Revert patch.

Revert patch.

2021-08-24  Michael Meissner  <meissner@linux.ibm.com>

gcc/
	Revert patch.
	* config/rs6000/constraints.md (eW): New constraint.
	* config/rs6000/predicates.md (xxspltiw_operand): New predicate.
	(easy_vector_constant): If we can use XXSPLTIW, the vector
	constant is easy.
	* config/rs6000/rs6000-protos.h (xxspltiw_constant_p): New
	declaration.
	* config/rs6000/rs6000.c (xxspltib_constant_p): If we can generate
	XXSPLTIW, don't generate a XXSPLTIB and an extend instruction.
	(const_vector_all_elements_equal_p): New function.
	(xxspltiw_constant_p): New function.
	(output_vec_const_move): Add support for loading up vector
	constants with XXSPLTIW.
	(prefixed_permute_p): Recognize xxspltiw instructions as
	prefixed.
	* config/rs6000/rs6000.opt (-mxxspltiw): New debug switch.
	* config/rs6000/vsx.md (vsx_mov<mode>_64bit): Add support for
	constants loaded with XXSPLTIW.
	(vsx_mov<mode>_32bit): Likewise.
	(vsx_splat_v8hi_xxspltiw): New insn.
	(vsx_splat_v4si_xxspltiw): New insn.
	(vsx_splat_v4sf_xxspltiw): New insn.

gcc/testsuite/
	Revert patch.
	* gcc.target/powerpc/vec-splat-constant-v16qi.c: New test.
	* gcc.target/powerpc/vec-splat-constant-v4sf.c: New test.
	* gcc.target/powerpc/vec-splat-constant-v4si.c: New test.
	* gcc.target/powerpc/vec-splat-constant-v8hi.c: New test.
	* gcc.target/powerpc/vec-splati-runnable.c: Update insn counts.