Use llvm::copy. NFC

llvm-svn: 347126
diff --git a/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp b/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp
index bbd1dcd..f17c236 100644
--- a/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp
+++ b/llvm/lib/CodeGen/MIRCanonicalizerPass.cpp
@@ -677,8 +677,7 @@
 
   std::vector<MachineInstr *> Candidates = populateCandidates(MBB);
   std::vector<MachineInstr *> VisitedMIs;
-  std::copy(Candidates.begin(), Candidates.end(),
-            std::back_inserter(VisitedMIs));
+  llvm::copy(Candidates, std::back_inserter(VisitedMIs));
 
   std::vector<TypedVReg> VRegs;
   for (auto candidate : Candidates) {