[NFC][MachineInstr] Pass-by-value DebugLoc in CreateMachineInstr

DebugLoc is cheap to move, passing it by-val rather than const ref to
take advantage of the fact that it is consumed that way by the
MachineInstr ctor, which creates some optimization oportunities.

Differential Revision: https://reviews.llvm.org/D115208

llvm/include/llvm/CodeGen/MachineFunction.h

@@ -890,7 +890,7 @@ class LLVM_EXTERNAL_VISIBILITY MachineFunction {
 
   /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
   /// of `new MachineInstr'.
-  MachineInstr *CreateMachineInstr(const MCInstrDesc &MCID, const DebugLoc &DL,
+  MachineInstr *CreateMachineInstr(const MCInstrDesc &MCID, DebugLoc DL,
                                    bool NoImplicit = false);
 
   /// Create a new MachineInstr which is a copy of \p Orig, identical in all

llvm/lib/CodeGen/MachineFunction.cpp

@@ -350,10 +350,10 @@ void MachineFunction::assignBeginEndSections() {
 
 /// Allocate a new MachineInstr. Use this instead of `new MachineInstr'.
 MachineInstr *MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
-                                                  const DebugLoc &DL,
+                                                  DebugLoc DL,
                                                   bool NoImplicit) {
   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
-      MachineInstr(*this, MCID, DL, NoImplicit);
+      MachineInstr(*this, MCID, std::move(DL), NoImplicit);
 }
 
 /// Create a new MachineInstr which is a copy of the 'Orig' instruction,