rs6000 Add vector blend, permute builtin support

rs6000 Add vector blend, permute builtin support

GCC maintainers:

The following patch adds support for the vec_blendv and vec_permx
builtins.

The patch has been compiled and tested on

  powerpc64le-unknown-linux-gnu (Power 8 LE)
  powerpc64le-unknown-linux-gnu (Power 9 LE)

with no regression errors.

The test cases were compiled on a Power 9 system and then tested on
Mambo.

                         Carl Love

rs6000 RFC2609 vector blend, permute instructions

gcc/ChangeLog

	    2020-08-04  Carl Love  <cel@us.ibm.com>

	* config/rs6000/altivec.h (vec_blendv, vec_permx): Add define.
	* config/rs6000/altivec.md (UNSPEC_XXBLEND, UNSPEC_XXPERMX.): New
	unspecs.
	(VM3): New define_mode.
	(VM3_char): New define_attr.
	(xxblend_<mode> mode VM3): New define_insn.
	(xxpermx): New define_expand.
	(xxpermx_inst): New define_insn.
	* config/rs6000/rs6000-builtin.def (VXXBLEND_V16QI, VXXBLEND_V8HI,
	VXXBLEND_V4SI, VXXBLEND_V2DI, VXXBLEND_V4SF, VXXBLEND_V2DF): New
	BU_P10V_3 definitions.
	(XXBLEND): New BU_P10_OVERLOAD_3 definition.
	(XXPERMX): New BU_P10_OVERLOAD_4 definition.
	* config/rs6000/rs6000-c.c (altivec_resolve_overloaded_builtin):
	(P10_BUILTIN_VXXPERMX): Add if statement.
	* config/rs6000/rs6000-call.c (P10_BUILTIN_VXXBLEND_V16QI,
	P10_BUILTIN_VXXBLEND_V8HI, P10_BUILTIN_VXXBLEND_V4SI,
	P10_BUILTIN_VXXBLEND_V2DI, P10_BUILTIN_VXXBLEND_V4SF,
	P10_BUILTIN_VXXBLEND_V2DF, P10_BUILTIN_VXXPERMX): Define
	overloaded arguments.
	(rs6000_expand_quaternop_builtin): Add if case for CODE_FOR_xxpermx.
	(builtin_quaternary_function_type): Add v16uqi_type and xxpermx_type
	variables, add case statement for P10_BUILTIN_VXXPERMX.
	(builtin_function_type): Add case statements for
	P10_BUILTIN_VXXBLEND_V16QI, P10_BUILTIN_VXXBLEND_V8HI,
	P10_BUILTIN_VXXBLEND_V4SI, P10_BUILTIN_VXXBLEND_V2DI.
	* doc/extend.texi: Add documentation for vec_blendv and vec_permx.

gcc/testsuite/ChangeLog

	    2020-08-04  Carl Love  <cel@us.ibm.com>
	* gcc.target/powerpc/vec-blend-runnable.c: New test.
	* gcc.target/powerpc/vec-permute-ext-runnable.c: New test.