feat(linalg): add a way to pass controlFn to foldIntoPackUnpackPatterns (#143685)

This PR adds a mechanism, so that downstream consumers can pass in
control functions for the application of these patterns. This change
shouldn't affect any consumers of this method that do not specify a
controlFn. The controlFn always gets the source operand of the consumer
in each of the patterns as a parameter.

In IREE, we (will) use it to control preventing folding patterns that
would inhibit fusion. See IREE issue
[#20896](https://github.com/iree-org/iree/issues/20896) for more
details.
This commit is contained in:
Ege Beysel
2025-07-01 16:22:38 +02:00
committed by GitHub
parent f9413e1754
commit ace5108f37
4 changed files with 165 additions and 10 deletions

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@@ -1984,10 +1984,15 @@ void populateDecomposeWinogradOpsPatterns(RewritePatternSet &patterns);
/// convert to a `linalg.dot`.
void populateContractionOpRankReducingPatterns(RewritePatternSet &patterns);
/// Function type which is used to control folding operations like `tensor.pad`
/// and `tensor.extract_slice` into linalg.pack/unpack ops.
using ControlFoldIntoPackUnpackFn = std::function<bool(OpOperand *opOperand)>;
/// Populates `patterns` with patterns that fold operations like `tensor.pad`
/// and `tensor.extract_slice` into `tensor.pack` and `tensor.unpack` operations
/// respectively.
void populateFoldIntoPackAndUnpackPatterns(RewritePatternSet &patterns);
void populateFoldIntoPackAndUnpackPatterns(
RewritePatternSet &patterns,
const ControlFoldIntoPackUnpackFn &controlFn = nullptr);
/// Populates `patterns` with patterns that fold operations like `linalg.pack`
/// and `linalg.unpack` into `tensor.empty`.

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@@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/Linalg/IR/Linalg.h"
#include "mlir/Dialect/Linalg/Transforms/Transforms.h"
#include "mlir/Dialect/Tensor/IR/Tensor.h"
#include "mlir/Dialect/Tensor/Transforms/Transforms.h"
#include "mlir/Dialect/Utils/IndexingUtils.h"
@@ -197,7 +198,9 @@ struct SimplifyUnPackToCollapseShape : public OpRewritePattern<UnPackOp> {
/// Fold a `pad` -> `pack` into `pack` if they have the same padding values and
/// the pad op has zero low paddings, or if `pack` has no padding values.
struct FoldPadWithPackOp : public OpRewritePattern<PackOp> {
using OpRewritePattern<PackOp>::OpRewritePattern;
public:
FoldPadWithPackOp(MLIRContext *context, ControlFoldIntoPackUnpackFn controlFn)
: OpRewritePattern<PackOp>(context), controlFn(std::move(controlFn)) {}
LogicalResult matchAndRewrite(PackOp packOp,
PatternRewriter &rewriter) const override {
@@ -206,6 +209,10 @@ struct FoldPadWithPackOp : public OpRewritePattern<PackOp> {
if (!padOp || padOp.getNofold() || !padOp.hasZeroLowPad())
return failure();
// User controlled folding function.
if (controlFn && !controlFn(&packOp.getSourceMutable()))
return failure();
Value constantPaddingValue = padOp.getConstantPaddingValue();
if (!constantPaddingValue)
return failure();
@@ -220,13 +227,20 @@ struct FoldPadWithPackOp : public OpRewritePattern<PackOp> {
packOp.getOuterDimsPerm());
return success();
}
private:
ControlFoldIntoPackUnpackFn controlFn;
};
/// Fold a `unpack` -> `extract_slice` into the `unpack` since it already
/// has extract_slice semantics.
struct FoldUnpackWithExtractSliceOp
: public OpRewritePattern<tensor::ExtractSliceOp> {
using OpRewritePattern<tensor::ExtractSliceOp>::OpRewritePattern;
public:
FoldUnpackWithExtractSliceOp(MLIRContext *context,
ControlFoldIntoPackUnpackFn controlFn)
: OpRewritePattern<tensor::ExtractSliceOp>(context),
controlFn(std::move(controlFn)) {}
LogicalResult matchAndRewrite(tensor::ExtractSliceOp sliceOp,
PatternRewriter &rewriter) const override {
@@ -234,6 +248,10 @@ struct FoldUnpackWithExtractSliceOp
if (!unpackOp)
return failure();
// User controlled folding function.
if (controlFn && !controlFn(&sliceOp.getSourceMutable()))
return failure();
if (sliceOp.getResultType().getRank() != unpackOp.getDestType().getRank()) {
return rewriter.notifyMatchFailure(
sliceOp, "rank-reduced folding is not supported");
@@ -255,6 +273,9 @@ struct FoldUnpackWithExtractSliceOp
unpackOp.getMixedTiles(), unpackOp.getOuterDimsPerm());
return success();
}
private:
ControlFoldIntoPackUnpackFn controlFn;
};
// Applies 'permutation' on 'inVec' and stores the result in resVec.
@@ -284,7 +305,12 @@ static bool checkAndPermute(ArrayRef<int64_t> permutation,
/// semantics.
struct FoldProducerPackWithConsumerLinalgTransposeOp
: public OpInterfaceRewritePattern<linalg::LinalgOp> {
using OpInterfaceRewritePattern<linalg::LinalgOp>::OpInterfaceRewritePattern;
public:
FoldProducerPackWithConsumerLinalgTransposeOp(
MLIRContext *context, ControlFoldIntoPackUnpackFn controlFn)
: OpInterfaceRewritePattern<linalg::LinalgOp>(context),
controlFn(std::move(controlFn)) {}
LogicalResult matchAndRewrite(linalg::LinalgOp linalgOp,
PatternRewriter &rewriter) const override {
@@ -293,6 +319,10 @@ struct FoldProducerPackWithConsumerLinalgTransposeOp
if (!packOp)
return failure();
// User controlled folding function.
if (controlFn && !controlFn(&linalgOp->getOpOperand(0)))
return failure();
FailureOr<SmallVector<int64_t>> maybePerm =
getTransposeOpPermutation(linalgOp);
if (failed(maybePerm))
@@ -331,13 +361,20 @@ struct FoldProducerPackWithConsumerLinalgTransposeOp
return success();
}
private:
ControlFoldIntoPackUnpackFn controlFn;
};
/// Fold 'transpose' -> 'pack' into 'pack' since 'pack' already has transpose
/// semantics.
struct FoldConsumerPackWithProducerLinalgTransposeOp
: public OpRewritePattern<PackOp> {
using OpRewritePattern<PackOp>::OpRewritePattern;
public:
FoldConsumerPackWithProducerLinalgTransposeOp(
MLIRContext *context, ControlFoldIntoPackUnpackFn controlFn)
: OpRewritePattern<PackOp>(context), controlFn(std::move(controlFn)) {}
LogicalResult matchAndRewrite(PackOp packOp,
PatternRewriter &rewriter) const override {
@@ -345,6 +382,10 @@ struct FoldConsumerPackWithProducerLinalgTransposeOp
if (!linalgOp)
return failure();
// User controlled folding function.
if (controlFn && !controlFn(&packOp.getSourceMutable()))
return failure();
FailureOr<SmallVector<int64_t>> maybePerm =
getTransposeOpPermutation(linalgOp);
if (failed(maybePerm))
@@ -375,13 +416,21 @@ struct FoldConsumerPackWithProducerLinalgTransposeOp
return success();
}
private:
ControlFoldIntoPackUnpackFn controlFn;
};
/// Fold 'unpack' -> 'transpose' into 'unpack' since 'unpack' already has
/// transpose semantics.
struct FoldProducerUnPackWithConsumerLinalgTransposeOp
: public OpInterfaceRewritePattern<linalg::LinalgOp> {
using OpInterfaceRewritePattern<linalg::LinalgOp>::OpInterfaceRewritePattern;
public:
FoldProducerUnPackWithConsumerLinalgTransposeOp(
MLIRContext *context, ControlFoldIntoPackUnpackFn controlFn)
: OpInterfaceRewritePattern<linalg::LinalgOp>(context),
controlFn(std::move(controlFn)) {}
LogicalResult matchAndRewrite(linalg::LinalgOp linalgOp,
PatternRewriter &rewriter) const override {
@@ -390,6 +439,10 @@ struct FoldProducerUnPackWithConsumerLinalgTransposeOp
if (!unPackOp)
return failure();
// User controlled folding function.
if (controlFn && !controlFn(&linalgOp->getOpOperand(0)))
return failure();
FailureOr<SmallVector<int64_t>> maybePerm =
getTransposeOpPermutation(linalgOp);
if (failed(maybePerm))
@@ -416,6 +469,9 @@ struct FoldProducerUnPackWithConsumerLinalgTransposeOp
return success();
}
private:
ControlFoldIntoPackUnpackFn controlFn;
};
/// Fold 'transpose' -> 'unpack' into 'unpack' since 'unpack' already has
@@ -424,12 +480,21 @@ struct FoldConsumerUnPackWithProducerLinalgTransposeOp
: public OpRewritePattern<UnPackOp> {
using OpRewritePattern<UnPackOp>::OpRewritePattern;
public:
FoldConsumerUnPackWithProducerLinalgTransposeOp(
MLIRContext *context, ControlFoldIntoPackUnpackFn controlFn)
: OpRewritePattern<UnPackOp>(context), controlFn(std::move(controlFn)) {}
LogicalResult matchAndRewrite(UnPackOp unPackOp,
PatternRewriter &rewriter) const override {
auto linalgOp = unPackOp.getSource().getDefiningOp<linalg::LinalgOp>();
if (!linalgOp)
return failure();
// User controlled folding function.
if (controlFn && !controlFn(&unPackOp.getSourceMutable()))
return failure();
FailureOr<SmallVector<int64_t>> maybePerm =
getTransposeOpPermutation(linalgOp);
if (failed(maybePerm))
@@ -474,6 +539,9 @@ struct FoldConsumerUnPackWithProducerLinalgTransposeOp
return success();
}
private:
ControlFoldIntoPackUnpackFn controlFn;
};
/// tensor.empty does not define any tensor contents, so an unpadded pack
@@ -521,13 +589,14 @@ struct FoldEmptyTensorWithUnPackOp : public OpRewritePattern<UnPackOp> {
} // namespace
void populateFoldIntoPackAndUnpackPatterns(RewritePatternSet &patterns) {
void populateFoldIntoPackAndUnpackPatterns(
RewritePatternSet &patterns, const ControlFoldIntoPackUnpackFn &controlFn) {
patterns.insert<FoldUnpackWithExtractSliceOp, FoldPadWithPackOp,
FoldProducerPackWithConsumerLinalgTransposeOp,
FoldConsumerPackWithProducerLinalgTransposeOp,
FoldConsumerUnPackWithProducerLinalgTransposeOp,
FoldProducerUnPackWithConsumerLinalgTransposeOp>(
patterns.getContext());
patterns.getContext(), controlFn);
}
void populateSimplifyPackAndUnpackPatterns(RewritePatternSet &patterns) {

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@@ -1,4 +1,5 @@
// RUN: mlir-opt -split-input-file -test-linalg-transform-patterns=test-fold-into-pack-and-unpack %s | FileCheck %s
// RUN: mlir-opt -split-input-file -test-linalg-transform-patterns=test-fold-into-pack-and-unpack-control %s | FileCheck %s --check-prefix=CONTROL
func.func @fold_unpack_slice(%arg0 : tensor<?x?x8x4xf32>, %arg1 : tensor<?x?xf32>,
%arg2 : index, %arg3 : index) -> tensor<?x?xf32> {
@@ -373,6 +374,36 @@ func.func @linalg_transpose_linalg.pack_fold(%arg0: tensor<56x57x1x64xf32>) -> t
// -----
func.func @linalg_transpose_linalg.pack_fold_multi_result(%arg0: tensor<56x57x1x64xf32>) -> (tensor<1x56x57x64xf32>, tensor<1x57x56x2x32xf32>) {
%0 = tensor.empty() : tensor<1x56x57x64xf32>
%transposed = linalg.transpose
ins(%arg0 : tensor<56x57x1x64xf32>)
outs(%0 : tensor<1x56x57x64xf32>)
permutation = [2, 0, 1, 3]
%1 = tensor.empty() : tensor<1x57x56x2x32xf32>
%pack = linalg.pack %transposed
outer_dims_perm = [0, 2, 1, 3]
inner_dims_pos = [3]
inner_tiles = [32]
into %1 : tensor<1x56x57x64xf32> -> tensor<1x57x56x2x32xf32>
return %transposed, %pack : tensor<1x56x57x64xf32>, tensor<1x57x56x2x32xf32>
}
// CHECK-LABEL: func @linalg_transpose_linalg.pack_fold_multi_result(
// CHECK-SAME: %[[ARG0:.+]]: tensor<56x57x1x64xf32>)
// CHECK: %[[TRANSPOSE:.+]] = linalg.transpose
// CHECK: %[[PACK:.+]] = linalg.pack %[[ARG0]]
// CHECK-SAME: outer_dims_perm = [2, 1, 0, 3]
// CHECK: return %[[TRANSPOSE]], %[[PACK]]
// CONTROL-LABEL: func @linalg_transpose_linalg.pack_fold_multi_result(
// CONTROL: %[[TRANSPOSE:.+]] = linalg.transpose
// CONTROL: %[[PACK:.+]] = linalg.pack %[[TRANSPOSE]]
// CONTROL-SAME: outer_dims_perm = [0, 2, 1, 3]
// CONTROL: return %[[TRANSPOSE]], %[[PACK]]
// -----
func.func @linalg_transpose_linalg.pack_fold_with_padding(%arg0: tensor<56x57x1x55xf32>, %padding: f32) -> tensor<1x57x56x2x32xf32> {
%0 = tensor.empty() : tensor<1x56x57x55xf32>
%transpose = linalg.transpose
@@ -550,6 +581,36 @@ func.func @linalg_transpose_linalg.unpack_fold(%arg0: tensor<1x1x4x16xi32>) -> t
// -----
func.func @linalg_transpose_linalg.unpack_fold_multi_result(%arg0: tensor<1x1x4x16xi32>) -> (tensor<1x1x16x4xi32>, tensor<16x4xi32>) {
%0 = tensor.empty() : tensor<1x1x16x4xi32>
%transposed = linalg.transpose ins(%arg0 : tensor<1x1x4x16xi32>)
outs(%0 : tensor<1x1x16x4xi32>)
permutation = [1, 0, 3, 2]
%1 = tensor.empty() : tensor<16x4xi32>
%unpack = linalg.unpack %transposed
outer_dims_perm = [0, 1]
inner_dims_pos = [0, 1]
inner_tiles = [16, 4] into
%1 : tensor<1x1x16x4xi32> -> tensor<16x4xi32>
return %transposed, %unpack : tensor<1x1x16x4xi32>, tensor<16x4xi32>
}
//CHECK-LABEL: func.func @linalg_transpose_linalg.unpack_fold_multi_result(
// CHECK-SAME: %[[ARG0:.+]]: tensor<1x1x4x16xi32>)
// CHECK: %[[TRANSPOSE:.+]] = linalg.transpose
// CHECK: %[[UNPACK:.+]] = linalg.unpack %[[ARG0]]
// CHECK-SAME: outer_dims_perm = [1, 0]
// CHECK: return %[[TRANSPOSE]], %[[UNPACK]]
// CHECK: }
//CONTROL-LABEL: func.func @linalg_transpose_linalg.unpack_fold_multi_result(
// CONTROL: %[[TRANSPOSE:.+]] = linalg.transpose
// CONTROL: %[[UNPACK:.+]] = linalg.unpack %[[TRANSPOSE]]
// CONTROL-SAME: outer_dims_perm = [0, 1]
// CONTROL: return %[[TRANSPOSE]], %[[UNPACK]]
// CONTROL: }
// -----
func.func @linalg_transpose_linalg.unpack_fold_partial_tile(%arg0: tensor<1x1x4x16xi32>) -> tensor<15x3xi32> {
%0 = tensor.empty() : tensor<1x1x16x4xi32>
%transposed = linalg.transpose ins(%arg0 : tensor<1x1x4x16xi32>)

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@@ -130,6 +130,11 @@ struct TestLinalgTransforms
*this, "test-fold-into-pack-and-unpack",
llvm::cl::desc("Test folding ops into linalg.pack and linalg.unpack"),
llvm::cl::init(false)};
Option<bool> testFoldIntoPackAndUnpackWithControlFn{
*this, "test-fold-into-pack-and-unpack-control",
llvm::cl::desc(
"Test controlling folding ops into linalg.pack and linalg.unpack"),
llvm::cl::init(false)};
Option<bool> testSimplifyPackUnpackPatterns{
*this, "test-simplify-pack-unpack-patterns",
llvm::cl::desc("Test patterns to simplify linalg.pack and linalg.unpack"),
@@ -222,9 +227,11 @@ static void applyDecomposeWinogradOps(func::FuncOp funcOp) {
(void)applyPatternsGreedily(funcOp, std::move(patterns));
}
static void applyFoldIntoPackAndUnpackPatterns(Operation *rootOp) {
static void applyFoldIntoPackAndUnpackPatterns(
Operation *rootOp,
linalg::ControlFoldIntoPackUnpackFn controlFn = nullptr) {
RewritePatternSet patterns(rootOp->getContext());
linalg::populateFoldIntoPackAndUnpackPatterns(patterns);
linalg::populateFoldIntoPackAndUnpackPatterns(patterns, controlFn);
(void)applyPatternsGreedily(rootOp, std::move(patterns));
}
@@ -263,6 +270,19 @@ void TestLinalgTransforms::runOnOperation() {
Operation *rootOp = getOperation();
if (testFoldIntoPackAndUnpack)
applyFoldIntoPackAndUnpackPatterns(rootOp);
if (testFoldIntoPackAndUnpackWithControlFn) {
linalg::ControlFoldIntoPackUnpackFn controlFn = [](OpOperand *opOperand) {
Operation *producer = opOperand->get().getDefiningOp();
Operation *consumer = opOperand->getOwner();
// If we have a pack/unpack consumer and a producer that has multiple
// uses, do not apply the folding patterns.
if (isa<linalg::PackOp, linalg::UnPackOp>(consumer) &&
isa<TilingInterface>(producer) && !producer->hasOneUse())
return false;
return true;
};
applyFoldIntoPackAndUnpackPatterns(rootOp, controlFn);
}
if (testSimplifyPackUnpackPatterns)
applySimplifyPackUnpackPatterns(rootOp);
}