diff options
author | Richard Biener <rguenther@suse.de> | 2020-03-03 11:01:09 +0100 |
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committer | Richard Biener <rguenther@suse.de> | 2020-03-03 11:02:28 +0100 |
commit | 3d6fd7ce6dc4b6baa11920387d62dc001980aa70 (patch) | |
tree | 8254ced343f8ecb9cdfe76b13dd1680c361cbbef /gcc/tree-ssa-alias.c | |
parent | 01eb1bb0237a24fe50ed0631857f3dfc31782f54 (diff) |
tree-optimization/93946 - fix bogus redundant store removal in FRE, DSE and DOM
This fixes a common mistake in removing a store that looks redudnant but
is not because it changes the dynamic type of the memory and thus makes
a difference for following loads with TBAA.
2020-03-03 Richard Biener <rguenther@suse.de>
PR tree-optimization/93946
* alias.h (refs_same_for_tbaa_p): Declare.
* alias.c (refs_same_for_tbaa_p): New function.
* tree-ssa-alias.c (ao_ref_alias_set): For a NULL ref return
zero.
* tree-ssa-scopedtables.h
(avail_exprs_stack::lookup_avail_expr): Add output argument
giving access to the hashtable entry.
* tree-ssa-scopedtables.c (avail_exprs_stack::lookup_avail_expr):
Likewise.
* tree-ssa-dom.c: Include alias.h.
(dom_opt_dom_walker::optimize_stmt): Validate TBAA state before
removing redundant store.
* tree-ssa-sccvn.h (vn_reference_s::base_set): New member.
(ao_ref_init_from_vn_reference): Adjust prototype.
(vn_reference_lookup_pieces): Likewise.
(vn_reference_insert_pieces): Likewise.
* tree-ssa-sccvn.c: Track base alias set in addition to alias
set everywhere.
(eliminate_dom_walker::eliminate_stmt): Also check base alias
set when removing redundant stores.
(visit_reference_op_store): Likewise.
* dse.c (record_store): Adjust valdity check for redundant
store removal.
* gcc.dg/torture/pr93946-1.c: New testcase.
* gcc.dg/torture/pr93946-2.c: Likewise.
Diffstat (limited to 'gcc/tree-ssa-alias.c')
-rw-r--r-- | gcc/tree-ssa-alias.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c index 2e8290f35d5..df9ba0de0d6 100644 --- a/gcc/tree-ssa-alias.c +++ b/gcc/tree-ssa-alias.c @@ -697,6 +697,8 @@ ao_ref_alias_set (ao_ref *ref) { if (ref->ref_alias_set != -1) return ref->ref_alias_set; + if (!ref->ref) + return 0; ref->ref_alias_set = get_alias_set (ref->ref); return ref->ref_alias_set; } |