2017-12-07  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/83296
	PR tree-optimization/67769
	* tree-ssa-phiopt.c (conditional_replacement): Do not reset
	flow sensitive info in an unrelated BB.
	(value_replacement): Use reset_flow_sensitive_info.
	(minmax_replacement): Reset flow sensitive info on the def
	we move.  Do not reset flow sensitive info in the whole BB
	we move the stmt to.
	(abs_replacement): Likewise.

	* g++.dg/warn/Wstringop-overflow-1.C: New testcase.

From-SVN: r255466