Use SmallVectorImpl& instead of SmallVector to avoid repeating small vector size.

llvm-svn: 186274
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index cef0495..6f94a7c 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -1198,9 +1198,9 @@
                                MapVector<Value *, RRInfo> &Retains,
                                DenseMap<Value *, RRInfo> &Releases,
                                Module *M,
-                               SmallVector<Instruction *, 4> &NewRetains,
-                               SmallVector<Instruction *, 4> &NewReleases,
-                               SmallVector<Instruction *, 8> &DeadInsts,
+                               SmallVectorImpl<Instruction *> &NewRetains,
+                               SmallVectorImpl<Instruction *> &NewReleases,
+                               SmallVectorImpl<Instruction *> &DeadInsts,
                                RRInfo &RetainsToMove,
                                RRInfo &ReleasesToMove,
                                Value *Arg,
@@ -2477,9 +2477,9 @@
                                   MapVector<Value *, RRInfo> &Retains,
                                   DenseMap<Value *, RRInfo> &Releases,
                                   Module *M,
-                                  SmallVector<Instruction *, 4> &NewRetains,
-                                  SmallVector<Instruction *, 4> &NewReleases,
-                                  SmallVector<Instruction *, 8> &DeadInsts,
+                                  SmallVectorImpl<Instruction *> &NewRetains,
+                                  SmallVectorImpl<Instruction *> &NewReleases,
+                                  SmallVectorImpl<Instruction *> &DeadInsts,
                                   RRInfo &RetainsToMove,
                                   RRInfo &ReleasesToMove,
                                   Value *Arg,