tree-vrp.c (compare_values_warnv): Check TREE_NO_WARNING on a PLUS_EXPR or MINUS_EXPR...

tree-vrp.c (compare_values_warnv): Check TREE_NO_WARNING on a PLUS_EXPR or MINUS_EXPR node before setting...

./:	* tree-vrp.c (compare_values_warnv): Check TREE_NO_WARNING on a
	PLUS_EXPR or MINUS_EXPR node before setting *strict_overflow_p.
	(extract_range_from_assert): Set TREE_NO_WARNING when creating an
	expression.
	(test_for_singularity): Likewise.
testsuite/:
	* gcc.dg/Wstrict-overflow-19.c: New test.

From-SVN: r125334