[Mlir-commits] [mlir] [mlir][gpu][spirv] Add patterns for gpu.shuffle up/down (PR #139105)

[Lei Zhang]

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@@ -450,8 +452,19 @@ LogicalResult GPUShuffleConversion::matchAndRewrite(
     result = rewriter.create<spirv::GroupNonUniformShuffleOp>(
         loc, scope, adaptor.getValue(), adaptor.getOffset());
     break;
-  default:
-    return rewriter.notifyMatchFailure(shuffleOp, "unimplemented shuffle mode");
+  case gpu::ShuffleMode::DOWN:
+    result = rewriter.create<spirv::GroupNonUniformRotateKHROp>(
+        loc, scope, adaptor.getValue(), adaptor.getOffset(),
+        shuffleOp.getWidth());
+    break;
+  case gpu::ShuffleMode::UP: {
+    Value offsetForShuffleDown = rewriter.create<arith::SubIOp>(
+        loc, shuffleOp.getWidth(), adaptor.getOffset());
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antiagainst wrote:

Is this correct? Shouldn't we use subgroup size instead of width here? Width is just the cluster size which can be smaller than the subgroup size?

https://github.com/llvm/llvm-project/pull/139105