[Bug c/26528] New: [4.2 regression] gcc miscompiles FFTW 3.1

["martin at mpa-garching dot mpg dot de" <gcc-bugzilla at gcc dot gnu dot org>]

Current mainline gcc appears to miscompile FFTW:

wget http://fftw.org/fftw-3.1.tar.gz
tar xvzf fftw-3.1.tar.gz
cd fftw-3.1
/scratch/fftw-3.1> gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /scratch/gcc/configure --quiet
--prefix=/afs/mpa/data/martin/ugcc --enable-languages=c++,fortran
--with-gmp=/usr/local/appl/gmp-4.1.4 --enable-checking=release
--without-makeinfo
Thread model: posix
gcc version 4.2.0 20060301 (experimental)
/scratch/fftw-3.1> ./configure --enable-portable-binary
[...]
/scratch/fftw-3.1> make check
[...]
Executing "/scratch/fftw-3.1/tests/bench --verbose=1   --verify
ok12o10x6e10x11o00v7 --verify ik12o10x
6e10x11o00v7 --verify obr3v79 --verify ibr3v79 --verify ofr3v79 --verify
ifr3v79 --verify //obc3v79 --
verify //ibc3v79 --verify //ofc3v79 --verify //ifc3v79 --verify obc3v79
--verify ibc3v79 --verify ofc3
v79 --verify ifc3v79 --verify ok2hx5e00x3e10x7o11*6 --verify
ik2hx5e00x3e10x7o11*6 --verify //obr10x8x
33 --verify //ofr10x8x33 --verify obr10x8x33 --verify ibr10x8x33 --verify
ofr10x8x33 --verify ifr10x8x
33 --verify //obc10x8x33 --verify //ibc10x8x33 --verify //ofc10x8x33 --verify
//ifc10x8x33 --verify ob
c10x8x33 --verify ibc10x8x33 --verify ofc10x8x33 --verify ifc10x8x33 --verify
ok11o00*45 --verify ik11
o00*45 --verify obr6x4v7 --verify ibr6x4v7 --verify ofr6x4v7 --verify ifr6x4v7
--verify //obc6x4v7 --v
erify //ibc6x4v7 --verify //ofc6x4v7 --verify //ifc6x4v7 --verify obc6x4v7
--verify ibc6x4v7 --verify 
ofc6x4v7 --verify ifc6x4v7"
2.65417e-16 4.02852e-15 3.09912e-16
2.76156e-16 2.52972e-15 2.83568e-16
2.17601e-16 3.37283e-16 2.97118e-16
2.03315e-16 3.37283e-16 2.49555e-16
2.33093e-16 1.49904e-16 3.95845e-16
2.09027e-16 1.49904e-16 3.70199e-16
1.94987e-16 2.24855e-16 4.92525e-16
1.97747e-16 2.24855e-16 5.28462e-16
1.71722e-16 2.24855e-16 4.74119e-16
2.0242e-16 2.24855e-16 5.51321e-16
1.85902e-16 2.24855e-16 4.94966e-16
2.13346e-16 2.24855e-16 4.9348e-16
2.12188e-16 2.24855e-16 5.26624e-16
2.12652e-16 2.24855e-16 4.99894e-16
2.75703e-16 2.60691e-15 2.91529e-16
4.46832e-16 4.43175e-15 3.46477e-16
FAILED /scratch/fftw-3.1/tests/bench:  --verify ok12o10x6e10x11o00v7 --verify
ik12o10x6e10x11o00v7 --v
erify obr3v79 --verify ibr3v79 --verify ofr3v79 --verify ifr3v79 --verify
//obc3v79 --verify //ibc3v79
 --verify //ofc3v79 --verify //ifc3v79 --verify obc3v79 --verify ibc3v79
--verify ofc3v79 --verify ifc
3v79 --verify ok2hx5e00x3e10x7o11*6 --verify ik2hx5e00x3e10x7o11*6 --verify
//obr10x8x33 --verify //of
r10x8x33 --verify obr10x8x33 --verify ibr10x8x33 --verify ofr10x8x33 --verify
ifr10x8x33 --verify //ob
c10x8x33 --verify //ibc10x8x33 --verify //ofc10x8x33 --verify //ifc10x8x33
--verify obc10x8x33 --verif
y ibc10x8x33 --verify ofc10x8x33 --verify ifc10x8x33 --verify ok11o00*45
--verify ik11o00*45 --verify 
obr6x4v7 --verify ibr6x4v7 --verify ofr6x4v7 --verify ifr6x4v7 --verify
//obc6x4v7 --verify //ibc6x4v7
 --verify //ofc6x4v7 --verify //ifc6x4v7 --verify obc6x4v7 --verify ibc6x4v7
--verify ofc6x4v7 --verif
y ifc6x4v7
received signal 11
make[2]: *** [check-local] Error 1
make[2]: Leaving directory `/scratch/fftw-3.1/tests'
make[1]: *** [check-am] Error 2
make[1]: Leaving directory `/scratch/fftw-3.1/tests'
make: *** [check-recursive] Error 1


The current 4.1 and 4.0 branches pass the FFTW tests. Gomp-branch fails.

I know that this is not a very useful bug report, but I have no idea how
to reduce the problem. A regression hunt might at least localise the
problematic
commit and help to decide whether gcc or FFTW is to blame.


-- 
           Summary: [4.2 regression] gcc miscompiles FFTW 3.1
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: martin at mpa-garching dot mpg dot de
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


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