On Tue, Sep 8, 2015 at 3:16 PM, Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx> wrote: > On 2015.09.08 at 14:40 +0200, Mathieu Malaterre wrote: >> On Tue, Sep 8, 2015 at 2:00 PM, Mathieu Malaterre <malat@xxxxxxxxxx> wrote: >> > FYI, >> > >> > On Tue, Sep 8, 2015 at 12:04 PM, Jonathan Wakely <jwakely.gcc@xxxxxxxxx> wrote: >> > [...] >> >> That's not the only option. You could compile one file with GCC and >> >> all others with Clang and see if you can reproduce it. Repeat for each >> >> file, which will narrow down the file where the problem occurs. Then >> >> you can try splitting that file into smaller pieces, with one function >> >> per file, and repeat the process. That would tell you which function >> >> or functions get miscompiled by GCC. >> > >> > Ok so if I compile eveything with gcc and then only `tcd.c` using >> > clang, then everything works as expected (no symptoms). >> > ref: https://github.com/uclouvain/openjpeg/blob/master/src/lib/openjp2/tcd.c >> > >> > I'll repeat your approach to find the culprit function. >> >> And the culprit function is `opj_tcd_makelayer`: >> >> https://github.com/uclouvain/openjpeg/blob/master/src/lib/openjp2/tcd.c#L218 >> >> Other than the `if (dd / dr >= thresh)` I do not see anything >> obviously suspicious. > > Looks like a x87 vs. SSE2 issue. You could try adding "-msse2 > -mfpmath=sse" for the -m32 case. Indeed that fixes the symptoms. I'll check with upstream how best to rewrite the floating point comparison. Thx for the help everyone.
