[Mlir-commits] [mlir] [mlir][vector] Adds pattern rewrite for maskable Ops (PR #83827)

Andrzej WarzyƄski llvmlistbot at llvm.org
Mon Mar 4 03:22:14 PST 2024


https://github.com/banach-space created https://github.com/llvm/llvm-project/pull/83827

Adds a generic pattern rewrite for maskable Ops that we would like to
work for both masked and un-masked cases, e.g. for both `vector.mask
{vector.contract}` and `vector.contract` (this is a very contrived
example - just to demonstrate the idea).

This helps to reduce code-duplication and standardise how we implement
such patterns.

Fixes #78787


>From b706e7851a02206c57fdd3cd1f79309f9fa9b129 Mon Sep 17 00:00:00 2001
From: Andrzej Warzynski <andrzej.warzynski at arm.com>
Date: Mon, 4 Mar 2024 09:23:36 +0000
Subject: [PATCH] [mlir][vector] Adds pattern rewrite for maskable Ops

Adds a generic pattern rewrite for maskable Ops that we would like to
work for both masked and un-masked cases, e.g. for both `vector.mask
{vector.contract}` and `vector.contract` (this is a very contrived
example - just to demonstrate the idea).

This helps to reduce code-duplication and standardise how we implement
such patterns.

Fixes #78787
---
 .../Vector/Transforms/LowerVectorContract.cpp | 251 ++++++++++--------
 1 file changed, 143 insertions(+), 108 deletions(-)

diff --git a/mlir/lib/Dialect/Vector/Transforms/LowerVectorContract.cpp b/mlir/lib/Dialect/Vector/Transforms/LowerVectorContract.cpp
index 0eaf9f71a37d21..6480b295c49cb6 100644
--- a/mlir/lib/Dialect/Vector/Transforms/LowerVectorContract.cpp
+++ b/mlir/lib/Dialect/Vector/Transforms/LowerVectorContract.cpp
@@ -41,7 +41,6 @@ using namespace mlir::vector;
 //===----------------------------------------------------------------------===//
 // Helper functions
 //===----------------------------------------------------------------------===//
-
 // Helper to find an index in an affine map.
 static std::optional<int64_t> getResultIndex(AffineMap map, int64_t index) {
   for (int64_t i = 0, e = map.getNumResults(); i < e; ++i) {
@@ -212,6 +211,64 @@ static Value createMul(Location loc, Value x, Value y, bool isInt,
 
 namespace {
 
+/// A pattern for ops that implement `MaskableOpInterface` and that _might_ be
+/// masked (i.e. inside `vector.mask` Op region). In particular:
+///   1. It matches `SourceOp` operation, Op.
+///   2. If Op is masked, retrieves the mask and updates the insertion point to
+///   avoid inserting new ops into `vector.mask` Op region (which only allows
+///   one Op). If the Op is not masked, this step is a nop.
+///   3. Invokes `matchAndRewriteMaskableOp` on Op that might be nested (not
+///   required) in the matched `vector.mask` operation from step 2.
+///
+/// It frees the patterns implementing this class from worrying about the
+/// logic to update the insertion point. However, those patterns are still
+/// responsible for providing an updated version of:
+///   * the source Op when mask _is not_ present,
+///   * the source Op *and* the mask Op when mask _is_ present.
+template <class SourceOp>
+struct MaybeMaskedOpRewritePattern : OpRewritePattern<SourceOp> {
+  using OpRewritePattern<SourceOp>::OpRewritePattern;
+
+private:
+  LogicalResult matchAndRewrite(SourceOp sourceOp,
+                                PatternRewriter &rewriter) const final {
+    auto maskableOp =
+        dyn_cast_if_present<MaskableOpInterface>(sourceOp.getOperation());
+    if (!maskableOp)
+      return failure();
+
+    // Retrieve the mask if present
+    MaskingOpInterface maskOp;
+    if (maskableOp.isMasked())
+      maskOp = maskableOp.getMaskingOp();
+
+    // If this Op is masked, update the insertion point to avoid inserting into
+    // the vector.mask Op region.
+    OpBuilder::InsertionGuard guard(rewriter);
+    Operation *rootOp = sourceOp;
+    if (maskOp) {
+      rewriter.setInsertionPoint(maskOp);
+      rootOp = maskOp;
+    }
+
+    FailureOr<Value> newOp =
+        matchAndRewriteMaskableOp(sourceOp, maskOp, rewriter);
+    if (failed(newOp))
+      return failure();
+
+    rewriter.replaceOp(rootOp, *newOp);
+    return success();
+  }
+
+public:
+  // Matches SourceOp that can potentially be masked with `maskingOp`. If the
+  // latter is present, returns an updated masking op (with a replacement for
+  // `sourceOp` nested inside). Otherwise, returns an updated `sourceOp`.
+  virtual FailureOr<Value>
+  matchAndRewriteMaskableOp(SourceOp sourceOp, MaskingOpInterface maskingOp,
+                            PatternRewriter &rewriter) const = 0;
+};
+
 /// Progressive lowering of a `vector.contract %a, %b, %c` with row-major matmul
 /// semantics to:
 /// ```
@@ -226,9 +283,9 @@ namespace {
 /// This only kicks in when VectorTransformsOptions is set to OuterProduct and
 /// the vector.contract op is a row-major matrix multiply.
 class ContractionOpToMatmulOpLowering
-    : public OpRewritePattern<vector::ContractionOp> {
+    : public MaybeMaskedOpRewritePattern<vector::ContractionOp> {
 public:
-  using OpRewritePattern::OpRewritePattern;
+  using MaybeMaskedOpRewritePattern::MaybeMaskedOpRewritePattern;
 
   using FilterConstraintType =
       std::function<LogicalResult(vector::ContractionOp op)>;
@@ -241,12 +298,13 @@ class ContractionOpToMatmulOpLowering
       vector::VectorTransformsOptions vectorTransformOptions,
       MLIRContext *context, PatternBenefit benefit = 1,
       FilterConstraintType constraint = defaultFilter)
-      : OpRewritePattern<vector::ContractionOp>(context, benefit),
+      : MaybeMaskedOpRewritePattern<vector::ContractionOp>(context, benefit),
         vectorTransformOptions(vectorTransformOptions),
         filter(std::move(constraint)) {}
 
-  LogicalResult matchAndRewrite(vector::ContractionOp op,
-                                PatternRewriter &rewriter) const override;
+  FailureOr<Value>
+  matchAndRewriteMaskableOp(vector::ContractionOp op, MaskingOpInterface maskOp,
+                            PatternRewriter &rewriter) const override;
 
 private:
   /// Options to control the vector patterns.
@@ -270,9 +328,9 @@ class ContractionOpToMatmulOpLowering
 /// This only kicks in when VectorTransformsOptions is set to OuterProduct and
 /// the vector.contract op is a row-major matrix multiply.
 class ContractionOpToOuterProductOpLowering
-    : public OpRewritePattern<vector::ContractionOp> {
+    : public MaybeMaskedOpRewritePattern<vector::ContractionOp> {
 public:
-  using OpRewritePattern::OpRewritePattern;
+  using MaybeMaskedOpRewritePattern::MaybeMaskedOpRewritePattern;
 
   using FilterConstraintType =
       std::function<LogicalResult(vector::ContractionOp op)>;
@@ -285,12 +343,13 @@ class ContractionOpToOuterProductOpLowering
       vector::VectorTransformsOptions vectorTransformOptions,
       MLIRContext *context, PatternBenefit benefit = 1,
       FilterConstraintType constraint = defaultFilter)
-      : OpRewritePattern<vector::ContractionOp>(context, benefit),
+      : MaybeMaskedOpRewritePattern<vector::ContractionOp>(context, benefit),
         vectorTransformOptions(vectorTransformOptions),
         filter(std::move(constraint)) {}
 
-  LogicalResult matchAndRewrite(vector::ContractionOp op,
-                                PatternRewriter &rewriter) const override;
+  FailureOr<Value>
+  matchAndRewriteMaskableOp(vector::ContractionOp op, MaskingOpInterface maskOp,
+                            PatternRewriter &rewriter) const override;
 
 private:
   /// Options to control the vector patterns.
@@ -317,9 +376,9 @@ class ContractionOpToOuterProductOpLowering
 /// This only kicks in when VectorTransformsOptions is set to Dot and
 /// the vector.contract op is a row-major matmul or matvec.
 class ContractionOpToDotLowering
-    : public OpRewritePattern<vector::ContractionOp> {
+    : public MaybeMaskedOpRewritePattern<vector::ContractionOp> {
 public:
-  using OpRewritePattern::OpRewritePattern;
+  using MaybeMaskedOpRewritePattern::MaybeMaskedOpRewritePattern;
 
   using FilterConstraintType =
       std::function<LogicalResult(vector::ContractionOp op)>;
@@ -332,11 +391,12 @@ class ContractionOpToDotLowering
       vector::VectorTransformsOptions vectorTransformOptions,
       MLIRContext *context, PatternBenefit benefit = 1,
       const FilterConstraintType &constraint = defaultFilter)
-      : OpRewritePattern<vector::ContractionOp>(context, benefit),
+      : MaybeMaskedOpRewritePattern<vector::ContractionOp>(context, benefit),
         vectorTransformOptions(vectorTransformOptions), filter(defaultFilter) {}
 
-  LogicalResult matchAndRewrite(vector::ContractionOp op,
-                                PatternRewriter &rewriter) const override;
+  FailureOr<Value>
+  matchAndRewriteMaskableOp(vector::ContractionOp op, MaskingOpInterface maskOp,
+                            PatternRewriter &rewriter) const override;
 
 private:
   /// Options to control the vector patterns.
@@ -344,23 +404,10 @@ class ContractionOpToDotLowering
   FilterConstraintType filter;
 };
 
-/// Progressive lowering of ContractionOp.
-///
-/// One:
-///   %x = vector.contract with at least one free/batch dimension
-/// is replaced by:
-///   %a = vector.contract with one less free/batch dimension
-///   %b = vector.contract with one less free/batch dimension
-///   ..
-///   %x = combine %a %b ..
-/// until a pure contraction is reached (no free/batch dimensions),
-/// which is replaced by a dot-product.
-///
-/// This only kicks in when either VectorTransformsOptions is set
-/// to Dot or when other contraction patterns fail.
-class ContractionOpLowering : public OpRewritePattern<vector::ContractionOp> {
+class ContractionOpLowering
+    : public MaybeMaskedOpRewritePattern<vector::ContractionOp> {
 public:
-  using OpRewritePattern::OpRewritePattern;
+  using MaybeMaskedOpRewritePattern::MaybeMaskedOpRewritePattern;
   using FilterConstraintType =
       std::function<LogicalResult(vector::ContractionOp op)>;
 
@@ -371,12 +418,13 @@ class ContractionOpLowering : public OpRewritePattern<vector::ContractionOp> {
   ContractionOpLowering(vector::VectorTransformsOptions vectorTransformOptions,
                         MLIRContext *context, PatternBenefit benefit = 1,
                         FilterConstraintType constraint = defaultFilter)
-      : OpRewritePattern<vector::ContractionOp>(context, benefit),
+      : MaybeMaskedOpRewritePattern<vector::ContractionOp>(context, benefit),
         vectorTransformOptions(vectorTransformOptions),
         filter(std::move(constraint)) {}
 
-  LogicalResult matchAndRewrite(vector::ContractionOp op,
-                                PatternRewriter &rewriter) const override;
+  FailureOr<Value>
+  matchAndRewriteMaskableOp(vector::ContractionOp op, MaskingOpInterface maskOp,
+                            PatternRewriter &rewriter) const override;
 
 private:
   /// Options to control the vector patterns.
@@ -634,8 +682,10 @@ struct UnrolledOuterProductGenerator
 ///
 /// This only kicks in when VectorTransformsOptions is set to OuterProduct but
 /// otherwise supports any layout permutation of the matrix-multiply.
-LogicalResult ContractionOpToOuterProductOpLowering::matchAndRewrite(
-    vector::ContractionOp op, PatternRewriter &rewriter) const {
+FailureOr<Value>
+ContractionOpToOuterProductOpLowering::matchAndRewriteMaskableOp(
+    vector::ContractionOp op, MaskingOpInterface maskOp,
+    PatternRewriter &rewriter) const {
   if (vectorTransformOptions.vectorContractLowering !=
       vector::VectorContractLowering::OuterProduct)
     return failure();
@@ -643,43 +693,25 @@ LogicalResult ContractionOpToOuterProductOpLowering::matchAndRewrite(
   if (failed(filter(op)))
     return failure();
 
-  // Vector mask setup.
-  OpBuilder::InsertionGuard guard(rewriter);
-  auto maskableOp = cast<vector::MaskableOpInterface>(op.getOperation());
-  Operation *rootOp;
-  if (maskableOp.isMasked()) {
-    rewriter.setInsertionPoint(maskableOp.getMaskingOp());
-    rootOp = maskableOp.getMaskingOp();
-  } else {
-    rootOp = op;
-  }
-
   UnrolledOuterProductGenerator e(rewriter, op);
   FailureOr<Value> matmatRes = e.matmat();
   if (succeeded(matmatRes)) {
-    rewriter.replaceOp(rootOp, *matmatRes);
-    return success();
+    return matmatRes;
   }
   FailureOr<Value> matvecRes = e.matvec();
   if (succeeded(matvecRes)) {
-    rewriter.replaceOp(rootOp, *matvecRes);
-    return success();
-  }
-  FailureOr<Value> tmatvecRes = e.tmatvec();
-  if (succeeded(tmatvecRes)) {
-    rewriter.replaceOp(rootOp, *tmatvecRes);
-    return success();
+    return matvecRes;
   }
 
-  return failure();
+  FailureOr<Value> tmatvecRes = e.tmatvec();
+  return tmatvecRes;
 }
 
-LogicalResult
-ContractionOpToDotLowering::matchAndRewrite(vector::ContractionOp op,
-                                            PatternRewriter &rewriter) const {
+FailureOr<Value> ContractionOpToDotLowering::matchAndRewriteMaskableOp(
+    vector::ContractionOp op, MaskingOpInterface maskOp,
+    PatternRewriter &rewriter) const {
   // TODO: Support vector.mask.
-  auto maskableOp = cast<MaskableOpInterface>(op.getOperation());
-  if (maskableOp.isMasked())
+  if (maskOp)
     return failure();
 
   if (failed(filter(op)))
@@ -788,15 +820,14 @@ ContractionOpToDotLowering::matchAndRewrite(vector::ContractionOp op,
   }
   if (auto acc = op.getAcc())
     res = createAdd(op.getLoc(), res, acc, isInt, rewriter);
-  rewriter.replaceOp(op, res);
-  return success();
+  return res;
 }
 
 /// Lower vector.contract with all size one reduction dimensions to
 /// elementwise ops when possible.
 struct ContractOpToElementwise
-    : public OpRewritePattern<vector::ContractionOp> {
-  using OpRewritePattern::OpRewritePattern;
+    : public MaybeMaskedOpRewritePattern<vector::ContractionOp> {
+  using MaybeMaskedOpRewritePattern::MaybeMaskedOpRewritePattern;
   using FilterConstraintType =
       std::function<LogicalResult(vector::ContractionOp op)>;
   static LogicalResult defaultFilter(vector::ContractionOp op) {
@@ -806,14 +837,15 @@ struct ContractOpToElementwise
       vector::VectorTransformsOptions vectorTransformOptions,
       MLIRContext *context, PatternBenefit benefit = 1,
       const FilterConstraintType &constraint = defaultFilter)
-      : OpRewritePattern<vector::ContractionOp>(context, benefit),
+      : MaybeMaskedOpRewritePattern<vector::ContractionOp>(context, benefit),
         vectorTransformOptions(vectorTransformOptions), filter(defaultFilter) {}
 
-  LogicalResult matchAndRewrite(vector::ContractionOp contractOp,
-                                PatternRewriter &rewriter) const override {
+  FailureOr<Value>
+  matchAndRewriteMaskableOp(vector::ContractionOp contractOp,
+                            MaskingOpInterface maskOp,
+                            PatternRewriter &rewriter) const override {
     // TODO: Support vector.mask.
-    auto maskableOp = cast<MaskableOpInterface>(contractOp.getOperation());
-    if (maskableOp.isMasked())
+    if (maskOp)
       return failure();
 
     if (failed(filter(contractOp)))
@@ -903,8 +935,10 @@ struct ContractOpToElementwise
     std::optional<Value> result =
         createContractArithOp(loc, newLhs, newRhs, contractOp.getAcc(),
                               contractOp.getKind(), rewriter, isInt);
-    rewriter.replaceOp(contractOp, {*result});
-    return success();
+    if (result)
+      return *result;
+
+    return failure();
   }
 
 private:
@@ -930,9 +964,9 @@ struct ContractOpToElementwise
 // TODO: break down into transpose/reshape/cast ops
 //               when they become available to avoid code dup
 // TODO: investigate lowering order impact on performance
-LogicalResult
-ContractionOpLowering::matchAndRewrite(vector::ContractionOp op,
-                                       PatternRewriter &rewriter) const {
+FailureOr<Value> ContractionOpLowering::matchAndRewriteMaskableOp(
+    vector::ContractionOp op, MaskingOpInterface maskOp,
+    PatternRewriter &rewriter) const {
   if (failed(filter(op)))
     return failure();
 
@@ -951,29 +985,36 @@ ContractionOpLowering::matchAndRewrite(vector::ContractionOp op,
 
   // TODO: implement benefits, cost models.
   MLIRContext *ctx = op.getContext();
+
   ContractionOpToMatmulOpLowering pat1(vectorTransformOptions, ctx);
-  if (succeeded(pat1.matchAndRewrite(op, rewriter)))
-    return success();
+  FailureOr<Value> newVal1 =
+      pat1.matchAndRewriteMaskableOp(op, maskOp, rewriter);
+  if (!failed(newVal1))
+    return newVal1;
+
   ContractionOpToOuterProductOpLowering pat2(vectorTransformOptions, ctx);
-  if (succeeded(pat2.matchAndRewrite(op, rewriter)))
-    return success();
+  FailureOr<Value> newVal2 =
+      pat2.matchAndRewriteMaskableOp(op, maskOp, rewriter);
+  if (!failed(newVal2))
+    return newVal2;
+
   ContractionOpToDotLowering pat3(vectorTransformOptions, ctx);
-  if (succeeded(pat3.matchAndRewrite(op, rewriter)))
-    return success();
+  FailureOr<Value> newVal3 =
+      pat3.matchAndRewriteMaskableOp(op, maskOp, rewriter);
+  if (!failed(newVal3))
+    return newVal3;
+
   ContractOpToElementwise pat4(vectorTransformOptions, ctx);
-  if (succeeded(pat4.matchAndRewrite(op, rewriter)))
-    return success();
+  FailureOr<Value> newVal4 =
+      pat4.matchAndRewriteMaskableOp(op, maskOp, rewriter);
+  if (!failed(newVal4))
+    return newVal4;
 
   // Vector mask setup.
-  OpBuilder::InsertionGuard guard(rewriter);
-  Operation *rootOp = op;
-  Value mask;
-  if (op.isMasked()) {
-    rewriter.setInsertionPoint(op.getMaskingOp());
-    rootOp = op.getMaskingOp();
-    mask = op.getMaskingOp().getMask();
-  }
 
+  Value mask;
+  if (maskOp)
+    mask = maskOp.getMask();
   // Find first batch dimension in LHS/RHS, and lower when found.
   std::vector<std::pair<int64_t, int64_t>> batchDimMap = op.getBatchDimMap();
   if (!batchDimMap.empty()) {
@@ -982,8 +1023,7 @@ ContractionOpLowering::matchAndRewrite(vector::ContractionOp op,
     auto newOp = lowerParallel(rewriter, op, lhsIndex, rhsIndex, mask);
     if (failed(newOp))
       return failure();
-    rewriter.replaceOp(rootOp, *newOp);
-    return success();
+    return newOp;
   }
 
   // Collect contracting dimensions.
@@ -1003,8 +1043,7 @@ ContractionOpLowering::matchAndRewrite(vector::ContractionOp op,
       auto newOp = lowerParallel(rewriter, op, lhsIndex, /*rhsIndex=*/-1, mask);
       if (failed(newOp))
         return failure();
-      rewriter.replaceOp(rootOp, *newOp);
-      return success();
+      return newOp;
     }
   }
 
@@ -1015,8 +1054,7 @@ ContractionOpLowering::matchAndRewrite(vector::ContractionOp op,
       auto newOp = lowerParallel(rewriter, op, /*lhsIndex=*/-1, rhsIndex, mask);
       if (failed(newOp))
         return failure();
-      rewriter.replaceOp(rootOp, *newOp);
-      return success();
+      return newOp;
     }
   }
 
@@ -1025,8 +1063,7 @@ ContractionOpLowering::matchAndRewrite(vector::ContractionOp op,
     auto newOp = lowerReduction(rewriter, op, mask);
     if (failed(newOp))
       return failure();
-    rewriter.replaceOp(rootOp, *newOp);
-    return success();
+    return newOp;
   }
 
   return failure();
@@ -1291,12 +1328,11 @@ class OuterProductOpLowering : public OpRewritePattern<vector::OuterProductOp> {
 /// This only kicks in when VectorTransformsOptions is set to `Matmul`.
 /// vector.transpose operations are inserted if the vector.contract op is not a
 /// row-major matrix multiply.
-LogicalResult
-ContractionOpToMatmulOpLowering::matchAndRewrite(vector::ContractionOp op,
-                                                 PatternRewriter &rew) const {
+FailureOr<Value> ContractionOpToMatmulOpLowering::matchAndRewriteMaskableOp(
+    vector::ContractionOp op, MaskingOpInterface maskOp,
+    PatternRewriter &rew) const {
   // TODO: Support vector.mask.
-  auto maskableOp = cast<MaskableOpInterface>(op.getOperation());
-  if (maskableOp.isMasked())
+  if (maskOp)
     return failure();
 
   if (vectorTransformOptions.vectorContractLowering !=
@@ -1379,8 +1415,7 @@ ContractionOpToMatmulOpLowering::matchAndRewrite(vector::ContractionOp op,
           : static_cast<Value>(
                 rew.create<arith::AddFOp>(loc, op.getAcc(), mul));
 
-  rew.replaceOp(op, res);
-  return success();
+  return res;
 }
 } // namespace
 



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