8sa1-gcc/gcc/alias.h
Richard Biener 3d6fd7ce6d 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.
2020-03-03 11:02:28 +01:00

50 lines
2.1 KiB
C

/* Exported functions from alias.c
Copyright (C) 2004-2020 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#ifndef GCC_ALIAS_H
#define GCC_ALIAS_H
extern alias_set_type new_alias_set (void);
extern alias_set_type get_alias_set (tree);
extern alias_set_type get_deref_alias_set (tree);
extern alias_set_type get_varargs_alias_set (void);
extern alias_set_type get_frame_alias_set (void);
extern tree component_uses_parent_alias_set_from (const_tree);
extern bool ends_tbaa_access_path_p (const_tree);
extern bool alias_set_subset_of (alias_set_type, alias_set_type);
extern void record_alias_subset (alias_set_type, alias_set_type);
extern void record_component_aliases (tree);
extern int alias_sets_conflict_p (alias_set_type, alias_set_type);
extern int alias_sets_must_conflict_p (alias_set_type, alias_set_type);
extern int objects_must_conflict_p (tree, tree);
extern int nonoverlapping_memrefs_p (const_rtx, const_rtx, bool);
extern void dump_alias_stats_in_alias_c (FILE *s);
tree reference_alias_ptr_type (tree);
bool alias_ptr_types_compatible_p (tree, tree);
int compare_base_decls (tree, tree);
bool refs_same_for_tbaa_p (tree, tree);
/* This alias set can be used to force a memory to conflict with all
other memories, creating a barrier across which no memory reference
can move. Note that there are other legacy ways to create such
memory barriers, including an address of SCRATCH. */
#define ALIAS_SET_MEMORY_BARRIER ((alias_set_type) -1)
#endif /* GCC_ALIAS_H */