--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/opt/ptrintsum1.C	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,29 @@
+// PR c++/4401
+// This testcase was miscompiled on 64-bit platforms, resulting to
+// operating on a[0x100000000] instead of a[0].
+// { dg-do run }
+// { dg-options "-O2" }
+
+char *a;
+char b[] = "AAAA";
+
+extern "C" void abort (void);
+extern "C" void exit (int);
+
+void foo (void)
+{
+  unsigned int i, j;
+
+  i = 2;
+  j = 3;
+  a[i + 1 - j] += i;
+}
+
+int main (void)
+{
+  a = b;
+  foo ();
+  if (b[0] != 'A' + 2)
+    abort ();
+  exit (0);
+}