--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/ipa/pr91831.C	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 --param uninlined-thunk-insns=1000"  } */
+
+struct A {
+  virtual void m_fn1();
+};
+struct B {
+  virtual void *m_fn2(int, int) = 0;
+};
+struct C : A, B {
+  void *m_fn2(int, int) { return this; }
+};
+void *fn1(B &p1) { return p1.m_fn2(0, 0); }
+
+int main() {
+  C c;
+  fn1(c);
+  return 0;
+}