Use SmallVectorImpl instead of SmallVector for iterators and references to avoid specifying the vector size unnecessarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185512 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index 4dafbe5..757f60b 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -537,8 +537,8 @@
       // We give successors with smaller loop depth higher priority.
       SmallVector<MachineBasicBlock*, 4> Succs(MBB->succ_begin(), MBB->succ_end());
       std::stable_sort(Succs.begin(), Succs.end(), SuccessorSorter(LI));
-      for (SmallVector<MachineBasicBlock*, 4>::iterator SI = Succs.begin(),
-           E = Succs.end(); SI != E; ++SI) {
+      for (SmallVectorImpl<MachineBasicBlock *>::iterator SI = Succs.begin(),
+             E = Succs.end(); SI != E; ++SI) {
         MachineBasicBlock *SuccBlock = *SI;
         bool LocalUse = false;
         if (AllUsesDominatedByBlock(Reg, SuccBlock, MBB,
@@ -697,7 +697,7 @@
                        ++MachineBasicBlock::iterator(MI));
 
   // Move debug values.
-  for (SmallVector<MachineInstr *, 2>::iterator DBI = DbgValuesToSink.begin(),
+  for (SmallVectorImpl<MachineInstr *>::iterator DBI = DbgValuesToSink.begin(),
          DBE = DbgValuesToSink.end(); DBI != DBE; ++DBI) {
     MachineInstr *DbgMI = *DBI;
     SuccToSinkTo->splice(InsertPos, ParentBlock,  DbgMI,