[PATCH] D124472: [AMDGPU] Properly mark MUBUF and FLAT LDS DMA instructions. NFC.

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/BUFInstructions.td:518
+  let VALU = isLds;
+  let hasSideEffects = isLds;
 }
----------------
foad wrote:
> arsenm wrote:
> > rampitec wrote:
> > > arsenm wrote:
> > > > Loads and stores shouldn't be marked hasSideEffects, only mayLoad/mayStore
> > > How do you suggest to mark that it can read and write virtually any memory?
> > > Note that atomics have hasSideEffects flag.
> > They shouldn't have it set either. mayLoad or mayStore indicate this. the MMO may just not have meaningful pointer info
> So these pseudos should either have 0 MMOs (no info, conservatively correct) or 2 MMOs (one for the BUF access and one for the LDS). Having just 1 MMO would be wrong.
They should have 2 (I have no idea how to to distinguish load and store for a DMA). But the reality is I cannot express this operation in terms of pointers  and ranges. This is scatter on the load side and gather on the store side. Or vice versa for the opposite operation.


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  https://reviews.llvm.org/D124472/new/

https://reviews.llvm.org/D124472