--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/c90-const-expr-2.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,45 @@
+/* Test for constant expressions: details of what is a null pointer
+   constant.
+*/
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1990" } */
+/* Note: not using -pedantic since the -std option alone should be enough
+   to give the correct behavior to conforming programs.  If -pedantic is
+   needed to make (say) (0, 0) not be a constant expression, this is a
+   bug.
+*/
+
+int *a;
+int b;
+long *c;
+
+#if defined(_LP64)
+#define ZERO 0L
+#elif defined(_WIN64)
+#define ZERO 0LL
+#else
+#define ZERO 0
+#endif
+
+/* Assertion that n is a null pointer constant: so the conditional expression
+   has type 'int *' instead of 'void *'.
+*/
+#define ASSERT_NPC(n)	(b = *(1 ? a : (n)))
+/* Assertion that n is not a null pointer constant: so the conditional
+   expressions has type 'void *' instead of 'int *'.
+*/
+#define ASSERT_NOT_NPC(n)	(c = (1 ? a : (n)))
+
+void
+foo (void)
+{
+  ASSERT_NPC (0);
+  ASSERT_NPC ((void *)0);
+  ASSERT_NOT_NPC ((void *)(void *)0); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
+  ASSERT_NOT_NPC ((void *)(char *)0); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
+  ASSERT_NOT_NPC ((void *)(0, ZERO)); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
+  ASSERT_NOT_NPC ((void *)(&"Foobar"[0] - &"Foobar"[0])); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
+  /* This last one is a null pointer constant in C99 only.  */
+  ASSERT_NOT_NPC ((void *)(1 ? ZERO : (0, ZERO))); /* { dg-bogus "incompatible" "bogus null pointer constant" } */
+}