Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size.

llvm-svn: 216158
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 9b45144..aa4d6a2 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1178,7 +1178,7 @@
 }
 
 static bool markAliveBlocks(BasicBlock *BB,
-                            SmallPtrSet<BasicBlock*, 128> &Reachable) {
+                            SmallPtrSetImpl<BasicBlock*> &Reachable) {
 
   SmallVector<BasicBlock*, 128> Worklist;
   Worklist.push_back(BB);