diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f831b094f676e0..aee4252c2bd597 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -15552,7 +15552,8 @@ Decl *Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, Decl *D,
   // Builtin functions cannot be defined.
   if (unsigned BuiltinID = FD->getBuiltinID()) {
     if (!Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID) &&
-        !Context.BuiltinInfo.isPredefinedRuntimeFunction(BuiltinID)) {
+        !Context.BuiltinInfo.isPredefinedRuntimeFunction(BuiltinID) &&
+        !Context.BuiltinInfo.isPredefinedPASTAFunction(BuiltinID)) {
       Diag(FD->getLocation(), diag::err_builtin_definition) << FD;
       FD->setInvalidDecl();
     }