Index: llvm/lib/Transforms/Utils/ValueMapper.cpp
===================================================================
--- llvm/lib/Transforms/Utils/ValueMapper.cpp
+++ llvm/lib/Transforms/Utils/ValueMapper.cpp
@@ -528,6 +528,8 @@
     return getVM()[V] = UndefValue::get(NewTy);
   if (isa<ConstantAggregateZero>(C))
     return getVM()[V] = ConstantAggregateZero::get(NewTy);
+  if (isa<UnknownProvenance>(C))
+    return getVM()[V] = UnknownProvenance::get(cast<PointerType>(NewTy));
   assert(isa<ConstantPointerNull>(C));
   return getVM()[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
 }