true /*IsDef*/,
true /*IsImp*/,
false /*IsKill*/));
+ // Record small dead def live-ranges for all the subregisters
+ // of the destination register.
+ // Otherwise, variables that live through may miss some
+ // interferences, thus creating invalid allocation.
+ // E.g., i386 code:
+ // vreg1 = somedef ; vreg1 GR8
+ // vreg2 = remat ; vreg2 GR32
+ // CL = COPY vreg2.sub_8bit
+ // = somedef vreg1 ; vreg1 GR8
+ // =>
+ // vreg1 = somedef ; vreg1 GR8
+ // ECX<def, dead> = remat ; CL<imp-def>
+ // = somedef vreg1 ; vreg1 GR8
+ // vreg1 will see the inteferences with CL but not with CH since
+ // no live-ranges would have been created for ECX.
+ // Fix that!
+ SlotIndex NewMIIdx = LIS->getInstructionIndex(NewMI);
+ for (MCRegUnitIterator Units(NewMI->getOperand(0).getReg(), TRI);
+ Units.isValid(); ++Units)
+ if (LiveRange *LR = LIS->getCachedRegUnit(*Units))
+ LR->createDeadDef(NewMIIdx.getRegSlot(), LIS->getVNInfoAllocator());
}
if (NewMI->getOperand(0).getSubReg())