tree-optimization: Add bitop reduction simplifications against zero

This patch introduces a simplification rule in match.pd to reduce bitwise
expressions against zero. Specifically, it simplifies patterns where a
variable checked against zero is combined via bitwise AND/OR with a compounded
bitwise OR check against zero.

        PR tree-optimization/125442

gcc/ChangeLog:

	* match.pd: Add simplification rules for
	(a == 0) | ((a | b) == 0) -> (a == 0) and
	(a != 0) & ((a | b) != 0) -> (a != 0).

gcc/testsuite/ChangeLog:

	* gcc.dg/int-bwise-opt-3.c: New test.
	* gcc.dg/int-bwise-opt-4.c: New test.

Suggested-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
Signed-off-by: Souradipto Das <souradiptodas6@gmail.com>