Add -mcpu=future support.

Add -mcpu=future support.

This patch adds the future option to the -mcpu= and -mtune= switches.

This patch treats the future like a power11 in terms of costs and reassociation
width.

This patch issues a ".machine future" to the assembly file if you use
-mcpu=power11.

This patch defines _ARCH_PWR_FUTURE if the user uses -mcpu=future.

This patch allows GCC to be configured with the --with-cpu=future and
--with-tune=future options.

This patch passes -mfuture to the assembler if the user uses -mcpu=future.

2024-03-18  Michael Meissner  <meissner@linux.ibm.com>

gcc/

	* config.gcc (rs6000*-*-*, powerpc*-*-*): Add support for power11.
	* config/rs6000/aix71.h (ASM_CPU_SPEC): Add support for -mcpu=power11.
	* config/rs6000/aix72.h (ASM_CPU_SPEC): Likewise.
	* config/rs6000/aix73.h (ASM_CPU_SPEC): Likewise.
	* config/rs6000/driver-rs6000.cc (asm_names): Likewise.
	* config/rs6000/rs6000-c.cc (rs6000_target_modify_macros): Define
	_ARCH_PWR_FUTURE if -mcpu=future.
	* config/rs6000/rs6000-cpus.def (ISA_FUTURE_MASKS_SERVER): New define.
	(POWERPC_MASKS): Add future isa bit.
	(power11 cpu): Add future definition.
	* config/rs6000/rs6000-opts.h (PROCESSOR_FUTURE): Add future processor.
	* config/rs6000/rs6000-string.cc (expand_compare_loop): Likewise.
	* config/rs6000/rs6000-tables.opt: Regenerate.
	* config/rs6000/rs6000.cc (rs6000_option_override_internal): Add future
	support.
	(rs6000_machine_from_flags): Likewise.
	(rs6000_reassociation_width): Likewise.
	(rs6000_adjust_cost): Likewise.
	(rs6000_issue_rate): Likewise.
	(rs6000_sched_reorder): Likewise.
	(rs6000_sched_reorder2): Likewise.
	(rs6000_register_move_cost): Likewise.
	(rs6000_opt_masks): Likewise.
	* config/rs6000/rs6000.h (ASM_CPU_SPEC): Likewise.
	* config/rs6000/rs6000.md (cpu attribute): Add future.
	* config/rs6000/rs6000.opt (-mpower11): Add internal future ISA flag.
	* doc/invoke.texi (RS/6000 and PowerPC Options): Document -mcpu=future.