re PR tree-optimization/91597 (GCC miscompiles a branch depending on a pointer tag)

	PR tree-optimization/91597
	* tree-vrp.c (extract_range_from_binary_expr): Remove unsafe
	BIT_AND_EXPR optimization for pointers, even if both operand
	ranges don't include NULL, the result can be NULL.

	* gcc.c-torture/execute/pr91597.c: New test.

Co-Authored-By: Richard Biener <rguenther@suse.de>

From-SVN: r275330