https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110732
Bug ID: 110732 Summary: Wrong code at -Os on x86_64-linux-gnu (recent regression) Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: shaohua.li at inf dot ethz.ch Target Milestone: --- This looks like a recent regression. gcc at -Os produces the wrong code. Compiler explorer: https://godbolt.org/z/WWdxfzPrc $ cat a.c int printf(const char *, ...); int a; char c[] = {0, 0, -4L}; char d, e; int main() { int f; int *g = &a; *g = 1; for (; e <= 2; e++) for (;;) { { { int b = c[e]; f = b < 0 ? b : b >> 6; } d = f && a; } break; } printf("%d\n", d); } $ $ gcc-tk -O0 a.c && ./a.out 1 $ gcc-tk -Os a.c && ./a.out -1 $ $ gcc-tk -v Using built-in specs. COLLECT_GCC=gcc-tk COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-322d17ae51ea0137167424e0018d7fa355948f9f/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../configure --disable-multilib --disable-bootstrap --enable-languages=c,c++ --prefix=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-322d17ae51ea0137167424e0018d7fa355948f9f Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.0 20230711 (experimental) (GCC) $