[LLVMdev] MachineMemOperands

David Greene dag at cray.com
Tue Dec 1 11:43:14 PST 2009


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.

                               -Dave



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