flags.h (POINTER_TYPE_OVERFLOW_UNDEFINED): Define.

flags.h (POINTER_TYPE_OVERFLOW_UNDEFINED): Define.

./:	* flags.h (POINTER_TYPE_OVERFLOW_UNDEFINED): Define.
	* fold-const.c (fold_overflow_warning): Remove assertion.
	(pointer_may_wrap_p): New static function.
	(fold_comparison): If appropriate, test
	POINTER_TYPE_OVERFLOW_UNDEFINED, and issue an overflow warning.
	(fold_binary): Test POINTER_TYPE_OVERFLOW_UNDEFINED when
	reassociating a pointer type.
	* doc/invoke.texi (Optimize Options): Document that
	-fstrict-overflow applies to pointer wraparound.
testsuite/:
	* gcc.dg/strict-overflow-6.c: New.
	* gcc.dg/no-strict-overflow-7.c: New.
	* gcc.dg/Wstrict-overflow-22.c: New.
	* gcc.c-torture/compile/20080419-1.c: New.
	* gcc.dg/tree-ssa/loop-17.c: Use -O2.

From-SVN: r135222