[llvm] [mlir] [mlir][mesh] Add all-scatter operation (PR #81218)

[Chengji Yao via llvm-commits]

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@@ -341,6 +342,68 @@ def Mesh_AllReduceOp : Mesh_CollectiveCommunicationOpBase<"all_reduce", [
   let hasCanonicalizer = 1;
 }
 
+def Mesh_AllScatterOp : Mesh_CollectiveCommunicationOpBase<"all_scatter", [
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yaochengji wrote:

I'm wondering if it's appropriate to include scatter in the operation's name, as scatter typically implies that the operation involves communication.

https://github.com/llvm/llvm-project/pull/81218