Replace std::copy with a back inserter with vector append where feasible

All of the cases were just appending from random access iterators to a
vector. Using insert/append can grow the vector to the perfect size
directly and moves the growing out of the loop. No intended functionalty
change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230845 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/PeepholeOptimizer.cpp

@@ -411,8 +411,7 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
 
   if (ExtendLife && !ExtendedUses.empty())
     // Extend the liveness of the extension result.
-    std::copy(ExtendedUses.begin(), ExtendedUses.end(),
-              std::back_inserter(Uses));
+    Uses.append(ExtendedUses.begin(), ExtendedUses.end());
 
   // Now replace all uses.
   bool Changed = false;