[TII] Use optional destination and source pair as a return value; NFC

Refactor usage of isCopyInstrImpl, isCopyInstr and isAddImmediate methods
to return optional machine operand pair of destination and source
registers.

Patch by Nikola Prica

Differential Revision: https://reviews.llvm.org/D69622

1 files changed, 9 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/LiveDebugValues.cpp b/llvm/lib/CodeGen/LiveDebugValues.cpp
index b15c594..d38840b 100644
--- a/llvm/lib/CodeGen/LiveDebugValues.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues.cpp
@@ -997,10 +997,14 @@ void LiveDebugValues::transferRegisterCopy(MachineInstr &MI,
                                            OpenRangesSet &OpenRanges,
                                            VarLocMap &VarLocIDs,
                                            TransferMap &Transfers) {
-  const MachineOperand *SrcRegOp, *DestRegOp;
 
-  if (!TII->isCopyInstr(MI, SrcRegOp, DestRegOp) || !SrcRegOp->isKill() ||
-      !DestRegOp->isDef())
+  auto DestSrc = TII->isCopyInstr(MI);
+  if (!DestSrc)
+    return;
+
+  const MachineOperand &DestRegOp = DestSrc->Destination;
+  const MachineOperand &SrcRegOp = DestSrc->Source;
+  if (!SrcRegOp.isKill() || !DestRegOp.isDef())
     return;
 
   auto isCalleeSavedReg = [&](unsigned Reg) {
@@ -1010,8 +1014,8 @@ void LiveDebugValues::transferRegisterCopy(MachineInstr &MI,
     return false;
   };
 
-  Register SrcReg = SrcRegOp->getReg();
-  Register DestReg = DestRegOp->getReg();
+  Register SrcReg = SrcRegOp.getReg();
+  Register DestReg = DestRegOp.getReg();
 
   // We want to recognize instructions where destination register is callee
   // saved register. If register that could be clobbered by the call is