Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -10425,6 +10425,25 @@
 
     // We don't really have anything else to say about viable candidates.
     S.NoteOverloadCandidate(Cand->FoundDecl, Fn);
+
+    // If this is a builtin function, give the available definitions.
+    if (S.getLangOpts().OpenCL && Fn->isImplicit()) {
+      raw_ostream &OS = llvm::outs();
+      unsigned NumParams = Fn->getNumParams();
+
+      OS << Fn->getReturnType().getAsString() << " ";
+      OS << Fn->getNameInfo().getAsString() << "(";
+
+      if (NumParams > 0) {
+        OS << Fn->getParamDecl(0)->getOriginalType().getAsString();
+      }
+      for (unsigned i = 1; i < NumParams; i++) {
+        OS << ", ";
+        OS << Fn->getParamDecl(i)->getOriginalType().getAsString();
+      }
+      OS << ")\n";
+    }
+
     return;
   }