[Mlir-commits] [mlir] [mlir][vector] Move extract_strided_slice canonicalization to folding (PR #135676)
llvmlistbot at llvm.org
llvmlistbot at llvm.org
Tue Apr 15 00:27:53 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-mlir-vector
Author: James Newling (newling)
<details>
<summary>Changes</summary>
Folders are preferred: https://mlir.llvm.org/docs/Canonicalization/#when-to-use-the-fold-method-vs-rewriterpatterns-for-canonicalizations
Included here : some missing `-----` between lit test file with mlir-opt with `-split-input-file` flag
---
Full diff: https://github.com/llvm/llvm-project/pull/135676.diff
2 Files Affected:
- (modified) mlir/lib/Dialect/Vector/IR/VectorOps.cpp (+58-102)
- (modified) mlir/test/Dialect/Vector/canonicalize.mlir (+7)
``````````diff
diff --git a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
index bee5c1fd6ed58..1eb6daa402422 100644
--- a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
+++ b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
@@ -3717,6 +3717,58 @@ OpFoldResult ExtractStridedSliceOp::fold(FoldAdaptor adaptor) {
return getVector();
if (succeeded(foldExtractStridedOpFromInsertChain(*this)))
return getResult();
+
+ // All subsequent successful folds require a constant input.
+ Attribute foldInput = adaptor.getVector();
+ if (!foldInput)
+ return {};
+
+ // ExtractStridedSliceOp(splat ConstantOp) -> ConstantOp.
+ if (auto splat = llvm::dyn_cast<SplatElementsAttr>(foldInput))
+ DenseElementsAttr::get(getType(), splat.getSplatValue<Attribute>());
+
+ // ExtractStridedSliceOp(non-splat ConstantOp) -> ConstantOp.
+ if (auto dense = llvm::dyn_cast<DenseElementsAttr>(foldInput)) {
+ // TODO: Handle non-unit strides when they become available.
+ if (hasNonUnitStrides())
+ return {};
+
+ VectorType sourceVecTy = getSourceVectorType();
+ ArrayRef<int64_t> sourceShape = sourceVecTy.getShape();
+ SmallVector<int64_t, 4> sourceStrides = computeStrides(sourceShape);
+
+ VectorType sliceVecTy = getType();
+ ArrayRef<int64_t> sliceShape = sliceVecTy.getShape();
+ int64_t rank = sliceVecTy.getRank();
+
+ // Expand offsets and sizes to match the vector rank.
+ SmallVector<int64_t, 4> offsets(rank, 0);
+ copy(getI64SubArray(getOffsets()), offsets.begin());
+
+ SmallVector<int64_t, 4> sizes(sourceShape);
+ copy(getI64SubArray(getSizes()), sizes.begin());
+
+ // Calculate the slice elements by enumerating all slice positions and
+ // linearizing them. The enumeration order is lexicographic which yields a
+ // sequence of monotonically increasing linearized position indices.
+ const auto denseValuesBegin = dense.value_begin<Attribute>();
+ SmallVector<Attribute> sliceValues;
+ sliceValues.reserve(sliceVecTy.getNumElements());
+ SmallVector<int64_t> currSlicePosition(offsets.begin(), offsets.end());
+ do {
+ int64_t linearizedPosition = linearize(currSlicePosition, sourceStrides);
+ assert(linearizedPosition < sourceVecTy.getNumElements() &&
+ "Invalid index");
+ sliceValues.push_back(*(denseValuesBegin + linearizedPosition));
+ } while (
+ succeeded(incSlicePosition(currSlicePosition, sliceShape, offsets)));
+
+ assert(static_cast<int64_t>(sliceValues.size()) ==
+ sliceVecTy.getNumElements() &&
+ "Invalid number of slice elements");
+ return DenseElementsAttr::get(sliceVecTy, sliceValues);
+ }
+
return {};
}
@@ -3781,98 +3833,6 @@ class StridedSliceConstantMaskFolder final
}
};
-// Pattern to rewrite a ExtractStridedSliceOp(splat ConstantOp) -> ConstantOp.
-class StridedSliceSplatConstantFolder final
- : public OpRewritePattern<ExtractStridedSliceOp> {
-public:
- using OpRewritePattern::OpRewritePattern;
-
- LogicalResult matchAndRewrite(ExtractStridedSliceOp extractStridedSliceOp,
- PatternRewriter &rewriter) const override {
- // Return if 'ExtractStridedSliceOp' operand is not defined by a splat
- // ConstantOp.
- Value sourceVector = extractStridedSliceOp.getVector();
- Attribute vectorCst;
- if (!matchPattern(sourceVector, m_Constant(&vectorCst)))
- return failure();
-
- auto splat = llvm::dyn_cast<SplatElementsAttr>(vectorCst);
- if (!splat)
- return failure();
-
- auto newAttr = SplatElementsAttr::get(extractStridedSliceOp.getType(),
- splat.getSplatValue<Attribute>());
- rewriter.replaceOpWithNewOp<arith::ConstantOp>(extractStridedSliceOp,
- newAttr);
- return success();
- }
-};
-
-// Pattern to rewrite a ExtractStridedSliceOp(non-splat ConstantOp) ->
-// ConstantOp.
-class StridedSliceNonSplatConstantFolder final
- : public OpRewritePattern<ExtractStridedSliceOp> {
-public:
- using OpRewritePattern::OpRewritePattern;
-
- LogicalResult matchAndRewrite(ExtractStridedSliceOp extractStridedSliceOp,
- PatternRewriter &rewriter) const override {
- // Return if 'ExtractStridedSliceOp' operand is not defined by a non-splat
- // ConstantOp.
- Value sourceVector = extractStridedSliceOp.getVector();
- Attribute vectorCst;
- if (!matchPattern(sourceVector, m_Constant(&vectorCst)))
- return failure();
-
- // The splat case is handled by `StridedSliceSplatConstantFolder`.
- auto dense = llvm::dyn_cast<DenseElementsAttr>(vectorCst);
- if (!dense || dense.isSplat())
- return failure();
-
- // TODO: Handle non-unit strides when they become available.
- if (extractStridedSliceOp.hasNonUnitStrides())
- return failure();
-
- auto sourceVecTy = llvm::cast<VectorType>(sourceVector.getType());
- ArrayRef<int64_t> sourceShape = sourceVecTy.getShape();
- SmallVector<int64_t, 4> sourceStrides = computeStrides(sourceShape);
-
- VectorType sliceVecTy = extractStridedSliceOp.getType();
- ArrayRef<int64_t> sliceShape = sliceVecTy.getShape();
- int64_t sliceRank = sliceVecTy.getRank();
-
- // Expand offsets and sizes to match the vector rank.
- SmallVector<int64_t, 4> offsets(sliceRank, 0);
- copy(getI64SubArray(extractStridedSliceOp.getOffsets()), offsets.begin());
-
- SmallVector<int64_t, 4> sizes(sourceShape);
- copy(getI64SubArray(extractStridedSliceOp.getSizes()), sizes.begin());
-
- // Calculate the slice elements by enumerating all slice positions and
- // linearizing them. The enumeration order is lexicographic which yields a
- // sequence of monotonically increasing linearized position indices.
- auto denseValuesBegin = dense.value_begin<Attribute>();
- SmallVector<Attribute> sliceValues;
- sliceValues.reserve(sliceVecTy.getNumElements());
- SmallVector<int64_t> currSlicePosition(offsets.begin(), offsets.end());
- do {
- int64_t linearizedPosition = linearize(currSlicePosition, sourceStrides);
- assert(linearizedPosition < sourceVecTy.getNumElements() &&
- "Invalid index");
- sliceValues.push_back(*(denseValuesBegin + linearizedPosition));
- } while (
- succeeded(incSlicePosition(currSlicePosition, sliceShape, offsets)));
-
- assert(static_cast<int64_t>(sliceValues.size()) ==
- sliceVecTy.getNumElements() &&
- "Invalid number of slice elements");
- auto newAttr = DenseElementsAttr::get(sliceVecTy, sliceValues);
- rewriter.replaceOpWithNewOp<arith::ConstantOp>(extractStridedSliceOp,
- newAttr);
- return success();
- }
-};
-
// Pattern to rewrite an ExtractStridedSliceOp(BroadcastOp) to
// BroadcastOp(ExtractStrideSliceOp).
class StridedSliceBroadcast final
@@ -4016,8 +3976,7 @@ void ExtractStridedSliceOp::getCanonicalizationPatterns(
RewritePatternSet &results, MLIRContext *context) {
// Pattern to rewrite a ExtractStridedSliceOp(ConstantMaskOp) ->
// ConstantMaskOp and ExtractStridedSliceOp(ConstantOp) -> ConstantOp.
- results.add<StridedSliceConstantMaskFolder, StridedSliceSplatConstantFolder,
- StridedSliceNonSplatConstantFolder, StridedSliceBroadcast,
+ results.add<StridedSliceConstantMaskFolder, StridedSliceBroadcast,
StridedSliceSplat, ContiguousExtractStridedSliceToExtract>(
context);
}
@@ -5657,10 +5616,8 @@ OpFoldResult ShapeCastOp::fold(FoldAdaptor adaptor) {
// shape_cast(constant) -> constant
if (auto splatAttr =
- llvm::dyn_cast_if_present<SplatElementsAttr>(adaptor.getSource())) {
- return DenseElementsAttr::get(resultType,
- splatAttr.getSplatValue<Attribute>());
- }
+ llvm::dyn_cast_if_present<SplatElementsAttr>(adaptor.getSource()))
+ return splatAttr.reshape(getType());
// shape_cast(poison) -> poison
if (llvm::dyn_cast_if_present<ub::PoisonAttr>(adaptor.getSource())) {
@@ -6004,10 +5961,9 @@ void vector::TransposeOp::build(OpBuilder &builder, OperationState &result,
OpFoldResult vector::TransposeOp::fold(FoldAdaptor adaptor) {
// Eliminate splat constant transpose ops.
- if (auto attr =
- llvm::dyn_cast_if_present<DenseElementsAttr>(adaptor.getVector()))
- if (attr.isSplat())
- return attr.reshape(getResultVectorType());
+ if (auto splat =
+ llvm::dyn_cast_if_present<SplatElementsAttr>(adaptor.getVector()))
+ return splat.reshape(getResultVectorType());
// Eliminate identity transpose ops. This happens when the dimensions of the
// input vector remain in their original order after the transpose operation.
diff --git a/mlir/test/Dialect/Vector/canonicalize.mlir b/mlir/test/Dialect/Vector/canonicalize.mlir
index 78b0ea78849e8..6556df22e069b 100644
--- a/mlir/test/Dialect/Vector/canonicalize.mlir
+++ b/mlir/test/Dialect/Vector/canonicalize.mlir
@@ -1121,6 +1121,8 @@ func.func @bitcast_folding(%I1: vector<4x8xf32>, %I2: vector<2xi32>) -> (vector<
return %0, %2 : vector<4x8xf32>, vector<2xi32>
}
+// -----
+
// CHECK-LABEL: func @bitcast_f16_to_f32
// bit pattern: 0x40004000
// CHECK-DAG: %[[CST1:.+]] = arith.constant dense<2.00390625> : vector<4xf32>
@@ -1135,6 +1137,8 @@ func.func @bitcast_f16_to_f32() -> (vector<4xf32>, vector<4xf32>) {
return %cast0, %cast1: vector<4xf32>, vector<4xf32>
}
+// -----
+
// CHECK-LABEL: func @bitcast_i8_to_i32
// bit pattern: 0xA0A0A0A0
// CHECK-DAG: %[[CST1:.+]] = arith.constant dense<-1600085856> : vector<4xi32>
@@ -1710,6 +1714,7 @@ func.func @vector_multi_reduction_unit_dimensions(%source: vector<5x1x4x1x20xf32
}
// -----
+
// CHECK-LABEL: func.func @vector_multi_reduction_scalable(
// CHECK-SAME: %[[VAL_0:.*]]: vector<1x[4]x1xf32>,
// CHECK-SAME: %[[VAL_1:.*]]: vector<1x[4]xf32>,
@@ -2251,6 +2256,8 @@ func.func @transpose_splat_constant() -> vector<8x4xf32> {
return %0 : vector<8x4xf32>
}
+// -----
+
// CHECK-LABEL: func @transpose_splat2(
// CHECK-SAME: %[[VAL_0:.*]]: f32) -> vector<3x4xf32> {
// CHECK: %[[VAL_1:.*]] = vector.splat %[[VAL_0]] : vector<3x4xf32>
``````````
</details>
https://github.com/llvm/llvm-project/pull/135676
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