[RS4GC] Use DenseMap::count() instead of DenseMap::find()/DenseMap::end(). NFC.

llvm-svn: 256586

lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

@@ -1140,7 +1140,7 @@ static Value *findBasePointer(Value *I, DefiningValueMapTy &cache) {
     }
     cache[BDV] = base;
   }
-  assert(cache.find(def) != cache.end());
+  assert(cache.count(def));
   return cache[def];
 }