http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61045
Bug ID: 61045 Summary: Wrong constant folding Product: gcc Version: 4.10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: ishiura-compiler at ml dot kwansei.ac.jp GCC 4.4.7 - 4.10.0 for x86_64 miscompiles the following code. $ cat test.c int main (void) { long a = 0; long b = 0x7FFFFFFFFFFFFFFFL; int t = (a - 2) > (b - 1); if (t != 0) { __builtin_abort(); }; return 0; } $ x86_64-unknown-linux-gnu-gcc-4.10.0 test.c -O2 $ ./a.out Aborted (core dumped) $ x86_64-unknown-linux-gnu-gcc-4.10.0 -v Using built-in specs. COLLECT_GCC=x86_64-unknown-linux-gnu-gcc-4.10.0 COLLECT_LTO_WRAPPER=/usr/local/x86_64-tools/gcc-4.10.0/libexec/gcc/x86_64-unknown-linux-gnu/4.10.0/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: /home/hassy/gcc/configure --prefix=/usr/local/x86_64-tools/gcc-4.10.0/ --with-gmp=/usr/local/gmp-5.1.1/ --with-mpfr=/usr/local/mpfr-3.1.2/ --with-mpc=/usr/local/mpc-1.0.1/ --disable-multilib --disable-nls --enable-languages=c Thread model: posix gcc version 4.10.0 20140502 (experimental) (GCC)