re PR tree-optimization/88217 (Compile time and memory hog w/ -O2 -fstrict-enums -fno-tree-forwprop -fno-tree-fre)

2018-11-28  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/88217
	* vr-values.c (vr_values::extract_range_from_phi_node): Make
	sure to handle results > +INF and < -INF correctly when
	trying to drop down to +INF - 1 or -INF + 1.

	* g++.dg/pr88217.C: New testcase.

From-SVN: r266557