--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/pr81281-3.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,105 @@
+/* PR sanitizer/81281 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-not "\[+=-] \?123\[ ;]" "optimized" } } */
+
+#ifdef __SIZEOF_INT128__
+__int128
+f1 (int a, long long b)
+{
+  __int128 f = 123 + a;
+  __int128 g = 123 + b;
+  return f - g;
+}
+#endif
+
+signed char
+f2 (int a, long long b)
+{
+  signed char f = 123 + a;
+  signed char g = 123 + b;
+  return f - g;
+}
+
+signed char
+f3 (unsigned int a, unsigned long long b)
+{
+  signed char f = 123 + a;
+  signed char g = 123 + b;
+  return f - g;
+}
+
+unsigned char
+f4 (unsigned int a, unsigned long long b)
+{
+  unsigned char f = 123 + a;
+  unsigned char g = 123 + b;
+  return f - g;
+}
+
+/* This isn't optimized yet.  */
+#if 0
+long long
+f5 (int a)
+{
+  long long f = 123 + a;
+  long long g = 123;
+  return f - g;
+}
+#endif
+
+signed char
+f6 (long long a)
+{
+  signed char f = 123 + a;
+  signed char g = 123;
+  return f - g;
+}
+
+signed char
+f7 (unsigned int a)
+{
+  signed char f = 123 + a;
+  signed char g = 123;
+  return f - g;
+}
+
+unsigned char
+f8 (unsigned long int a)
+{
+  unsigned char f = 123 + a;
+  unsigned char g = 123;
+  return f - g;
+}
+
+long long
+f9 (int a)
+{
+  long long f = 123;
+  long long g = 123 + a;
+  return f - g;
+}
+
+signed char
+f10 (long long a)
+{
+  signed char f = 123;
+  signed char g = 123 + a;
+  return f - g;
+}
+
+signed char
+f11 (unsigned int a)
+{
+  signed char f = 123;
+  signed char g = 123 + a;
+  return f - g;
+}
+
+unsigned char
+f12 (unsigned long int a)
+{
+  unsigned char f = 123;
+  unsigned char g = 123 + a;
+  return f - g;
+}