Avoid warning on non assert builds.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151025 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 345c8a7..5c52b88 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -503,8 +503,9 @@
     V = InsertNoopCastOfTo(V,
        Type::getInt8PtrTy(Ty->getContext(), PTy->getAddressSpace()));
 
-    Instruction *Inst = dyn_cast<Instruction>(V);
-    assert(!Inst || SE.DT->properlyDominates(Inst, Builder.GetInsertPoint()));
+    assert(!dyn_cast<Instruction>(V) ||
+           SE.DT->properlyDominates(dyn_cast<Instruction>(V),
+                                    Builder.GetInsertPoint()));
 
     // Expand the operands for a plain byte offset.
     Value *Idx = expandCodeFor(SE.getAddExpr(Ops), Ty);