S/390 Invalid vector binary ops

S/390 Invalid vector binary ops

This is a first try to implement at least some of the requirements
regarding the vector bool type documented for IBM XLC.

With this patch error messages will be issued for invalid uses of
vector bool types in binary operators.

vector bool types are being marked opaque in order to prevent the
front-end from complaining about "vector bool long" vs "vector bool
long long" combinations on 64 bit.  The opaque flag basically
suppresses any type checking. However, we still want vector bool to be
accepted only in contexts specified in the documentation (to be
published soon).  Implementing the invalid binary op hook does this
for binary operators at least.  But this is far from being complete :(

gcc/
	* config/s390/s390.c (s390_vector_bool_type_p): New function.
	(s390_invalid_binary_op): New function.
	(TARGET_INVALID_BINARY_OP): Define macro.

From-SVN: r223404