2012-03-22 Richard Guenther <rguenther@suse.de>

2012-03-22  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/52548
	* tree-ssa-pre.c (valid_in_sets): Remove handling of invalidation
	because of clobbers.
	(prune_clobbered_mems): New function.
	(compute_antic_aux): Use it to prune ANTIC_OUT.
	(compute_partial_antic_aux): Use it to prune PA_IN.
	(compute_avail): Only insert expressions into EXP_GEN that
	are not invalidated when translated up to the beginning of
	the block.

	* gcc.dg/tree-ssa/ssa-pre-29.c: New testcase.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@185691 138bc75d-0d04-0410-961f-82ee72b054a4