re PR tree-optimization/53465 (wrong code with -O1 -ftree-vrp)

re PR tree-optimization/53465 (wrong code with -O1 -ftree-vrp)

	PR tree-optimization/53465
	* tree-vrp.c (extract_range_from_cond_expr): First copy_value_range
	vr0 into *vr, then vrp_meet that.
	(vrp_meet): If one vr type is VR_UNDEFINED, ensure the result doesn't
	have any equivalences.
	(vrp_visit_phi_node): Call copy_value_range instead of vrp_meet the
	first time.

	* gcc.c-torture/execute/pr53465.c: New test.

From-SVN: r187827