[NDS32] Add hard float support.

[NDS32] Add hard float support.

gcc/
	* config.gcc (nds32*-*-*): Add v2j v3f v3s checking.
	(nds32*-*-*): Add float and fpu_config into supported_defaults.
	* common/config/nds32/nds32-common.c (TARGET_DEFAULT_TARGET_FLAGS):
	Include TARGET_DEFAULT_FPU_ISA and TARGET_DEFAULT_FPU_FMA.
	* config/nds32/constants.md (unspec_element): Add UNSPEC_COPYSIGN,
	UNSPEC_FCPYNSD, UNSPEC_FCPYNSS, UNSPEC_FCPYSD and UNSPEC_FCPYSS.
	* config/nds32/constraints.md: New constraints and checking for hard
	float configuration.
	* config/nds32/iterators.md: New mode iterator and attribute for hard
	float configuration.
	* config/nds32/nds32-doubleword.md: Use hard float alternatives and
	patterns.
	* config/nds32/nds32-fpu.md: New file.
	* config/nds32/nds32-md-auxiliary.c: New functions and checkings to
	deal with hard float code generation.
	* config/nds32/nds32-opts.h (nds32_arch_type): Add ARCH_V3F and
	ARCH_V3S.
	(abi_type, float_reg_number): New enum type.
	* config/nds32/nds32-predicates.c: New predicates for hard float.
	* config/nds32/nds32-protos.h: Declare functions for hard float.
	* config/nds32/nds32.c: Implementation for hard float configuration.
	* config/nds32/nds32.h: Definitions for hard float configuration.
	* config/nds32/nds32.md: Include hard float machine description and
	modify patterns for hard float configuration.
	* config/nds32/nds32.opt: New options for hard float configuration.
	* config/nds32/predicates.md: New predicates for hard float
	configuration.

Co-Authored-By: Chung-Ju Wu <jasonwucj@gmail.com>
From-SVN: r259161