With IBM z14 officially announced we can add support for z14 as
preferred CPU name.  We still pass arch12 to Binutils in order to keep
older Binutils versions supported.

gcc/ChangeLog:

2017-07-31  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* config.gcc: Add z14.
	* config/s390/driver-native.c (s390_host_detect_local_cpu): Add
	CPU model numbers for z13s and z14.
	* config/s390/s390-c.c (s390_resolve_overloaded_builtin): Replace
	arch12 with z14.
	* config/s390/s390-opts.h (enum processor_type): Rename
	PROCESSOR_ARCH12 to PROCESSOR_3906_Z14.
	* config/s390/s390.c (processor_table): Add field for CPU name to
	be passed to Binutils.
	(s390_asm_output_machine_for_arch): Use the new field in
	processor_table for Binutils.
	(s390_expand_builtin): Replace arch12 with z14.
	(s390_issue_rate): Rename PROCESSOR_ARCH12 to PROCESSOR_3906_Z14.
	(s390_get_sched_attrmask): Likewise.
	(s390_get_unit_mask): Likewise.
	* config/s390/s390.opt: Add z14 to processor_type enum.

From-SVN: r250739