Created attachment 515984 [details] Test program There is something wrong with quadruple precision on i686, the results are rounded to double precision. This was picked up in fftw http://koji.fedoraproject.org/koji/taskinfo?taskID=3240201 A test program, compliments of fftw upstream is attached. $ gcc -m64 quadtest.c -lquadmath $ ./a.out 6.28318530717958647692528676655900559495813619627459 3.00000000000000000000000000000000000000000000000000 2.00000000000000000000000000000000000000000000000000 4.18879020478639098461685784437267065342941671581451 -0.49999999999999999999999999999999980740700556127641 -0.50000000000000000000000000000000000000000000000000 -0.86602540378443864676372317075293625737304587806740 0.86602540378443864676372317075293616107654865870560 round-off error here ^ $ gcc -m32 quadtest.c -lquadmath $ ./a.out 6.28318530717958647692528676655900559495813619627459 3.00000000000000000000000000000000000000000000000000 2.00000000000000000000000000000000000000000000000000 4.18879020478639098461685784437267065342941671581451 -0.50000000000000004643091056722032931785465127180831 -0.50000000000000000000000000000000000000000000000000 -0.86602540378443861995682445604883787468431152485478 0.86602540378443864676372317075293616107654865870560 round-off here ^
Excess precision issues :( Fixed upstream so far: http://gcc.gnu.org/ml/gcc-patches/2011-08/msg00014.html
gcc-4.6.1-6.fc16 has been submitted as an update for Fedora 16. https://admin.fedoraproject.org/updates/gcc-4.6.1-6.fc16
Can you fix this on Fedora 15 as well? It suffers from the same bug...
Eventually yes, but will wait a bit to accumulate more issues, get the new OpenMP 3.1 stuff tested, etc.
Package gcc-4.6.1-6.fc16: * should fix your issue, * was pushed to the Fedora 16 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing gcc-4.6.1-6.fc16' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/gcc-4.6.1-6.fc16 then log in and leave karma (feedback).
Please push and build gcc-4.6.1-6 (or newer) on rawhide, since the current version there is 4.6.1-3.fc16...
All that is needed is one karma from a proventester...
Package gcc-4.6.1-7.fc16: * should fix your issue, * was pushed to the Fedora 16 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing gcc-4.6.1-7.fc16' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/gcc-4.6.1-7.fc16 then log in and leave karma (feedback).
gcc-4.6.1-7.fc16 has been pushed to the Fedora 16 stable repository. If problems still persist, please make note of it in this bug report.