gcc reports ICE when compiling SVMlight software package (http://svmlight.joachims.org/) on x86_64 with -funsafe-math-optimizations. The following is the reduced code from the svm_hideo.c in SVMlight 6.01.
Occurs on: gcc-4.2.2 on x86_64, gcc-4.3.0 on x86_64, gcc-4.2.3 on i386, gcc-4.3.0 on i386 Doesn't occur on: gcc-4.1.3 on x86_64, gcc-4.1.3 on i386 $ cat >test.i <<__END__ double optimize_hildreth_despo(long n,long b1,long b2, double *g, double *g0, double *ce, double *ce0, double *low, double *up, double *init) { double t; if(ce[b1] != ce[b2]) { t = 0; } else if(((g[b1*n+b1]>0) || (g[b2*n+b2]>0))) { t=((ce[b2]/ce[b1])*g0[b1]-g0[b2]+ce0[0]*(g[b1*n+b1]*ce[b2]/ce[b1]-g[b1*n+b2]/ce[b1]))/((ce[b2]*ce[b2]/(ce[b1]*ce[b1]))*g[b1*n+b1]+g[b2*n+b2]-2*(g[b1*n+b2]*ce[b2]/ce[b1]))-init[b2]; if((up[b2]-init[b2]) < t) { t=up[b2]-init[b2]; } if((init[b2]-low[b2]) < -t) { t=-(init[b2]-low[b2]); } if((up[b1]-init[b1]) < -t) { t=-(up[b1]-init[b1]); } if((init[b1]-low[b1]) < t) { t=init[b1]-low[b1]; } } return t; } __END__ $ gcc-4.3 -funsafe-math-optimizations -O -c test.i test.i: In function 'optimize_hildreth_despo': test.i:2: internal compiler error: Segmentation fault Please submit a full bug report, with preprocessed source if appropriate. See <URL:http://gcc.gnu.org/bugs.html> for instructions. $ gcc-4.3 -v Using built-in specs. Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Debian 4.3-20080104-1' --with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3 --program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.3.0 20080104 (experimental) [trunk revision 131316] (Debian 4.3-20080104-1) $ uname -a Linux rainbow 2.6.22-3-amd64 #1 SMP Thu Oct 11 15:23:23 UTC 2007 x86_64 GNU/Linux -- Summary: ICE (SIGSEGV) in compiling valid code with -funsafe- math-optimizations Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: t-gcc-bugzilla at snowelm dot com GCC build triplet: x86_64-linux-gnu GCC host triplet: x86_64-linux-gnu GCC target triplet: x86_64-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34825