[mlir][linalg][bufferize] Decouple ComprehensiveBufferize from Linalg

[springerm]

Summary

The remaining dialects will be decoupled from ComprehensiveBufferize in separate commits.

Depends On D113458

[springerm]

Add missing CMakeLists

mlir/include/mlir/Dialect/Linalg/ComprehensiveBufferize/ComprehensiveBufferize.h

struct BufferizationOptions {
   unsigned analysisFuzzerSeed = 0;
   bool testAnalysisOnly = false;
   std::vector<std::unique_ptr<PostAnalysisStep>> postAnalysisSteps;
 };
 
 LogicalResult runComprehensiveBufferize(ModuleOp moduleOp,
                                         const BufferizationOptions &options);
 
-namespace linalg_ext {
-
-struct InitTensorEliminationStep : public PostAnalysisStep {
-  /// Try to eliminate InitTensorOps inside `funcOp`.
-  ///
-  /// * `rewriteFunc` generates the replacement for the InitTensorOp.
-  /// * Only InitTensorOps that are anchored on a matching OpOperand as per
-  ///   `anchorMatchFunc` are considered. "Anchored" means that there is a path
-  ///   on the reverse SSA use-def chain, starting from the OpOperand and always
-  ///   following the aliasing  OpOperand, that eventually ends at a single
-  ///   InitTensorOp.
-  /// * The result of `rewriteFunc` must usually be analyzed for inplacability.
-  ///   This analysis can be skipped with `skipAnalysis`.
-  LogicalResult eliminateInitTensors(
-      FuncOp funcOp, BufferizationAliasInfo &aliasInfo, DominanceInfo &domInfo,
-      std::function<bool(OpOperand &)> anchorMatchFunc,
-      std::function<Value(OpBuilder &, Location, OpOperand &)> rewriteFunc,
-      SmallVector<Operation *> &newOps);
-};
-
-/// Try to eliminate InitTensorOps inside funcOp that are anchored on an
-/// InsertSliceOp, i.e., if it is eventually inserted into another tensor
-/// (and some other conditions are met).
-struct InsertSliceAnchoredInitTensorEliminationStep
-    : public InitTensorEliminationStep {
-  LogicalResult run(FuncOp funcOp, BufferizationAliasInfo &aliasInfo,
-                    DominanceInfo &domInfo,
-                    SmallVector<Operation *> &newOps) override;
-};
-
-} // namespace linalg_ext
-
 } // namespace comprehensive_bufferize
 } // namespace linalg
 } // namespace mlir
 
 #endif // MLIR_DIALECT_LINALG_COMPREHENSIVEBUFFERIZE_COMPREHENSIVE_BUFFERIZE_H

mlir/include/mlir/Dialect/Linalg/ComprehensiveBufferize/LinalgInterfaceImpl.h

+#ifndef MLIR_DIALECT_LINALG_COMPREHENSIVEBUFFERIZE_LINALG_INTERFACE_IMPL_H
+#define MLIR_DIALECT_LINALG_COMPREHENSIVEBUFFERIZE_LINALG_INTERFACE_IMPL_H
+
+#include "mlir/Dialect/Linalg/ComprehensiveBufferize/BufferizableOpInterface.h"
+
+namespace mlir {
+
+class DialectRegistry;
+
+namespace linalg {
+namespace comprehensive_bufferize {
+
+class BufferizationAliasInfo;
+
+namespace linalg_ext {
+
+struct InitTensorEliminationStep : public PostAnalysisStep {
+  /// Try to eliminate InitTensorOps inside `funcOp`.
+  ///
+  /// * `rewriteFunc` generates the replacement for the InitTensorOp.
+  /// * Only InitTensorOps that are anchored on a matching OpOperand as per
+  ///   `anchorMatchFunc` are considered. "Anchored" means that there is a path
+  ///   on the reverse SSA use-def chain, starting from the OpOperand and always
+  ///   following the aliasing  OpOperand, that eventually ends at a single
+  ///   InitTensorOp.
+  /// * The result of `rewriteFunc` must usually be analyzed for inplacability.
+  ///   This analysis can be skipped with `skipAnalysis`.
+  LogicalResult eliminateInitTensors(
+      FuncOp funcOp, BufferizationAliasInfo &aliasInfo, DominanceInfo &domInfo,
+      std::function<bool(OpOperand &)> anchorMatchFunc,
+      std::function<Value(OpBuilder &, Location, OpOperand &)> rewriteFunc,
+      SmallVector<Operation *> &newOps);
+};
+
+/// Try to eliminate InitTensorOps inside funcOp that are anchored on an
+/// InsertSliceOp, i.e., if it is eventually inserted into another tensor
+/// (and some other conditions are met).
+struct InsertSliceAnchoredInitTensorEliminationStep
+    : public InitTensorEliminationStep {
+  LogicalResult run(FuncOp funcOp, BufferizationAliasInfo &aliasInfo,
+                    DominanceInfo &domInfo,
+                    SmallVector<Operation *> &newOps) override;
+};
+
+void registerBufferizableOpInterfaceExternalModels(DialectRegistry &registry);
+
+} // namespace linalg_ext
+} // namespace comprehensive_bufferize
+} // namespace linalg
+} // namespace mlir
+
+#endif // MLIR_DIALECT_LINALG_COMPREHENSIVEBUFFERIZE_LINALG_INTERFACE_IMPL_H

mlir/lib/Dialect/Linalg/ComprehensiveBufferize/CMakeLists.txt

 set(LLVM_OPTIONAL_SOURCES
   BufferizableOpInterface.cpp
   ComprehensiveBufferize.cpp
+  LinalgInterfaceImpl.cpp
 )
 
 add_mlir_dialect_library(MLIRBufferizableOpInterface
   BufferizableOpInterface.cpp
 
   DEPENDS
   MLIRBufferizableOpInterfaceIncGen
 
   LINK_LIBS PUBLIC
   MLIRIR
 )
 
+add_mlir_dialect_library(MLIRLinalgBufferizableOpInterfaceImpl
+  LinalgInterfaceImpl.cpp
+
+  LINK_LIBS PUBLIC
+  MLIRBufferizableOpInterface
+  MLIRIR
+  MLIRLinalg
+  MLIRTensor
+)
+
 add_mlir_dialect_library(MLIRComprehensiveBufferize
   ComprehensiveBufferize.cpp
 
   LINK_LIBS PUBLIC
+  MLIRAffine
   MLIRBufferizableOpInterface
   MLIRInferTypeOpInterface
   MLIRIR
   MLIRMemRef
-  MLIRLinalg
   MLIRSCF
   MLIRStandard
   MLIRStandardOpsTransforms
   MLIRTensor
   MLIRVector
 )

mlir/lib/Dialect/Linalg/ComprehensiveBufferize/ComprehensiveBufferize.cpp

 //  canonical strided layout of the proper rank. This ensures compatibility with
 //  expected layouts after transformations. Combinations of memref.cast +
 //  canonicalization are responsible for clean ups.
 
 #include "mlir/Dialect/Linalg/ComprehensiveBufferize/ComprehensiveBufferize.h"
 
 #include <random>
 
+#include "mlir/Dialect/Affine/IR/AffineOps.h"
 #include "mlir/Dialect/Linalg/ComprehensiveBufferize/BufferizableOpInterface.h"
-#include "mlir/Dialect/Linalg/IR/LinalgOps.h"
 #include "mlir/Dialect/MemRef/IR/MemRef.h"
 #include "mlir/Dialect/SCF/SCF.h"
 #include "mlir/Dialect/Utils/StaticValueUtils.h"
 #include "mlir/Dialect/Vector/VectorOps.h"
 #include "mlir/IR/AsmState.h"
+#include "mlir/IR/BlockAndValueMapping.h"
 #include "mlir/IR/Operation.h"
+#include "mlir/IR/TypeUtilities.h"
 #include "mlir/Interfaces/InferTypeOpInterface.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Pass/PassManager.h"
 #include "mlir/Transforms/BufferUtils.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/TypeSwitch.h"
for (FuncOp funcOp : orderedFuncOps) {
 
     // Finally set the funcOp type to update the arguments.
     auto newFuncType = FunctionType::get(moduleOp.getContext(), argumentTypes,
                                          funcOp.getType().getResults());
     funcOp.setType(newFuncType);
   }
 }
 
-/// Try to eliminate InitTensorOps inside funcOp. An InitTensorOp is replaced
-/// with the the result of `rewriteFunc` if it is anchored on a matching
-/// OpOperand. "Anchored" means that there is a path on the reverse SSA use-def
-/// chain, starting from the OpOperand and always following the aliasing
-/// OpOperand, that eventually ends at a single InitTensorOp.
-LogicalResult mlir::linalg::comprehensive_bufferize::linalg_ext::
-    InitTensorEliminationStep::eliminateInitTensors(
-        FuncOp funcOp, BufferizationAliasInfo &aliasInfo,
-        DominanceInfo &domInfo,
-        std::function<bool(OpOperand &)> anchorMatchFunc,
-        std::function<Value(OpBuilder &, Location, OpOperand &)> rewriteFunc,
-        SmallVector<Operation *> &newOps) {
-  OpBuilder b(funcOp->getContext());
-
-  WalkResult status = funcOp->walk([&](Operation *op) {
-    for (OpOperand &operand : op->getOpOperands()) {
-      // Is this a matching OpOperand?
-      if (!anchorMatchFunc(operand))
-        continue;
-
-      SetVector<Value> maybeInitTensor =
-          findValueInReverseUseDefChain(operand.get(), [&](Value val) {
-            // Continue traversal until this function returns true.
-            OpResult opResult = val.dyn_cast<OpResult>();
-            if (!opResult)
-              return true;
-            if (!aliasInfo.isInPlace(opResult))
-              return true;
-            // Only equivalent tensors are supported at the moment.
-            // TODO: Support cases such as extract_slice(init_tensor).
-            SmallVector<OpOperand *> opOperands =
-                getAliasingOpOperand(opResult);
-            if (!llvm::all_of(opOperands, [](OpOperand *operand) {
-                  return bufferRelation(*operand) == BufferRelation::Equivalent;
-                }))
-              return true;
-            return false;
-          });
-
-      // Replace only if the reverse use-def chain ends at exactly one
-      // InitTensorOp.
-      if (maybeInitTensor.size() != 1 ||
-          !maybeInitTensor.front().getDefiningOp<InitTensorOp>())
-        return WalkResult::skip();
-      Value initTensor = maybeInitTensor.front();
-
-      // Create a replacement for the InitTensorOp.
-      b.setInsertionPoint(initTensor.getDefiningOp());
-      Value replacement = rewriteFunc(b, initTensor.getLoc(), operand);
-      if (!replacement)
-        continue;
-
-      // Uses of the InitTensorOp are replaced here, but the op is not deleted.
-      // InitTensorOps without uses are ignored by the bufferization.
-      initTensor.replaceAllUsesWith(replacement);
-      aliasInfo.createAliasInfoEntry(replacement);
-      aliasInfo.unionAliasSets(initTensor, replacement);
-      aliasInfo.unionEquivalenceClasses(initTensor, replacement);
-
-      // Register replacement ops.
-      if (Operation *newOp = replacement.getDefiningOp())
-        newOps.push_back(newOp);
-    }
-
-    // Advance to the next operation.
-    return WalkResult::advance();
-  });
-
-  return failure(status.wasInterrupted());
-}
-
-/// Try to eliminate InitTensorOps inside funcOp. An InitTensorOp can be
-/// eliminated if it is eventually inserted into another tensor (and some other
-/// conditions are met).
-///
-/// E.g.:
-/// %0 = linalg.init_tensor
-/// %1 = linalg.fill(%cst, %0) {inplace = [true]}
-/// %2 = tensor.insert_slice %1 into %t[10][20][1]
-///
-/// InitTensorOp elimination will try to fill %t inplace instead of filling a
-/// new allocation %0 and inserting it into %t. This is done by replacing the
-/// InitTensorOp with:
-///
-/// %0 = tensor.extract_slice %t[10][20][1]
-///
-/// The analysis looks for matching ExtractSliceOp/InsertSliceOp pairs and lets
-/// those bufferize inplace in the absence of other conflicts.
-///
-/// Starting from an InsertSliceOp, an InitTensorOp at the end of the insert
-/// source's reverse use-def chain is eliminated if:
-/// * The InsertSliceOp was decided to bufferize inplace.
-/// * On the reverse use-def chain path from the InsertSliceOp to the
-///   InitTensorOp, all ops were decided to bufferize inplace and the buffer
-///   relation is "equivalent" (TODO: can be relaxed if needed).
-/// * The reverse use-def chain has exactly one end, which is the InitTensorOp.
-///
-/// Note that the newly inserted ExtractSliceOp may have to bufferize
-/// out-of-place due to RaW conflicts.
-LogicalResult mlir::linalg::comprehensive_bufferize::linalg_ext::
-    InsertSliceAnchoredInitTensorEliminationStep::run(
-        FuncOp funcOp, BufferizationAliasInfo &aliasInfo,
-        DominanceInfo &domInfo, SmallVector<Operation *> &newOps) {
-  return eliminateInitTensors(
-      funcOp, aliasInfo, domInfo,
-      [&](OpOperand &operand) {
-        auto insertSliceOp = dyn_cast<InsertSliceOp>(operand.getOwner());
-        if (!insertSliceOp)
-          return false;
-        // Only inplace bufferized InsertSliceOps are eligible.
-        if (!aliasInfo.isInPlace(insertSliceOp->getOpResult(0)))
-          return false;
-        return &operand == &insertSliceOp->getOpOperand(0) /*source*/;
-      },
-      [](OpBuilder &b, Location loc, OpOperand &operand) {
-        auto insertSliceOp = cast<InsertSliceOp>(operand.getOwner());
-        auto extractOp = b.create<tensor::ExtractSliceOp>(
-            loc, insertSliceOp.dest(), insertSliceOp.getMixedOffsets(),
-            insertSliceOp.getMixedSizes(), insertSliceOp.getMixedStrides());
-        return extractOp.result();
-      },
-      newOps);
-}
-
 #ifndef NDEBUG
 /// Assert that the current bufferization decisions are consistent.
 static void checkAliasInfoConsistency(FuncOp funcOp,
                                       const DominanceInfo &domInfo,
                                       const BufferizationAliasInfo &aliasInfo) {
   funcOp.walk([&](Operation *op) {
     if (auto bufferizableOp = dyn_cast<BufferizableOpInterface>(op))
       for (OpOperand &opOperand : op->getOpOperands())
bool isWritable(Operation *op, Value value) const {
     // Memory locations returned by memref::GetGlobalOp may not be written to.
     assert(value.isa<OpResult>());
     return false;
   }
 };
 
 } // namespace arith_ext
 
-// TODO: Ops in the linalg dialect can directly implement this interface.
-namespace linalg_ext {
-
-/// Helper function for LinalgOp bufferization.
-/// When allocating a new buffer, analyze whether `op` wants to read form that
-/// buffer. Only in that case, a copy of the result buffer may be needed.
-static LogicalResult
-allocateBuffersForResults(OpBuilder &b, Location loc, LinalgOp op,
-                          SmallVectorImpl<Value> &resultBuffers,
-                          BufferizationState &state) {
-  // Take a guard before anything else.
-  OpBuilder::InsertionGuard g(b);
-  b.setInsertionPoint(op);
-
-  // TODO: provide the proper interface to iterate on OpResults and get the
-  // matching OpOperands.
-  for (OpOperand *opOperand : op.getOutputOperands()) {
-    OpResult opResult = cast<BufferizableOpInterface>(op.getOperation())
-                            .getAliasingOpResult(*opOperand);
-    assert(opResult && "could not find correspond OpResult");
-    Value resultBuffer = getResultBuffer(b, opResult, state);
-    if (!resultBuffer)
-      return failure();
-    resultBuffers.push_back(resultBuffer);
-  }
-
-  if (op->getNumResults())
-    state.mapBuffer(op->getResults(), resultBuffers);
-
-  return success();
-}
-
-/// Generic conversion for any LinalgOp on tensors.
-static LogicalResult bufferizeLinalgOp(OpBuilder &b, LinalgOp op,
-                                       BufferizationState &state) {
-  // Take a guard before anything else.
-  OpBuilder::InsertionGuard g(b);
-
-  // Ensure op has only tensors. Allow mixed tensor-buffer mode on a per-need
-  // basis.
-  if (!op.hasTensorSemantics())
-    return op->emitError() << "op does not have tensor semantics";
-
-  Location loc = op.getLoc();
-  SmallVector<Value> newInputBuffers;
-  newInputBuffers.reserve(op.getNumInputs());
-  for (OpOperand *opOperand : op.getInputOperands()) {
-    if (op.isScalar(opOperand)) {
-      newInputBuffers.push_back(opOperand->get());
-      continue;
-    }
-    newInputBuffers.push_back(state.lookupBuffer(opOperand->get()));
-  }
-  SmallVector<Value> newOutputBuffers;
-  // Try to allocate new buffers depending on op's inplace semantics.
-  if (failed(allocateBuffersForResults(b, loc, op, newOutputBuffers, state)))
-    return failure();
-
-  // Clone the newly bufferized op.
-  SmallVector<Value> newOperands = newInputBuffers;
-  newOperands.append(newOutputBuffers.begin(), newOutputBuffers.end());
-
-  // Set insertion point now that potential alloc/dealloc are introduced.
-  b.setInsertionPoint(op);
-  op.clone(b, loc, /*resultTypes=*/TypeRange{}, newOperands);
-
-  // Replace the results of the old op with the new output buffers.
-  if (op->getNumResults())
-    state.mapBuffer(op->getResults(), newOutputBuffers);
-
-  // The original op will be DCE'd away later.
-
-  return success();
-}
-
-template <typename OpTy>
-struct LinalgOpInterface
-    : public BufferizableOpInterface::ExternalModel<LinalgOpInterface<OpTy>,
-                                                    OpTy> {
-  bool bufferizesToMemoryRead(Operation *op, OpOperand &opOperand) const {
-    auto genericOp = cast<linalg::LinalgOp>(op);
-    return (genericOp.isInputTensor(&opOperand) ||
-            genericOp.isInitTensor(&opOperand)) &&
-           genericOp.payloadUsesValueFromOperand(&opOperand);
-  }
-
-  bool bufferizesToMemoryWrite(Operation *op, OpOperand &opOperand) const {
-    auto genericOp = cast<linalg::LinalgOp>(op);
-    return genericOp.isOutputTensor(&opOperand);
-  }
-
-  SmallVector<OpOperand *> getAliasingOpOperand(Operation *op,
-                                                OpResult opResult) const {
-    auto genericOp = cast<linalg::LinalgOp>(op);
-    return {genericOp.getOutputTensorOperands()[opResult.getResultNumber()]};
-  }
-
-  OpResult getAliasingOpResult(Operation *op, OpOperand &opOperand) const {
-    auto genericOp = cast<linalg::LinalgOp>(op);
-    if (!opOperand.get().getType().isa<RankedTensorType>())
-      return OpResult();
-    // For now assume inputs are never inplaceable.
-    // TODO: refine this.
-    if (opOperand.getOperandNumber() < genericOp.getNumInputs())
-      return OpResult();
-    int64_t outputOperandIndex =
-        opOperand.getOperandNumber() - genericOp.getNumInputs();
-    int64_t numOutputBuffers = 0;
-    for (unsigned idx = 0; idx < outputOperandIndex; ++idx)
-      if (!genericOp.getOutputOperand(idx)->get().getType().isa<TensorType>())
-        ++numOutputBuffers;
-    return genericOp->getResult(outputOperandIndex - numOutputBuffers);
-  }
-
-  BufferRelation bufferRelation(Operation *op, OpOperand &opOperand) const {
-    return BufferRelation::Equivalent;
-  }
-
-  LogicalResult bufferize(Operation *op, OpBuilder &b,
-                          BufferizationState &state) const {
-    return bufferizeLinalgOp(b, cast<LinalgOp>(op), state);
-  }
-};
-
-struct InitTensorOpInterface
-    : public BufferizableOpInterface::ExternalModel<InitTensorOpInterface,
-                                                    linalg::InitTensorOp> {
-  SmallVector<OpOperand *> getAliasingOpOperand(Operation *op,
-                                                OpResult opResult) const {
-    return {};
-  }
-
-  bool isMemoryWrite(Operation *op, OpResult opResult) const {
-    // InitTensorOps allocate but do not write.
-    return false;
-  }
-
-  LogicalResult bufferize(Operation *op, OpBuilder &b,
-                          BufferizationState &state) const {
-    auto initTensorOp = cast<linalg::InitTensorOp>(op);
-
-    // The InitTensorOp may have been eliminated.
-    if (initTensorOp->getUses().empty())
-      return success();
-
-    // Take a guard before anything else.
-    OpBuilder::InsertionGuard g(b);
-    b.setInsertionPoint(initTensorOp);
-
-    Value alloc = createNewAllocDeallocPairForShapedValue(
-        b, initTensorOp->getLoc(), initTensorOp.result(), state);
-    state.mapBuffer(initTensorOp.result(), alloc);
-    return success();
-  }
-};
-
-struct TiledLoopOpInterface
-    : public BufferizableOpInterface::ExternalModel<TiledLoopOpInterface,
-                                                    linalg::TiledLoopOp> {
-  bool bufferizesToMemoryRead(Operation *op, OpOperand &opOperand) const {
-    // TiledLoop alone doesn't bufferize to a memory read, one of the uses of
-    // its matching bbArg may.
-    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
-    return isValueRead(tiledLoopOp.getTiedBlockArgument(opOperand));
-  }
-
-  bool bufferizesToMemoryWrite(Operation *op, OpOperand &opOperand) const {
-    // TiledLoop alone doesn't bufferize to a memory write, one of the uses of
-    // its matching bbArg may.
-    auto bufferizableOp = cast<BufferizableOpInterface>(op);
-    return static_cast<bool>(bufferizableOp.getAliasingOpResult(opOperand));
-  }
-
-  SmallVector<OpOperand *> getAliasingOpOperand(Operation *op,
-                                                OpResult opResult) const {
-    // TODO: TiledLoopOp helper method to avoid leaking impl details.
-    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
-    return {&op->getOpOperand(tiledLoopOp.getNumControlOperands() +
-                              tiledLoopOp.getNumInputs() +
-                              opResult.getResultNumber())};
-  }
-
-  OpResult getAliasingOpResult(Operation *op, OpOperand &opOperand) const {
-    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
-    return tiledLoopOp.getTiedOpResult(opOperand);
-  }
-
-  BufferRelation bufferRelation(Operation *op, OpOperand &opOperand) const {
-    return BufferRelation::Equivalent;
-  }
-
-  bool isWritable(Operation *op, Value value) const {
-    // Interestingly, linalg::TiledLoopOp's bbArg can **always** be viewed
-    // inplace from the perspective of ops nested under:
-    //   1. Either the matching iter operand is not bufferized inplace and an
-    //      alloc + optional copy makes the bbArg itself inplaceable.
-    //   2. Or the matching iter operand is bufferized inplace and bbArg just
-    //      bufferizes to that too.
-    return true;
-  }
-
-  bool isAllocationHoistingBarrier(Operation *op) const { return true; }
-
-  LogicalResult bufferize(Operation *op, OpBuilder &b,
-                          BufferizationState &state) const {
-    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
-
-    // Take a guard before anything else.
-    OpBuilder::InsertionGuard g(b);
-
-    // Allocate output buffers if needed, forward output tensor args to the
-    // terminator.
-    Operation *yieldOp = tiledLoopOp.getBody()->getTerminator();
-    Block *body = tiledLoopOp.getBody();
-
-    // Take copies of the old input and output operands, so we can insert
-    // inplace easily.
-    auto oldInputs = llvm::to_vector<4>(tiledLoopOp.inputs());
-    auto oldOutputs = llvm::to_vector<4>(tiledLoopOp.outputs());
-
-    int numLoops = tiledLoopOp.getNumLoops();
-    int numControlOperands = tiledLoopOp.getNumControlOperands();
-
-    // Add buffers for outputs and the corresponding block arguments.
-    // Keep separate iterators to increment without further leaking impl.
-    // details. Start with outputs to avoid interference from new input buffers.
-    int numNewOutputBuffers = 0;
-    int resultIndex = 0;
-    int oldOutputBBArgIndex = numLoops + oldInputs.size();
-    int nextOutputBBArgIndex = numLoops + oldInputs.size() + oldOutputs.size();
-    int nextOutputOperandIndex =
-        numControlOperands + oldInputs.size() + oldOutputs.size();
-    for (Value oldOutputTensor : oldOutputs) {
-      if (!oldOutputTensor.getType().isa<TensorType>()) {
-        // Skip and increment the old bbarg index only.
-        ++oldOutputBBArgIndex;
-        // Do not increment resultIndex as only tensors are returned.
-        // TODO: better interface to avoid leaking such impl details.
-        continue;
-      }
-
-      assert(oldOutputTensor.getType().isa<RankedTensorType>() &&
-             "bufferizable output must be a ranked tensor");
-
-      const OpResult &opResult = tiledLoopOp->getResult(resultIndex);
-      OpOperand &yieldOperand = yieldOp->getOpOperand(resultIndex);
-      Value resultBuffer = getResultBuffer(b, opResult, state);
-      if (!resultBuffer)
-        return failure();
-
-      // Insert mapping and aliasing info.
-      state.aliasInfo.createAliasInfoEntry(resultBuffer);
-      state.aliasInfo.insertNewBufferEquivalence(opResult, resultBuffer);
-      state.mapBuffer(opResult, resultBuffer);
-
-      // Insert new operand and bbArg.
-      tiledLoopOp->insertOperands(nextOutputOperandIndex, resultBuffer);
-      BlockArgument newBufferBBArg =
-          body->insertArgument(nextOutputBBArgIndex, resultBuffer.getType());
-      BlockArgument oldTensorBBArg = body->getArgument(oldOutputBBArgIndex);
-      // Insert mapping and aliasing info.
-      state.aliasInfo.createAliasInfoEntry(newBufferBBArg);
-      state.aliasInfo.insertNewBufferEquivalence(oldTensorBBArg,
-                                                 newBufferBBArg);
-      state.mapBuffer(oldTensorBBArg, newBufferBBArg);
-
-      // Set operand of `linalg.yield` to the bbArg so it just canonicalizes
-      // away later.
-      yieldOperand.set(oldTensorBBArg);
-
-      // Increment indices.
-      ++numNewOutputBuffers;
-      ++resultIndex;
-      ++oldOutputBBArgIndex;
-      ++nextOutputBBArgIndex;
-      ++nextOutputOperandIndex;
-    }
-
-    // Add buffers for inputs and the corresponding block arguments.
-    // Keep separate iterators to increment without further leaking impl.
-    // details.
-    int numNewInputBuffers = 0;
-    int oldInputBBArgIndex = numLoops;
-    int nextInputBBArgIndex = numLoops + oldInputs.size();
-    int nextInputOperandIndex = numControlOperands + oldInputs.size();
-    for (Value oldInputTensor : oldInputs) {
-      if (!oldInputTensor.getType().isa<TensorType>()) {
-        // Skip and increment the old bbarg index only.
-        ++oldInputBBArgIndex;
-        continue;
-      }
-
-      Value inputBuffer = state.lookupBuffer(oldInputTensor);
-
-      // Insert new operand and bbArg.
-      tiledLoopOp->insertOperands(nextInputOperandIndex, inputBuffer);
-      BlockArgument newBufferBBArg =
-          body->insertArgument(nextInputBBArgIndex, inputBuffer.getType());
-      BlockArgument oldTensorBBArg = body->getArgument(oldInputBBArgIndex);
-
-      // Insert mapping and aliasing info.
-      state.aliasInfo.createAliasInfoEntry(newBufferBBArg);
-      state.aliasInfo.insertNewBufferEquivalence(oldTensorBBArg,
-                                                 newBufferBBArg);
-      state.mapBuffer(oldTensorBBArg, newBufferBBArg);
-
-      // Increment indices.
-      ++numNewInputBuffers;
-      ++oldInputBBArgIndex;
-      ++nextInputBBArgIndex;
-      ++nextInputOperandIndex;
-    }
-
-    // Update segment sizes.
-    // TODO: Helper method to avoid leaking impl details.
-    tiledLoopOp->setAttr(
-        TiledLoopOp::getOperandSegmentSizeAttr(),
-        b.getI32VectorAttr(
-            {numLoops, numLoops, numLoops,
-             static_cast<int>(oldInputs.size()) + numNewInputBuffers,
-             static_cast<int>(oldOutputs.size()) + numNewOutputBuffers}));
-
-    return success();
-  }
-};
-
-struct YieldOpInterface
-    : public BufferizableOpInterface::ExternalModel<YieldOpInterface,
-                                                    linalg::YieldOp> {
-  bool bufferizesToMemoryRead(Operation *op, OpOperand &opOperand) const {
-    return true;
-  }
-
-  bool bufferizesToMemoryWrite(Operation *op, OpOperand &opOperand) const {
-    return false;
-  }
-
-  OpResult getAliasingOpResult(Operation *op, OpOperand &opOperand) const {
-    return OpResult();
-  }
-
-  LogicalResult bufferize(Operation *op, OpBuilder &b,
-                          BufferizationState &state) const {
-    auto yieldOp = cast<linalg::YieldOp>(op);
-
-    // Take a guard before anything else.
-    OpBuilder::InsertionGuard g(b);
-    // Cannot create IR past a yieldOp.
-    b.setInsertionPoint(yieldOp);
-
-    // No tensors -> success.
-    if (!llvm::any_of(yieldOp.getOperandTypes(), isaTensor))
-      return success();
-    // linalg::YieldOp nested under TiledLoop must just canonicalize.
-    if (yieldOp->getParentOfType<TiledLoopOp>())
-      return success();
-    llvm_unreachable("unexpected yieldOp");
-  }
-};
-
-} // namespace linalg_ext
-
 namespace scf_ext {
 
 struct IfOpInterface
     : public BufferizableOpInterface::ExternalModel<IfOpInterface, scf::IfOp> {
   SmallVector<OpOperand *> getAliasingOpOperand(Operation *op,
                                                 OpResult opResult) const {
     // IfOps do not have tensor OpOperands. The yielded value can be any SSA
     // value that is in scope. To allow for use-def chain traversal through
LogicalResult bufferize(Operation *op, OpBuilder &b,
     state.mapBuffer(op->getResult(0), resultBuffer);
 
     return success();
   }
 };
 
 } // namespace vector_ext
 
-namespace {
-
-/// Helper structure that iterates over all LinalgOps in `OpTys` and registers
-/// the `BufferizableOpInterface` with each of them.
-template <typename... OpTys> struct LinalgOpInterfaceHelper;
-
-template <typename First, typename... Others>
-struct LinalgOpInterfaceHelper<First, Others...> {
-  static void registerOpInterface(DialectRegistry &registry) {
-    registry.addOpInterface<First, linalg_ext::LinalgOpInterface<First>>();
-    LinalgOpInterfaceHelper<Others...>::registerOpInterface(registry);
-  }
-};
-
-template <> struct LinalgOpInterfaceHelper<> {
-  static void registerOpInterface(DialectRegistry &registry) {}
-};
-
-} // namespace
-
 void registerBufferizableOpInterfaceExternalModels(DialectRegistry &registry) {
   registry.addOpInterface<arith::ConstantOp, arith_ext::ConstantOpInterface>();
-  registry.addOpInterface<linalg::InitTensorOp,
-                          linalg_ext::InitTensorOpInterface>();
-  registry
-      .addOpInterface<linalg::TiledLoopOp, linalg_ext::TiledLoopOpInterface>();
-  registry.addOpInterface<linalg::YieldOp, linalg_ext::YieldOpInterface>();
   registry.addOpInterface<scf::ForOp, scf_ext::ForOpInterface>();
   registry.addOpInterface<scf::IfOp, scf_ext::IfOpInterface>();
   registry.addOpInterface<scf::YieldOp, scf_ext::YieldOpInterface>();
   registry.addOpInterface<CallOp, std_ext::CallOpInterface>();
   registry.addOpInterface<ReturnOp, std_ext::ReturnOpInterface>();
   registry.addOpInterface<tensor::CastOp, tensor_ext::CastOpInterface>();
   registry.addOpInterface<tensor::DimOp, tensor_ext::DimOpInterface>();
   registry.addOpInterface<tensor::ExtractSliceOp,
                           tensor_ext::ExtractSliceOpInterface>();
   registry.addOpInterface<tensor::ExtractOp, tensor_ext::ExtractOpInterface>();
   registry.addOpInterface<tensor::InsertSliceOp,
                           tensor_ext::InsertSliceOpInterface>();
   registry.addOpInterface<vector::TransferReadOp,
                           vector_ext::TransferReadOpInterface>();
   registry.addOpInterface<vector::TransferWriteOp,
                           vector_ext::TransferWriteOpInterface>();
 
   // Ops that are not bufferizable but are allocation hoisting barriers.
   registry.addOpInterface<FuncOp, AllocationHoistingBarrierOnly<FuncOp>>();
   registry.addOpInterface<scf::ParallelOp,
                           AllocationHoistingBarrierOnly<scf::ParallelOp>>();
   registry.addOpInterface<AffineParallelOp,
                           AllocationHoistingBarrierOnly<AffineParallelOp>>();
-
-  // Register all Linalg structured ops. `LinalgOp` is an interface and it is
-  // not possible to attach an external interface to an existing interface.
-  // Therefore, attach the `BufferizableOpInterface` to all ops one-by-one.
-  LinalgOpInterfaceHelper<
-#define GET_OP_LIST
-#include "mlir/Dialect/Linalg/IR/LinalgStructuredOps.cpp.inc"
-      >::registerOpInterface(registry);
 }
 
 } // namespace comprehensive_bufferize
 } // namespace linalg
 } // namespace mlir

mlir/lib/Dialect/Linalg/ComprehensiveBufferize/LinalgInterfaceImpl.cpp

+//===- LinalgInterfaceImpl.cpp - Linalg Impl. of BufferizableOpInterface --===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Linalg/ComprehensiveBufferize/LinalgInterfaceImpl.h"
+#include "mlir/Dialect/Linalg/ComprehensiveBufferize/BufferizableOpInterface.h"
+#include "mlir/Dialect/Linalg/IR/LinalgOps.h"
+#include "mlir/Dialect/Tensor/IR/Tensor.h"
+#include "mlir/IR/Dialect.h"
+#include "mlir/IR/Operation.h"
+
+using namespace mlir;
+using namespace linalg;
+using namespace comprehensive_bufferize;
+
+namespace {
+
+// TODO: Ops in the linalg dialect can directly implement this interface.
+
+/// Helper function for LinalgOp bufferization.
+/// When allocating a new buffer, analyze whether `op` wants to read form that
+/// buffer. Only in that case, a copy of the result buffer may be needed.
+static LogicalResult
+allocateBuffersForResults(OpBuilder &b, Location loc, LinalgOp op,
+                          SmallVectorImpl<Value> &resultBuffers,
+                          BufferizationState &state) {
+  // Take a guard before anything else.
+  OpBuilder::InsertionGuard g(b);
+  b.setInsertionPoint(op);
+
+  // TODO: provide the proper interface to iterate on OpResults and get the
+  // matching OpOperands.
+  for (OpOperand *opOperand : op.getOutputOperands()) {
+    OpResult opResult = cast<BufferizableOpInterface>(op.getOperation())
+                            .getAliasingOpResult(*opOperand);
+    assert(opResult && "could not find correspond OpResult");
+    Value resultBuffer = getResultBuffer(b, opResult, state);
+    if (!resultBuffer)
+      return failure();
+    resultBuffers.push_back(resultBuffer);
+  }
+
+  if (op->getNumResults())
+    state.mapBuffer(op->getResults(), resultBuffers);
+
+  return success();
+}
+
+/// Generic conversion for any LinalgOp on tensors.
+static LogicalResult bufferizeLinalgOp(OpBuilder &b, LinalgOp op,
+                                       BufferizationState &state) {
+  // Take a guard before anything else.
+  OpBuilder::InsertionGuard g(b);
+
+  // Ensure op has only tensors. Allow mixed tensor-buffer mode on a per-need
+  // basis.
+  if (!op.hasTensorSemantics())
+    return op->emitError() << "op does not have tensor semantics";
+
+  Location loc = op.getLoc();
+  SmallVector<Value> newInputBuffers;
+  newInputBuffers.reserve(op.getNumInputs());
+  for (OpOperand *opOperand : op.getInputOperands()) {
+    if (op.isScalar(opOperand)) {
+      newInputBuffers.push_back(opOperand->get());
+      continue;
+    }
+    newInputBuffers.push_back(state.lookupBuffer(opOperand->get()));
+  }
+  SmallVector<Value> newOutputBuffers;
+  // Try to allocate new buffers depending on op's inplace semantics.
+  if (failed(allocateBuffersForResults(b, loc, op, newOutputBuffers, state)))
+    return failure();
+
+  // Clone the newly bufferized op.
+  SmallVector<Value> newOperands = newInputBuffers;
+  newOperands.append(newOutputBuffers.begin(), newOutputBuffers.end());
+
+  // Set insertion point now that potential alloc/dealloc are introduced.
+  b.setInsertionPoint(op);
+  op.clone(b, loc, /*resultTypes=*/TypeRange{}, newOperands);
+
+  // Replace the results of the old op with the new output buffers.
+  if (op->getNumResults())
+    state.mapBuffer(op->getResults(), newOutputBuffers);
+
+  // The original op will be DCE'd away later.
+
+  return success();
+}
+
+template <typename OpTy>
+struct LinalgOpInterface
+    : public BufferizableOpInterface::ExternalModel<LinalgOpInterface<OpTy>,
+                                                    OpTy> {
+  bool bufferizesToMemoryRead(Operation *op, OpOperand &opOperand) const {
+    auto genericOp = cast<linalg::LinalgOp>(op);
+    return (genericOp.isInputTensor(&opOperand) ||
+            genericOp.isInitTensor(&opOperand)) &&
+           genericOp.payloadUsesValueFromOperand(&opOperand);
+  }
+
+  bool bufferizesToMemoryWrite(Operation *op, OpOperand &opOperand) const {
+    auto genericOp = cast<linalg::LinalgOp>(op);
+    return genericOp.isOutputTensor(&opOperand);
+  }
+
+  SmallVector<OpOperand *> getAliasingOpOperand(Operation *op,
+                                                OpResult opResult) const {
+    auto genericOp = cast<linalg::LinalgOp>(op);
+    return {genericOp.getOutputTensorOperands()[opResult.getResultNumber()]};
+  }
+
+  OpResult getAliasingOpResult(Operation *op, OpOperand &opOperand) const {
+    auto genericOp = cast<linalg::LinalgOp>(op);
+    if (!opOperand.get().getType().isa<RankedTensorType>())
+      return OpResult();
+    // For now assume inputs are never inplaceable.
+    // TODO: refine this.
+    if (opOperand.getOperandNumber() < genericOp.getNumInputs())
+      return OpResult();
+    int64_t outputOperandIndex =
+        opOperand.getOperandNumber() - genericOp.getNumInputs();
+    int64_t numOutputBuffers = 0;
+    for (unsigned idx = 0; idx < outputOperandIndex; ++idx)
+      if (!genericOp.getOutputOperand(idx)->get().getType().isa<TensorType>())
+        ++numOutputBuffers;
+    return genericOp->getResult(outputOperandIndex - numOutputBuffers);
+  }
+
+  BufferRelation bufferRelation(Operation *op, OpOperand &opOperand) const {
+    return BufferRelation::Equivalent;
+  }
+
+  LogicalResult bufferize(Operation *op, OpBuilder &b,
+                          BufferizationState &state) const {
+    return bufferizeLinalgOp(b, cast<LinalgOp>(op), state);
+  }
+};
+
+struct InitTensorOpInterface
+    : public BufferizableOpInterface::ExternalModel<InitTensorOpInterface,
+                                                    linalg::InitTensorOp> {
+  SmallVector<OpOperand *> getAliasingOpOperand(Operation *op,
+                                                OpResult opResult) const {
+    return {};
+  }
+
+  bool isMemoryWrite(Operation *op, OpResult opResult) const {
+    // InitTensorOps allocate but do not write.
+    return false;
+  }
+
+  LogicalResult bufferize(Operation *op, OpBuilder &b,
+                          BufferizationState &state) const {
+    auto initTensorOp = cast<linalg::InitTensorOp>(op);
+
+    // The InitTensorOp may have been eliminated.
+    if (initTensorOp->getUses().empty())
+      return success();
+
+    // Take a guard before anything else.
+    OpBuilder::InsertionGuard g(b);
+    b.setInsertionPoint(initTensorOp);
+
+    Value alloc = state.allocationFns.createAllocDeallocFn(
+        b, initTensorOp->getLoc(), initTensorOp.result(), state);
+    state.mapBuffer(initTensorOp.result(), alloc);
+    return success();
+  }
+};
+
+struct TiledLoopOpInterface
+    : public BufferizableOpInterface::ExternalModel<TiledLoopOpInterface,
+                                                    linalg::TiledLoopOp> {
+  bool bufferizesToMemoryRead(Operation *op, OpOperand &opOperand) const {
+    // TiledLoop alone doesn't bufferize to a memory read, one of the uses of
+    // its matching bbArg may.
+    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
+    return isValueRead(tiledLoopOp.getTiedBlockArgument(opOperand));
+  }
+
+  bool bufferizesToMemoryWrite(Operation *op, OpOperand &opOperand) const {
+    // TiledLoop alone doesn't bufferize to a memory write, one of the uses of
+    // its matching bbArg may.
+    auto bufferizableOp = cast<BufferizableOpInterface>(op);
+    return static_cast<bool>(bufferizableOp.getAliasingOpResult(opOperand));
+  }
+
+  SmallVector<OpOperand *> getAliasingOpOperand(Operation *op,
+                                                OpResult opResult) const {
+    // TODO: TiledLoopOp helper method to avoid leaking impl details.
+    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
+    return {&op->getOpOperand(tiledLoopOp.getNumControlOperands() +
+                              tiledLoopOp.getNumInputs() +
+                              opResult.getResultNumber())};
+  }
+
+  OpResult getAliasingOpResult(Operation *op, OpOperand &opOperand) const {
+    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
+    return tiledLoopOp.getTiedOpResult(opOperand);
+  }
+
+  BufferRelation bufferRelation(Operation *op, OpOperand &opOperand) const {
+    return BufferRelation::Equivalent;
+  }
+
+  bool isWritable(Operation *op, Value value) const {
+    // Interestingly, linalg::TiledLoopOp's bbArg can **always** be viewed
+    // inplace from the perspective of ops nested under:
+    //   1. Either the matching iter operand is not bufferized inplace and an
+    //      alloc + optional copy makes the bbArg itself inplaceable.
+    //   2. Or the matching iter operand is bufferized inplace and bbArg just
+    //      bufferizes to that too.
+    return true;
+  }
+
+  bool isAllocationHoistingBarrier(Operation *op) const { return true; }
+
+  LogicalResult bufferize(Operation *op, OpBuilder &b,
+                          BufferizationState &state) const {
+    auto tiledLoopOp = cast<linalg::TiledLoopOp>(op);
+
+    // Take a guard before anything else.
+    OpBuilder::InsertionGuard g(b);
+
+    // Allocate output buffers if needed, forward output tensor args to the
+    // terminator.
+    Operation *yieldOp = tiledLoopOp.getBody()->getTerminator();
+    Block *body = tiledLoopOp.getBody();
+
+    // Take copies of the old input and output operands, so we can insert
+    // inplace easily.
+    auto oldInputs = llvm::to_vector<4>(tiledLoopOp.inputs());
+    auto oldOutputs = llvm::to_vector<4>(tiledLoopOp.outputs());
+
+    int numLoops = tiledLoopOp.getNumLoops();
+    int numControlOperands = tiledLoopOp.getNumControlOperands();
+
+    // Add buffers for outputs and the corresponding block arguments.
+    // Keep separate iterators to increment without further leaking impl.
+    // details. Start with outputs to avoid interference from new input buffers.
+    int numNewOutputBuffers = 0;
+    int resultIndex = 0;
+    int oldOutputBBArgIndex = numLoops + oldInputs.size();
+    int nextOutputBBArgIndex = numLoops + oldInputs.size() + oldOutputs.size();
+    int nextOutputOperandIndex =
+        numControlOperands + oldInputs.size() + oldOutputs.size();
+    for (Value oldOutputTensor : oldOutputs) {
+      if (!oldOutputTensor.getType().isa<TensorType>()) {
+        // Skip and increment the old bbarg index only.
+        ++oldOutputBBArgIndex;
+        // Do not increment resultIndex as only tensors are returned.
+        // TODO: better interface to avoid leaking such impl details.
+        continue;
+      }
+
+      assert(oldOutputTensor.getType().isa<RankedTensorType>() &&
+             "bufferizable output must be a ranked tensor");
+
+      const OpResult &opResult = tiledLoopOp->getResult(resultIndex);
+      OpOperand &yieldOperand = yieldOp->getOpOperand(resultIndex);
+      Value resultBuffer = getResultBuffer(b, opResult, state);
+      if (!resultBuffer)
+        return failure();
+
+      // Insert mapping and aliasing info.
+      state.aliasInfo.createAliasInfoEntry(resultBuffer);
+      state.aliasInfo.insertNewBufferEquivalence(opResult, resultBuffer);
+      state.mapBuffer(opResult, resultBuffer);
+
+      // Insert new operand and bbArg.
+      tiledLoopOp->insertOperands(nextOutputOperandIndex, resultBuffer);
+      BlockArgument newBufferBBArg =
+          body->insertArgument(nextOutputBBArgIndex, resultBuffer.getType());
+      BlockArgument oldTensorBBArg = body->getArgument(oldOutputBBArgIndex);
+      // Insert mapping and aliasing info.
+      state.aliasInfo.createAliasInfoEntry(newBufferBBArg);
+      state.aliasInfo.insertNewBufferEquivalence(oldTensorBBArg,
+                                                 newBufferBBArg);
+      state.mapBuffer(oldTensorBBArg, newBufferBBArg);
+
+      // Set operand of `linalg.yield` to the bbArg so it just canonicalizes
+      // away later.
+      yieldOperand.set(oldTensorBBArg);
+
+      // Increment indices.
+      ++numNewOutputBuffers;
+      ++resultIndex;
+      ++oldOutputBBArgIndex;
+      ++nextOutputBBArgIndex;
+      ++nextOutputOperandIndex;
+    }
+
+    // Add buffers for inputs and the corresponding block arguments.
+    // Keep separate iterators to increment without further leaking impl.
+    // details.
+    int numNewInputBuffers = 0;
+    int oldInputBBArgIndex = numLoops;
+    int nextInputBBArgIndex = numLoops + oldInputs.size();
+    int nextInputOperandIndex = numControlOperands + oldInputs.size();
+    for (Value oldInputTensor : oldInputs) {
+      if (!oldInputTensor.getType().isa<TensorType>()) {
+        // Skip and increment the old bbarg index only.
+        ++oldInputBBArgIndex;
+        continue;
+      }
+
+      Value inputBuffer = state.lookupBuffer(oldInputTensor);
+
+      // Insert new operand and bbArg.
+      tiledLoopOp->insertOperands(nextInputOperandIndex, inputBuffer);
+      BlockArgument newBufferBBArg =
+          body->insertArgument(nextInputBBArgIndex, inputBuffer.getType());
+      BlockArgument oldTensorBBArg = body->getArgument(oldInputBBArgIndex);
+
+      // Insert mapping and aliasing info.
+      state.aliasInfo.createAliasInfoEntry(newBufferBBArg);
+      state.aliasInfo.insertNewBufferEquivalence(oldTensorBBArg,
+                                                 newBufferBBArg);
+      state.mapBuffer(oldTensorBBArg, newBufferBBArg);
+
+      // Increment indices.
+      ++numNewInputBuffers;
+      ++oldInputBBArgIndex;
+      ++nextInputBBArgIndex;
+      ++nextInputOperandIndex;
+    }
+
+    // Update segment sizes.
+    // TODO: Helper method to avoid leaking impl details.
+    tiledLoopOp->setAttr(
+        TiledLoopOp::getOperandSegmentSizeAttr(),
+        b.getI32VectorAttr(
+            {numLoops, numLoops, numLoops,
+             static_cast<int>(oldInputs.size()) + numNewInputBuffers,
+             static_cast<int>(oldOutputs.size()) + numNewOutputBuffers}));
+
+    return success();
+  }
+};
+
+struct YieldOpInterface
+    : public BufferizableOpInterface::ExternalModel<YieldOpInterface,
+                                                    linalg::YieldOp> {
+  bool bufferizesToMemoryRead(Operation *op, OpOperand &opOperand) const {
+    return true;
+  }
+
+  bool bufferizesToMemoryWrite(Operation *op, OpOperand &opOperand) const {
+    return false;
+  }
+
+  OpResult getAliasingOpResult(Operation *op, OpOperand &opOperand) const {
+    return OpResult();
+  }
+
+  LogicalResult bufferize(Operation *op, OpBuilder &b,
+                          BufferizationState &state) const {
+    auto yieldOp = cast<linalg::YieldOp>(op);
+
+    // Take a guard before anything else.
+    OpBuilder::InsertionGuard g(b);
+    // Cannot create IR past a yieldOp.
+    b.setInsertionPoint(yieldOp);
+
+    // No tensors -> success.
+    if (!llvm::any_of(yieldOp.getOperandTypes(),
+                      [](Type t) { return t.isa<TensorType>(); }))
+      return success();
+    // linalg::YieldOp nested under TiledLoop must just canonicalize.
+    if (yieldOp->getParentOfType<TiledLoopOp>())
+      return success();
+    llvm_unreachable("unexpected yieldOp");
+  }
+};
+
+/// Helper structure that iterates over all LinalgOps in `OpTys` and registers
+/// the `BufferizableOpInterface` with each of them.
+template <typename... OpTys>
+struct LinalgOpInterfaceHelper;
+
+template <typename First, typename... Others>
+struct LinalgOpInterfaceHelper<First, Others...> {
+  static void registerOpInterface(DialectRegistry &registry) {
+    registry.addOpInterface<First, LinalgOpInterface<First>>();
+    LinalgOpInterfaceHelper<Others...>::registerOpInterface(registry);
+  }
+};
+
+template <>
+struct LinalgOpInterfaceHelper<> {
+  static void registerOpInterface(DialectRegistry &registry) {}
+};
+
+} // namespace
+
+/// Try to eliminate InitTensorOps inside funcOp. An InitTensorOp is replaced
+/// with the the result of `rewriteFunc` if it is anchored on a matching
+/// OpOperand. "Anchored" means that there is a path on the reverse SSA use-def
+/// chain, starting from the OpOperand and always following the aliasing
+/// OpOperand, that eventually ends at a single InitTensorOp.
+LogicalResult mlir::linalg::comprehensive_bufferize::linalg_ext::
+    InitTensorEliminationStep::eliminateInitTensors(
+        FuncOp funcOp, BufferizationAliasInfo &aliasInfo,
+        DominanceInfo &domInfo,
+        std::function<bool(OpOperand &)> anchorMatchFunc,
+        std::function<Value(OpBuilder &, Location, OpOperand &)> rewriteFunc,
+        SmallVector<Operation *> &newOps) {
+  OpBuilder b(funcOp->getContext());
+
+  WalkResult status = funcOp->walk([&](Operation *op) {
+    for (OpOperand &operand : op->getOpOperands()) {
+      // Is this a matching OpOperand?
+      if (!anchorMatchFunc(operand))
+        continue;
+
+      SetVector<Value> maybeInitTensor =
+          findValueInReverseUseDefChain(operand.get(), [&](Value val) {
+            // Continue traversal until this function returns true.
+            OpResult opResult = val.dyn_cast<OpResult>();
+            if (!opResult)
+              return true;
+            if (!aliasInfo.isInPlace(opResult))
+              return true;
+            // Only equivalent tensors are supported at the moment.
+            // TODO: Support cases such as extract_slice(init_tensor).
+            SmallVector<OpOperand *> opOperands =
+                getAliasingOpOperand(opResult);
+            if (!llvm::all_of(opOperands, [](OpOperand *operand) {
+                  return bufferRelation(*operand) == BufferRelation::Equivalent;
+                }))
+              return true;
+            return false;
+          });
+
+      // Replace only if the reverse use-def chain ends at exactly one
+      // InitTensorOp.
+      if (maybeInitTensor.size() != 1 ||
+          !maybeInitTensor.front().getDefiningOp<InitTensorOp>())
+        return WalkResult::skip();
+      Value initTensor = maybeInitTensor.front();
+
+      // Create a replacement for the InitTensorOp.
+      b.setInsertionPoint(initTensor.getDefiningOp());
+      Value replacement = rewriteFunc(b, initTensor.getLoc(), operand);
+      if (!replacement)
+        continue;
+
+      // Uses of the InitTensorOp are replaced here, but the op is not deleted.
+      // InitTensorOps without uses are ignored by the bufferization.
+      initTensor.replaceAllUsesWith(replacement);
+      aliasInfo.createAliasInfoEntry(replacement);
+      aliasInfo.unionAliasSets(initTensor, replacement);
+      aliasInfo.unionEquivalenceClasses(initTensor, replacement);
+
+      // Register replacement ops.
+      if (Operation *newOp = replacement.getDefiningOp())
+        newOps.push_back(newOp);
+    }
+
+    // Advance to the next operation.
+    return WalkResult::advance();
+  });
+
+  return failure(status.wasInterrupted());
+}
+
+/// Try to eliminate InitTensorOps inside funcOp. An InitTensorOp can be
+/// eliminated if it is eventually inserted into another tensor (and some other
+/// conditions are met).
+///
+/// E.g.:
+/// %0 = linalg.init_tensor
+/// %1 = linalg.fill(%cst, %0) {inplace = [true]}
+/// %2 = tensor.insert_slice %1 into %t[10][20][1]
+///
+/// InitTensorOp elimination will try to fill %t inplace instead of filling a
+/// new allocation %0 and inserting it into %t. This is done by replacing the
+/// InitTensorOp with:
+///
+/// %0 = tensor.extract_slice %t[10][20][1]
+///
+/// The analysis looks for matching ExtractSliceOp/InsertSliceOp pairs and lets
+/// those bufferize inplace in the absence of other conflicts.
+///
+/// Starting from an InsertSliceOp, an InitTensorOp at the end of the insert
+/// source's reverse use-def chain is eliminated if:
+/// * The InsertSliceOp was decided to bufferize inplace.
+/// * On the reverse use-def chain path from the InsertSliceOp to the
+///   InitTensorOp, all ops were decided to bufferize inplace and the buffer
+///   relation is "equivalent" (TODO: can be relaxed if needed).
+/// * The reverse use-def chain has exactly one end, which is the InitTensorOp.
+///
+/// Note that the newly inserted ExtractSliceOp may have to bufferize
+/// out-of-place due to RaW conflicts.
+LogicalResult mlir::linalg::comprehensive_bufferize::linalg_ext::
+    InsertSliceAnchoredInitTensorEliminationStep::run(
+        FuncOp funcOp, BufferizationAliasInfo &aliasInfo,
+        DominanceInfo &domInfo, SmallVector<Operation *> &newOps) {
+  return eliminateInitTensors(
+      funcOp, aliasInfo, domInfo,
+      [&](OpOperand &operand) {
+        auto insertSliceOp =
+            dyn_cast<tensor::InsertSliceOp>(operand.getOwner());
+        if (!insertSliceOp)
+          return false;
+        // Only inplace bufferized InsertSliceOps are eligible.
+        if (!aliasInfo.isInPlace(insertSliceOp->getOpResult(0)))
+          return false;
+        return &operand == &insertSliceOp->getOpOperand(0) /*source*/;
+      },
+      [](OpBuilder &b, Location loc, OpOperand &operand) {
+        auto insertSliceOp = cast<tensor::InsertSliceOp>(operand.getOwner());
+        auto extractOp = b.create<tensor::ExtractSliceOp>(
+            loc, insertSliceOp.dest(), insertSliceOp.getMixedOffsets(),
+            insertSliceOp.getMixedSizes(), insertSliceOp.getMixedStrides());
+        return extractOp.result();
+      },
+      newOps);
+}
+
+void mlir::linalg::comprehensive_bufferize::linalg_ext::
+    registerBufferizableOpInterfaceExternalModels(DialectRegistry &registry) {
+  registry.addOpInterface<linalg::InitTensorOp, InitTensorOpInterface>();
+  registry.addOpInterface<linalg::TiledLoopOp, TiledLoopOpInterface>();
+  registry.addOpInterface<linalg::YieldOp, YieldOpInterface>();
+
+  // Register all Linalg structured ops. `LinalgOp` is an interface and it is
+  // not possible to attach an external interface to an existing interface.
+  // Therefore, attach the `BufferizableOpInterface` to all ops one-by-one.
+  LinalgOpInterfaceHelper<
+#define GET_OP_LIST
+#include "mlir/Dialect/Linalg/IR/LinalgStructuredOps.cpp.inc"
+      >::registerOpInterface(registry);
+}

mlir/lib/Dialect/Linalg/Transforms/CMakeLists.txt

add_mlir_dialect_library(MLIRLinalgTransforms
   MLIRAnalysis
   MLIRArithmetic
   MLIRBufferizableOpInterface
   MLIRComplex
   MLIRComprehensiveBufferize
   MLIRInferTypeOpInterface
   MLIRIR
   MLIRMemRef
-  MLIRLinalgAnalysis
   MLIRLinalg
+  MLIRLinalgAnalysis
+  MLIRLinalgBufferizableOpInterfaceImpl
   MLIRLinalgUtils
   MLIRSCF
   MLIRSCFTransforms
   MLIRPass
   MLIRStandard
   MLIRStandardOpsTransforms
   MLIRStandardToLLVM
   MLIRTensor
   MLIRTransforms
   MLIRTransformUtils
   MLIRVector
   MLIRX86VectorTransforms
   MLIRVectorToSCF
 )

mlir/lib/Dialect/Linalg/Transforms/ComprehensiveBufferizePass.cpp

 //===- ComprehensiveBufferize.cpp - Single pass bufferization -------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 #include "PassDetail.h"
 #include "mlir/Dialect/Linalg/ComprehensiveBufferize/BufferizableOpInterface.h"
 #include "mlir/Dialect/Linalg/ComprehensiveBufferize/ComprehensiveBufferize.h"
+#include "mlir/Dialect/Linalg/ComprehensiveBufferize/LinalgInterfaceImpl.h"
 #include "mlir/Dialect/Linalg/Passes.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Pass/PassManager.h"
 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
 #include "mlir/Transforms/Passes.h"
 
 using namespace mlir;
 using namespace mlir::linalg;
struct LinalgComprehensiveModuleBufferize
   void runOnOperation() override;
 
   void getDependentDialects(DialectRegistry &registry) const override {
     registry
         .insert<linalg::LinalgDialect, memref::MemRefDialect,
                 tensor::TensorDialect, vector::VectorDialect, scf::SCFDialect,
                 arith::ArithmeticDialect, StandardOpsDialect, AffineDialect>();
     registerBufferizableOpInterfaceExternalModels(registry);
+    linalg_ext::registerBufferizableOpInterfaceExternalModels(registry);
   }
 };
 } // end namespace
 
 static void applyEnablingTransformations(ModuleOp moduleOp) {
   RewritePatternSet patterns(moduleOp.getContext());
   patterns.add<GeneralizePadTensorOpPattern>(moduleOp.getContext());
   (void)applyPatternsAndFoldGreedily(moduleOp, std::move(patterns));

utils/bazel/llvm-project-overlay/mlir/BUILD.bazel

cc_library(
     deps = [
         ":BufferizableOpInterfaceIncGen",
         ":IR",
         ":Support",
         "//llvm:Support",
     ],
 )
 
+cc_library(
+    name = "LinalgBufferizableOpInterfaceImpl",
+    srcs = [
+        "lib/Dialect/Linalg/ComprehensiveBufferize/LinalgInterfaceImpl.cpp",
+    ],
+    hdrs = [
+        "include/mlir/Dialect/Linalg/ComprehensiveBufferize/LinalgInterfaceImpl.h",
+    ],
+    includes = ["include"],
+    deps = [
+        ":BufferizableOpInterface",
+        ":IR",
+        ":LinalgOps",
+        ":LinalgStructuredOpsIncGen",
+        ":Support",
+        ":TensorDialect",
+        "//llvm:Support",
+    ],
+)
+
 td_library(
     name = "LinalgDocTdFiles",
     srcs = ["include/mlir/Dialect/Linalg/IR/LinalgDoc.td"],
     includes = ["include"],
     deps = [
         ":LinalgOpsTdFiles",
         ":LinalgStructuredOpsTdFiles",
     ],
deps = [
         ":Analysis",
         ":ArithmeticDialect",
         ":BufferizableOpInterface",
         ":ComplexDialect",
         ":ComprehensiveBufferize",
         ":DialectUtils",
         ":IR",
         ":InferTypeOpInterface",
+        ":LinalgBufferizableOpInterfaceImpl",
         ":LinalgOps",
         ":LinalgPassIncGen",
         ":LinalgStructuredOpsIncGen",
         ":MathDialect",
         ":MemRefDialect",
         ":Pass",
         ":SCFDialect",
         ":SCFTransforms",
cc_library(
     srcs = [
         "lib/Dialect/Linalg/ComprehensiveBufferize/ComprehensiveBufferize.cpp",
     ],
     hdrs = [
         "include/mlir/Dialect/Linalg/ComprehensiveBufferize/ComprehensiveBufferize.h",
     ],
     includes = ["include"],
     deps = [
+        ":Affine",
         ":ArithmeticDialect",
         ":BufferizableOpInterface",
         ":DialectUtils",
         ":IR",
         ":InferTypeOpInterface",
-        ":LinalgOps",
-        ":LinalgStructuredOpsIncGen",
         ":MemRefDialect",
         ":Pass",
         ":SCFDialect",
         ":StandardOps",
         ":Support",
         ":TensorDialect",
         ":TransformUtils",
         ":VectorOps",