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[Bug middle-end/26528] [4.2 regression] gcc miscompiles FFTW 3.1
- From: "martin at mpa-garching dot mpg dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 2 Mar 2006 13:52:24 -0000
- Subject: [Bug middle-end/26528] [4.2 regression] gcc miscompiles FFTW 3.1
- References: <bug-26528-2736@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #6 from martin at mpa-garching dot mpg dot de 2006-03-02 13:52 -------
(In reply to comment #5)
> Can you try "-O3 -fwrapv"? It might be the source have undefined code in it
> for signed overflow and changes to VRP exposed it.
Bingo! Thanks for this hint, I wouldn't have found that alone!
> Also do you know which file is being miscompiled? If so can you attach the
> dump generated by doing -O3 -fdump-tree-vrp-details?
Unfortunately I don't know which file causes the problem. I'm not a FFTW
developer, I just stumbled on this by accident.
If I understand correctly, this is most likely a bug in FFTW, right? If so,
I'll report it to FFTW people.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26528