Fix bug in constraint-check generator, reported by Rask Ingemann

	Lambertsen:
	* genpreds.c (add_constraint): Don't remove anything from the
	expression here.
	(write_tm_constrs_h): Detect whether "op" argument is used, and
	mark it ARG_UNUSED if it isn't.
	(write_insn_const_int_ok_for_constraint): Skip the part of the
	expression that would test whether "op" (which is not available
	here) is a CONST_INT.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@117433 138bc75d-0d04-0410-961f-82ee72b054a4