2012-05-03  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-pre.c (valid_in_sets): Remove checking of trapping
	operations.
	(prune_clobbered_mems): Do it here.  Do not uselessly sort
	expressions.
	(compute_avail): Do not add possibly trapping operations to
	EXP_GEN if they might not be executed in the block.

	* gcc.dg/tree-ssa/ssa-pre-27.c: Remove XFAIL.

From-SVN: r187096