match: Improve the `x ==/!= ~x` pattern [PR118483]

match: Improve the `x ==/!= ~x` pattern [PR118483]

This improves this pattern by 2 ways:
* Allow for an optional convert, similar to how the few other
  `a OP ~a` patterns also allow for an optional convert.
* Use bitwise_inverted_equal_p/maybe_bit_not instead of directly
  matching bit_not. Just like the other patterns do too.

Note pr118483-2.c used to optimized for aarch64-linux-gnu with GCC 4.9.4
on the RTL level even though the gimple level was missing it.

	PR tree-optimization/118483

gcc/ChangeLog:

	* match.pd (`x ==/!= ~x`): Allow for an optional convert
	and use itwise_inverted_equal_p/maybe_bit_not instead of
	directly matching bit_not.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/pr118483-1.c: New test.
	* gcc.dg/tree-ssa/pr118483-2.c: New test.
	* gcc.dg/tree-ssa/pr118483-3.c: New test.
	* gcc.dg/tree-ssa/pr118483-4.c: New test.

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