[llvm-commits] [patch] Intruction Constraint DestReg!=SrcReg (for review)

[Evan Cheng]

On Jan 26, 2007, at 1:07 PM, Lauro Ramos Venancio wrote:

>> The facility does that have to be that general. There are 4 cycles
>> between every two instructions.  See LiveIntervalAnalysis:
>>
>>      struct InstrSlots {
>>        enum {
>>          LOAD  = 0,
>>          USE   = 1,
>>          DEF   = 2,
>>          STORE = 3,
>>          NUM   = 4
>>        };
>>      };
>>
>> We can restrict the constraint range to 1 - 3. This ensures the last
>> use is always the kill while retaining its flexibility.
>>
>> Evan
>
> I will try to implement this. Do you have any suggestion for
> constraint name and syntax?

I don't have any great ideas. Perhaps READ_LATENCY for constraint and  
something like

$src +lat 2

for syntax?

Feel free to choose something else if you have better ideas.

Thanks,

Evan

>
> Lauro