Pass DebugLoc and SDLoc by const ref.

This used to be free, copying and moving DebugLocs became expensive
after the metadata rewrite. Passing by reference eliminates a ton of
track/untrack operations. No functionality change intended.

llvm-svn: 272512
diff --git a/llvm/lib/Target/NVPTX/NVPTXInstrInfo.cpp b/llvm/lib/Target/NVPTX/NVPTXInstrInfo.cpp
index 523f375..3cebfce 100644
--- a/llvm/lib/Target/NVPTX/NVPTXInstrInfo.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXInstrInfo.cpp
@@ -30,9 +30,10 @@
 
 NVPTXInstrInfo::NVPTXInstrInfo() : NVPTXGenInstrInfo(), RegInfo() {}
 
-void NVPTXInstrInfo::copyPhysReg(
-    MachineBasicBlock &MBB, MachineBasicBlock::iterator I, DebugLoc DL,
-    unsigned DestReg, unsigned SrcReg, bool KillSrc) const {
+void NVPTXInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
+                                 MachineBasicBlock::iterator I,
+                                 const DebugLoc &DL, unsigned DestReg,
+                                 unsigned SrcReg, bool KillSrc) const {
   const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
   const TargetRegisterClass *DestRC = MRI.getRegClass(DestReg);
   const TargetRegisterClass *SrcRC = MRI.getRegClass(SrcReg);
@@ -226,9 +227,11 @@
   return 2;
 }
 
-unsigned NVPTXInstrInfo::InsertBranch(
-    MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB,
-    ArrayRef<MachineOperand> Cond, DebugLoc DL) const {
+unsigned NVPTXInstrInfo::InsertBranch(MachineBasicBlock &MBB,
+                                      MachineBasicBlock *TBB,
+                                      MachineBasicBlock *FBB,
+                                      ArrayRef<MachineOperand> Cond,
+                                      const DebugLoc &DL) const {
   // Shouldn't be a fall through.
   assert(TBB && "InsertBranch must not be told to insert a fallthrough");
   assert((Cond.size() == 1 || Cond.size() == 0) &&