[Bug tree-optimization/126965] New: ICE on valid code at -O{2,3} with -fno-tree-dominator-opts on x86_64-linux-gnu: Segmentation fault

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126965

            Bug ID: 126965
           Summary: ICE on valid code at -O{2,3} with
                    -fno-tree-dominator-opts on x86_64-linux-gnu:
                    Segmentation fault
           Product: gcc
           Version: 16.0
            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/WqhvMWc93

Note:
- fails: trunk
- works: 16.2 and earlier

[572] % 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/17.0.0/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++,lto --disable-werror
--disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 17.0.0 20260819 (experimental) (GCC) 
[573] % 
[573] % gcctk -O2 -fno-tree-dominator-opts small.c
gcctk: internal compiler error: cc1 terminated by signal 11 (Segmentation
fault)
Segmentation fault
[574] % 
[574] % cat small.c
int a[1], b;
short c;
unsigned short d;
int main() {
  for (int f = 0; f < 1; f++)
    if (c) {
      for (c = 0; c < 2; c++)
        for (b = 1; b; b = a[c + 1])
          ;
      d = c;
    }
  return 0;
}