re PR tree-optimization/88464 (AVX-512 vectorization of masked scatter failing with...

re PR tree-optimization/88464 (AVX-512 vectorization of masked scatter failing with "not suitable for scatter store")

	PR tree-optimization/88464
	PR target/88498
	* tree-vect-stmts.c (vect_build_gather_load_calls): For NARROWING
	and mask with integral masktype, don't try to permute mask vectors,
	instead emit VEC_UNPACK_{LO,HI}_EXPR.  Fix up NOP_EXPR operand.
	(vectorizable_store): Handle masked scatters with decl and integral
	mask type.
	(permute_vec_elements): Allow scalar_dest to be NULL.
	* config/i386/i386.c (ix86_get_builtin)
	<case IX86_BUILTIN_GATHER3ALTDIV16SF>: Use lowpart_subreg for masks.
	<case IX86_BUILTIN_GATHER3ALTDIV8SF>: Don't assume mask and src have
	to be the same.

	* gcc.target/i386/avx512f-pr88462-1.c: Rename to ...
	* gcc.target/i386/avx512f-pr88464-1.c: ... this.  Fix up PR number.
	Expect 4 vectorized loops instead of 3.
	(f4): New function.
	* gcc.target/i386/avx512f-pr88462-2.c: Rename to ...
	* gcc.target/i386/avx512f-pr88464-2.c: ... this.  Fix up PR number
	and #include.
	(avx512f_test): Prepare arguments for f4 and check the results.
	* gcc.target/i386/avx512f-pr88464-3.c: New test.
	* gcc.target/i386/avx512f-pr88464-4.c: New test.

From-SVN: r267169