[Bug ipa/64978] [5 Regression] ICE: in ipcp_verify_propagated_values, at ipa-cp.c:1060

["trippels at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64978

--- Comment #5 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Reduced testcase for comment 4:

trippels@gcc20 test % cat VTableBuilder.ii
class A {
public:
  A(int, int);
};
class B {
public:
  void m_fn1(bool, const int *, int &);
  unsigned m_fn2();
};
namespace {
class C {
  B &VTables;
  void m_fn3(A, unsigned, const int *, int &);

public:
  int VFTableBuilder_VisitedBases;
  B VFTableBuilder_VTables;
  C() : VTables(VFTableBuilder_VTables) {
    m_fn3(A(0, 0), 0, 0, VFTableBuilder_VisitedBases);
  }
};
}
int a;
void C::m_fn3(A, unsigned, const int *, int &) {
  for (;;)
    1 ? VTables.m_fn2() : 0;
}
void B::m_fn1(bool, const int *, int &) { C(); }
unsigned B::m_fn2() { m_fn1(0, 0, a); }

trippels@gcc20 test % g++ -O2 -c VTableBuilder.ii
VTableBuilder.ii:29:39: internal compiler error: in
ipcp_verify_propagated_values, at ipa-cp.c:1060