[Mlir-commits] [mlir] [mlir][gpu] Add patterns to break down subgroup reduce (PR #76271)

[Kunwar Grover]

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@@ -0,0 +1,139 @@
+//===- SubgroupReduceLowering.cpp - subgroup_reduce lowering patterns -----===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements gradual lowering of `gpu.subgroup_reduce` ops.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/GPU/IR/GPUDialect.h"
+#include "mlir/Dialect/GPU/Transforms/Passes.h"
+#include "mlir/Dialect/Vector/IR/VectorOps.h"
+#include "mlir/IR/Location.h"
+#include "mlir/IR/PatternMatch.h"
+#include "mlir/Support/LogicalResult.h"
+#include "llvm/Support/MathExtras.h"
+#include <cassert>
+
+using namespace mlir;
+
+namespace {
+
+/// Example:
+/// ```
+/// %a = gpu.subgroup_reduce add %x : (vector<3xf16>) -> vector<3xf16>
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Groverkss wrote:

Can you mention the maxShuffleBitwidth used here?

https://github.com/llvm/llvm-project/pull/76271