--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/Wrestrict-6.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,66 @@
+/* PR tree-optimization/83640 - ice in generic_overlap, at
+   gimple-ssa-warn-restrict.c:814
+   Test to verify that a pointer offset range whose upper bound is less
+   than its lower bound (when interpreted as a signed integer) is handled
+   correctly.
+   { dg-do compile }
+   { dg-options "-O2 -Wrestrict" }  */
+
+#include "range.h"
+
+extern char* strcpy (char*, const char*);
+extern char* stpcpy (char*, const char*);
+
+void sink (void*);
+
+void warn_2_smax_p2 (void)
+{
+  char a[7] = "01234";
+
+  char *d = a;
+
+  ptrdiff_t i = UR (2, DIFF_MAX + (size_t)2);
+
+  strcpy (d, d + i);          /* { dg-warning "accessing between 0 and 4 bytes at offsets 0 and \\\[2, 7] may overlap up to 2 bytes at offset 2" } */
+
+  sink (d);
+}
+
+void nowarn_3_smax_p2 (void)
+{
+  char a[7] = "12345";
+
+  char *d = a;
+
+  ptrdiff_t i = UR (3, DIFF_MAX + (size_t)2);
+
+  strcpy (d, d + i);
+
+  sink (d);
+}
+
+void warn_2u_smax_p2 (void)
+{
+  char a[7] = "23456";
+
+  char *d = a;
+
+  size_t i = UR (2, DIFF_MAX + (size_t)2);
+
+  strcpy (d, d + i);          /* { dg-warning "accessing between 0 and 4 bytes at offsets 0 and \\\[2, 7] may overlap up to 2 bytes at offset 2" } */
+
+  sink (d);
+}
+
+void nowarn_3u_smax_p2 (void)
+{
+  char a[7] = "34567";
+
+  char *d = a;
+
+  size_t i = UR (3, DIFF_MAX + (size_t)2);
+
+  strcpy (d, d + i);
+
+  sink (d);
+}