match: Add support for `a ^ CST` to bitwise_inverted_equal_p [PR115224]

match: Add support for `a ^ CST` to bitwise_inverted_equal_p [PR115224]

While looking into something else, I noticed that `a ^ CST` needed to be
special casing to bitwise_inverted_equal_p as it would simplify to `a ^ ~CST`
for the bitwise not.

Bootstrapped and tested on x86_64-linux-gnu with no regressions.

	PR tree-optimization/115224

gcc/ChangeLog:

	* generic-match-head.cc (bitwise_inverted_equal_p): Add `a ^ CST`
	case.
	* gimple-match-head.cc (gimple_bit_xor_cst): New declaration.
	(gimple_bitwise_inverted_equal_p): Add `a ^ CST` case.
	* match.pd (bit_xor_cst): New match.
	(maybe_bit_not): Add bit_xor_cst case.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/bitops-8.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>