Use more idiomatic assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151026 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 5c52b88..0f2a634 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -503,8 +503,8 @@
     V = InsertNoopCastOfTo(V,
        Type::getInt8PtrTy(Ty->getContext(), PTy->getAddressSpace()));
 
-    assert(!dyn_cast<Instruction>(V) ||
-           SE.DT->properlyDominates(dyn_cast<Instruction>(V),
+    assert(!isa<Instruction>(V) ||
+           SE.DT->properlyDominates(cast<Instruction>(V),
                                     Builder.GetInsertPoint()));
 
     // Expand the operands for a plain byte offset.