[Bug tree-optimization/120583] New: wrong code at -O{s,2} on x86_64-linux-gnu

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120583

            Bug ID: 120583
           Summary: wrong code at -O{s,2} 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: ---

Compiler Explorer: https://godbolt.org/z/1rfPr96s4

- works: 9.* and earlier
- fails: 10.* and later

It seems to be fixed by -fno-ivopts (but not -fno-tree-slsr). 

[511] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/home/suz/suz-local/software/local/gcc-trunk/bin/../libexec/gcc/x86_64-pc-linux-gnu/16.0.0/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
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 16.0.0 20250607 (experimental) (GCC) 
[512] % 
[512] % gcctk -O2 small.c
[513] % ./a.out
Aborted
[514] % gcctk -O2 -fno-ivopts small.c
[515] % ./a.out
[516] % 
[516] % cat small.c
int a, b, c;
static int d(int e) {
  do {
    c = a = -998 * b - 5000000;
    b = e + b - 2148000;
  } while (c <= 0 && 10 * b - a <= 0);
  return c;
}
int main() {
  if (a)
    d(1);
  if (d(0) != 2138704000)
    __builtin_abort();
  return 0;
}