re PR tree-optimization/67690 (wrong code with -O2 on x86_64/Linux)

re PR tree-optimization/67690 (wrong code with -O2 on x86_64/Linux)

	PR tree-optimization/67690
	* tree-ssa-ifcombine.c (pass_tree_ifcombine::execute): Call
	reset_flow_sensitive_info_in_bb.
	* tree-ssa-tail-merge.c (replace_block_by): Likewise.
	* tree-ssanames.c: Include "gimple-iterator.h".
	(reset_flow_sensitive_info_in_bb): New function.
	* tree-ssanames.h (reset_flow_sensitive_info_in_bb): Declare.

	* gcc.dg/torture/pr67690.c: New test.

From-SVN: r228284