r277963 - in /trunk/gcc: ChangeLog gimple-ssa-s...

[jakub at gcc dot gnu dot org]

Author: jakub
Date: Fri Nov  8 10:53:50 2019
New Revision: 277963

URL: https://gcc.gnu.org/viewcvs?rev=277963&root=gcc&view=rev
Log:
	PR target/92038
	* gimple-ssa-store-merging.c (find_constituent_stores): For return
	value only, return non-NULL if there is a single non-clobber
	constituent store even if there are constituent clobbers and return
	one of clobber constituent stores if all constituent stores are
	clobbers.
	(split_group): Handle clobbers.
	(imm_store_chain_info::output_merged_store): When computing
	bzero_first, look after all clobbers at the start.  Don't count
	clobber stmts in orig_num_stmts, except if the first orig store is
	a clobber covering the whole area and split_stores cover the whole
	area, consider equal number of stmts ok.  Punt if split_stores
	contains only ->orig stores and their number plus number of original
	clobbers is equal to original number of stmts.  For ->orig, look past
	clobbers in the constituent stores.
	(imm_store_chain_info::output_merged_stores): Don't remove clobber
	stmts.
	(rhs_valid_for_store_merging_p): Don't return false for clobber stmt
	rhs.
	(store_valid_for_store_merging_p): Allow clobber stmts.
	(verify_clear_bit_region_be): Fix up a thinko in function comment.

	* g++.dg/opt/store-merging-1.C: New test.
	* g++.dg/opt/store-merging-2.C: New test.
	* g++.dg/opt/store-merging-3.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/opt/store-merging-1.C
    trunk/gcc/testsuite/g++.dg/opt/store-merging-2.C
    trunk/gcc/testsuite/g++.dg/opt/store-merging-3.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-store-merging.c
    trunk/gcc/testsuite/ChangeLog