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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Fri, 23 Jun 2023 09:31:49 -0700
Message-ID: <CAKwvOdnimxv8oJ4mVY74zqtt1x7KTMrWvn2_T9x22SFDbU6rHQ@mail.gmail.com>
Subject: Re: [PATCH 8/9] Makefile: Add loongarch target flag for Clang compilation
To:     WANG Xuerui <kernel@xen0n.name>
Cc:     Huacai Chen <chenhuacai@kernel.org>,
        WANG Rui <wangrui@loongson.cn>, Xi Ruoyao <xry111@xry111.site>,
        loongarch@lists.linux.dev, linux-kbuild@vger.kernel.org,
        llvm@lists.linux.dev, linux-kernel@vger.kernel.org,
        WANG Xuerui <git@xen0n.name>
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On Fri, Jun 23, 2023 at 6:44=E2=80=AFAM WANG Xuerui <kernel@xen0n.name> wro=
te:
>
> From: WANG Xuerui <git@xen0n.name>
>
> The LoongArch kernel is 64-bit and built with the soft-float ABI,
> hence the loongarch64-linux-gnusf target. (The "libc" part doesn't
> matter.)

Technically, IIRC llvm may make different decisions on libcall
optimizations based on the libc part of the target triple.  For
instance, is bcmp defined in that libc or not?  That's why we specify
-gnu or -musl (I forgot we did that for hexagon) explicitly rather
than leave that part of the triple blank.  Minutia that doesn't need
to be in this commit message, but now it's explicitly documented on
LKML and linkable-to.

>
> Signed-off-by: WANG Xuerui <git@xen0n.name>

Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  scripts/Makefile.clang | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang
> index 058a4c0f864e..6c23c6af797f 100644
> --- a/scripts/Makefile.clang
> +++ b/scripts/Makefile.clang
> @@ -4,6 +4,7 @@
>  CLANG_TARGET_FLAGS_arm         :=3D arm-linux-gnueabi
>  CLANG_TARGET_FLAGS_arm64       :=3D aarch64-linux-gnu
>  CLANG_TARGET_FLAGS_hexagon     :=3D hexagon-linux-musl
> +CLANG_TARGET_FLAGS_loongarch   :=3D loongarch64-linux-gnusf
>  CLANG_TARGET_FLAGS_m68k                :=3D m68k-linux-gnu
>  CLANG_TARGET_FLAGS_mips                :=3D mipsel-linux-gnu
>  CLANG_TARGET_FLAGS_powerpc     :=3D powerpc64le-linux-gnu
> --
> 2.40.0
>
>


--=20
Thanks,
~Nick Desaulniers