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From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 2 Nov 2021 14:14:14 -0700
Message-ID: <CAMe9rOpJ_82UO3Bvkif_5KJFmY+9_J8Tj1hBO---f2gvEALq6g@mail.gmail.com>
Subject: Re: [PATCH] x86-64: Replace movzx with movzbl
To: Fangrui Song <maskray@google.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
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On Tue, Nov 2, 2021 at 1:45 PM Fangrui Song <maskray@google.com> wrote:
>
> Clang cannot assemble movzx in the AT&T dialect mode.
>
> ../sysdeps/x86_64/strcmp.S:2232:16: error: invalid operand for instruction
>  movzx (%rsi), %ecx
>                ^~~~
>
> Change movzx to movzbl, which follows the AT&T dialect and is used
> elsewhere in the file.
> ---
>  sysdeps/x86_64/strcmp.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/sysdeps/x86_64/strcmp.S b/sysdeps/x86_64/strcmp.S
> index c7cbe4042a..bfe83abede 100644
> --- a/sysdeps/x86_64/strcmp.S
> +++ b/sysdeps/x86_64/strcmp.S
> @@ -2229,8 +2229,8 @@ LABEL(strcmp_exitz):
>
>         .p2align 4
>  LABEL(Byte0):
> -       movzx   (%rsi), %ecx
> -       movzx   (%rdi), %eax
> +       movzbl  (%rsi), %ecx
> +       movzbl  (%rdi), %eax
>
>  #if defined USE_AS_STRCASECMP_L || defined USE_AS_STRNCASECMP_L
>         leaq    _nl_C_LC_CTYPE_tolower+128*4(%rip), %rdx
> --
> 2.33.1.1089.g2158813163f-goog
>

LGTM.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.

-- 
H.J.