[APX CCMP] Add targetm.have_ccmp hook [PR115370]

[APX CCMP] Add targetm.have_ccmp hook [PR115370]

In cfgexpand, there is an optimization for branch which tests
targetm.gen_ccmp_first == NULL. However for target like x86-64, the
hook was implemented but it does not indicate that ccmp was enabled.
Add a new target hook TARGET_HAVE_CCMP and replace the middle-end
check for the existance of gen_ccmp_first to avoid misoptimization.

gcc/ChangeLog:

	PR target/115370
	PR target/115463
	* target.def (have_ccmp): New target hook.
	* targhooks.cc (default_have_ccmp): New function.
	* targhooks.h (default_have_ccmp): New prototype.
	* doc/tm.texi.in: Add TARGET_HAVE_CCMP.
	* doc/tm.texi: Regenerate.
	* cfgexpand.cc (expand_gimple_cond): Call targetm.have_ccmp
	instead of checking if targetm.gen_ccmp_first exists.
	* expr.cc (expand_expr_real_gassign): Likewise.
	* config/i386/i386.cc (ix86_have_ccmp): New target hook to
	check if APX_CCMP enabled.
	(TARGET_HAVE_CCMP): Define.