--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/pr46777.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,49 @@
+/* PR rtl-optimization/46777 */
+/* { dg-do compile } */
+/* { dg-options "-fgcse -O -fno-tree-dominator-opts -funroll-loops" } */
+
+struct S { char s[256]; };
+
+static inline int
+foo (int x, int y)
+{
+  switch (x)
+    {
+    case 1:
+    case 2:
+      return 3;
+    case 3:
+    case 4:
+      return 2;
+    case 5:
+      switch (y)
+	{
+	case 4:
+	  return 1;
+	}
+    }
+  return 0;
+}
+
+void
+bar (struct S *x, int *y, int *z, int **w)
+{
+  switch (*y ? x->s[*y] : foo (y[1], y[0]))
+    {
+    case 3:
+      if (y + 2 == z)
+	for (;;)
+	  {
+	    y += 2;
+	    switch (*y ? x->s[*y] : foo (y[1], y[0]))
+	      {
+	      case 6:
+		break;
+	      default:
+		*w = y;
+	      }
+	    if (y == z)
+	      break;
+	  }
+    }
+}