[llvm-commits] [PATCH] Accidental <kill> on two-address operand

[Jakob Stoklund Olesen]

On 04/08/2009, at 08.13, Evan Cheng wrote:

>
> On Aug 3, 2009, at 11:07 PM, Jakob Stoklund Olesen wrote:
>
>>
>> On 02/08/2009, at 21.52, Eli Friedman wrote:
>>
>>> On Sun, Aug 2, 2009 at 12:18 PM, Jakob Stoklund
>>> Olesen<stoklund at 2pi.dk> wrote:
>>>> The generated code looks like this:
>>>>
>>>> %reg1032<def> = MOVENCC_z %reg1031<kill>
>>>> %reg1032<def> = BITTGL %reg1032, 0
>>>>
>>>> In this case a kill flag is also added to BITTGL, and
>>>> TwoAddressInstructionPass fails to remove it again. Probably  
>>>> because
>>>> it is expecting SSA code as input?
>>>
>>> AFAIK, all virtual registers are supposed to be SSA until the
>>> two-address pass runs.
>>
>> I will have to create a new vreg in copyRegToReg then.
>
> Sorry, I am still missing some details. Is MOVENCC_z the move
> instruction being inserted? Why do you need to introduce a VR then?

No, copyRegToReg inserts both instructions. It cannot do the move in  
just one instruction.