diff options
Diffstat (limited to 'gcc/tree-ssa-alias.c')
| -rw-r--r-- | gcc/tree-ssa-alias.c | 43 |
1 files changed, 20 insertions, 23 deletions
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c index 54e3a54..e1ea307 100644 --- a/gcc/tree-ssa-alias.c +++ b/gcc/tree-ssa-alias.c @@ -1265,20 +1265,6 @@ nonoverlapping_component_refs_since_match_p (tree match1, tree ref1, component_refs1.safe_push (ref1); ref1 = TREE_OPERAND (ref1, 0); } - if (TREE_CODE (ref1) == MEM_REF && ref1 != match1) - { - if (!integer_zerop (TREE_OPERAND (ref1, 1))) - { - ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias; - return -1; - } - } - /* TODO: Handle TARGET_MEM_REF later. */ - if (TREE_CODE (ref1) == TARGET_MEM_REF && ref1 != match1) - { - ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias; - return -1; - } /* Create the stack of handled components for REF2. */ while (handled_component_p (ref2) && ref2 != match2) @@ -1290,20 +1276,31 @@ nonoverlapping_component_refs_since_match_p (tree match1, tree ref1, component_refs2.safe_push (ref2); ref2 = TREE_OPERAND (ref2, 0); } - if (TREE_CODE (ref2) == MEM_REF && ref2 != match2) - { - if (!integer_zerop (TREE_OPERAND (ref2, 1))) - { - ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias; - return -1; - } - } - if (TREE_CODE (ref2) == TARGET_MEM_REF && ref2 != match2) + + bool mem_ref1 = TREE_CODE (ref1) == MEM_REF && ref1 != match1; + bool mem_ref2 = TREE_CODE (ref2) == MEM_REF && ref2 != match2; + + /* If only one of access path starts with MEM_REF check that offset is 0 + so the addresses stays the same after stripping it. + TODO: In this case we may walk the other access path until we get same + offset. + + If both starts with MEM_REF, offset has to be same. */ + if ((mem_ref1 && !mem_ref2 && !integer_zerop (TREE_OPERAND (ref1, 1))) + || (mem_ref2 && !mem_ref1 && !integer_zerop (TREE_OPERAND (ref2, 1))) + || (mem_ref1 && mem_ref2 + && !tree_int_cst_equal (TREE_OPERAND (ref1, 1), + TREE_OPERAND (ref2, 1)))) { ++alias_stats.nonoverlapping_component_refs_since_match_p_may_alias; return -1; } + /* TARGET_MEM_REF are never wrapped in handled components, so we do not need + to handle them here at all. */ + gcc_checking_assert (TREE_CODE (ref1) != TARGET_MEM_REF + && TREE_CODE (ref2) != TARGET_MEM_REF); + /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same rank. This is sufficient because we start from the same DECL and you cannot reference several fields at a time with COMPONENT_REFs (unlike |