unsigned leaInReg = RegInfo.createVirtualRegister(&X86::GR32RegClass);
unsigned leaOutReg = RegInfo.createVirtualRegister(&X86::GR32RegClass);
- MachineInstr *Ins =
- BuildMI(get(X86::INSERT_SUBREG), leaInReg).addReg(Src).addImm(2);
- Ins->copyKillDeadInfo(MI);
+ // Build and insert into an implicit UNDEF value. This is OK because
+ // well be shifting and then extracting the lower 16-bits.
+ MachineInstr *Ins =
+ BuildMI(get(X86::INSERT_SUBREG),leaInReg).addImm(X86::IMPL_VAL_UNDEF)
+ .addReg(Src).addImm(X86::SUBREG_16BIT);
NewMI = BuildMI(get(Opc), leaOutReg)
.addReg(0).addImm(1 << ShAmt).addReg(leaInReg).addImm(0);
MachineInstr *Ext =
- BuildMI(get(X86::EXTRACT_SUBREG), Dest).addReg(leaOutReg).addImm(2);
+ BuildMI(get(X86::EXTRACT_SUBREG), Dest)
+ .addReg(leaOutReg).addImm(X86::SUBREG_16BIT);
Ext->copyKillDeadInfo(MI);
MFI->insert(MBBI, Ins); // Insert the insert_subreg