[Bug middle-end/26528] [4.2 regression] gcc miscompiles FFTW 3.1

Thu Mar 2 13:52:00 GMT 2006

------- 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.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26528