https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111048
Bug ID: 111048 Summary: [14 Regression] Wrong AVX2 code on highway-1.0.6 on -O2 and above Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: slyfox at gcc dot gnu.org Target Milestone: --- Noticed wrong code with r14-3259-g24f7b20bbd87eb when running tests on highway-1.0.6. Extracted example: // $ cat bug.cc.cc typedef unsigned char u8; __attribute__((noipa)) static void check(const u8 * v) { if (*v != 15) __builtin_trap(); } __attribute__((noipa)) static void bug(void) { u8 in_lanes[32]; for (unsigned i = 0; i < 32; i += 2) { in_lanes[i + 0] = 0; in_lanes[i + 1] = ((u8)0xff) >> (i & 7); } check(&in_lanes[13]); } int main() { bug(); } Triggering: $ g++ bug.cc.cc -mavx2 -O2 -o bug2 && ./bug2 Illegal $ g++ bug.cc.cc -mavx2 -O1 -o bug1 && ./bug1 <ok> $ g++ -v Using built-in specs. COLLECT_GCC=/<<NIX>>/gcc-14.0.0/bin/g++ COLLECT_LTO_WRAPPER=/<<NIX>>/gcc-14.0.0/libexec/gcc/x86_64-unknown-linux-gnu/14.0.0/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: ../source/configure --prefix=/<<NIX>>/gcc-14.0.0 --with-gmp-include=/<<NIX>>/gmp-6.3.0-dev/include --with-gmp-lib=/<<NIX>>/gmp-6.3.0/lib --with-mpfr-include=/<<NIX>>/mpfr-4.2.0-12-dev/include --with-mpfr-lib=/<<NIX>>/mpfr-4.2.0-12/lib --with-mpc=/<<NIX>>/libmpc-1.3.1 --with-native-system-header-dir=/<<NIX>>/glibc-2.38-dev/include --with-build-sysroot=/ --program-prefix= --enable-lto --disable-libstdcxx-pch --without-included-gettext --with-system-zlib --enable-checking=release --enable-static --enable-languages=c,c++ --disable-multilib --enable-plugin --disable-libcc1 --with-isl=/<<NIX>>/isl-0.20 --disable-bootstrap --build=x86_64-unknown-linux-gnu --host=x86_64-unknown-linux-gnu --target=x86_64-unknown-linux-gnu Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.0 99999999 (experimental) (GCC)