--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/builtin-arith-overflow-2.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,109 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+/* MUL_OVERFLOW should not be folded into unsigned multiplication,
+   because it sometimes overflows and sometimes does not.  */
+__attribute__((noinline, noclone)) long int
+fn1 (long int x, long int y, int *ovf)
+{
+  long int res;
+  x &= 65535;
+  y = (y & 65535) - (__LONG_MAX__ / 65535 + 32768);
+  *ovf = __builtin_mul_overflow (x, y, &res);
+  return res;
+}
+
+/* MUL_OVERFLOW should not be folded into unsigned multiplication,
+   because it sometimes overflows and sometimes does not.  */
+__attribute__((noinline, noclone)) signed char
+fn2 (long int x, long int y, int *ovf)
+{
+  signed char res;
+  x = (x & 63) + (__SCHAR_MAX__ / 4);
+  y = (y & 3) + 4;
+  *ovf = __builtin_mul_overflow (x, y, &res);
+  return res;
+}
+
+/* ADD_OVERFLOW should be folded into unsigned additrion,
+   because it sometimes overflows and sometimes does not.  */
+__attribute__((noinline, noclone)) unsigned char
+fn3 (unsigned char x, unsigned char y, int *ovf)
+{
+  unsigned char res;
+  x = (x & 63) + ((unsigned char) ~0 - 65);
+  y = (y & 3);
+  *ovf = __builtin_add_overflow (x, y, &res);
+  return res;
+}
+
+/* ADD_OVERFLOW should be folded into unsigned additrion,
+   because it sometimes overflows and sometimes does not.  */
+__attribute__((noinline, noclone)) unsigned char
+fn4 (unsigned char x, unsigned char y, int *ovf)
+{
+  unsigned char res;
+  x = (x & 15) + ((unsigned char) ~0 - 16);
+  y = (y & 3) + 16;
+  *ovf = __builtin_add_overflow (x, y, &res);
+  return res;
+}
+
+/* MUL_OVERFLOW should not be folded into unsigned multiplication,
+   because it sometimes overflows and sometimes does not.  */
+__attribute__((noinline, noclone)) long int
+fn5 (long int x, unsigned long int y, int *ovf)
+{
+  long int res;
+  y = -65536UL + (y & 65535);
+  *ovf = __builtin_mul_overflow (x, y, &res);
+  return res;
+}
+
+int
+main ()
+{
+  int ovf;
+  if (fn1 (0, 0, &ovf) != 0
+      || ovf
+      || fn1 (65535, 0, &ovf) != (long int) ((__LONG_MAX__ / 65535 + 32768UL) * -65535UL)
+      || !ovf)
+    __builtin_abort ();
+  if (fn2 (0, 0, &ovf) != (signed char) (__SCHAR_MAX__ / 4 * 4U)
+      || ovf
+      || fn2 (0, 1, &ovf) != (signed char) (__SCHAR_MAX__ / 4 * 5U)
+      || !ovf)
+    __builtin_abort ();
+  if (fn3 (0, 0, &ovf) != (unsigned char) ~0 - 65
+      || ovf
+      || fn3 (63, 2, &ovf) != (unsigned char) ~0
+      || ovf
+      || fn3 (62, 3, &ovf) != (unsigned char) ~0
+      || ovf
+      || fn3 (63, 3, &ovf) != 0
+      || !ovf)
+    __builtin_abort ();
+  if (fn4 (0, 0, &ovf) != (unsigned char) ~0
+      || ovf
+      || fn4 (1, 0, &ovf) != 0
+      || !ovf
+      || fn4 (0, 1, &ovf) != 0
+      || !ovf
+      || fn4 (63, 3, &ovf) != 17
+      || !ovf)
+    __builtin_abort ();
+  if (fn5 (0, 0, &ovf) != 0
+      || ovf
+      || fn5 (1, 0, &ovf) != -65536L
+      || !ovf
+      || fn5 (2, 32768, &ovf) != -65536L
+      || !ovf
+      || fn5 (4, 32768 + 16384 + 8192, &ovf) != -32768L
+      || !ovf)
+    __builtin_abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "ADD_OVERFLOW" 2 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "SUB_OVERFLOW" 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "MUL_OVERFLOW" 3 "optimized" } } */