Add support for Loongson 2K1000 processor.

Add support for Loongson 2K1000 processor.

gcc/
	* config/mips/gs264e.md: New.
	* config/mips/mips-cpus.def: Define gs264e.
	* config/mips/mips-tables.opt: Regenerate.
	* config/mips/mips.c (mips_rtx_cost_data): Add DEFAULT_COSTS for
	gs264e.
	(mips_issue_rate): Add support for gs264e.
	(mips_multipass_dfa_lookahead): Likewise.
	* config/mips/mips.h: Define TARGET_GS264E and TUNE_GS264E.
	(MIPS_ISA_LEVEL_SPEC): Infer mips64r2 from gs264e.
	(MIPS_ASE_MSA_SPEC): New.
	(BASE_DRIVER_SELF_SPECS): march=gs264e implies -mmsa.
	(ISA_HAS_FUSED_MADD4): Enable for TARGET_GS264E.
	(ISA_HAS_UNFUSED_MADD4): Exclude TARGET_GS264E.
	* config/mips/mips.md: Include gs264e.md.
	(processor): Add gs264e.
	* config/mips/mips.opt (MSA): Use Mask instead of Var.
	* doc/invoke.texi: Add gs264e to supported architectures.

From-SVN: r265867