[LLVMdev] MachineMemOperands

Chris Lattner clattner at apple.com
Tue Dec 1 13:04:31 PST 2009

On Dec 1, 2009, at 11:43 AM, David Greene wrote:

> On Tuesday 01 December 2009 12:14, Dan Gohman wrote:
>> On Dec 1, 2009, at 9:03 AM, David Greene wrote:
>>> On Tuesday 01 December 2009 11:01, Chris Lattner wrote:
>>>> What are you trying to accomplish?  What would use this?
>>> I am trying to determine whether a MachineMemOperand is a vector
>>> operand.
>> Again, what's that for? If you're interested in which pipeline a load
>> feeds, ye olde Vector vs. Scalar isn't sufficient (on x86, for  
>> example).
>> If you're interested in the size and/or alignment, that information  
>> is
>> already there.
> Right, but vector/scalar is useful for tracking how much code is
> vectorized.  That can come in handy when doing performance analysis.
> Right now it's just for comments but I can imagine other uses, such
> as peeps and the like.
> The size is actually calculated from an EVT nearly everywhere (and
> where it's not it should be easy to add).  We could just replace the
> size with the EVT and have more information.

It sounds like you're looking for a property of an instruction, not an  
operand.  If you're looking for vector instructions, that should be  
captured in TargetInstrInfo, not in MachineInstrs/Operands.


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