$ gcc-4.2.0 -v Using built-in specs. Target: x86_64-unknown-linux-gnu Configured with: ../gcc-4.2.0/configure --enable-languages=c,c++,objc,obj-c++ --program-suffix=-4.2.0 Thread model: posix gcc version 4.2.0 $ gcc-4.2.0 divop.c -o divop $ ./divop 3CBA83 $ gcc-4.2.0 -ftree-vectorize -O2 divop.c -o divop $ ./divop 3CBA83 $ gcc-4.2.0 -ftree-vectorize -O2 -march=opteron divop.c -o divop $ ./divop 3CBA83 $ gcc-4.2.0 -ftree-vectorize -O2 -march=nocona divop.c -o divop $ ./divop 2B672F
This also affects GCC 4.1.1, I have not checked 4.1.2 or the 4.3 snapshots. In addition to -march=nocona it requires -O1/-O2/-O3 (-Os does not trigger it under 4.2.0, though it _does_ in 4.1.1). -- Summary: Miscompiles valid code with -ftree-vectorize and - march=nocona Product: gcc Version: 4.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: lloyd at randombit dot net 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=31966