From: "H.J. Lu" <hjl.tools@gmail.com>
To: Noah Goldstein <goldstein.w.n@gmail.com>
Cc: libc-alpha@sourceware.org, carlos@systemhalted.org
Subject: Re: [PATCH v1 4/4] x86: Use `testb` for FSRM check in memmove-vec-unaligned-erms
Date: Thu, 20 Oct 2022 10:03:39 -0700 [thread overview]
Message-ID: <CAMe9rOrAwCLTksJn2WZBh_y16FOads82vuDWi_T-fkfH45xRBQ@mail.gmail.com> (raw)
In-Reply-To: <20221020021338.3394281-4-goldstein.w.n@gmail.com>
On Wed, Oct 19, 2022 at 7:14 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> `testb` saves a bit of code size is the imm-operand can be encoded
> 1-bytes.
>
> Tested on x86-64.
> ---
> sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S b/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
> index 5b758cae5e..f6d7f3e88b 100644
> --- a/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
> +++ b/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S
> @@ -616,7 +616,11 @@ L(movsb):
> jae L(large_memcpy_2x_check)
> # if AVOID_SHORT_DISTANCE_REP_MOVSB || ALIGN_MOVSB
> /* Only avoid short movsb if CPU has FSRM. */
> +# if X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB < 256
> + testb $X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB, __x86_string_control(%rip)
> +# else
> testl $X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB, __x86_string_control(%rip)
> +# endif
> jz L(skip_short_movsb_check)
> # if AVOID_SHORT_DISTANCE_REP_MOVSB
> /* Avoid "rep movsb" if RCX, the distance between source and
> --
> 2.34.1
>
LGTM.
Thanks.
--
H.J.
next prev parent reply other threads:[~2022-10-20 17:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 2:13 [PATCH v1 1/4] x86: Use `testb` for case-locale check in str{n}casecmp-avx2 Noah Goldstein
2022-10-20 2:13 ` [PATCH v1 2/4] x86: Use `testb` for case-locale check in str{n}casecmp-sse2 Noah Goldstein
2022-10-20 17:03 ` H.J. Lu
2022-10-20 2:13 ` [PATCH v1 3/4] x86: Use `testb` for case-locale check in str{n}casecmp-sse42 Noah Goldstein
2022-10-20 17:03 ` H.J. Lu
2022-10-20 2:13 ` [PATCH v1 4/4] x86: Use `testb` for FSRM check in memmove-vec-unaligned-erms Noah Goldstein
2022-10-20 17:03 ` H.J. Lu [this message]
2022-10-20 17:02 ` [PATCH v1 1/4] x86: Use `testb` for case-locale check in str{n}casecmp-avx2 H.J. Lu
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