[Patch ARM 17/17] Enable _Float16 for ARM and fix PR target/63250

[Patch ARM 17/17] Enable _Float16 for ARM and fix PR target/63250

gcc/

	PR target/63250
	* config/arm/arm-builtins.c (arm_simd_floatHF_type_node): Rename to...
	(arm_fp16_type_node): ...This, make visibile.
	(arm_simd_builtin_std_type): Rename arm_simd_floatHF_type_node to
	arm_fp16_type_node.
	(arm_init_simd_builtin_types): Likewise.
	(arm_init_fp16_builtins): Likewise.
	* config/arm/arm.c (arm_excess_precision): New.
	(arm_floatn_mode): Likewise.
	(TARGET_C_EXCESS_PRECISION): Likewise.
	(TARGET_FLOATN_MODE): Likewise.
	(arm_promoted_type): Only promote arm_fp16_type_node.
	* config/arm/arm.h (arm_fp16_type_node): Declare.

gcc/testsuite/

	PR target/63250
	* lib/target-supports.exp (add_options_for_float16): Add
	-mfp16-format=ieee when testign arm*-*-*.

From-SVN: r242784