http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52754
Bug #: 52754 Summary: [4.7 regression, miscompilation] indirect indexing broken with -fpredictive-commoning Classification: Unclassified Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: other AssignedTo: unassig...@gcc.gnu.org ReportedBy: kr...@kde.org Created attachment 27022 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27022 testcase The attached testcase is compiled to access the indexes array at bogus offsets. If line 8 is removed and line 7 written as unsigned int indexes[8] = { 0, 1, 2, 3, 4, 5, 6, 7 }; the error disappears. % /opt/gcc-4.7.0/bin/g++ -msse2 -v -O1 -fpredictive-commoning main.cpp Using built-in specs. COLLECT_GCC=/opt/gcc-4.7.0/bin/g++ COLLECT_LTO_WRAPPER=/opt/gcc-4.7.0/libexec/gcc/x86_64-linux-gnu/4.7.0/lto-wrapper Target: x86_64-linux-gnu Configured with: ./configure --prefix=/opt/gcc-4.7.0 --build=x86_64-linux-gnu --host=x86_64-linux-gnu --enable-languages=c,c++,fortran --with-gmp=/opt/gcc-4.7.0 --with-mpfr=/opt/gcc-4.7.0 --with-ppl=/opt/gcc-4.7.0 --with-cloog=/opt/gcc-4.7.0 --with-libelf=/opt/gcc-4.7.0 --with-mpc=/opt/gcc-4.7.0 --enable-lto Thread model: posix gcc version 4.7.0 (GCC) COLLECT_GCC_OPTIONS='-msse2' '-v' '-O1' '-fpredictive-commoning' '-shared-libgcc' '-mtune=generic' '-march=x86-64' /opt/gcc-4.7.0/libexec/gcc/x86_64-linux-gnu/4.7.0/cc1plus -quiet -v -imultiarch x86_64-linux-gnu -D_GNU_SOURCE main.cpp -quiet -dumpbase main.cpp -msse2 -mtune=generic -march=x86-64 -auxbase main -O1 -version -fpredictive-commoning -o /tmp/ccmv6Zx9.s GNU C++ (GCC) version 4.7.0 (x86_64-linux-gnu) compiled by GNU C version 4.7.0, GMP version 5.0.4, MPFR version 3.1.0, MPC version 0.9 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu" ignoring nonexistent directory "/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../x86_64-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../include/c++/4.7.0 /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../include/c++/4.7.0/x86_64-linux-gnu /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../include/c++/4.7.0/backward /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/include /usr/local/include /opt/gcc-4.7.0/include /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/include-fixed /usr/include/x86_64-linux-gnu /usr/include End of search list. GNU C++ (GCC) version 4.7.0 (x86_64-linux-gnu) compiled by GNU C version 4.7.0, GMP version 5.0.4, MPFR version 3.1.0, MPC version 0.9 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: 32eb1a24aeca8b97e0c59b4b063f668f COLLECT_GCC_OPTIONS='-msse2' '-v' '-O1' '-fpredictive-commoning' '-shared-libgcc' '-mtune=generic' '-march=x86-64' /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../x86_64-linux-gnu/bin/as --64 -o /tmp/cca4x2R5.o /tmp/ccmv6Zx9.s COMPILER_PATH=/opt/gcc-4.7.0/libexec/gcc/x86_64-linux-gnu/4.7.0/:/opt/gcc-4.7.0/libexec/gcc/x86_64-linux-gnu/4.7.0/:/opt/gcc-4.7.0/libexec/gcc/x86_64-linux-gnu/:/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/:/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/:/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../x86_64-linux-gnu/bin/ LIBRARY_PATH=/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/:/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../lib64/:/lib/x86_64-linux-gnu/:/lib/../lib64/:/usr/lib/x86_64-linux-gnu/:/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../x86_64-linux-gnu/lib/:/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-msse2' '-v' '-O1' '-fpredictive-commoning' '-shared-libgcc' '-mtune=generic' '-march=x86-64' /opt/gcc-4.7.0/libexec/gcc/x86_64-linux-gnu/4.7.0/collect2 --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 /usr/lib/x86_64-linux-gnu/crt1.o /usr/lib/x86_64-linux-gnu/crti.o /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/crtbegin.o -L/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0 -L/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../lib64 -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../../../x86_64-linux-gnu/lib -L/opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/../../.. /tmp/cca4x2R5.o -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /opt/gcc-4.7.0/lib/gcc/x86_64-linux-gnu/4.7.0/crtend.o /usr/lib/x86_64-linux-gnu/crtn.o % ./a.out [1] 7716 bus error ./a.out