diff options
| author | Richard Biener <rguenther@suse.de> | 2020-03-03 11:01:09 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2020-03-03 11:02:28 +0100 |
| commit | 3d6fd7ce6dc4b6baa11920387d62dc001980aa70 (patch) | |
| tree | 8254ced343f8ecb9cdfe76b13dd1680c361cbbef /gcc/dse.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/dse.c')
| -rw-r--r-- | gcc/dse.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/gcc/dse.c b/gcc/dse.c index fe1181b502f..0d96bd43457 100644 --- a/gcc/dse.c +++ b/gcc/dse.c @@ -1540,9 +1540,12 @@ record_store (rtx body, bb_info_t bb_info) width) /* We can only remove the later store if the earlier aliases at least all accesses the later one. */ - && (MEM_ALIAS_SET (mem) == MEM_ALIAS_SET (s_info->mem) - || alias_set_subset_of (MEM_ALIAS_SET (mem), - MEM_ALIAS_SET (s_info->mem)))) + && ((MEM_ALIAS_SET (mem) == MEM_ALIAS_SET (s_info->mem) + || alias_set_subset_of (MEM_ALIAS_SET (mem), + MEM_ALIAS_SET (s_info->mem))) + && (!MEM_EXPR (s_info->mem) + || refs_same_for_tbaa_p (MEM_EXPR (s_info->mem), + MEM_EXPR (mem))))) { if (GET_MODE (mem) == BLKmode) { |