i386: Fix up splitters into vptest [PR119357]

The following testcase ICEs, because the splitters into vptest
create an invalid instruction.  The operands of all the UNSPEC_PTEST
using instructions use register_operand and vector_operand predicate,
these splitters use vector_operand predicate but create vptest
instruction which has the same argument twice, so one of them needs
to be in a register.
The following patch keeps vector_operand predicate on the splitters
but uses force_reg to force it into a REG if it was a MEM, that results
in better code generation e.g. on the included testcase, as combine
can match those even with MEM.
The difference on the testcase is
-       vpxor   %xmm0, %xmm0, %xmm0
-       vpcmpeqb        (%rdi), %xmm0, %xmm0
-       vpmovmskb       %xmm0, %eax
-       cmpl    $65535, %eax
+       vmovdqa (%rdi), %xmm0
+       vptest  %xmm0, %xmm0
(- for patch which changes the splitters to
s/vector_operand/register_operand/ and + for this patch).

2025-03-19  Jakub Jelinek  <jakub@redhat.com>

	PR target/119357
	* config/i386/sse.md (pmovmskb 0xffff to ptest splitter,
	*pmovsk_ptest_<mode>_avx512): Force operands[0] into a REG.

	* gcc.target/i386/avx512vlbw-pr119357.c: New test.

0 files changed, 0 insertions, 0 deletions