[Mlir-commits] [mlir] [mlir][gpu] Add subgroup_reduce to shuffle lowering (PR #76530)

[Kunwar Grover]

================
@@ -47,19 +48,37 @@ struct TestGpuSubgroupReduceLoweringPass
   MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(
       TestGpuSubgroupReduceLoweringPass)
 
+  TestGpuSubgroupReduceLoweringPass() = default;
+  TestGpuSubgroupReduceLoweringPass(
+      const TestGpuSubgroupReduceLoweringPass &pass)
+      : PassWrapper(pass) {}
+
   void getDependentDialects(DialectRegistry &registry) const override {
     registry.insert<arith::ArithDialect, vector::VectorDialect>();
   }
+
   StringRef getArgument() const final {
     return "test-gpu-subgroup-reduce-lowering";
   }
+
   StringRef getDescription() const final {
     return "Applies gpu.subgroup_reduce lowering patterns.";
   }
+
+  Option<bool> expandToShuffles{
+      *this, "expand-to-shuffles",
+      llvm::cl::desc("Expand subgroup_reduce ops to shuffle ops."),
+      llvm::cl::init(false)};
+
   void runOnOperation() override {
     RewritePatternSet patterns(&getContext());
     populateGpuBreakDownSubgrupReducePatterns(patterns,
-                                              /*maxShuffleBitwidth=*/32);
+                                              /*maxShuffleBitwidth=*/32,
+                                              PatternBenefit(2));
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Groverkss wrote:

Can you add a comment here on why you set the benefit to a non default value?

https://github.com/llvm/llvm-project/pull/76530