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| author | Richard Biener <rguenther@suse.de> | 2025-09-03 12:54:58 +0200 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2025-09-04 10:03:32 +0200 |
| commit | 95afbe4c7633459b59d434550888decc41b4d44f (patch) | |
| tree | 597bdae49cffdc7fecd8ceb4cd456a9885b78c90 /gcc/testsuite/gcc.dg/tree-ssa/phi-opt-value-5.c | |
| parent | b26033d579a9df55f38f3b9ff8400c21f2a5717d (diff) | |
| download | gcc-95afbe4c7633459b59d434550888decc41b4d44f.zip gcc-95afbe4c7633459b59d434550888decc41b4d44f.tar.gz gcc-95afbe4c7633459b59d434550888decc41b4d44f.tar.bz2 | |
tree-optimization/121740 - handle aggregate zeroing as skipped may-def
The following makes value-numbering handle a situation like
D.58046 = {};
SR.83_44->i = {};
pretmp_41 = MEM[(struct _Optional_payload_base &)&D.58046 + 8]._M_engaged;
where the intermediate may-def SR.83_44->i = {} prevents CSE of the
load to zero. The problem is two-fold here, one is that the code
skipping may-defs does not handle zeroing via a CTOR, the other is that
(partial) must-defs can be better handled by later code as otherwise
we may not find an appropriate definition to CSE to.
I've noticed we fail to guard against storage-order issues, so fixed
that on the fly.
PR tree-optimization/121740
* tree-ssa-sccvn.cc (vn_reference_lookup_3): Allow skipping
may-defs from CTORs. Do not skip may-defs with storage-order
issues or (partial) must-defs.
* gcc.dg/tree-ssa/ssa-fre-104.c: Un-XFAIL.
* gcc.dg/tree-ssa/ssa-fre-110.c: New testcase.
Diffstat (limited to 'gcc/testsuite/gcc.dg/tree-ssa/phi-opt-value-5.c')
0 files changed, 0 insertions, 0 deletions