--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/torture/pr83391.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,36 @@
+// PR debug/83391
+// { dg-do compile }
+// { dg-options "-g" }
+// { dg-additional-options "-mbranch-cost=1" { target { i?86-*-* x86_64-*-* mips*-*-* s390*-*-* avr*-*-* } } }
+
+unsigned char a;
+enum E { F, G, H } b;
+int c, d;
+
+void
+foo ()
+{
+  int e;
+  bool f;
+  E g = b;
+  while (1)
+    {
+      unsigned char h = a ? d : 0;
+      switch (g)
+	{
+	case 0:
+	  f = h <= 'Z' || h >= 'a' && h <= 'z';
+	  break;
+	case 1:
+	  {
+	    unsigned char i = h;
+	    e = 0;
+	  }
+	  if (e || h)
+	    g = H;
+	  /* FALLTHRU */
+	default:
+	  c = 0;
+	}
+    }
+}