[Bug tree-optimization/54939] Very poor vectorization of loops with complex arithmetic

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54939

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
                 CC|                            |crazylht at gmail dot com

--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
With SSE4.2 we now get

.L3:
        movupd  (%rdx,%rax), %xmm0
        movupd  (%rcx,%rax), %xmm4
        movapd  %xmm0, %xmm1
        palignr $8, %xmm0, %xmm0
        mulpd   %xmm3, %xmm1
        mulpd   %xmm2, %xmm0
        addpd   %xmm4, %xmm1
        addsubpd        %xmm0, %xmm1
        movups  %xmm1, (%rcx,%rax)
        addq    $16, %rax
        cmpq    %rsi, %rax
        jne     .L3

with AVX and FMA

.L4:
        vmovupd (%rdx,%rax), %ymm0
        vmovapd %ymm4, %ymm1
        vfmadd213pd     (%rcx,%rax), %ymm0, %ymm1
        vpermilpd       $5, %ymm0, %ymm0
        vmulpd  %ymm3, %ymm0, %ymm0
        vaddsubpd       %ymm0, %ymm1, %ymm1
        vmovupd %ymm1, (%rcx,%rax)
        addq    $32, %rax
        cmpq    %rsi, %rax
        jne     .L4

so I'd say fixed.  But.  With AVX512 we now get

.L4:
        vmovupd (%rdi,%rax), %zmm0
        vmovapd %zmm7, %zmm2
        vmovapd %zmm4, %zmm6
        vfmadd213pd     (%rcx,%rax), %zmm0, %zmm2
        vpermilpd       $85, %zmm0, %zmm0
        vfmadd132pd     %zmm0, %zmm2, %zmm6
        vfnmadd132pd    %zmm4, %zmm2, %zmm0
        vmovapd %zmm6, %zmm0{%k1}
        vmovupd %zmm0, (%rcx,%rax)
        addq    $64, %rax
        cmpq    %rax, %rsi
        jne     .L4

it's odd that this only happens with -mprefer-vector-width=512 though.  Do
we possibly miss vec_{fm,}{addsub,subadd} for those?  Looks like so.

Tracking in PR110767.  The vectorizer side is fixed.