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Diffstat (limited to 'gcc/tree-ssa-dse.c')
-rw-r--r--gcc/tree-ssa-dse.c155
1 files changed, 38 insertions, 117 deletions
diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index 93ceaeb0730..7676ae872c2 100644
--- a/gcc/tree-ssa-dse.c
+++ b/gcc/tree-ssa-dse.c
@@ -94,8 +94,6 @@ static void dse_optimize_stmt (struct dom_walk_data *,
block_stmt_iterator);
static void dse_record_phis (struct dom_walk_data *, basic_block);
static void dse_finalize_block (struct dom_walk_data *, basic_block);
-static void fix_phi_uses (tree, tree);
-static void fix_stmt_v_may_defs (tree, tree);
static void record_voperand_set (bitmap, bitmap *, unsigned int);
static unsigned max_stmt_uid; /* Maximal uid of a statement. Uids to phi
@@ -124,73 +122,6 @@ need_imm_uses_for (tree var)
}
-/* Replace uses in PHI which match V_MAY_DEF_RESULTs in STMT with the
- corresponding V_MAY_DEF_OP in STMT. */
-
-static void
-fix_phi_uses (tree phi, tree stmt)
-{
- stmt_ann_t ann = stmt_ann (stmt);
- v_may_def_optype v_may_defs;
- unsigned int i;
- int j;
-
- get_stmt_operands (stmt);
- v_may_defs = V_MAY_DEF_OPS (ann);
-
- /* Walk each V_MAY_DEF in STMT. */
- for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
- {
- tree v_may_def = V_MAY_DEF_RESULT (v_may_defs, i);
-
- /* Find any uses in the PHI which match V_MAY_DEF and replace
- them with the appropriate V_MAY_DEF_OP. */
- for (j = 0; j < PHI_NUM_ARGS (phi); j++)
- if (v_may_def == PHI_ARG_DEF (phi, j))
- SET_PHI_ARG_DEF (phi, j, V_MAY_DEF_OP (v_may_defs, i));
- }
-}
-
-/* Replace the V_MAY_DEF_OPs in STMT1 which match V_MAY_DEF_RESULTs
- in STMT2 with the appropriate V_MAY_DEF_OPs from STMT2. */
-
-static void
-fix_stmt_v_may_defs (tree stmt1, tree stmt2)
-{
- stmt_ann_t ann1 = stmt_ann (stmt1);
- stmt_ann_t ann2 = stmt_ann (stmt2);
- v_may_def_optype v_may_defs1;
- v_may_def_optype v_may_defs2;
- unsigned int i, j;
-
- get_stmt_operands (stmt1);
- get_stmt_operands (stmt2);
- v_may_defs1 = V_MAY_DEF_OPS (ann1);
- v_may_defs2 = V_MAY_DEF_OPS (ann2);
-
- /* Walk each V_MAY_DEF_OP in stmt1. */
- for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs1); i++)
- {
- tree v_may_def1 = V_MAY_DEF_OP (v_may_defs1, i);
-
- /* Find the appropriate V_MAY_DEF_RESULT in STMT2. */
- for (j = 0; j < NUM_V_MAY_DEFS (v_may_defs2); j++)
- {
- if (v_may_def1 == V_MAY_DEF_RESULT (v_may_defs2, j))
- {
- /* Update. */
- SET_V_MAY_DEF_OP (v_may_defs1, i, V_MAY_DEF_OP (v_may_defs2, j));
- break;
- }
- }
-
- /* If we did not find a corresponding V_MAY_DEF_RESULT, then something
- has gone terribly wrong. */
- gcc_assert (j != NUM_V_MAY_DEFS (v_may_defs2));
- }
-}
-
-
/* Set bit UID in bitmaps GLOBAL and *LOCAL, creating *LOCAL as needed. */
static void
record_voperand_set (bitmap global, bitmap *local, unsigned int uid)
@@ -261,58 +192,63 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
return;
if (TREE_CODE (stmt) == MODIFY_EXPR)
{
- dataflow_t df = get_immediate_uses (stmt);
- unsigned int num_uses = num_immediate_uses (df);
- tree use;
- tree skipped_phi;
-
+ unsigned int num_uses = 0, count = 0;
+ use_operand_p first_use_p = NULL_USE_OPERAND_P;
+ use_operand_p use_p;
+ tree use, use_stmt;
+ tree defvar = NULL_TREE, usevar = NULL_TREE;
+ use_operand_p var2;
+ def_operand_p var1;
+ ssa_op_iter op_iter;
+
+ FOR_EACH_SSA_MAYDEF_OPERAND (var1, var2, stmt, op_iter)
+ {
+ defvar = DEF_FROM_PTR (var1);
+ usevar = USE_FROM_PTR (var2);
+ num_uses += num_imm_uses (defvar);
+ count++;
+ if (num_uses > 1 || count > 1)
+ break;
+ }
- /* If there are no uses then there is nothing left to do. */
- if (num_uses == 0)
+ if (count == 1 && num_uses == 1)
+ {
+ single_imm_use (defvar, &use_p, &use_stmt);
+ gcc_assert (use_p != NULL_USE_OPERAND_P);
+ first_use_p = use_p;
+ use = USE_FROM_PTR (use_p);
+ }
+ else
{
record_voperand_set (dse_gd->stores, &bd->stores, ann->uid);
return;
}
- use = immediate_use (df, 0);
- skipped_phi = NULL;
-
/* Skip through any PHI nodes we have already seen if the PHI
represents the only use of this store.
Note this does not handle the case where the store has
multiple V_MAY_DEFs which all reach a set of PHI nodes in the
same block. */
- while (num_uses == 1
- && TREE_CODE (use) == PHI_NODE
- && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use)))
+ while (use_p != NULL_USE_OPERAND_P
+ && TREE_CODE (use_stmt) == PHI_NODE
+ && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt)))
{
- /* Record the first PHI we skip so that we can fix its
- uses if we find that STMT is a dead store. */
- if (!skipped_phi)
- skipped_phi = use;
-
/* Skip past this PHI and loop again in case we had a PHI
chain. */
- df = get_immediate_uses (use);
- num_uses = num_immediate_uses (df);
- use = immediate_use (df, 0);
+ if (single_imm_use (PHI_RESULT (use_stmt), &use_p, &use_stmt))
+ use = USE_FROM_PTR (use_p);
}
/* If we have precisely one immediate use at this point, then we may
have found redundant store. */
- if (num_uses == 1
- && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use))
+ if (use_p != NULL_USE_OPERAND_P
+ && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt))
&& operand_equal_p (TREE_OPERAND (stmt, 0),
- TREE_OPERAND (use, 0), 0))
+ TREE_OPERAND (use_stmt, 0), 0))
{
- /* We need to fix the operands if either the first PHI we
- skipped, or the store which we are not deleting if we did
- not skip any PHIs. */
- if (skipped_phi)
- fix_phi_uses (skipped_phi, stmt);
- else
- fix_stmt_v_may_defs (use, stmt);
+ /* We need to fix the operand of the consuming stmt. */
+ SET_USE (first_use_p, usevar);
if (dump_file && (dump_flags & TDF_DETAILS))
{
@@ -321,21 +257,12 @@ dse_optimize_stmt (struct dom_walk_data *walk_data,
fprintf (dump_file, "'\n");
}
- /* Any immediate uses which reference STMT need to instead
- reference the new consumer, either SKIPPED_PHI or USE.
- This allows us to cascade dead stores. */
- redirect_immediate_uses (stmt, skipped_phi ? skipped_phi : use);
-
- /* Be sure to remove any dataflow information attached to
- this statement. */
- free_df_for_stmt (stmt);
+ /* Remove the dead store. */
+ bsi_remove (&bsi);
/* And release any SSA_NAMEs set in this statement back to the
SSA_NAME manager. */
release_defs (stmt);
-
- /* Finally remove the dead store. */
- bsi_remove (&bsi);
}
record_voperand_set (dse_gd->stores, &bd->stores, ann->uid);
@@ -402,9 +329,6 @@ tree_ssa_dse (void)
dominators. */
calculate_dominance_info (CDI_POST_DOMINATORS);
- /* We also need immediate use information for virtual operands. */
- compute_immediate_uses (TDFA_USE_VOPS, need_imm_uses_for);
-
/* Dead store elimination is fundamentally a walk of the post-dominator
tree and a backwards walk of statements within each block. */
walk_data.walk_stmts_backward = true;
@@ -435,9 +359,6 @@ tree_ssa_dse (void)
/* Release the main bitmap. */
BITMAP_XFREE (dse_gd.stores);
- /* Free dataflow information. It's probably out of date now anyway. */
- free_df ();
-
/* For now, just wipe the post-dominator information. */
free_dominance_info (CDI_POST_DOMINATORS);
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-26 11:38:40 +0000