Re: [Bug tree-optimization/103300] New: wrong code at -O3 on x86_64-linux-gnu

[Jan Hubicka via Gcc-bugs]

Needs -O2  -floop-unroll-and-jam   --param early-inlining-insns=14
to fail, so I guess it may be issue with unrol-and-jam.

[Bug tree-optimization/103300] New: wrong code at -O3 on x86_64-linux-gnu

[zhendong.su at inf dot ethz.ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103300

Bug ID: 103300
   Summary: wrong code at -O3 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: ---

It appears to be a recent regression.

[596] % 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 2027 (experimental) [master r12-5333-g1a15a91a001] (GCC) 
[597] % 
[597] % gcctk -O2 small.c; ./a.out
[598] % 
[598] % gcc110 -O3 small.c; ./a.out
[599] % 
[599] % gcctk -O3 small.c
[600] % ./a.out
Aborted
[601] % 
[601] % cat small.c
int a, b[2], c, d, e, f;
int g(int h, int i) { return !i || h && i == 1 ? 0 : h % i; }
void j() {
  while (1)
while (1) {
  if (d)
  L:
if (f)
  break;
  if (e)
goto L;
  return;
}
}
int main() {
  j();
  for (c = 0; c < 3; c++)
for (a = 0; a < 2; a++)
  if (g(0, b[a]++))
while (1)
  ;
  if (b[1] != 3)
__builtin_abort();
  return 0;
}