gimple: Remove special handling of COND_EXPR for COMPARISON_CLASS_P [PR116949, PR114785]

gimple: Remove special handling of COND_EXPR for COMPARISON_CLASS_P [PR116949, PR114785]

After r13-707-g68e0063397ba82, COND_EXPR for gimple assign no longer could contain a comparison.
The vectorizer was builting gimple assigns with comparison until r15-4695-gd17e672ce82e69
(which added an assert to make sure it no longer builds it).

So let's remove the special handling COND_EXPR in a few places and add an assert to
gimple_build_assign_1 to make sure we don't build a gimple assign any more with a comparison.

Bootstrapped and tested on x86_64-linux-gnu.

gcc/ChangeLog:

	PR middle-end/114785
	PR middle-end/116949
	* gimple-match-exports.cc (maybe_push_res_to_seq): Remove special
	handling of COMPARISON_CLASS_P in COND_EXPR/VEC_COND_EXPR.
	(gimple_extract): Likewise.
	* gimple-walk.cc (walk_stmt_load_store_addr_ops): Likewise.
	* gimple.cc (gimple_build_assign_1): Add assert for COND_EXPR
	so its 1st operand is not a comparison.

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