[PATCH] x86: Don't enable LZCNT/POPCNT if disabled explicitly

[Uros Bizjak]

On Fri, Jul 30, 2021 at 3:04 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> gcc/
>
>         PR target/101685
>         * config/i386/i386-options.c (ix86_option_override_internal):
>         Don't enable LZCNT/POPCNT if they have been disabled explicitly.
>
> gcc/testsuite/
>
>         PR target/101685
>         * gcc.target/i386/pr-101685.c: New test.

OK.

Thanks,
Uros.

> ---
>  gcc/config/i386/i386-options.c            |  6 ++++--
>  gcc/testsuite/gcc.target/i386/pr-101685.c | 10 ++++++++++
>  2 files changed, 14 insertions(+), 2 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr-101685.c
>
> diff --git a/gcc/config/i386/i386-options.c b/gcc/config/i386/i386-options.c
> index 3416a4f1752..6b789988baa 100644
> --- a/gcc/config/i386/i386-options.c
> +++ b/gcc/config/i386/i386-options.c
> @@ -2124,8 +2124,10 @@ ix86_option_override_internal (bool main_args_p,
>         if (((processor_alias_table[i].flags & PTA_ABM) != 0)
>             && !TARGET_EXPLICIT_ABM_P (opts))
>           {
> -           SET_TARGET_LZCNT (opts);
> -           SET_TARGET_POPCNT (opts);
> +           if (!TARGET_EXPLICIT_LZCNT_P (opts))
> +             SET_TARGET_LZCNT (opts);
> +           if (!TARGET_EXPLICIT_POPCNT_P (opts))
> +             SET_TARGET_POPCNT (opts);
>           }
>
>         if ((processor_alias_table[i].flags
> diff --git a/gcc/testsuite/gcc.target/i386/pr-101685.c b/gcc/testsuite/gcc.target/i386/pr-101685.c
> new file mode 100644
> index 00000000000..0c743ecad00
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr-101685.c
> @@ -0,0 +1,10 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -march=amdfam10 -mno-lzcnt -mno-popcnt" } */
> +
> +#ifdef __LZCNT__
> +# error LZCNT should be disabled
> +#endif
> +
> +#ifdef __POPCNT__
> +# error POPCNT should be disabled
> +#endif
> --
> 2.31.1
>