[llvm-commits] [llvm] r118702 - in /llvm/trunk/lib/CodeGen: SplitKit.cpp SplitKit.h

[Dan Gohman]

On Nov 10, 2010, at 6:38 PM, Evan Cheng <evan.cheng at apple.com> wrote:
>
>>>> I wonder if 'isTriviallyReMaterializable' means that the  
>>>> instruction can be rematted anywhere without further checks? If  
>>>> so, I should perhaps be using the basic TID::isRematerializable()  
>>>> flag instead?
>>>
>>> Right. It's only meant for the existing brain dead remat.
>>
>> I see. X86InstrInfo::isReallyTriviallyReMaterializable in  
>> particular has many arbitrary restrictions. I'll look into  
>> something more generic.
>>
>> I would be useful to be able to remat loads that have been hoisted  
>> by early optimizations. Is there any way AliasAnalysis can be  
>> rigged to provide more information than AA->pointsToConstantMemory?

Yes.  The Values used with pointsToConstantMemory can also be used  
with normal AliasAnalysis::alias queries.  There's no memdep or other  
higher level abstraction for MachineInstrs currently though.

Dan