Re: [PATCH 1/2] Don't issue vzeroupper for vzeroupper call_insn.

[Uros Bizjak via Gcc-patches]

On Tue, Jun 27, 2023 at 7:55 AM liuhongt <hongtao....@intel.com> wrote:
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Ok for trunk?
>
> gcc/ChangeLog:
>
>         PR target/82735
>         * config/i386/i386.cc (ix86_avx_u127_mode_needed): Don't emit
>         vzeroupper for vzeroupper call_insn.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.target/i386/avx-vzeroupper-30.c: New test.
> ---
>  gcc/config/i386/i386.cc                           |  5 +++--
>  gcc/testsuite/gcc.target/i386/avx-vzeroupper-30.c | 15 +++++++++++++++
>  2 files changed, 18 insertions(+), 2 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/avx-vzeroupper-30.c
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> index 0761965344b..caca74d6dec 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -14489,8 +14489,9 @@ ix86_avx_u128_mode_needed (rtx_insn *insn)
>          modes wider than 256 bits.  It's only safe to issue a
>          vzeroupper if all SSE registers are clobbered.  */
>        const function_abi &abi = insn_callee_abi (insn);
> -      if (!hard_reg_set_subset_p (reg_class_contents[SSE_REGS],
> -                                 abi.mode_clobbers (V4DImode)))
> +      if (vzeroupper_pattern (PATTERN (insn), VOIDmode)
> +         || !hard_reg_set_subset_p (reg_class_contents[SSE_REGS],
> +                                    abi.mode_clobbers (V4DImode)))
>         return AVX_U128_ANY;

You also want to check for vzeroall_pattern here.

OK with the above change.

Thanks,
Uros.

>
>        return AVX_U128_CLEAN;
> diff --git a/gcc/testsuite/gcc.target/i386/avx-vzeroupper-30.c 
> b/gcc/testsuite/gcc.target/i386/avx-vzeroupper-30.c
> new file mode 100644
> index 00000000000..c1c9baa8fc4
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/avx-vzeroupper-30.c
> @@ -0,0 +1,15 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mavx -mvzeroupper -dp" } */
> +
> +#include <immintrin.h>
> +
> +extern __m256 x, y;
> +
> +void
> +foo ()
> +{
> +  x = y;
> +  _mm256_zeroupper ();
> +}
> +
> +/* { dg-final { scan-assembler-times "avx_vzeroupper" 1 } } */
> --
> 2.39.1.388.g2fc9e9ca3c
>