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Re: x86 inc/dec on core2
- From: "H. J. Lu" <hjl at lucon dot org>
- To: Uros Bizjak <ubizjak at gmail dot com>
- Cc: GCC <gcc at gcc dot gnu dot org>, Mike Stump <mrs at apple dot com>
- Date: Sat, 7 Apr 2007 07:10:47 -0700
- Subject: Re: x86 inc/dec on core2
- References: <4617648A.2050808@gmail.com>
On Sat, Apr 07, 2007 at 11:29:46AM +0200, Uros Bizjak wrote:
> Hello!
>
> >> I was wondering, if:
> >>
> >> /* X86_TUNE_USE_INCDEC */
> >> ~(m_PENT4 | m_NOCONA | m_CORE2 | m_GENERIC),
> >>
> >> is correct. Should it be:
> >>
> >> /* X86_TUNE_USE_INCDEC */
> >> ~(m_PENT4 | m_NOCONA | m_GENERIC),
> >>
> >> ?
> >
> >inc/dec has the same performance as add/sub on Core 2 Duo. But
> >inc/dec is shorter.
> >
>
> What about partial flag register dependency of inc/dec?
There is no partial flag register dependency on inc/dec.
H.J.