[Bug target/107093] AVX512 mask operations not simplified in fully masked loop

["crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107093

--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
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
34        addq    $32, %rax
35        kmovb   %esi, %k1
36        kortestb        %k1, %k1
37        jne     .L7
38        vzeroupper
39.L9:
40        ret
41        .p2align 4,,10
42        .p2align 3
43.L11:
44        vmovdqa .LC0(%rip), %xmm2
45        vpbroadcastd    %edi, %xmm1
46        vpcmpd  $1, %xmm1, %xmm2, %k1
47        jmp     .L3
48        .cfi_endproc