[Bug target/31667] Integer extensions vectorization could be improved

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31667

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
We produce this now:

        movdqa  x(%rip), %xmm1
        pxor    %xmm0, %xmm0
        movdqa  %xmm1, %xmm2
        punpckhbw       %xmm0, %xmm1
        movaps  %xmm1, y+16(%rip)
        movdqa  x+16(%rip), %xmm1
        punpcklbw       %xmm0, %xmm2
        movaps  %xmm2, y(%rip)
        movdqa  %xmm1, %xmm2
        punpckhbw       %xmm0, %xmm1
        movaps  %xmm1, y+48(%rip)
        movdqa  x+32(%rip), %xmm1
        punpcklbw       %xmm0, %xmm2
        movaps  %xmm2, y+32(%rip)
        movdqa  %xmm1, %xmm2
        punpckhbw       %xmm0, %xmm1
        movaps  %xmm1, y+80(%rip)
        movdqa  x+48(%rip), %xmm1
        punpcklbw       %xmm0, %xmm2
        movaps  %xmm2, y+64(%rip)
        movdqa  %xmm1, %xmm2
        punpckhbw       %xmm0, %xmm1
        punpcklbw       %xmm0, %xmm2
        movaps  %xmm1, y+112(%rip)
        movaps  %xmm2, y+96(%rip)

And even ICC produce a similar thing except scheduled differently.