[Bug tree-optimization/100810] New: wrong code at -O1 and above on x86_64-linux-gnu

zhendong.su at inf dot ethz.ch gcc-bugzilla@gcc.gnu.org
Fri May 28 08:59:21 GMT 2021


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100810

            Bug ID: 100810
           Summary: wrong code at -O1 and above on x86_64-linux-gnu
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

[511] % 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/12.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++
--disable-werror --enable-multilib --with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20210528 (experimental) [master revision
4774807e6e5:0e2d976f72b:cd62d089f6021fd1ad4537b8182836d15b14514f] (GCC) 
[512] % 
[512] % gcctk -O0 small.c; ./a.out
[513] % 
[513] % gcctk -O1 small.c
[514] % ./a.out
Aborted
[515] % 
[515] % cat small.c
int a, b = 1, c = 1, e, f = 1, g, h, j;
volatile int d;
static void k() {
  int i;
  h = b;
  if (c && a >= 0) {
    while (a) {
      i++;
      h--;
    }
    if (g)
      for (h = 0; h < 2; h++)
        ;
    if (!b)
      i &&d;
  }
}
static void l() {
  for (; j < 1; j++)
    if (!e && c && f)
      k();
}
int main() {
  if (f)
    l();
  if (h != 1)
    __builtin_abort();
  return 0;
}


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