re PR bootstrap/77768 (LTO/PGO -O3 bootstrap broken: tree-vrp.c:11053:0: internal compiler error: Segmentation fault)

2016-09-29  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/77768
	* tree-ssa-pre.c (eliminate_dom_walker::before_dom_children):
	Handle stores to readonly memory when removing redundant stores.

	* gcc.dg/torture/pr77768.c: New testcase.

From-SVN: r240617