Re: [PATCH] Disable avoid_false_dep_for_bmi for atom and icelake(and later) core processors.

[Uros Bizjak via Gcc-patches]

On Fri, May 26, 2023 at 4:46 AM liuhongt <hongtao....@intel.com> wrote:
>
> lzcnt/tzcnt has been fixed since skylake, popcnt has been fixed since
> icelake. At least for icelake and later intel Core processors, the
> errata tune is not needed. And the tune isn't need for ATOM either.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Ready to push to trunk.
>
>
> gcc/ChangeLog:
>
>         * config/i386/x86-tune.def (X86_TUNE_AVOID_FALSE_DEP_FOR_BMI):
>         Remove ATOM and ICELAKER(and later) core processors.

OK.

Thanks,
Uros.

> ---
>  gcc/config/i386/x86-tune.def | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/config/i386/x86-tune.def b/gcc/config/i386/x86-tune.def
> index 9d603cc84e4..e1c72cddf1f 100644
> --- a/gcc/config/i386/x86-tune.def
> +++ b/gcc/config/i386/x86-tune.def
> @@ -335,7 +335,8 @@ DEF_TUNE (X86_TUNE_USE_BT, "use_bt",
>  /* X86_TUNE_AVOID_FALSE_DEP_FOR_BMI: Avoid false dependency
>     for bit-manipulation instructions.  */
>  DEF_TUNE (X86_TUNE_AVOID_FALSE_DEP_FOR_BMI, "avoid_false_dep_for_bmi",
> -         m_SANDYBRIDGE | m_CORE_AVX2 | m_TREMONT | m_ALDERLAKE | m_CORE_ATOM
> +         m_SANDYBRIDGE | m_HASWELL | m_SKYLAKE | m_SKYLAKE_AVX512
> +         | m_CANNONLAKE | m_CASCADELAKE | m_COOPERLAKE
>           | m_LUJIAZUI | m_GENERIC)
>
>  /* X86_TUNE_ADJUST_UNROLL: This enables adjusting the unroll factor based
> --
> 2.39.1.388.g2fc9e9ca3c
>