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| author | Richard Biener <rguenther@suse.de> | 2019-07-05 12:48:42 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2019-07-05 12:48:42 +0000 |
| commit | 75fad0a98919da8212be4efc479d098499f4f1c3 (patch) | |
| tree | 3daeebb2ad8afb9e01b95c8297cb83c91f22ea97 /gcc/tree-ssa-sccvn.c | |
| parent | 1d776353135272b1fcb7453ae9c8bd4fafd9bd07 (diff) | |
| download | gcc-75fad0a98919da8212be4efc479d098499f4f1c3.zip gcc-75fad0a98919da8212be4efc479d098499f4f1c3.tar.gz gcc-75fad0a98919da8212be4efc479d098499f4f1c3.tar.bz2 | |
re PR tree-optimization/91091 ([missed optimization] Missing optimization in unaliased pointers)
2019-07-05 Richard Biener <rguenther@suse.de>
PR tree-optimization/91091
* tree-ssa-sccvn.c (vn_reference_lookup_3): Overlap of
accesses can happen with -fno-strict-aliasing.
* gcc.dg/tree-ssa/pr91091-1.c: New testcase.
* gcc.dg/tree-ssa/ssa-fre-61.c: Adjust.
From-SVN: r273134
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 22dd801..2cc76d8 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -1996,7 +1996,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_, activation of a union member via a store makes the values of untouched bytes unspecified. */ && (known_eq (ref->size, BITS_PER_UNIT) - || (get_alias_set (lhs) != 0 + || (flag_strict_aliasing + && get_alias_set (lhs) != 0 && ao_ref_alias_set (ref) != 0))) { tree *saved_last_vuse_ptr = data->last_vuse_ptr; |