https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102812
--- Comment #3 from Hongyu Wang <wwwhhhyyy333 at gmail dot com> ---
(In reply to Uroš Bizjak from comment #2)
> Please note that the code above should compile via ix86_expand_vector_set,
> similar to:
>
> --cut here--
> typedef short v8hi __attribute__((__vector_size__(16)));
>
> v8hi foo (short a)
> {
> return (v8hi) {a, 0, 0, 0, 0, 0, 0, 0 };
> }
> --cut here--
>
> that results in:
>
> vpxor %xmm0, %xmm0, %xmm0
> vpinsrw $0, %edi, %xmm0, %xmm0
> ret
Currently we have
if (TARGET_AVX512FP16 && VALID_AVX512FP16_REG_MODE (mode))
return true;
in ix86_vector_mode_supported_p, so for SSE2 target V8HFmode would be returned
in BLKmode.
After I put V8HFmode to VALID_SSE2_REG_MODE the code would be like
vmovss %xmm0, %xmm0, %xmm1
vpxor %xmm0, %xmm0, %xmm0
pextrw $0, %xmm1, -10(%rsp)
vpinsrw $0, -10(%rsp), %xmm0, %xmm0
Seems IRA spills the HF reg to memory..
I wonder whether we should move vector mode support to sse2 for now, as we
don't have sufficient HF vector arithmetic emulation for non-avx512fp16 target.
