Index: include/clang/Basic/Builtins.def
===================================================================
--- include/clang/Basic/Builtins.def
+++ include/clang/Basic/Builtins.def
@@ -802,6 +802,10 @@
 LIBBUILTIN(_setjmpex, "iJ", "fj",   "setjmpex.h", ALL_MS_LANGUAGES)
 
 // C99 library functions
+// C99 stdarg.h
+LIBBUILTIN(va_start, "vA.",       "fnt",   "stdarg.h", ALL_LANGUAGES)
+LIBBUILTIN(va_end, "vA",          "fn",    "stdarg.h", ALL_LANGUAGES)
+LIBBUILTIN(va_copy, "vAA",        "fn",    "stdarg.h", ALL_LANGUAGES)
 // C99 stdlib.h
 LIBBUILTIN(abort, "v",            "fr",    "stdlib.h", ALL_LANGUAGES)
 LIBBUILTIN(calloc, "v*zz",        "f",     "stdlib.h", ALL_LANGUAGES)