[PATCH] This patch introduces MemorySSA, a virtual SSA form for memory.Details on what it looks like are in MemorySSA.h

[Xinliang David Li]

This is the nature of may-def which does not strongly kills the previous
potential def of the same memory loc. That is why each may def also has an
implicit may-use to form factored def-def chain. Without that, memory
consumption will large for memory SSA -- N may-defs followed by M real
may-uses will result in MxN def-use chains.

David

On Wed, Feb 25, 2015 at 11:05 AM, James Molloy <james.molloy at arm.com> wrote:

> Hi Daniel,
>
> One inline comment about the design. Sorry for the naiveity.
>
> Cheers,
>
> James
>
>
> ================
> Comment at: include/llvm/Transforms/Utils/MemorySSA.h:150
> @@ +149,3 @@
> +// All defs also have a use
> +class MemoryDef : public MemoryUse {
> +public:
> ----------------
> I don't understand this: Firstly, why must all defs have a use? We can
> store without loading the resulting value back.
>
> Secondly, you've used inheritance which is an "is-a" relationship. Is
> there something fundamental I'm missing here?
>
> http://reviews.llvm.org/D7864
>
> EMAIL PREFERENCES
>   http://reviews.llvm.org/settings/panel/emailpreferences/
>
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150227/d5489649/attachment.html>