See https://wwws.clamav.net/bugzilla/show_bug.cgi?id=2190
$ g++-4.5 -fprefetch-loop-arrays TargetLowering.ii -c -O2 ../../../../clamav-devel/libclamav/c++/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp: In member function void llvm::TargetLowering::computeRegisterProperties(): ../../../../clamav-devel/libclamav/c++/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp:608:6: internal compiler error: in verify_expr, at tree-cfg.c:2541 Please submit a full bug report, with preprocessed source if appropriate. See <file:///usr/share/doc/gcc-4.5/README.Bugs> for instructions. g++-4.4 works: $ g++-4.4 -fprefetch-loop-arrays TargetLowering.ii -c -O2 $ g++-4.5 -v Using built-in specs. COLLECT_GCC=/usr/bin/g++-4.5 COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.5.1/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Debian 4.5.1-1' --with-bugurl=file:///usr/share/doc/gcc-4.5/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared --enable-multiarch --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.5 --program-suffix=-4.5 --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin --enable-gold --with-plugin-ld=ld.gold --enable-objc-gc --with-arch-32=i586 --with-tune=generic --enable-checking=yes --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.5.1 (Debian 4.5.1-1) -- Summary: g++4.5: -prefetch-loop-arrays internal compiler error: in verify_expr, at tree-cfg.c:2541 Product: gcc Version: 4.5.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: edwintorok at gmail 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=45260