https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107093
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Hongtao.liu from comment #4)
> change "*k, CBC" to "?k, CBC", in *mov{qi,hi,si,di}_internal.
> then RA works good to choose kxnor for setting constm1_rtx to mask register,
> and i got below with your attached patch(change #if 0 to #if 1), seems
> better than orginal patch.
>
> 6foo:
> 7.LFB0:
> 8 .cfi_startproc
> 9 testl %edi, %edi
> 10 jle .L9
> 11 kxnorb %k1, %k1, %k1
> 12 cmpl $4, %edi
> 13 jl .L11
> 14.L3:
> 15 vbroadcastsd .LC2(%rip), %ymm3
> 16 vmovdqa .LC0(%rip), %xmm2
> 17 xorl %eax, %eax
> 18 xorl %ecx, %ecx
> 19 .p2align 4,,10
> 20 .p2align 3
> 21.L7:
> 22 vmovapd b(%rax), %ymm0{%k1}
> 23 addl $4, %ecx
> 24 movl %edi, %edx
> 25 vmulpd %ymm3, %ymm0, %ymm1
> 26 subl %ecx, %edx
> 27 cmpl $4, %edx
> 28 vmovapd %ymm1, a(%rax){%k1}
> 29 vpbroadcastd %edx, %xmm1
> 30 movl $-1, %edx
> 31 vpcmpd $1, %xmm1, %xmm2, %k1
> 32 kmovb %k1, %esi
> 33 cmovge %edx, %esi
not sure if the round-trip to GPRs for the sake
of a cmovge is worth, I guess a branch would be
better.
