[Bug tree-optimization/123372] New: [15/16 Regression] ICE in expand_fn_using_insn on .SAT_SUB while building OpenTTD with LTO since r15-1671

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123372

            Bug ID: 123372
           Summary: [15/16 Regression] ICE in expand_fn_using_insn on
                    .SAT_SUB while building OpenTTD with LTO since
                    r15-1671
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
  Target Milestone: ---

On x86_64-linux -O2 -fgimple -m32 ICEs with
internal compiler error: in expand_fn_using_insn, at internal-fn.cc:270
starting with r15-1671-gf2476a2649e9975d454d179145574c21d8218aee

Manually reduced to:

unsigned int __GIMPLE (ssa,startwith("phiopt4"))
foo (long long unsigned int a, long long unsigned int b)
{
  long long unsigned int d;
  unsigned int _1;
  bool _5;
  unsigned int _6;

  __BB(2):
  _5 = a_2(D) >= b_3(D);
  d_4 = a_2(D) - b_3(D);
  _6 = (unsigned int) d_4;
  _1 = _5 ? _6 : 0U;
  return _1;
}