0; -} - - -struct tree_opt_pass pass_build_ssa = -{ - "ssa", /* name */ - NULL, /* gate */ - rewrite_into_ssa, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - 0, /* tv_id */ - PROP_cfg | PROP_referenced_vars, /* properties_required */ - PROP_ssa, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - TODO_dump_func - | TODO_verify_ssa - | TODO_remove_unused_locals, /* todo_flags_finish */ - 0 /* letter */ -}; - - -/* Mark the definition of VAR at STMT and BB as interesting for the - renamer. BLOCKS is the set of blocks that need updating. */ - -static void -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; - - if (insert_phi_p) - { - bool is_phi_p = TREE_CODE (stmt) == PHI_NODE; - - set_def_block (var, bb, is_phi_p); - - /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition - site for both itself and all the old names replaced by it. */ - if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) - { - bitmap_iterator bi; - unsigned i; - bitmap set = names_replaced_by (var); - if (set) - EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) - set_def_block (ssa_name (i), bb, is_phi_p); - } - } -} - - -/* 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. */ - -static inline void -mark_use_interesting (tree var, tree stmt, basic_block bb, bool insert_phi_p) -{ - 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 - definition because if VAR is one of the names in OLD_SSA_NAMES, - it will have several definitions (itself and all the names that - replace it). */ - if (insert_phi_p) - { - 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); - } -} - - -/* Do a dominator walk starting at BB processing statements that - 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. - - 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. */ - -static void -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 symbols that we are interested in. */ - for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) - { - tree lhs_sym, lhs = PHI_RESULT (phi); - - lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); - - 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) - { - mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); - } - } - - /* Process the statements. */ - for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) - { - tree stmt; - ssa_op_iter i; - use_operand_p use_p; - def_operand_p def_p; - - stmt = bsi_stmt (si); - - FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, 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)) - mark_use_interesting (use, stmt, bb, 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)) - mark_def_interesting (def, stmt, bb, insert_phi_p); - } - - FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, 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)) - { - mark_use_interesting (sym, stmt, bb, insert_phi_p); - mark_def_interesting (sym, stmt, bb, insert_phi_p); - } - } - - 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, insert_phi_p); - } - } - - /* Now visit all the blocks dominated by BB. */ - 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_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_use_sites_for (tree name, bool insert_phi_p) -{ - 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_block_for_update (bb); - mark_def_interesting (name, stmt, bb, insert_phi_p); - } -} - - -/* 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_names_to_update (bool insert_phi_p) -{ - 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 - defining basic block (which most likely doesn't exist). Notice - that we cannot do the same with names in OLD_SSA_NAMES because we - want to replace existing instances. */ - if (names_to_release) - 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, 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 all the names replaced by NAME to FILE. */ - -void -dump_names_replaced_by (FILE *file, tree name) -{ - unsigned i; - bitmap old_set; - bitmap_iterator bi; - - print_generic_expr (file, name, 0); - fprintf (file, " -> { "); - - old_set = names_replaced_by (name); - EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) - { - print_generic_expr (file, ssa_name (i), 0); - fprintf (file, " "); - } - - fprintf (file, "}\n"); -} - - -/* Dump all the names replaced by NAME to stderr. */ - -void -debug_names_replaced_by (tree name) -{ - dump_names_replaced_by (stderr, name); -} - - -/* Dump SSA update information to FILE. */ - -void -dump_update_ssa (FILE *file) -{ - unsigned i = 0; - bitmap_iterator bi; - - if (!need_ssa_update_p ()) - return; - - 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, 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 (names_to_release && !bitmap_empty_p (names_to_release)) - { - fprintf (file, "\n\nSSA names to release after updating the SSA web\n\n"); - EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) - { - print_generic_expr (file, ssa_name (i), 0); - fprintf (file, " "); - } - } - - fprintf (file, "\n\n"); -} - - -/* Dump SSA update information to stderr. */ - -void -debug_update_ssa (void) -{ - dump_update_ssa (stderr); -} - - -/* Initialize data structures used for incremental SSA updates. */ - -static void -init_update_ssa (void) -{ - /* 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); - sbitmap_zero (old_ssa_names); - - new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); - sbitmap_zero (new_ssa_names); - - 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; - 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. */ - -void -delete_update_ssa (void) -{ - unsigned i; - bitmap_iterator bi; - - sbitmap_free (old_ssa_names); - old_ssa_names = NULL; - - sbitmap_free (new_ssa_names); - new_ssa_names = NULL; - - htab_delete (repl_tbl); - repl_tbl = NULL; - - need_to_initialize_update_ssa_p = true; - need_to_update_vops_p = false; - BITMAP_FREE (syms_to_rename); - BITMAP_FREE (update_ssa_stats.virtual_symbols); - - if (names_to_release) - { - EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) - release_ssa_name (ssa_name (i)); - BITMAP_FREE (names_to_release); - } - - clear_ssa_name_info (); -} - - -/* Create a new name for OLD_NAME in statement STMT and replace the - operand pointed to by DEF_P with the newly created name. Return - the new name and register the replacement mapping <NEW, OLD> in - update_ssa's tables. */ - -tree -create_new_def_for (tree old_name, tree stmt, def_operand_p def) -{ - tree new_name = duplicate_ssa_name (old_name, stmt); - - SET_DEF (def, new_name); - - if (TREE_CODE (stmt) == PHI_NODE) - { - edge e; - edge_iterator ei; - basic_block bb = bb_for_stmt (stmt); - - /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ - FOR_EACH_EDGE (e, ei, bb->preds) - if (e->flags & EDGE_ABNORMAL) - { - SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = 1; - break; - } - } - - register_new_name_mapping (new_name, old_name); - - /* For the benefit of passes that will be updating the SSA form on - their own, set the current reaching definition of OLD_NAME to be - NEW_NAME. */ - set_current_def (old_name, new_name); - - return new_name; -} - - -/* Register name NEW to be a replacement for name OLD. This function - must be called for every replacement that should be performed by - update_ssa. */ - -void -register_new_name_mapping (tree new, tree old) -{ - if (need_to_initialize_update_ssa_p) - init_update_ssa (); - - add_new_name_mapping (new, old); -} - - -/* Register symbol SYM to be renamed by update_ssa. */ - -void -mark_sym_for_renaming (tree sym) -{ - if (need_to_initialize_update_ssa_p) - init_update_ssa (); - - bitmap_set_bit (syms_to_rename, DECL_UID (sym)); - - if (!is_gimple_reg (sym)) - need_to_update_vops_p = true; -} - - -/* Register all the symbols in SET to be renamed by update_ssa. */ - -void -mark_set_for_renaming (bitmap set) -{ - bitmap_iterator bi; - unsigned i; - - if (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; - } -} - - -/* Return true if there is any work to be done by update_ssa. */ - -bool -need_ssa_update_p (void) -{ - return syms_to_rename || old_ssa_names || new_ssa_names; -} - - -/* Return true if name N has been registered in the replacement table. */ - -bool -name_registered_for_update_p (tree n) -{ - if (!need_ssa_update_p ()) - return false; - - return is_new_name (n) - || is_old_name (n) - || symbol_marked_for_renaming (SSA_NAME_VAR (n)); -} - - -/* Return the set of all the SSA names marked to be replaced. */ - -bitmap -ssa_names_to_replace (void) -{ - unsigned i = 0; - bitmap ret; - sbitmap_iterator sbi; - - ret = BITMAP_ALLOC (NULL); - EXECUTE_IF_SET_IN_SBITMAP (old_ssa_names, 0, i, sbi) - bitmap_set_bit (ret, i); - - return ret; -} - - -/* Mark NAME to be released after update_ssa has finished. */ - -void -release_ssa_name_after_update_ssa (tree name) -{ - gcc_assert (!need_to_initialize_update_ssa_p); - - if (names_to_release == NULL) - names_to_release = BITMAP_ALLOC (NULL); - - bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); -} - - -/* Insert new PHI nodes to replace VAR. DFS contains dominance - frontier information. BLOCKS is the set of blocks to be updated. - - This is slightly different than the regular PHI insertion - algorithm. The value of UPDATE_FLAGS controls how PHI nodes for - real names (i.e., GIMPLE registers) are inserted: - - - 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 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 - blocks. When computing the iterated dominance frontier (IDF), any - block not strictly dominated by ENTRY is ignored. - - We then call the standard PHI insertion algorithm with the pruned - IDF. - - - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real - names is not pruned. PHI nodes are inserted at every IDF block. */ - -static void -insert_updated_phi_nodes_for (tree var, bitmap *dfs, bitmap blocks, - unsigned update_flags) -{ - basic_block entry; - struct def_blocks_d *db; - bitmap idf, pruned_idf; - bitmap_iterator bi; - unsigned i; - -#if defined ENABLE_CHECKING - if (TREE_CODE (var) == SSA_NAME) - gcc_assert (is_old_name (var)); - else - gcc_assert (symbol_marked_for_renaming (var)); -#endif - - /* Get all the definition sites for VAR. */ - db = find_def_blocks_for (var); - - /* No need to do anything if there were no definitions to VAR. */ - if (db == NULL || bitmap_empty_p (db->def_blocks)) - return; - - /* Compute the initial iterated dominance frontier. */ - idf = find_idf (db->def_blocks, dfs); - pruned_idf = BITMAP_ALLOC (NULL); - - if (TREE_CODE (var) == SSA_NAME) - { - if (update_flags == TODO_update_ssa) - { - /* If doing regular SSA updates for GIMPLE registers, we are - only interested in IDF blocks dominated by the nearest - 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 - && dominated_by_p (CDI_DOMINATORS, BASIC_BLOCK (i), entry)) - bitmap_set_bit (pruned_idf, i); - } - else - { - /* Otherwise, do not prune the IDF for VAR. */ - gcc_assert (update_flags == TODO_update_ssa_full_phi); - bitmap_copy (pruned_idf, idf); - } - } - else - { - /* Otherwise, VAR is a symbol that needs to be put into SSA form - for the first time, so we need to compute the full IDF for - it. */ - bitmap_copy (pruned_idf, idf); - } - - if (!bitmap_empty_p (pruned_idf)) - { - /* Make sure that PRUNED_IDF blocks and all their feeding blocks - are included in the region to be updated. The feeding blocks - are important to guarantee that the PHI arguments are renamed - properly. */ - bitmap_ior_into (blocks, pruned_idf); - EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) - { - edge e; - edge_iterator ei; - basic_block bb = BASIC_BLOCK (i); - - FOR_EACH_EDGE (e, ei, bb->preds) - if (e->src->index >= 0) - bitmap_set_bit (blocks, e->src->index); - } - - insert_phi_nodes_for (var, pruned_idf, true); - } - - BITMAP_FREE (pruned_idf); - BITMAP_FREE (idf); -} - - -/* 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); - - bitmap_ior_into (syms_to_rename, 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: - - 1- The names in OLD_SSA_NAMES dominated by the definitions of - NEW_SSA_NAMES are all re-written to be reached by the - appropriate definition from NEW_SSA_NAMES. - - 2- If needed, new PHI nodes are added to the iterated dominance - frontier of the blocks where each of NEW_SSA_NAMES are defined. - - The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by - calling register_new_name_mapping for every pair of names that the - caller wants to replace. - - The caller identifies the new names that have been inserted and the - names that need to be replaced by calling register_new_name_mapping - for every pair <NEW, OLD>. Note that the function assumes that the - new names have already been inserted in the IL. - - For instance, given the following code: - - 1 L0: - 2 x_1 = PHI (0, x_5) - 3 if (x_1 < 10) - 4 if (x_1 > 7) - 5 y_2 = 0 - 6 else - 7 y_3 = x_1 + x_7 - 8 endif - 9 x_5 = x_1 + 1 - 10 goto L0; - 11 endif - - Suppose that we insert new names x_10 and x_11 (lines 4 and 8). - - 1 L0: - 2 x_1 = PHI (0, x_5) - 3 if (x_1 < 10) - 4 x_10 = ... - 5 if (x_1 > 7) - 6 y_2 = 0 - 7 else - 8 x_11 = ... - 9 y_3 = x_1 + x_7 - 10 endif - 11 x_5 = x_1 + 1 - 12 goto L0; - 13 endif - - We want to replace all the uses of x_1 with the new definitions of - x_10 and x_11. Note that the only uses that should be replaced are - those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should - *not* be replaced (this is why we cannot just mark symbol 'x' for - renaming). - - Additionally, we may need to insert a PHI node at line 11 because - that is a merge point for x_10 and x_11. So the use of x_1 at line - 11 will be replaced with the new PHI node. The insertion of PHI - nodes is optional. They are not strictly necessary to preserve the - SSA form, and depending on what the caller inserted, they may not - even be useful for the optimizers. UPDATE_FLAGS controls various - aspects of how update_ssa operates, see the documentation for - TODO_update_ssa*. */ - -void -update_ssa (unsigned update_flags) -{ - basic_block bb, start_bb; - bitmap_iterator bi; - 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); - - /* Only one update flag should be set. */ - gcc_assert (update_flags == TODO_update_ssa - || update_flags == TODO_update_ssa_no_phi - || update_flags == TODO_update_ssa_full_phi - || update_flags == TODO_update_ssa_only_virtuals); - - /* If we only need to update virtuals, remove all the mappings for - 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); - } - - insert_phi_p = (update_flags != TODO_update_ssa_no_phi); - - if (insert_phi_p) - { - /* 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 - blocks have uses of N (i.e., N is live-on-entry in those - blocks). */ - def_blocks = htab_create (num_ssa_names, def_blocks_hash, - def_blocks_eq, def_blocks_free); - } - else - { - def_blocks = 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 (); - - /* 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) - { - prepare_names_to_update (insert_phi_p); - - /* 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 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 - { - /* 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, 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) - { - 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, 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_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_to_update); - } - - /* Reset the current definition for name and symbol before renaming - the sub-graph. */ - 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_to_update, 0, i, bi) - SET_BIT (tmp, i); - - rewrite_blocks (start_bb, REWRITE_UPDATE, tmp); - - sbitmap_free (tmp); - - /* Debugging dumps. */ - if (dump_file) - { - int c; - unsigned i; - - 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_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", - c, PERCENT (c, last_basic_block)); - - if (dump_flags & TDF_DETAILS) - { - fprintf (dump_file, "Affected blocks: "); - EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) - fprintf (dump_file, "%u ", i); - fprintf (dump_file, "\n"); - } - - fprintf (dump_file, "\n\n"); - } - - /* Free allocated memory. */ -done: - EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) - { - tree_vec phis = VEC_index (tree_vec, phis_to_rewrite, i); - - 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); - delete_update_ssa (); - - timevar_pop (TV_TREE_SSA_INCREMENTAL); -} |