Add support for Loongson EXT2 instructions.

Add support for Loongson EXT2 instructions.

gcc/
	* config/mips/mips-protos.h
	(mips_loongson_ext2_prefetch_cookie): New prototype.
	* config/mips/mips.c (mips_loongson_ext2_prefetch_cookie): New.
	(mips_option_override): Enable TARGET_LOONGSON_EXT when
	TARGET_LOONGSON_EXT2 is true.
	* config/mips/mips.h (TARGET_CPU_CPP_BUILTINS): Define
	__mips_loongson_ext2, __mips_loongson_ext_rev=2.
	(ISA_HAS_CTZ_CTO): New, true if TARGET_LOONGSON_EXT2.
	(ISA_HAS_PREFETCH): Include TARGET_LOONGSON_EXT and
	TARGET_LOONGSON_EXT2.
	(ASM_SPEC): Add mloongson-ext2 and mno-loongson-ext2.
	(define_insn "ctz<mode>2"): New insn pattern.
	(define_insn "prefetch"): Include TARGET_LOONGSON_EXT2.
	(define_insn "prefetch_indexed_<mode>"): Include
	TARGET_LOONGSON_EXT and TARGET_LOONGSON_EXT2.
	* config/mips/mips.opt (-mloongson-ext2): Add option.
	* gcc/doc/invoke.texi (-mloongson-ext2): Document.

gcc/testsuite/
	* gcc.target/mips/loongson-ctz.c: New test.
	* gcc.target/mips/loongson-dctz.c: Likewise.
	* gcc.target/mips/mips.exp (mips_option_groups): Add
	-mloongson-ext2 option.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@265864 138bc75d-0d04-0410-961f-82ee72b054a4