https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107833
--- Comment #2 from Aldy Hernandez <aldyh at gcc dot gnu.org> --- (In reply to Zhendong Su from comment #0) > Compiler Explorer: https://godbolt.org/z/Tc8vbearG > > It appears to be a regression from 11.3. > > [561] % gcctk -v > Using built-in specs. > COLLECT_GCC=gcctk > COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/ > x86_64-pc-linux-gnu/13.0.0/lto-wrapper > Target: x86_64-pc-linux-gnu > Configured with: ../gcc-trunk/configure --disable-bootstrap > --enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk > --enable-sanitizers --enable-languages=c,c++ --disable-werror > --enable-multilib --with-system-zlib > Thread model: posix > Supported LTO compression algorithms: zlib > gcc version 13.0.0 20221123 (experimental) [master r13-4262-g1cac00d0138] > (GCC) > [562] % > [562] % gcctk -O1 small.c; ./a.out > [563] % > [563] % gcctk -Os small.c > [564] % ./a.out > Segmentation fault > [565] % > [565] % cat small.c > int printf(const char *, ...); > int a, b[1] = {0}, c, *d = b, e, *f, g; > int main() { > int h = 0; > for (; a < 2; a++) { > int i; > for (g = 0; g < 2; g++) > if (a < h) { > e = i % 2; Isn't there an uninitialized read from "i" here? At least on the second time through the outer loop, if (a < h) is true since 1 < 0. > c = *f; > } > for (h = 0; h < 3; h++) { > if (d) > break; d is nonzero so h will always be 0 in this function. > i--; > printf("0"); > } > } > return 0; > } Unless I'm missing something....
