[PATCH] D79391: [DSE] Remove noop stores in MSSA.

[Zoe Carver via Phabricator via llvm-commits]

zoecarver marked an inline comment as done.
zoecarver added inline comments.


================
Comment at: llvm/test/Transforms/DeadStoreElimination/MSSA/simple.ll:588
+  store i32 %a, i32* %Q
+  ret void
+}
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jfb wrote:
> Can you add the reverse:
> ```
>   %a = load i32, i32* %Q
>   store volatile i32 %a, i32* %Q
> ```
> 
> This one we can't eliminate.
> 
> As well as, can you add these two cases with `atomic` instead? We can do some optimizations there but need to be careful around release sequences, see https://wg21.link/n4455
Good call. Luckily this is done when building the `DSEState` so I won't have to add checks for it in this patch. But I have added both the atomic and volatile tests. 


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