Fix variable set but no used warning on NDEBUG builds. NFCI.

llvm-svn: 370317
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 3a01d9c..940e555 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4981,9 +4981,9 @@
   // For scalars, SimplifyICmpInst should have already handled
   // the edge cases for us, so we just assert on them.
   // For vectors, we must handle the edge cases.
-  if (auto *CI = dyn_cast<ConstantInt>(C)) {
+  if (isa<ConstantInt>(C)) {
     // A <= MAX -> TRUE ; A >= MIN -> TRUE
-    assert(ConstantIsOk(CI));
+    assert(ConstantIsOk(cast<ConstantInt>(C)));
   } else if (Type->isVectorTy()) {
     // TODO? If the edge cases for vectors were guaranteed to be handled as they
     // are for scalar, we could remove the min/max checks. However, to do that,