Fix optimization when setting sp.

Author: jacobly0

llvm/lib/Target/Z80/Z80PostSelectCombiner.cpp

@@ -143,8 +143,8 @@ bool Z80PostSelectCombiner::runOnMachineFunction(MachineFunction &MF) {
         BuildMI(MBB, MI, MI.getDebugLoc(), TII.get(TargetOpcode::COPY), TmpReg)
             .add(MI.getOperand(1));
         MI.setDesc(TII.get(DstReg == Z80::SPL ? Z80::LD24SP : Z80::LD16SP));
+        MI.RemoveOperand(0);
         MI.getOperand(0).setReg(TmpReg);
-        MI.RemoveOperand(1);
         Changed = true;
         break;
       }