[MLIR][XeGPU] Add pattern for arith.constant for wg to sg distribution #151977
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@llvm/pr-subscribers-mlir-gpu Author: Nishant Patel (nbpatel) ChangesFull diff: https://github.com/llvm/llvm-project/pull/151977.diff 3 Files Affected:
diff --git a/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp b/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp
index 850f70cca288f..878638061db5c 100644
--- a/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp
+++ b/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp
@@ -649,6 +649,52 @@ struct UnrealizedConversionCastOpPattern
}
};
+// This pattern distributes arith.constant op into subgroup-level constants
+struct WgToSgArithConstantOp : public OpConversionPattern<arith::ConstantOp> {
+ using OpConversionPattern<arith::ConstantOp>::OpConversionPattern;
+
+ LogicalResult
+ matchAndRewrite(arith::ConstantOp op, OneToNOpAdaptor adaptor,
+ ConversionPatternRewriter &rewriter) const override {
+ auto vecAttr = dyn_cast<DenseElementsAttr>(op.getValue());
+ auto vecType = dyn_cast<VectorType>(op.getType());
+ if (!vecAttr || !vecType)
+ return failure();
+
+ xegpu::LayoutAttr layout = xegpu::getLayoutAttr(op.getResult());
+ if (!layout || !layout.getSgLayout())
+ return failure();
+
+ ArrayRef<int64_t> wgShape = vecType.getShape();
+ SmallVector<int64_t> sgShape;
+ int count;
+ std::tie(sgShape, count) = getSgShapeAndCount(wgShape, layout);
+
+ // Current limitation: constant of vector with single value.
+ // TODO: support more complex cases, e.g., vector with multiple values.
+ Attribute singleVal;
+ if (vecAttr.isSplat())
+ singleVal = vecAttr.getSplatValue<Attribute>();
+ else
+ return failure();
+
+ SmallVector<Value> newConsts;
+ auto newType = VectorType::get(sgShape, vecType.getElementType());
+ auto newLayout = layout.dropSgLayoutAndData();
+ for (int i = 0; i < count; ++i) {
+ auto sgAttr = DenseElementsAttr::get(newType, singleVal);
+ auto cstOp =
+ rewriter.create<arith::ConstantOp>(op.getLoc(), newType, sgAttr);
+ if (newLayout)
+ xegpu::setLayoutAttr(cstOp->getResult(0), newLayout);
+ newConsts.push_back(cstOp);
+ }
+
+ rewriter.replaceOpWithMultiple(op, {newConsts});
+ return success();
+ }
+};
+
} // namespace
namespace mlir {
@@ -657,8 +703,8 @@ void populateXeGPUWgToSgDistributePatterns(RewritePatternSet &patterns) {
patterns.add<WgToSgCreateNdOp, WgToSgLoadNdOp, WgToSgStoreNdOp,
WgToSgUpdateNdOffsetOp, WgToSgDpasOp, WgToSgPrefetchNdOp,
UnrealizedConversionCastOpPattern, WgToSgElementwiseOp,
- WgToSgVectorBroadcastOp, WgToSgConvertLayoutOp>(
- patterns.getContext());
+ WgToSgVectorBroadcastOp, WgToSgConvertLayoutOp,
+ WgToSgArithConstantOp>(patterns.getContext());
}
} // namespace xegpu
} // namespace mlir
@@ -770,6 +816,14 @@ void XeGPUWgToSgDistributePass::runOnOperation() {
return isLegal(xegpu::getLayoutAttr(op.getResult()));
});
+ target.addDynamicallyLegalOp<arith::ConstantOp>(
+ [=](arith::ConstantOp op) -> bool {
+ auto vecType = dyn_cast<VectorType>(op.getType());
+ if (!vecType)
+ return true;
+ return isLegal(xegpu::getLayoutAttr(op.getResult()));
+ });
+
target.addDynamicallyLegalOp<xegpu::ConvertLayoutOp>(
[=](xegpu::ConvertLayoutOp op) -> bool {
return isLegal(op.getInputLayout()) && isLegal(op.getTargetLayout());
diff --git a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir
index d67bdb487d8bf..65f4b46ad6d26 100644
--- a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir
+++ b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir
@@ -225,4 +225,11 @@ gpu.module @test_round_robin_assignment {
target_layout = #xegpu.layout<sg_layout = [2, 2], sg_data = [16, 16], inst_data = [8, 16]>}> : vector<32x64xf32>
gpu.return
}
+
+ // CHECK-LABEL: distribute_constant
+ gpu.func @distribute_constant() {
+ // CHECK-COUNT-4: arith.constant dense<1.000000e+00> : vector<16x16xf32>
+ %cst = arith.constant {layout_result_0 = #xegpu.layout<sg_layout = [8, 4], sg_data = [16, 16]>} dense<1.0> : vector<256x128xf32>
+ gpu.return
+ }
}
diff --git a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir
index d51122417fb61..415753a652092 100644
--- a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir
+++ b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir
@@ -393,4 +393,11 @@ gpu.func @dpas_no_sg_data(%a: memref<24x32xf32>, %b: memref<32x24xf32>) {
} {sg_id_range = #xegpu.range<[3, 19]>}
gpu.return
}
+
+ // CHECK-LABEL: distribute_constant
+ gpu.func @distribute_constant() {
+ // CHECK: arith.constant dense<1.000000e+00> : vector<32x32xf32>
+ %cst = arith.constant {layout_result_0 = #xegpu.layout<sg_layout = [8, 4], sg_data = [32, 32]>} dense<1.0> : vector<256x128xf32>
+ gpu.return
+ }
}
|
|
@llvm/pr-subscribers-mlir Author: Nishant Patel (nbpatel) ChangesFull diff: https://github.com/llvm/llvm-project/pull/151977.diff 3 Files Affected:
diff --git a/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp b/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp
index 850f70cca288f..878638061db5c 100644
--- a/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp
+++ b/mlir/lib/Dialect/XeGPU/Transforms/XeGPUWgToSgDistribute.cpp
@@ -649,6 +649,52 @@ struct UnrealizedConversionCastOpPattern
}
};
+// This pattern distributes arith.constant op into subgroup-level constants
+struct WgToSgArithConstantOp : public OpConversionPattern<arith::ConstantOp> {
+ using OpConversionPattern<arith::ConstantOp>::OpConversionPattern;
+
+ LogicalResult
+ matchAndRewrite(arith::ConstantOp op, OneToNOpAdaptor adaptor,
+ ConversionPatternRewriter &rewriter) const override {
+ auto vecAttr = dyn_cast<DenseElementsAttr>(op.getValue());
+ auto vecType = dyn_cast<VectorType>(op.getType());
+ if (!vecAttr || !vecType)
+ return failure();
+
+ xegpu::LayoutAttr layout = xegpu::getLayoutAttr(op.getResult());
+ if (!layout || !layout.getSgLayout())
+ return failure();
+
+ ArrayRef<int64_t> wgShape = vecType.getShape();
+ SmallVector<int64_t> sgShape;
+ int count;
+ std::tie(sgShape, count) = getSgShapeAndCount(wgShape, layout);
+
+ // Current limitation: constant of vector with single value.
+ // TODO: support more complex cases, e.g., vector with multiple values.
+ Attribute singleVal;
+ if (vecAttr.isSplat())
+ singleVal = vecAttr.getSplatValue<Attribute>();
+ else
+ return failure();
+
+ SmallVector<Value> newConsts;
+ auto newType = VectorType::get(sgShape, vecType.getElementType());
+ auto newLayout = layout.dropSgLayoutAndData();
+ for (int i = 0; i < count; ++i) {
+ auto sgAttr = DenseElementsAttr::get(newType, singleVal);
+ auto cstOp =
+ rewriter.create<arith::ConstantOp>(op.getLoc(), newType, sgAttr);
+ if (newLayout)
+ xegpu::setLayoutAttr(cstOp->getResult(0), newLayout);
+ newConsts.push_back(cstOp);
+ }
+
+ rewriter.replaceOpWithMultiple(op, {newConsts});
+ return success();
+ }
+};
+
} // namespace
namespace mlir {
@@ -657,8 +703,8 @@ void populateXeGPUWgToSgDistributePatterns(RewritePatternSet &patterns) {
patterns.add<WgToSgCreateNdOp, WgToSgLoadNdOp, WgToSgStoreNdOp,
WgToSgUpdateNdOffsetOp, WgToSgDpasOp, WgToSgPrefetchNdOp,
UnrealizedConversionCastOpPattern, WgToSgElementwiseOp,
- WgToSgVectorBroadcastOp, WgToSgConvertLayoutOp>(
- patterns.getContext());
+ WgToSgVectorBroadcastOp, WgToSgConvertLayoutOp,
+ WgToSgArithConstantOp>(patterns.getContext());
}
} // namespace xegpu
} // namespace mlir
@@ -770,6 +816,14 @@ void XeGPUWgToSgDistributePass::runOnOperation() {
return isLegal(xegpu::getLayoutAttr(op.getResult()));
});
+ target.addDynamicallyLegalOp<arith::ConstantOp>(
+ [=](arith::ConstantOp op) -> bool {
+ auto vecType = dyn_cast<VectorType>(op.getType());
+ if (!vecType)
+ return true;
+ return isLegal(xegpu::getLayoutAttr(op.getResult()));
+ });
+
target.addDynamicallyLegalOp<xegpu::ConvertLayoutOp>(
[=](xegpu::ConvertLayoutOp op) -> bool {
return isLegal(op.getInputLayout()) && isLegal(op.getTargetLayout());
diff --git a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir
index d67bdb487d8bf..65f4b46ad6d26 100644
--- a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir
+++ b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg-rr.mlir
@@ -225,4 +225,11 @@ gpu.module @test_round_robin_assignment {
target_layout = #xegpu.layout<sg_layout = [2, 2], sg_data = [16, 16], inst_data = [8, 16]>}> : vector<32x64xf32>
gpu.return
}
+
+ // CHECK-LABEL: distribute_constant
+ gpu.func @distribute_constant() {
+ // CHECK-COUNT-4: arith.constant dense<1.000000e+00> : vector<16x16xf32>
+ %cst = arith.constant {layout_result_0 = #xegpu.layout<sg_layout = [8, 4], sg_data = [16, 16]>} dense<1.0> : vector<256x128xf32>
+ gpu.return
+ }
}
diff --git a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir
index d51122417fb61..415753a652092 100644
--- a/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir
+++ b/mlir/test/Dialect/XeGPU/xegpu-wg-to-sg.mlir
@@ -393,4 +393,11 @@ gpu.func @dpas_no_sg_data(%a: memref<24x32xf32>, %b: memref<32x24xf32>) {
} {sg_id_range = #xegpu.range<[3, 19]>}
gpu.return
}
+
+ // CHECK-LABEL: distribute_constant
+ gpu.func @distribute_constant() {
+ // CHECK: arith.constant dense<1.000000e+00> : vector<32x32xf32>
+ %cst = arith.constant {layout_result_0 = #xegpu.layout<sg_layout = [8, 4], sg_data = [32, 32]>} dense<1.0> : vector<256x128xf32>
+ gpu.return
+ }
}
|
chencha3
reviewed
Aug 4, 2025
adam-smnk
reviewed
Aug 5, 2025
tkarna
pushed a commit
to tkarna/llvm-project
that referenced
this pull request
Aug 26, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.