[Bug middle-end/86864] New: [9 Regression] ICE in commit_one_edge_insertion, at cfgrtl.c:2025 since r261795

[belyshev at depni dot sinp.msu.ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86864

            Bug ID: 86864
           Summary: [9 Regression] ICE in commit_one_edge_insertion, at
                    cfgrtl.c:2025 since r261795
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: belyshev at depni dot sinp.msu.ru
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

r261795 caused the following ICE, reduced from i386.c:

long a;
void f ();
void g (int b, int c, int d)
{
  switch (b)
    {
    case 42:
    case 29:
    case 48:
    case 40:
    case 32:
      c = 2;
      break;
    case 0:
      c = 1;
      break;
    default:
      __builtin_unreachable ();
    }
  if (d || a)
    f ();
  if (c == 1)
    f ();
}

during RTL pass: expand
bug.c: In function 'g':
bug.c:24:1: internal compiler error: in commit_one_edge_insertion, at
cfgrtl.c:2025