[mlir][Transforms] LISH: Improve bypass analysis for loop-like ops #70623
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@llvm/pr-subscribers-mlir-bufferization @llvm/pr-subscribers-mlir-core Author: Matthias Springer (matthias-springer) ChangesImprove the bypass analysis for loop-like ops. Until now, loop-like ops were treated like any other non-subset ops: they prevent hoisting of any sort because the analysis does not know which parts of a tensor init operand are accessed by the loop-like op. With this change, the analysis can look into loop-like ops and analyze which subset they are operating on. Depends on #70535, #70617 and #70619. Only review the top commit. Patch is 90.58 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/70623.diff 34 Files Affected:
diff --git a/mlir/include/mlir/Dialect/Bufferization/IR/Bufferization.h b/mlir/include/mlir/Dialect/Bufferization/IR/Bufferization.h
index c035190f43e3950..e98b5728b38ef81 100644
--- a/mlir/include/mlir/Dialect/Bufferization/IR/Bufferization.h
+++ b/mlir/include/mlir/Dialect/Bufferization/IR/Bufferization.h
@@ -15,7 +15,7 @@
#include "mlir/Interfaces/CopyOpInterface.h"
#include "mlir/Interfaces/DestinationStyleOpInterface.h"
#include "mlir/Interfaces/InferTypeOpInterface.h"
-#include "mlir/Interfaces/SubsetInsertionOpInterface.h"
+#include "mlir/Interfaces/SubsetOpInterface.h"
//===----------------------------------------------------------------------===//
// Bufferization Dialect
diff --git a/mlir/include/mlir/Dialect/Bufferization/IR/BufferizationOps.td b/mlir/include/mlir/Dialect/Bufferization/IR/BufferizationOps.td
index 72a4aa712f49c98..e6b6d052df96a8c 100644
--- a/mlir/include/mlir/Dialect/Bufferization/IR/BufferizationOps.td
+++ b/mlir/include/mlir/Dialect/Bufferization/IR/BufferizationOps.td
@@ -15,7 +15,7 @@ include "mlir/Dialect/Bufferization/IR/BufferizationBase.td"
include "mlir/Interfaces/DestinationStyleOpInterface.td"
include "mlir/Interfaces/InferTypeOpInterface.td"
include "mlir/Interfaces/SideEffectInterfaces.td"
-include "mlir/Interfaces/SubsetInsertionOpInterface.td"
+include "mlir/Interfaces/SubsetOpInterface.td"
include "mlir/Interfaces/CopyOpInterface.td"
class Bufferization_Op<string mnemonic, list<Trait> traits = []>
@@ -220,6 +220,7 @@ def Bufferization_MaterializeInDestinationOp
AllElementTypesMatch<["source", "dest"]>,
BufferizableOpInterface, DestinationStyleOpInterface,
DeclareOpInterfaceMethods<ReifyRankedShapedTypeOpInterface>,
+ DeclareOpInterfaceMethods<SubsetOpInterface>,
DeclareOpInterfaceMethods<SubsetInsertionOpInterface,
["getSourceOperand", "getValuesNeededToBuildSubsetExtraction",
"buildSubsetExtraction", "isEquivalentSubset"]>,
diff --git a/mlir/include/mlir/Dialect/Linalg/Transforms/SubsetInsertionOpInterfaceImpl.h b/mlir/include/mlir/Dialect/Linalg/Transforms/SubsetInsertionOpInterfaceImpl.h
index 023a46df2620109..94b0fb25b506650 100644
--- a/mlir/include/mlir/Dialect/Linalg/Transforms/SubsetInsertionOpInterfaceImpl.h
+++ b/mlir/include/mlir/Dialect/Linalg/Transforms/SubsetInsertionOpInterfaceImpl.h
@@ -13,8 +13,7 @@ namespace mlir {
class DialectRegistry;
namespace linalg {
-void registerSubsetInsertionOpInterfaceExternalModels(
- DialectRegistry ®istry);
+void registerSubsetOpInterfaceExternalModels(DialectRegistry ®istry);
} // namespace linalg
} // namespace mlir
diff --git a/mlir/include/mlir/Dialect/Tensor/Transforms/SubsetInsertionOpInterfaceImpl.h b/mlir/include/mlir/Dialect/Tensor/Transforms/SubsetInsertionOpInterfaceImpl.h
index e21b07d8a2705a0..019da189a8c991b 100644
--- a/mlir/include/mlir/Dialect/Tensor/Transforms/SubsetInsertionOpInterfaceImpl.h
+++ b/mlir/include/mlir/Dialect/Tensor/Transforms/SubsetInsertionOpInterfaceImpl.h
@@ -13,8 +13,7 @@ namespace mlir {
class DialectRegistry;
namespace tensor {
-void registerSubsetInsertionOpInterfaceExternalModels(
- DialectRegistry ®istry);
+void registerSubsetOpInterfaceExternalModels(DialectRegistry ®istry);
} // namespace tensor
} // namespace mlir
diff --git a/mlir/include/mlir/InitAllDialects.h b/mlir/include/mlir/InitAllDialects.h
index 00f400aab5d50a0..7c2ffb7408d9afd 100644
--- a/mlir/include/mlir/InitAllDialects.h
+++ b/mlir/include/mlir/InitAllDialects.h
@@ -151,7 +151,7 @@ inline void registerAllDialects(DialectRegistry ®istry) {
cf::registerBufferDeallocationOpInterfaceExternalModels(registry);
gpu::registerBufferDeallocationOpInterfaceExternalModels(registry);
linalg::registerBufferizableOpInterfaceExternalModels(registry);
- linalg::registerSubsetInsertionOpInterfaceExternalModels(registry);
+ linalg::registerSubsetOpInterfaceExternalModels(registry);
linalg::registerTilingInterfaceExternalModels(registry);
linalg::registerValueBoundsOpInterfaceExternalModels(registry);
memref::registerAllocationOpInterfaceExternalModels(registry);
@@ -167,7 +167,7 @@ inline void registerAllDialects(DialectRegistry ®istry) {
tensor::registerBufferizableOpInterfaceExternalModels(registry);
tensor::registerFindPayloadReplacementOpInterfaceExternalModels(registry);
tensor::registerInferTypeOpInterfaceExternalModels(registry);
- tensor::registerSubsetInsertionOpInterfaceExternalModels(registry);
+ tensor::registerSubsetOpInterfaceExternalModels(registry);
tensor::registerTilingInterfaceExternalModels(registry);
tensor::registerValueBoundsOpInterfaceExternalModels(registry);
vector::registerBufferizableOpInterfaceExternalModels(registry);
diff --git a/mlir/include/mlir/Interfaces/CMakeLists.txt b/mlir/include/mlir/Interfaces/CMakeLists.txt
index 36a04ff0eaeaf4b..d81298bb4daf014 100644
--- a/mlir/include/mlir/Interfaces/CMakeLists.txt
+++ b/mlir/include/mlir/Interfaces/CMakeLists.txt
@@ -12,7 +12,7 @@ add_mlir_interface(ParallelCombiningOpInterface)
add_mlir_interface(RuntimeVerifiableOpInterface)
add_mlir_interface(ShapedOpInterfaces)
add_mlir_interface(SideEffectInterfaces)
-add_mlir_interface(SubsetInsertionOpInterface)
+add_mlir_interface(SubsetOpInterface)
add_mlir_interface(TilingInterface)
add_mlir_interface(ValueBoundsOpInterface)
add_mlir_interface(VectorInterfaces)
diff --git a/mlir/include/mlir/Interfaces/SubsetInsertionOpInterface.h b/mlir/include/mlir/Interfaces/SubsetInsertionOpInterface.h
deleted file mode 100644
index 3a6dfceadcce7c0..000000000000000
--- a/mlir/include/mlir/Interfaces/SubsetInsertionOpInterface.h
+++ /dev/null
@@ -1,27 +0,0 @@
-//===- SubsetInsertionOpInterface.h - Tensor Subsets ------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef MLIR_INTERFACES_SUBSETINSERTIONOPINTERFACE_H_
-#define MLIR_INTERFACES_SUBSETINSERTIONOPINTERFACE_H_
-
-#include "mlir/IR/OpDefinition.h"
-
-namespace mlir {
-namespace detail {
-
-/// Return the destination/"init" operand of the op if it implements the
-/// `DestinationStyleOpInterface` and has exactly one "init" operand. Asserts
-/// otherwise.
-OpOperand &defaultGetDestinationOperand(Operation *op);
-
-} // namespace detail
-} // namespace mlir
-
-#include "mlir/Interfaces/SubsetInsertionOpInterface.h.inc"
-
-#endif // MLIR_INTERFACES_SUBSETINSERTIONOPINTERFACE_H_
diff --git a/mlir/include/mlir/Interfaces/SubsetInsertionOpInterface.td b/mlir/include/mlir/Interfaces/SubsetInsertionOpInterface.td
deleted file mode 100644
index ef94a8ae9a60efd..000000000000000
--- a/mlir/include/mlir/Interfaces/SubsetInsertionOpInterface.td
+++ /dev/null
@@ -1,155 +0,0 @@
-//===-- SubsetInsertionOpInterface.td - Tensor Subsets -----*- tablegen -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef SUBSET_INSERTION_OP_INTERFACE
-#define SUBSET_INSERTION_OP_INTERFACE
-
-include "mlir/IR/OpBase.td"
-
-def SubsetInsertionOpInterface : OpInterface<"SubsetInsertionOpInterface"> {
- let description = [{
- This interface can be implemented by ops that insert a source tensor into
- a destination tensor.
-
- The elements in the destination tensor that are overwritten by this
- insertion are called the "subset". How the subset is defined is up to the
- op. E.g., "tensor.insert_slice" defines the subset via a hyperrectangular
- slice. A scatter operation could define the subset via a list of indices.
-
- Ops that deal with tensor subsets come in two flavours:
- - Insertion flavor: Ops that insert a source tensor into a destination
- tensor at the specified subset. Such ops usually return a new destination
- tensor and implement the `DestinationStyleOpInterface`. Insertion ops can
- implement the `SubsetInsertionOpInterface`. Example: "tensor.insert_slice"
- - Extraction flavor: Ops that define a tensor subset. They extract a
- specified subset from a tensor. There is currently no op interface for
- such ops. Example: "tensor.extract_slice"
-
- This interface provides helper methods for efficient bufferization of
- subset-based tensor IR. Tensor subsets can bufferize to buffer "views"/
- "aliases" (in contrast to one or multiple less efficient buffer allocation).
-
- This interface is queried by One-Shot Bufferize to detect cases where a
- seeming read-after-write is not actually a conflict because the respective
- ops are operating on equivalent subsets. More details can be found in the
- documentation of One-Shot Analysis (see `areNonConflictingSubsets`).
-
- Note: This interface currently assumes that a subset op inserts a single
- tensor (source) into a destination tensor at a single subset.
- }];
- let cppNamespace = "::mlir";
- let methods = [
- InterfaceMethod<
- /*desc=*/[{
- Return the source tensor operand.
- }],
- /*retType=*/"::mlir::OpOperand &",
- /*methodName=*/"getSourceOperand",
- /*args=*/(ins)
- >,
- InterfaceMethod<
- /*desc=*/[{
- Return the destination tensor operand.
- }],
- /*retType=*/"::mlir::OpOperand &",
- /*methodName=*/"getDestinationOperand",
- /*args=*/(ins),
- /*methodBody=*/"",
- /*defaultImplementation=*/[{
- return ::mlir::detail::defaultGetDestinationOperand(
- $_op.getOperation());
- }]
- >,
- InterfaceMethod<
- /*desc=*/[{
- Return "true" if this operation inserts into a subset that is
- equivalent to the subset defined by `candidate`.
-
- Two subsets are "equivalent" and "same" if they can bufferize to the
- same buffer views/aliases. If they are "equivalent", the tensor IR
- may be expressed in terms of different SSA values (but they could
- bufferize to MemRef SSA values that can CSE without breaking
- correctness). `equivalenceFn` should return "true" if the two given
- values are equivalent.
-
- Example:
- ```
- // The subset of the SubsetInsertionOpInterface op %1 is equivalent to
- // the subset defined by %2 (but not "same"):
- %0 = arith.select %c, %t, %t : tensor<?xf32>
- %1 = tensor.insert_slice %x into %0[0][5][1]
- : tensor<5xf32> into tensor<?xf32>
- %2 = tensor.extract_slice %t[0][5][1] : tensor<?xf32> to tensor<5xf32>
-
- // The subset of the SubsetInsertionOpInterface op %1 is equivalent to
- // and "same" as the subset defined by %2.
- %1 = tensor.insert_slice %x into %t[0][5][1]
- : tensor<5xf32> into tensor<?xf32>
- %2 = tensor.extract_slice %t[0][5][1] : tensor<?xf32> to tensor<5xf32>
- ```
- }],
- /*retType=*/"bool",
- /*methodName=*/"isEquivalentSubset",
- /*args=*/(ins
- "::mlir::Value":$candidate,
- "::llvm::function_ref<bool(Value, Value)>":$equivalenceFn)
- >,
- InterfaceMethod<
- /*desc=*/[{
- Return the subset of the destination tensor that this operation
- inserts into.
-
- Example:
- ```
- // SubsetOpInterface op:
- %0 = tensor.insert_slice %t0 into %t1[%pos][5][1]
- : tensor<5xf32> into tensor<?xf32>
- // Subset (built by this function):
- %1 = tensor.extract_slice %t1[%pos][5][1]
- : tensor<?xf32> to tensor<5xf32>
- ```
-
- Note: Implementations do not necessarily have to build new IR. They
- may return existing SSA values.
- }],
- /*retType=*/"::mlir::Value",
- /*methodName=*/"buildSubsetExtraction",
- /*args=*/(ins "::mlir::OpBuilder &":$builder, "Location":$loc)
- >,
- InterfaceMethod<
- /*desc=*/[{
- Return all SSA values that are needed (i.e., must be in scope) at the
- insertion of the builder when calling `buildSubsetExtraction`. Users
- of `buildSubsetExtraction` can use this helper method to find a
- suitable insertion point.
-
- Example: The SSA values needed to build the subset in the example of
- `buildSubsetExtraction` are %t1 and %pos.
- }],
- /*retType=*/"::llvm::SmallVector<::mlir::Value>",
- /*methodName=*/"getValuesNeededToBuildSubsetExtraction",
- /*args=*/(ins)
- >,
- ];
-
- let extraClassDeclaration = [{
- /// Return "true" if this operation inserts into the same subset as defined
- /// by `candidate`.
- ///
- /// Note: This function is useful outside of bufferization, where no tensor
- /// equivalence information is available.
- bool isSameSubset(OpResult candidate) {
- auto subsetOp = cast<::mlir::SubsetInsertionOpInterface>(
- getOperation());
- return subsetOp.isEquivalentSubset(
- candidate, [](Value v1, Value v2) { return v1 == v2; });
- }
- }];
-}
-
-#endif // SUBSET_INSERTION_OP_INTERFACE
diff --git a/mlir/include/mlir/Interfaces/SubsetOpInterface.h b/mlir/include/mlir/Interfaces/SubsetOpInterface.h
new file mode 100644
index 000000000000000..049cf2456a9c842
--- /dev/null
+++ b/mlir/include/mlir/Interfaces/SubsetOpInterface.h
@@ -0,0 +1,45 @@
+//===- SubsetOpInterface.h - Tensor Subsets ---------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_INTERFACES_SUBSETOPINTERFACE_H_
+#define MLIR_INTERFACES_SUBSETOPINTERFACE_H_
+
+#include "mlir/IR/OpDefinition.h"
+
+namespace mlir {
+class SubsetOpInterface;
+class SubsetExtractionOpInterface;
+class SubsetInsertionOpInterface;
+
+namespace detail {
+
+/// Return the destination/"init" operand of the op if it implements the
+/// `DestinationStyleOpInterface` and has exactly one "init" operand. Asserts
+/// otherwise.
+OpOperand &defaultGetDestinationOperand(Operation *op);
+
+/// Return the updated destination result of the op if it implements the
+/// `DestinationStyleOpInterface`.
+OpResult defaultGetUpdatedDestination(Operation *op);
+
+/// Default implementation of `isEquivalentSubset`.
+bool defaultIsEquivalentSubset(Operation *op, Value candidate,
+ function_ref<bool(Value, Value)> equivalenceFn);
+
+/// Verify `SubsetOpInterface`.
+LogicalResult verifySubsetOpInterface(SubsetOpInterface op);
+
+/// Verify `SubsetExtractionOpInterface`.
+LogicalResult verifySubsetExtractionOpInterface(SubsetExtractionOpInterface op);
+
+} // namespace detail
+} // namespace mlir
+
+#include "mlir/Interfaces/SubsetOpInterface.h.inc"
+
+#endif // MLIR_INTERFACES_SUBSETOPINTERFACE_H_
diff --git a/mlir/include/mlir/Interfaces/SubsetOpInterface.td b/mlir/include/mlir/Interfaces/SubsetOpInterface.td
new file mode 100644
index 000000000000000..07d62b8319c2961
--- /dev/null
+++ b/mlir/include/mlir/Interfaces/SubsetOpInterface.td
@@ -0,0 +1,267 @@
+//===-- SubsetOpInterface.td - Tensor Subsets --------------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SUBSET_OP_INTERFACE
+#define SUBSET_OP_INTERFACE
+
+include "mlir/IR/OpBase.td"
+
+def SubsetOpInterface : OpInterface<"SubsetOpInterface"> {
+ let description = [{
+ This interface can be implemented by ops that operate on tensor subsets. A
+ "subset" is a part of a tensor. This interface describes the subset that
+ an implementing op operates on. Only the specified subset may be accessed by
+ the op.
+
+ Subset ops come in two flavours and ops that implement the
+ `SubsetOpInterface` must also implement one of the respective interfaces.
+ - Insertion flavor: Ops that insert a source value into a destination
+ tensor at the specified subset. Such ops return an updated destination
+ tensor and usually implement the `DestinationStyleOpInterface`. Insertion
+ ops must implement the `SubsetInsertionOpInterface`.
+ - Extraction flavor: Ops that extract at a subset. Extraction ops must
+ implement the `SubsetExtractionOpInterface`.
+
+ How the subset is specified is up to the implementing op. E.g.:
+ - `tensor.extract_slice/insert_slice` describe the subset as a
+ hyperrectangular slice.
+ - `tensor.gather/scatter` describe the subset as list of indices. (Not
+ implemented yet.)
+
+ Note: This interface does not expose any interface methods to get a
+ description of the accessed subset. That is because there is currently no
+ efficient way to describe arbitrary subsets. This interface merely provides
+ interface methods to check if two subsets are equivalent or disjoint.
+ }];
+
+ let cppNamespace = "::mlir";
+ let methods = [
+ InterfaceMethod<
+ /*desc=*/[{
+ Return "true" if this op and the given candidate subset op operate on
+ an equivalent subset. Return "false" is the two subsets are disjoint
+ or cannot be proven to be equivalent.
+ }],
+ /*retType=*/"bool",
+ /*methodName=*/"operatesOnEquivalentSubset",
+ /*args=*/(ins
+ "::mlir::SubsetOpInterface":$candidate,
+ "::llvm::function_ref<bool(Value, Value)>":$equivalenceFn)
+ >,
+ InterfaceMethod<
+ /*desc=*/[{
+ Return "true" if this op and the given candidate subset op operate on
+ disjoint subsets. Return "false" is the two subsets are equivalent,
+ overlapping or cannot be proven to be disjoint.
+ }],
+ /*retType=*/"bool",
+ /*methodName=*/"operatesOnDisjointSubset",
+ /*args=*/(ins
+ "::mlir::SubsetOpInterface":$candidate,
+ "::llvm::function_ref<bool(Value, Value)>":$equivalenceFn)
+ >,
+ ];
+
+ let verify = [{
+ return ::mlir::detail::verifySubsetOpInterface(
+ ::mlir::cast<::mlir::SubsetOpInterface>($_op));
+ }];
+}
+
+def SubsetExtractionOpInterface
+ : OpInterface<"SubsetExtractionOpInterface", [SubsetOpInterface]> {
+ let description = [{
+ This interface can be implemented by ops that extract a value from
+ a source tensor at a specified subset. The elements in the source tensor
+ that are read by this extraction are called "subset".
+
+ Extraction ops must have a single result value.
+ }];
+
+ let cppNamespace = "::mlir";
+ let methods = [
+ InterfaceMethod<
+ /*desc=*/[{
+ Return the source tensor operand.
+ }],
+ /*retType=*/"::mlir::OpOperand &",
+ /*methodName=*/"getSourceOperand",
+ /*args=*/(ins)
+ >,
+ ];
+
+ let verify = [{
+ return ::mlir::detail::verifySubsetExtractionOpInterface(
+ ::mlir::cast<::mlir::SubsetExtractionOpInterface>($_op));
+ }];
+
+ let extraClassDeclaration = [{
+ /// Return the single result of this op.
+ ::mlir::Value getResult() {
+ return getOperation()->getResult(0);
+ }
+ }];
+}
+
+def SubsetInsertionOpInterface
+ : OpInterface<"SubsetInsertionOpInterface", [SubsetOpInterface]> {
+ let description = [{
+ This interface can be implemented by ops that insert a source value into
+ a destination tensor at a specified subset. The elements in the destination
+ tensor that are overwritten by this insertion are called "subset". The
+ updated destination tensor is returned.
+
+ This interface provides helper methods for efficient bufferization of
+ subset-based tensor IR. Tensor subsets can bufferize to buffe...
[truncated]
|
matthias-springer
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matthias-springer
changed the title
This was referenced Oct 30, 2023
nicolasvasilache
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Oct 31, 2023
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Improve the bypass analysis for loop-like ops. Until now, loop-like ops were treated like any other non-subset ops: they prevent hoisting of any sort because the analysis does not know which parts of a tensor init operand are accessed by the loop-like op. With this change, the analysis can look into loop-like ops and analyze which subset they are operating on.