[llvm-commits] [llvm] r48521 - in /llvm/trunk: include/llvm/CodeGen/LiveVariables.h lib/CodeGen/LiveVariables.cpp test/CodeGen/PowerPC/2008-03-18-RegScavengerAssert.ll test/CodeGen/X86/x86-64-ret0.ll

[Evan Cheng]

On Mar 24, 2008, at 10:01 PM, Owen Anderson wrote:

> On Mar 24, 2008, at 11:48 PM, Chris Lattner wrote:
>
>>
>> On Mar 24, 2008, at 6:41 PM, Evan Cheng wrote:
>>
>>>> How about using reg_iterators to do this?  I assume this only  
>>>> applies
>>>> to vregs.  If you walk the use_iterator list for the register,  
>>>> you can
>>>> very efficiently discard uses in other blocks (check User- 
>>>> >getparent()
>>>> == MBB).  Any uses within the same block are either a) in phi  
>>>> nodes,
>>>> in which case they are above the instruction or b) users later in  
>>>> the
>>>> block.
>>>
>>> No, this applies to physical registers only.
>>>
>>> We need def / use information for physical registers and MI to
>>> distance from top of MBB mapping to quickly determine this property.
>>> This is not *yet* showing up to be a compile time issue, so I am
>>> ignoring it for now.
>>>
>>> Isn't Owen going to do something about LiveVariables? Can I  
>>> volunteer
>>> Own to own this problem? :-)
>>
>> Sure you can volunteer him; lets see how much he fights back!  What  
>> do you say Owen? :)
>
> Gah, what am I being volunteered for?  I'm not planning to do  
> anything to LV anymore.  That plan got revised when I changed the  
> pass ordering for StrongPHIElimination.

Fear not young man. I've fixed this. I'll volunteer you for something  
else another time. :-)

Evan

>
>
> --Owen
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