[MLIR][Linalg] Adjust documentation (NFC)

[chelini]

Summary

Adjust docs for tensor.pad, tensor.collapse_shape and tensor.expand_shape.

mlir/include/mlir/Dialect/Linalg/Transforms/Transforms.h

 //===- Transforms.h - Linalg transformations as patterns --------*- 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
 //
 //===----------------------------------------------------------------------===//
 

 
 protected:
   OptimizeCopyFn optimizeCopyFn;
   Value createFillOrGenerateOp(PatternRewriter &rewriter, tensor::PadOp padOp,
                                Value dest,
                                const SmallVector<Value> &dynSizes) const;
 };
 
-/// Populates `patterns` with patterns that vectorize linalg.pad_tensor.
+/// Populates `patterns` with patterns that vectorize tensor.pad.
 /// These patterns are meant to apply in a complementary fashion. Benefits
 /// are used to encode a certain ordering of pattern application. To avoid
 /// scattering magic constants throughout the code base, the patterns must be
 /// added with this function. `baseBenefit` can be used to offset the benefit
 /// of all tensor::PadOp vectorization patterns by a certain value.
 void populatePadOpVectorizationPatterns(RewritePatternSet &patterns,
                                         PatternBenefit baseBenefit = 1);
 

 ///   non-local transformation effects. This allows creating custom fused
 ///   transformations where patterns can be ordered and applied at a finer
 ///   granularity than a sequence of traditional compiler passes.
 LogicalResult applyStagedPatterns(
     Operation *op, ArrayRef<FrozenRewritePatternSet> stage1Patterns,
     const FrozenRewritePatternSet &stage2Patterns,
     function_ref<LogicalResult(Operation *)> stage3Lambda = nullptr);
 
-/// Rewrite extract_slice(pad_tensor(x)) into pad_tensor(extract_slice(x)).
+/// Rewrite extract_slice(tensor.pad(x)) into tensor.pad(extract_slice(x)).
 struct ExtractSliceOfPadTensorSwapPattern
     : public OpRewritePattern<tensor::ExtractSliceOp> {
   /// A function to control pattern application and rewrite logic.
   ///
   /// The function will be given the slice op and should return:
   /// -  None: to fail the match and not apply the pattern;
   /// -  true: to apply the pattern with zero slice guard;
   /// - false: to apply the pattern without zero slice guard.

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

 //===- ElementwiseOpFusion.cpp - Implementation of linalg Fusion ---------===///
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //

 ///  %c = linalg.generic ins(%a, %b : memref<?x?x?xf32>, memref<?x?xf32>)
 ///         indexing_maps = [affine_map<(d0, d1, d2) -> (d1, d0, d2)>,
 ///                          affine_map<(d0, d1, d2) -> (d1, d2)>,
 ///                          affine_map<(d0, d1, d2) -> (d0, d2, d1)>]
 ///  %d = tensor.expand_shape %c [[0, 1], [2], [3, 4, 5]]
 ///       : tensor<?x?x?xf32> into tensor<?x?x?x?x?x?xf32>
 ///
 ///  The reshape can be folded into the `genericOp` if its loop dimensionality
-///  is increased to match the result (operand) of the tensor_expand_shape.
+///  is increased to match the result (operand) of the tensor.expand_shape.
 ///  The indexing_map of the fused tensor in the `genericOp` and the
 ///  reassociation map helps compute the indexing maps of the modified op.
 ///  For the above example, based on the reassociation map it
 ///  can be concluded that
 ///
 ///  - The loop used to access the first dimension of the fused tensor is split
 ///    into two.
 ///  - The loop used to access the second dimension of the fused tensor is kept
for (auto it : llvm::zip(expandedDimsShape, expandedIndices)) {
       newIndex = rewriter.create<AffineApplyOp>(
           indexOp.getLoc(), idx + acc * std::get<0>(it),
           ValueRange{std::get<1>(it), newIndex});
     }
     rewriter.replaceOp(indexOp, newIndex);
   }
 }
 
-/// Implements the fusion of a tensor_collapse_shape or a tensor_expand_shape op
+/// Implements the fusion of a tensor.collapse_shape or a tensor.expand_shape op
 /// and a generic op as explained in `isFusableWithReshapeByExpansion`. Assumes
 /// that those conditions have been satisfied.
 static Optional<SmallVector<Value>>
 fuseWithReshapeByExpansion(GenericOp genericOp, Operation *reshapeOp,
                            OpOperand *fusableOpOperand,
                            PatternRewriter &rewriter) {
   assert(isFusableWithReshapeByDimExpansion(genericOp, fusableOpOperand) &&
          "preconditions for fuse operation failed");
for (OpResult opResult : genericOp->getOpResults()) {
     }
   }
   // Assuming a single result.
   return resultVals;
 }
 
 namespace {
 
-/// Pattern to fuse a tensor_collapse_shape op with its consumer generic op,
+/// Pattern to fuse a tensor.collapse_shape op with its consumer generic op,
 /// when the reshape op is collapsing dimensions. The dimensionality of the loop
 /// in the consumer is expanded.
 class FoldWithProducerReshapeOpByExpansion
     : public OpRewritePattern<GenericOp> {
 public:
   FoldWithProducerReshapeOpByExpansion(MLIRContext *context,
                                        ControlFusionFn foldReshapes,
                                        PatternBenefit benefit = 1)
LogicalResult matchAndRewrite(GenericOp genericOp,
     }
     return failure();
   }
 
 private:
   ControlFusionFn controlFoldingReshapes;
 };
 
-/// Pattern to fold a tensor_expand_shape op with its producer generic op
+/// Pattern to fold a tensor.expand_shape op with its producer generic op
 /// by expanding the dimensionality of the loop in the producer op.
 struct FoldReshapeWithGenericOpByExpansion
     : public OpRewritePattern<tensor::ExpandShapeOp> {
 
   FoldReshapeWithGenericOpByExpansion(MLIRContext *context,
                                       ControlFusionFn foldReshapes,
                                       PatternBenefit benefit = 1)
       : OpRewritePattern<tensor::ExpandShapeOp>(context, benefit),

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

 //===- Vectorization.cpp - Implementation of linalg Vectorization ---------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //

 
 protected:
   virtual LogicalResult rewriteUser(PatternRewriter &rewriter,
                                     tensor::PadOp padOp, OpTy op) const = 0;
 };
 
 /// Rewrite use of tensor::PadOp result in TransferReadOp. E.g.:
 /// ```
-/// %0 = linalg.pad_tensor %src ... : tensor<?x?xf32> to tensor<17x5xf32>
+/// %0 = tensor.pad %src ... : tensor<?x?xf32> to tensor<17x5xf32>
 /// %r = vector.transfer_read %0[%c0, %c0], %cst
 ///     {in_bounds = [true, true]} : tensor<17x5xf32>, vector<17x5xf32>
 /// ```
 /// is rewritten to:
 /// ```
 /// %r = vector.transfer_read %src[%c0, %c0], %padding
 ///     {in_bounds = [true, true]}
 ///     : tensor<?x?xf32>, vector<17x5xf32>

 /// Rewrite use of tensor::PadOp result in TransferWriteOp.
 /// This pattern rewrites TransferWriteOps that write to a padded tensor
 /// value, where the same amount of padding is immediately removed again after
 /// the write. In such cases, the TransferWriteOp can write to the non-padded
 /// tensor value and apply out-of-bounds masking. E.g.:
 /// ```
 /// %0 = tensor.extract_slice ...[...] [%s0, %s1] [1, 1]
 ///     : tensor<...> to tensor<?x?xf32>
-/// %1 = linalg.pad_tensor %0 ... : tensor<?x?xf32> to tensor<17x5xf32>
+/// %1 = tensor.pad %0 ... : tensor<?x?xf32> to tensor<17x5xf32>
 /// %2 = vector.transfer_write %vec, %1[...]
 ///     : vector<17x5xf32>, tensor<17x5xf32>
 /// %r = tensor.extract_slice %2[0, 0] [%s0, %s1] [1, 1]
 ///     : tensor<17x5xf32> to tensor<?x?xf32>
 /// ```
 /// is rewritten to:
 /// ```
 /// %0 = tensor.extract_slice ...[...] [%s0, %s1] [1, 1]
bool hasSameTensorSize(Value beforePadding,
 
     // All tests passed.
     return true;
   }
 };
 
 /// Rewrite use of tensor::PadOp result in InsertSliceOp. E.g.:
 /// ```
-/// %0 = linalg.pad_tensor %src ... : tensor<?x?xf32> to tensor<17x5xf32>
+/// %0 = tensor.pad %src ... : tensor<?x?xf32> to tensor<17x5xf32>
 /// %r = tensor.insert_slice %0
 ///     into %dest[%a, %b, 0, 0] [1, 1, 17, 5] [1, 1, 1, 1]
 ///     : tensor<17x5xf32> into tensor<?x?x17x5xf32>
 /// ```
 /// is rewritten to:
 /// ```
 /// %0 = vector.transfer_read %src[%c0, %c0], %padding
 ///     : tensor<?x?xf32>, vector<17x5xf32>

mlir/test/lib/Dialect/Linalg/TestLinalgTransforms.cpp

 //===- TestLinalgTransforms.cpp - Test Linalg transformation patterns -----===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
Option<bool> testTransformPadTensor{
       llvm::cl::desc("Test transform pad tensor by copying with generic ops"),
       llvm::cl::init(false)};
   Option<bool> testGeneralizePadTensor{
       *this, "test-generalize-pad-tensor",
       llvm::cl::desc("Test transform pad tensor by copying with generic ops"),
       llvm::cl::init(false)};
   Option<bool> testSwapSubTensorPadTensor{
       *this, "test-swap-subtensor-padtensor",
-      llvm::cl::desc("Test rewrite of subtensor(pad_tensor) into "
-                     "pad_tensor(subtensor)"),
+      llvm::cl::desc("Test rewrite of subtensor(tensor.pad) into "
+                     "tensor.pad(subtensor)"),
       llvm::cl::init(false)};
   Option<bool> testSplitReduction{
       *this, "test-split-reduction",
       llvm::cl::desc("Test split reduction transformation"),
       llvm::cl::init(false)};
   ListOption<int64_t> peeledLoops{
       *this, "peeled-loops",
       llvm::cl::desc("Loops to be peeled when test-tile-pattern"),