[Bug tree-optimization/122898] New: ICE on valid code at -O{s,2,3} with "-fno-tree-forwprop -fno-tree-fre" 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=122898

            Bug ID: 122898
           Summary: ICE on valid code at -O{s,2,3} with
                    "-fno-tree-forwprop -fno-tree-fre" on
                    x86_64-linux-gnu: Segmentation fault
           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/b1Gr6n1vG

Note:
- fails: trunk
- works: 15.2 and earlier

[516] % 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 20251127 (experimental) (GCC) 
[517] % 
[517] % gcctk -O3 -c -fno-tree-forwprop -fno-tree-fre small.c
gcctk: internal compiler error: Segmentation fault signal terminated program
cc1
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
See <https://gcc.gnu.org/bugs/> for instructions.
[518] % 
[518] % cat small.c
extern void o();
int a, b, c, d, e, f, g, h, i, k, l, m, n;
volatile int j;
static void p() {
  if (d) {
  q:
    if (a) {
      if (k) {
        if (!(d && e))
          goto r;
        if (i)
          goto q;
        o();
      }
      h || j;
    }
  s:
    d || j;
    if (a)
      goto q;
  r:
    if (b) {
      if (c)
        goto t;
      if (b)
        goto r;
      if (m)
        goto q;
    }
    while (j)
      ;
  u:
    if (g) {
      o();
      goto s;
    }
    if (h) {
    t:
      if (n)
        goto v;
      o();
      goto r;
    }
    int w = i & 1;
  v:
    if (w <= l)
      if (f)
        goto u;
    goto q;
  }
  if (a)
    goto v;
}
int main() { p(); }