MATCH: Simplify (a ? x : y) eq/ne (b ? x : y) [PR111150]

MATCH: Simplify (a ? x : y) eq/ne (b ? x : y) [PR111150]

This patch adds match pattern for `(a ? x : y) eq/ne (b ? x : y)`.
In forwprop1 pass, depending on the type of `a` and `b`, GCC produces
`vec_cond` or `cond_expr`. Based on the observation that `(x != y)` is
TRUE, the pattern can be optimized to produce `(a^b ? TRUE : FALSE)`.

The patch adds match pattern for a, b:
(a ? x : y) != (b ? x : y) --> (a^b) ? TRUE  : FALSE
(a ? x : y) == (b ? x : y) --> (a^b) ? FALSE : TRUE
(a ? x : y) != (b ? y : x) --> (a^b) ? TRUE  : FALSE
(a ? x : y) == (b ? y : x) --> (a^b) ? FALSE : TRUE

	PR tree-optimization/111150

gcc/ChangeLog:

	* match.pd (`(a ? x : y) eq/ne (b ? x : y)`): New pattern.
	(`(a ? x : y) eq/ne (b ? y : x)`): New pattern.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/pr111150.c: New test.
	* gcc.dg/tree-ssa/pr111150-1.c: New test.
	* g++.dg/tree-ssa/pr111150.C: New test.

Signed-off-by: Eikansh Gupta <quic_eikagupt@quicinc.com>