https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110491
Bug ID: 110491 Summary: Wrong code at -O2 on x86_64-linux-gnu (a 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: --- gcc at -O2 produced wrong code. Compiler explorer: https://godbolt.org/z/cbM1q13G7 $ cat a.c int printf(const char *, ...); int a, c, d, e; short b; void f(int *g) { c &= *g; } void h(void); void i() { a = 1; h(); f(&a); } void h() { int *j = &c; *j = 5; k: for (; 4 + b <= 0;) ; for (; d;) { c = e == 0; goto k; } } int main() { i(); printf("%d\n", c); } $ $ gcc-tk -O0 a.c &&./a.out 1 $ gcc-tk -O2 a.c && ./a.out -2003318871 $ $ gcc-tk -v Using built-in specs. COLLECT_GCC=gcc-tk COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-5f590ee3174cf6058ac882c3a84a96ae639349c8/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-5f590ee3174cf6058ac882c3a84a96ae639349c8 Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.0 20230629 (experimental) (GCC) $