rs6000-c.c: Add support for built-in functions vector float vec_extract_fp32_from_sho...

rs6000-c.c: Add support for built-in functions vector float vec_extract_fp32_from_shorth...

gcc/ChangeLog:

2017-07-24  Carl Love  <cel@us.ibm.com>

	* config/rs6000/rs6000-c.c: Add support for built-in functions
	vector float vec_extract_fp32_from_shorth (vector unsigned short);
	vector float vec_extract_fp32_from_shortl (vector unsigned short);
	* config/rs6000/altivec.h (vec_extract_fp_from_shorth,
	vec_extract_fp_from_shortl): Add defines for the two builtins.
	* config/rs6000/rs6000-builtin.def (VEXTRACT_FP_FROM_SHORTH,
	VEXTRACT_FP_FROM_SHORTL): Add BU_P9V_OVERLOAD_1 and BU_P9V_VSX_1
	new builtins.
	* config/rs6000/vsx.md vsx_xvcvhpsp): Add define_insn.
	(vextract_fp_from_shorth, vextract_fp_from_shortl): Add define_expands.
	* doc/extend.texi: Update the built-in documentation file for the
	new built-in function.

gcc/testsuite/ChangeLog:

2017-07-24  Carl Love  <cel@us.ibm.com>

	* gcc.target/powerpc/builtins-3-p9-runnable.c: Add new test file for
	the new built-ins.

From-SVN: r250477