[Mlir-commits] [mlir] [mlir][gpu] Add 'cluster_size' attribute to gpu.subgroup_reduce (PR #104851)

[Jakub Kuderski]

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@@ -183,6 +190,13 @@ struct ScalarSubgroupReduceToShuffles final
 
   LogicalResult matchAndRewrite(gpu::SubgroupReduceOp op,
                                 PatternRewriter &rewriter) const override {
+    std::optional<uint32_t> clusterSize = op.getClusterSize();
+    if (clusterSize && *clusterSize > subgroupSize)
+      return op.emitError()
+             << "cluster size " << *clusterSize
+             << " is greater than subgroup size " << subgroupSize;
+    unsigned effectiveClusterSize = clusterSize ? *clusterSize : subgroupSize;
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kuhar wrote:

We can use `clusterSize.value_or(subgroup_size)`

https://github.com/llvm/llvm-project/pull/104851