When I compile GSL 1.5 with the actual snapshot of gcc41 (gcc-4.1-20050410) I get an ICE:
gcc41 -O2 -fpeel-loops -ftree-vectorize -c permute.i -o permute.o permute_source.c: In function 'gsl_permute_complex_inverse': permute_source.c:87: internal compiler error: in check_loop_closed_ssa_use, at tree-ssa-loop-manip.c:394 Please submit a full bug report, with preprocessed source if appropriate. gcc41 -v Using built-in specs. Target: x86_64-unknown-linux-gnu Configured with: ../gcc-4.1-20050410/configure --prefix=/usr/local/gcc41g -- program-suffix=41g --with-arch=opteron --enable-languages=c,c++ --enable- checking Thread model: posix gcc version 4.1.0 20050410 (experimental) This ICE doesn't occur at -O1 or with snapshot gcc-4.1-20050403. Michael Cieslinski -- Summary: ICE in check_loop_closed_ssa_use, at tree-ssa-loop- manip.c:394 Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: micis at gmx dot de CC: gcc-bugs at gcc dot gnu dot org GCC build triplet: x86_64-unknown-linux-gnu GCC host triplet: x86_64-unknown-linux-gnu GCC target triplet: x86_64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20947