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| author | Richard Guenther <rguenther@suse.de> | 2009-04-17 15:35:13 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2009-04-17 15:35:13 +0000 |
| commit | 61e20b90d9ae993af2c3c2f34198432eeafbfb65 (patch) | |
| tree | 232ca820961c5ca6d4c72735553a7ca8785bf2f3 /gcc | |
| parent | 90c6fd8a8b15fed7e3b65826fd8d259b90bedb48 (diff) | |
| download | gcc-61e20b90d9ae993af2c3c2f34198432eeafbfb65.zip gcc-61e20b90d9ae993af2c3c2f34198432eeafbfb65.tar.gz gcc-61e20b90d9ae993af2c3c2f34198432eeafbfb65.tar.bz2 | |
tree-ssa-alias.c (refs_may_alias_p_1): Do not use TBAA for decl-vs-decl disambiguation.
2009-04-17 Richard Guenther <rguenther@suse.de>
* tree-ssa-alias.c (refs_may_alias_p_1): Do not use TBAA
for decl-vs-decl disambiguation.
From-SVN: r146273
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/tree-ssa-alias.c | 34 |
2 files changed, 26 insertions, 13 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f5b87a1..5b09ac2 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2009-04-17 Richard Guenther <rguenther@suse.de> + + * tree-ssa-alias.c (refs_may_alias_p_1): Do not use TBAA + for decl-vs-decl disambiguation. + 2009-04-17 Andreas Krebbel <krebbel1@de.ibm.com> * config/s390/s390.h (s390_tune_attr): New macro definition. diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c index 5207bc9..8982280 100644 --- a/gcc/tree-ssa-alias.c +++ b/gcc/tree-ssa-alias.c @@ -670,16 +670,6 @@ refs_may_alias_p_1 (tree ref1, tree ref2) || INDIRECT_REF_P (ref2) || TREE_CODE (ref2) == TARGET_MEM_REF)); - /* Defer to TBAA if possible. */ - if (flag_strict_aliasing - && !alias_sets_conflict_p (get_alias_set (ref1), get_alias_set (ref2))) - return false; - - /* If one reference is a TARGET_MEM_REF weird things are allowed. */ - if (TREE_CODE (ref1) == TARGET_MEM_REF - || TREE_CODE (ref2) == TARGET_MEM_REF) - return true; - /* Decompose the references into their base objects and the access. */ base1 = get_ref_base_and_extent (ref1, &offset1, &size1, &max_size1); base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &max_size2); @@ -693,14 +683,32 @@ refs_may_alias_p_1 (tree ref1, tree ref2) || is_gimple_min_invariant (base2)) return false; + /* Defer to simple offset based disambiguation if we have + references based on two decls. Do this before defering to + TBAA to handle must-alias cases in conformance with the + GCC extension of allowing type-punning through unions. */ var1_p = SSA_VAR_P (base1); var2_p = SSA_VAR_P (base2); - ind1_p = INDIRECT_REF_P (base1); - ind2_p = INDIRECT_REF_P (base2); if (var1_p && var2_p) return decl_refs_may_alias_p (base1, offset1, max_size1, base2, offset2, max_size2); - else if (var1_p && ind2_p) + + /* First defer to TBAA if possible. */ + if (flag_strict_aliasing + && !alias_sets_conflict_p (get_alias_set (ref1), get_alias_set (ref2))) + return false; + + /* If one reference is a TARGET_MEM_REF weird things are allowed. Still + TBAA disambiguation based on the access type is possible, so bail + out only after that check. */ + if (TREE_CODE (ref1) == TARGET_MEM_REF + || TREE_CODE (ref2) == TARGET_MEM_REF) + return true; + + /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ + ind1_p = INDIRECT_REF_P (base1); + ind2_p = INDIRECT_REF_P (base2); + if (var1_p && ind2_p) return indirect_ref_may_alias_decl_p (ref2, TREE_OPERAND (base2, 0), offset2, max_size2, -1, ref1, base1, |