--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/c99-static-1.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,35 @@
+/* It is a constraint violation for a static function to be declared
+   but not defined if it is used except in a sizeof expression whose
+   result is an integer constant.  The use of the function simply
+   being unevaluated is not enough.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-O2 -std=iso9899:1999 -pedantic-errors" } */
+
+/* Constraint violation (trivial case, where function is used).  */
+static void f0(void); /* { dg-error "used but never defined" } */
+void g0(void) { f0(); }
+
+/* Constraint violation.  */
+static void f1(void); /* { dg-error "used but never defined" } */
+void g1(void) { if (0) { f1(); } }
+
+/* Constraint violation.  */
+static int f2(void); /* { dg-error "used but never defined" } */
+void g2(void) { 0 ? f2() : 0; }
+
+/* OK.  */
+static int f3(void);
+void g3(void) { sizeof(f3()); }
+
+/* OK (VM type, not VLA).  */
+static int f4(void);
+void g4(void) { sizeof(int (*)[f4()]); }
+
+/* Constraint violation (VLA).  */
+static int f5(void); /* { dg-error "used but never defined" "VLA" } */
+void g5(void) { sizeof(int [0 ? f5() : 1]); }
+
+/* OK (non-constant sizeof inside constant sizeof).  */
+static int f6(void);
+void g6(void) { sizeof(sizeof(int [f6()])); }