[InstCombine] Fix an unused variable warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353630 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index ab7c3a5..56d5c89 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -4350,7 +4350,7 @@
                 PN->getParent() == II->getUnwindDest())
               return false;
       // FIXME: Be conservative for callbr to avoid a quadratic search.
-      if (CallBrInst *CBI = dyn_cast<CallBrInst>(Caller))
+      if (isa<CallBrInst>(Caller))
         return false;
     }
   }