diff options
Diffstat (limited to 'gcc/tree-ssa-alias.c')
| -rw-r--r-- | gcc/tree-ssa-alias.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c index e6e21e8..6efe4c3 100644 --- a/gcc/tree-ssa-alias.c +++ b/gcc/tree-ssa-alias.c @@ -1483,6 +1483,16 @@ refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) ao_ref_alias_set (ref2))) return false; + /* If the reference is based on a pointer that points to memory + that may not be written to then the other reference cannot possibly + clobber it. */ + if ((TREE_CODE (TREE_OPERAND (base2, 0)) == SSA_NAME + && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2, 0))) + || (ind1_p + && TREE_CODE (TREE_OPERAND (base1, 0)) == SSA_NAME + && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1, 0)))) + return false; + /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ if (var1_p && ind2_p) return indirect_ref_may_alias_decl_p (ref2->ref, base2, @@ -1991,6 +2001,14 @@ call_may_clobber_ref_p_1 (gcall *call, ao_ref *ref) || !is_global_var (base))) return false; + /* If the reference is based on a pointer that points to memory + that may not be written to then the call cannot possibly clobber it. */ + if ((TREE_CODE (base) == MEM_REF + || TREE_CODE (base) == TARGET_MEM_REF) + && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME + && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base, 0))) + return false; + callee = gimple_call_fndecl (call); /* Handle those builtin functions explicitly that do not act as |