Introduce support for PKU instructions.

Introduce support for PKU instructions.

gcc/
	* common/config/i386/i386-common.c (OPTION_MASK_ISA_PKU_SET): New.
	(OPTION_MASK_ISA_PKU_UNSET): Ditto.
	(ix86_handle_option): Handle OPT_mpku.
	* config.gcc: Add pkuintrin.h to i[34567]86-*-* and x86_64-*-*
	targets.
	* config/i386/cpuid.h (host_detect_local_cpu): Detect PKU feature.
	* config/i386/i386-c.c (ix86_target_macros_internal): Handle PKU ISA
	flag.
	* config/i386/i386.c (ix86_target_string): Add "-mpku" to
	ix86_target_opts.
	(ix86_option_override_internal): Define PTA_PKU, mention new key
	in skylake-avx512. Handle new ISA bits.
	(ix86_valid_target_attribute_inner_p): Add "pku".
	(enum ix86_builtins): Add IX86_BUILTIN_RDPKRU and IX86_BUILTIN_WRPKRU.
	(builtin_description bdesc_special_args[]): Add new built-ins.
	* config/i386/i386.h (define TARGET_PKU): New.
	(define TARGET_PKU_P): Ditto.
	* config/i386/i386.md (define_c_enum "unspecv"): Add UNSPEC_PKU.
	(define_expand "rdpkru"): New.
	(define_insn "*rdpkru"): Ditto.
	(define_expand "wrpkru"): Ditto.
	(define_insn "*wrpkru"): Ditto.
	* config/i386/i386.opt (mpku): Ditto.
	* config/i386/pkuintrin.h: New file.
	* config/i386/x86intrin.h: Include pkuintrin.h
	* doc/extend.texi: Describe new built-ins.
	* doc/invoke.texi: Describe new switches.
gcc/testsuite/
	* g++.dg/other/i386-2.C: Add -mpku.
	* g++.dg/other/i386-3.C: Ditto.
	* gcc.target/i386/rdpku-1.c: New test.
	* gcc.target/i386/sse-12.c: Add -mpku.
	* gcc.target/i386/sse-13.c: Ditto.
	* gcc.target/i386/sse-22.c: Ditto.
	* gcc.target/i386/sse-33.c: Ditto.
	* gcc.target/i386/wrpku-1.c: New test.

From-SVN: r231944