1 files changed, 13 insertions, 4 deletions
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index e85024fc55..7951a71e4e 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -1198,10 +1198,19 @@ Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
   // concrete integer type we should convert to is.
   unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
   const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
-  IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
-  FunctionDecl *NewBuiltinDecl =
-    cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
-                                           TUScope, false, DRE->getLocStart()));
+  FunctionDecl *NewBuiltinDecl;
+  if (NewBuiltinID == BuiltinID)
+    NewBuiltinDecl = FDecl;
+  else {
+    // Perform builtin lookup to avoid redeclaring it.
+    DeclarationName DN(&Context.Idents.get(NewBuiltinName));
+    LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName);
+    LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true);
+    assert(Res.getFoundDecl());
+    NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl());
+    if (NewBuiltinDecl == 0)
+      return ExprError();
+  }
 
   // The first argument --- the pointer --- has a fixed type; we
   // deduce the types of the rest of the arguments accordingly.  Walk