diff options
Diffstat (limited to 'gcc/tree-ssa-pre.c')
| -rw-r--r-- | gcc/tree-ssa-pre.c | 97 |
1 files changed, 37 insertions, 60 deletions
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c index 769aadb2..0875584 100644 --- a/gcc/tree-ssa-pre.c +++ b/gcc/tree-ssa-pre.c @@ -1237,21 +1237,18 @@ fully_constant_expression (pre_expr e) return e; } -/* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that - it has the value it would have in BLOCK. Set *SAME_VALID to true +/* Translate the VUSE backwards through phi nodes in E->dest, so that + it has the value it would have in E->src. Set *SAME_VALID to true in case the new vuse doesn't change the value id of the OPERANDS. */ static tree translate_vuse_through_block (vec<vn_reference_op_s> operands, alias_set_type set, alias_set_type base_set, - tree type, tree vuse, - basic_block phiblock, - basic_block block, bool *same_valid) + tree type, tree vuse, edge e, bool *same_valid) { + basic_block phiblock = e->dest; gimple *phi = SSA_NAME_DEF_STMT (vuse); ao_ref ref; - edge e = NULL; - bool use_oracle; if (same_valid) *same_valid = true; @@ -1259,59 +1256,40 @@ translate_vuse_through_block (vec<vn_reference_op_s> operands, if (gimple_bb (phi) != phiblock) return vuse; - unsigned int cnt = param_sccvn_max_alias_queries_per_access; - use_oracle = ao_ref_init_from_vn_reference (&ref, set, base_set, - type, operands); - - /* Use the alias-oracle to find either the PHI node in this block, - the first VUSE used in this block that is equivalent to vuse or - the first VUSE which definition in this block kills the value. */ - if (gimple_code (phi) == GIMPLE_PHI) - e = find_edge (block, phiblock); - else if (use_oracle) - while (cnt > 0 - && !stmt_may_clobber_ref_p_1 (phi, &ref)) - { - --cnt; - vuse = gimple_vuse (phi); - phi = SSA_NAME_DEF_STMT (vuse); - if (gimple_bb (phi) != phiblock) - return vuse; - if (gimple_code (phi) == GIMPLE_PHI) - { - e = find_edge (block, phiblock); - break; - } - } - else - return NULL_TREE; - - if (e) + /* We have pruned expressions that are killed in PHIBLOCK via + prune_clobbered_mems but we have not rewritten the VUSE to the one + live at the start of the block. If there is no virtual PHI to translate + through return the VUSE live at entry. Otherwise the VUSE to translate + is the def of the virtual PHI node. */ + phi = get_virtual_phi (phiblock); + if (!phi) + return BB_LIVE_VOP_ON_EXIT + (get_immediate_dominator (CDI_DOMINATORS, phiblock)); + + if (same_valid + && ao_ref_init_from_vn_reference (&ref, set, base_set, type, operands)) { - if (use_oracle && same_valid) - { - bitmap visited = NULL; - /* Try to find a vuse that dominates this phi node by skipping - non-clobbering statements. */ - vuse = get_continuation_for_phi (phi, &ref, true, - cnt, &visited, false, NULL, NULL); - if (visited) - BITMAP_FREE (visited); - } - else - vuse = NULL_TREE; - /* If we didn't find any, the value ID can't stay the same. */ - if (!vuse && same_valid) - *same_valid = false; - /* ??? We would like to return vuse here as this is the canonical - upmost vdef that this reference is associated with. But during - insertion of the references into the hash tables we only ever - directly insert with their direct gimple_vuse, hence returning - something else would make us not find the other expression. */ - return PHI_ARG_DEF (phi, e->dest_idx); + bitmap visited = NULL; + /* Try to find a vuse that dominates this phi node by skipping + non-clobbering statements. */ + unsigned int cnt = param_sccvn_max_alias_queries_per_access; + vuse = get_continuation_for_phi (phi, &ref, true, + cnt, &visited, false, NULL, NULL); + if (visited) + BITMAP_FREE (visited); } - - return NULL_TREE; + else + vuse = NULL_TREE; + /* If we didn't find any, the value ID can't stay the same. */ + if (!vuse && same_valid) + *same_valid = false; + + /* ??? We would like to return vuse here as this is the canonical + upmost vdef that this reference is associated with. But during + insertion of the references into the hash tables we only ever + directly insert with their direct gimple_vuse, hence returning + something else would make us not find the other expression. */ + return PHI_ARG_DEF (phi, e->dest_idx); } /* Like bitmap_find_leader, but checks for the value existing in SET1 *or* @@ -1630,8 +1608,7 @@ phi_translate_1 (bitmap_set_t dest, newvuse = translate_vuse_through_block (newoperands.exists () ? newoperands : operands, ref->set, ref->base_set, - ref->type, - vuse, phiblock, pred, + ref->type, vuse, e, changed ? NULL : &same_valid); if (newvuse == NULL_TREE) |