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Re: [v3] libstdc++/44413 (for ext/vstring)

From: Paolo Carlini <paolo dot carlini at oracle dot com>
To: Doug Semler <dougsemler at gmail dot com>
Cc: libstdc++ <libstdc++ at gcc dot gnu dot org>
Date: Wed, 09 Jun 2010 15:59:40 +0200
Subject: Re: [v3] libstdc++/44413 (for ext/vstring)
References: <4C0F5D67.9010405@oracle.com> <AANLkTikQK8oOy3jRmpTV7NrtuYAfcr3haQ71DY4lusUY@mail.gmail.com>

On 06/09/2010 03:52 PM, Doug Semler wrote:
> I don't see it. You're really hurting the 32 bit side with this. The
> original is reduced to a subtraction, while the new code adds:
>
>         xorl    %eax, %eax
>         cmpl    $0, %edx
>         je      .L3
>         setg    %al
>         movzbl  %al, %eax
>         leal    -1(%eax,%eax), %eax
> .L3
>         ret
>
> In addition, it seems that the attempt only reduces the code by one move?
>   
Agreed, let's revert this. I don't think we are going to do much before
the next ABI, at least.

Paolo.

References:
- [v3] libstdc++/44413 (for ext/vstring)
  - From: Paolo Carlini
- Re: [v3] libstdc++/44413 (for ext/vstring)
  - From: Doug Semler

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