1 files changed, 26 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/pr30457.c b/gcc/testsuite/gcc.dg/pr30457.c
new file mode 100644
index 000000000..f52332d0a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr30457.c
@@ -0,0 +1,26 @@
+/* PR 30457 warn about va_start(ap, invalid) */
+/* { dg-do compile } */
+/* { dg-options "-std=c99" } */
+
+/* Undefined by C99 7.15.1.4p4 (va_start):
+   "If the parameter parmN is declared with the register storage
+    class, with a function or array type, or with a type that is
+    not compatible with the type that results after application of
+    the default argument promotions, the behavior is undefined."  */
+
+#include <stdarg.h>
+
+void foo(register short paramN, ...)
+{
+  va_list ap;
+
+  va_start(ap, paramN); /* { dg-warning "undefined behaviour when second parameter of 'va_start' is declared with 'register' storage" } */
+  
+  /* Undefined by C99 7.15.1.1p2:  */
+  (void) va_arg(ap, char); /* { dg-warning "'char' is promoted to 'int' when passed through '...'" } */
+  /* { dg-message "note: .so you should pass .int. not .char. to .va_arg.." "" { target *-*-* } 20 } */
+  /* { dg-message "note: if this code is reached, the program will abort"  "" { target *-*-* } 20 } */
+
+  va_end(ap);
+}
+