i386: Vectorize basic V2SFmode operations [PR94913]

i386: Vectorize basic V2SFmode operations [PR94913]

Enable V2SFmode vectorization and vectorize V2SFmode PLUS,
MINUS, MULT, MIN and MAX operations using XMM registers.

To avoid unwanted secondary effects (e.g. exceptions), load values
to XMM registers using MOVQ that clears high bits of the XMM
register outside V2SFmode.

The compiler now vectorizes e.g.:

float r[2], a[2], b[2];

void
test_plus (void)
{
  for (int i = 0; i < 2; i++)
    r[i] = a[i] + b[i];
}

to:
        movq    a(%rip), %xmm0
        movq    b(%rip), %xmm1
        addps   %xmm1, %xmm0
        movlps  %xmm0, r(%rip)
        ret

gcc/ChangeLog:

	PR target/95046
	* config/i386/i386.c (ix86_vector_mode_supported_p):
	Vectorize 3dNOW! vector modes for TARGET_MMX_WITH_SSE.
	* config/i386/mmx.md (*mov<mode>_internal): Do not set
	mode of alternative 13 to V2SF for TARGET_MMX_WITH_SSE.

	(mmx_addv2sf3): Change operand predicates from
	nonimmediate_operand to register_mmxmem_operand.
	(addv2sf3): New expander.
	(*mmx_addv2sf3): Add SSE/AVX alternatives.  Change operand
	predicates from nonimmediate_operand to register_mmxmem_operand.
	Enable instruction pattern for TARGET_MMX_WITH_SSE.

	(mmx_subv2sf3): Change operand predicate from
	nonimmediate_operand to register_mmxmem_operand.
	(mmx_subrv2sf3): Ditto.
	(subv2sf3): New expander.
	(*mmx_subv2sf3): Add SSE/AVX alternatives.  Change operand
	predicates from nonimmediate_operand to register_mmxmem_operand.
	Enable instruction pattern for TARGET_MMX_WITH_SSE.

	(mmx_mulv2sf3): Change operand predicates from
	nonimmediate_operand to register_mmxmem_operand.
	(mulv2sf3): New expander.
	(*mmx_mulv2sf3): Add SSE/AVX alternatives.  Change operand
	predicates from nonimmediate_operand to register_mmxmem_operand.
	Enable instruction pattern for TARGET_MMX_WITH_SSE.

	(mmx_<code>v2sf3): Change operand predicates from
	nonimmediate_operand to register_mmxmem_operand.
	(<code>v2sf3): New expander.
	(*mmx_<code>v2sf3): Add SSE/AVX alternatives.  Change operand
	predicates from nonimmediate_operand to register_mmxmem_operand.
	Enable instruction pattern for TARGET_MMX_WITH_SSE.
	(mmx_ieee_<ieee_maxmin>v2sf3): Ditto.

testsuite/ChangeLog:

	PR target/95046
	* gcc.target/i386/pr95046-1.c: New test.