From: Denys Vlasenko <vda.linux@googlemail.com>
To: Rich Felker <dalias@libc.org>
Cc: musl <musl@lists.openwall.com>
Subject: Re: [PATCH] x86_64/memset: use "small block" code for blocks up to 30 bytes long
Date: Mon, 16 Feb 2015 11:09:25 +0100 [thread overview]
Message-ID: <CAK1hOcNRpkN_cK_sfW396+c41iops4weO_jVu2JEb7rs2h2JyQ@mail.gmail.com> (raw)
In-Reply-To: <20150215225559.GV23507@brightrain.aerifal.cx>
On Sun, Feb 15, 2015 at 11:55 PM, Rich Felker <dalias@libc.org> wrote:
>> "sub $8,%rcx" can be folded into lea.
>
> No, it can't, for the above reason.
Why can't?
lea -9(%rdx), %rcx
will also underflow for %rdx == 0, just like "lea -1".
next prev parent reply other threads:[~2015-02-16 10:09 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-13 16:39 Denys Vlasenko
2015-02-14 19:35 ` Rich Felker
2015-02-15 4:06 ` Rich Felker
2015-02-15 14:07 ` Denys Vlasenko
2015-02-15 15:03 ` Rich Felker
2015-02-15 21:44 ` Denys Vlasenko
2015-02-15 22:55 ` Rich Felker
2015-02-16 10:09 ` Denys Vlasenko [this message]
2015-02-16 15:12 ` Rich Felker
2015-02-16 17:36 ` Rich Felker
2015-02-17 13:08 ` Denys Vlasenko
2015-02-17 16:12 ` Rich Felker
2015-02-17 16:51 ` Denys Vlasenko
2015-02-17 17:30 ` Denys Vlasenko
2015-02-17 17:40 ` Rich Felker
2015-02-17 18:53 ` Denys Vlasenko
2015-02-17 21:12 ` Rich Felker
2015-02-18 9:05 ` Denys Vlasenko
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