>>>>> - (mop.isUse() + mop.isDef()) * pow(10.0F, (int)
>>>>> loopDepth);
>>>>> + if (!RegInt.remat) {
>>>>> + RegInt.weight +=
>>>>> + (mop.isUse() + mop.isDef()) * pow(10.0F, (int)
>>>>> loopDepth);
>>>>> + }
>>>>
>>>> Should it really be zero? It should definitely be lower that a
>>>> normal value, but zero seems low. The loop depth should still
>>>> be taken into consideration.
>>>
>>> Funny you should mention this. I am re-evaluating this right now.
>>> My thinking is loads (load from constantpool or stack slots)
>>> would have the normal weight. The rest will have half the weight.
>>
>> Why not just make everything half weight? What would be lost?
>
> To avoid a common problem. A value live-in to a function and is
> loaded from stack slot and used in a loop. You do not want to
> rematerialize this and end up issuing the load in the loop.
>
> This is tricky to get right. I am not sure simple heuristics can
> cover all the cases.
Okay, so just look to see if the instr has the TargetInstrInfo::LOAD
flag on it?
-Chris
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