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Re: Predictive commoning miscompiles 482.sphinx3 in SPEC CPU 2006
- From: "H. J. Lu" <hjl at lucon dot org>
- To: gcc at gcc dot gnu dot org
- Cc: dvorakz at suse dot cz
- Date: Fri, 1 Jun 2007 09:44:20 -0700
- Subject: Re: Predictive commoning miscompiles 482.sphinx3 in SPEC CPU 2006
- References: <20070601163754.GA9949@lucon.org>
On Fri, Jun 01, 2007 at 09:37:54AM -0700, H. J. Lu wrote:
> The predictive commoning patch:
>
> http://gcc.gnu.org/ml/gcc-patches/2007-05/msg01061.html
>
> miscompiles 482.sphinx3 in SPEC CPU 2006 with -O2 -ffast-math on
> Linux/x86-64. Zdenek, do you have any ideas?
>
Something is wrong. Predictive commoning is supposed to be turned
on at -O3. But it definitely afffects -O2. Why?
H.J.