[Bug target/95488] Suboptimal multiplication codegen for v16qi

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95488

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
   Last reconfirmed|                            |2020-06-16
         Resolution|FIXED                       |---
     Ever confirmed|0                           |1

--- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> ---
 -march=skylake-avx512 gave:

[hjl@gnu-cfl-2 gcc]$
/export/build/gnu/tools-build/gcc-debug/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/tools-build/gcc-debug/build-x86_64-linux/gcc/
/export/gnu/import/git/sources/gcc/gcc/testsuite/gcc.target/i386/avx512bw-pr95488-1.c
 -march=skylake-avx512   -fno-diagnostics-show-caret
-fno-diagnostics-show-line-numbers -fdiagnostics-color=never 
-fdiagnostics-urls=never  -O2  -ffat-lto-objects -fno-ident -S -o
avx512bw-pr95488-1.s
[hjl@gnu-cfl-2 gcc]$ cat avx512bw-pr95488-1.s
        .file   "avx512bw-pr95488-1.c"
        .text
        .p2align 4
        .globl  mul_512
        .type   mul_512, @function
mul_512:
.LFB0:
        .cfi_startproc
        vpunpcklbw      %ymm0, %ymm0, %ymm3
        vpunpcklbw      %ymm1, %ymm1, %ymm2
        vpunpckhbw      %ymm0, %ymm0, %ymm0
        vpunpckhbw      %ymm1, %ymm1, %ymm1
        vpmullw %ymm3, %ymm2, %ymm2
        vpmullw %ymm0, %ymm1, %ymm1
        vpshufb .LC0(%rip), %ymm2, %ymm0
        vpshufb .LC1(%rip), %ymm1, %ymm1
        vpor    %ymm1, %ymm0, %ymm0
        ret
        .cfi_endproc
.LFE0:
        .size   mul_512, .-mul_512
        .p2align 4
        .globl  umul_512
        .type   umul_512, @function
umul_512:
.LFB1:
        .cfi_startproc
        vpunpcklbw      %ymm0, %ymm0, %ymm3
        vpunpcklbw      %ymm1, %ymm1, %ymm2
        vpunpckhbw      %ymm0, %ymm0, %ymm0
        vpunpckhbw      %ymm1, %ymm1, %ymm1
        vpmullw %ymm3, %ymm2, %ymm2
        vpmullw %ymm0, %ymm1, %ymm1
        vpshufb .LC0(%rip), %ymm2, %ymm0
        vpshufb .LC1(%rip), %ymm1, %ymm1
        vpor    %ymm1, %ymm0, %ymm0
        ret
        .cfi_endproc
.LFE1:
        .size   umul_512, .-umul_512