Refactor the LowerVectorTransfers pass to use the RewritePattern infra - NFC

This is step 1/n in refactoring infrastructure along the Vector dialect to make it ready for retargetability and composable progressive lowering.

PiperOrigin-RevId: 280529784

mlir/include/mlir/Conversion/VectorConversions/VectorConversions.h

@@ -1,4 +1,4 @@
-//===- VectorToLLVM.h - Pass converting vector to LLVM dialect --*- C++ -*-===//
+//===- VectorConversions.h - Utils to convert from the vector dialect -----===//
 //
 // Copyright 2019 The MLIR Authors.
 //
@@ -19,10 +19,17 @@
 
 namespace mlir {
 class LLVMTypeConverter;
+class MLIRContext;
 class ModuleOp;
+template <typename T> class OpPassBase;
 class OwningRewritePatternList;
 
-template <typename T> class OpPassBase;
+/// Collect a set of patterns to convert from the Vector dialect to affine loops
+/// surrounding ops in different dialects (vector, std etc).
+/// This is the general place where we want to implement Vector -> Vector and
+/// Vector -> Std legalizations.
+void populateVectorToAffineLoopsConversionPatterns(
+    MLIRContext *context, OwningRewritePatternList &patterns);
 
 /// Collect a set of patterns to convert from the Vector dialect to LLVM.
 void populateVectorToLLVMConversionPatterns(LLVMTypeConverter &converter,
@@ -30,6 +37,7 @@ void populateVectorToLLVMConversionPatterns(LLVMTypeConverter &converter,
 
 /// Create a pass to convert vector operations to the LLVMIR dialect.
 OpPassBase<ModuleOp> *createLowerVectorToLLVMPass();
+
 } // namespace mlir
 
 #endif // MLIR_CONVERSION_VECTORTOLLVM_VECTORTOLLVM_H_

mlir/include/mlir/Transforms/Passes.h

@@ -122,9 +122,6 @@ std::unique_ptr<OpPassBase<FuncOp>> createAffineDataCopyGenerationPass(
     unsigned tagMemorySpace = 0, int minDmaTransferSize = 1024,
     uint64_t fastMemCapacityBytes = std::numeric_limits<uint64_t>::max());
 
-/// Creates a pass to lower VectorTransferReadOp and VectorTransferWriteOp.
-std::unique_ptr<OpPassBase<FuncOp>> createLowerVectorTransfersPass();
-
 /// Creates a pass to perform optimizations relying on memref dataflow such as
 /// store to load forwarding, elimination of dead stores, and dead allocs.
 std::unique_ptr<OpPassBase<FuncOp>> createMemRefDataFlowOptPass();

mlir/lib/Conversion/CMakeLists.txt

@@ -7,4 +7,4 @@ add_subdirectory(LoopsToGPU)
 add_subdirectory(LoopToStandard)
 add_subdirectory(StandardToLLVM)
 add_subdirectory(StandardToSPIRV)
-add_subdirectory(VectorToLLVM)
+add_subdirectory(VectorConversions)

mlir/lib/Conversion/VectorConversions/CMakeLists.txt

@@ -1,8 +1,9 @@
 add_llvm_library(MLIRVectorToLLVM
   VectorToLLVM.cpp
+  VectorToLoops.cpp
 
   ADDITIONAL_HEADER_DIRS
-  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Conversion/VectorToLLVM
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Conversion/VectorConversions
 )
 set(LIBS
   MLIRLLVMIR

mlir/lib/Conversion/VectorConversions/VectorToLLVM.cpp

@@ -1,4 +1,4 @@
-//===- LowerToLLVMDialect.cpp - conversion from Linalg to LLVM dialect ----===//
+//===- VectorToLLVM.cpp - Conversion from Vector to the LLVM dialect ------===//
 //
 // Copyright 2019 The MLIR Authors.
 //
@@ -15,7 +15,7 @@
 // limitations under the License.
 // =============================================================================
 
-#include "mlir/Conversion/VectorToLLVM/VectorToLLVM.h"
+#include "mlir/Conversion/VectorConversions/VectorConversions.h"
 #include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVM.h"
 #include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVMPass.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"

mlir/lib/Conversion/VectorConversions/VectorToLoops.cpp

@@ -1,4 +1,4 @@
-//===- LowerVectorTransfers.cpp - LowerVectorTransfers Pass Impl ----------===//
+//===- VectorToLoops.cpp - Conversion from Vector to mix of Loops and Std -===//
 //
 // Copyright 2019 The MLIR Authors.
 //
@@ -21,12 +21,7 @@
 
 #include <type_traits>
 
-#include "mlir/Analysis/AffineAnalysis.h"
-#include "mlir/Analysis/NestedMatcher.h"
-#include "mlir/Analysis/Utils.h"
-#include "mlir/Analysis/VectorAnalysis.h"
-#include "mlir/Dialect/LoopOps/LoopOps.h"
-#include "mlir/Dialect/StandardOps/Ops.h"
+#include "mlir/Conversion/VectorConversions/VectorConversions.h"
 #include "mlir/Dialect/VectorOps/VectorOps.h"
 #include "mlir/EDSC/Builders.h"
 #include "mlir/EDSC/Helpers.h"
@@ -39,9 +34,12 @@
 #include "mlir/IR/OperationSupport.h"
 #include "mlir/IR/PatternMatch.h"
 #include "mlir/IR/Types.h"
-#include "mlir/Pass/Pass.h"
-#include "mlir/Support/Functional.h"
-#include "mlir/Transforms/Passes.h"
+
+using namespace mlir;
+using vector::VectorTransferReadOp;
+using vector::VectorTransferWriteOp;
+
+namespace {
 
 /// Implements lowering of VectorTransferReadOp and VectorTransferWriteOp to a
 /// proper abstraction for the hardware.
@@ -58,7 +56,7 @@
 ///    loop.for %i0 = 0 to %0 {
 ///      loop.for %i1 = 0 to %1 step %c256 {
 ///        loop.for %i2 = 0 to %2 step %c32 {
-///          %v = vector.transfer_read %A[%i0, %i1, %i2], (%f0)
+///          %v = vector.transfer_read %A[%i0, %i1, %i2], %f0
 ///               {permutation_map: (d0, d1, d2) -> (d2, d1)} :
 ///               memref<?x?x?xf32>, vector<32x256xf32>
 ///    }}}
@@ -81,17 +79,16 @@
 /// which creates individual indexing expressions of the form:
 ///
 /// ```mlir-dsc
-///    SELECT(i + ii < zero, zero, SELECT(i + ii < N, i + ii, N - one))
+///    auto condMax = i + ii < N;
+///    auto max = select(condMax, i + ii, N - one)
+///    auto cond = i + ii < zero;
+///    select(cond, zero, max);
 /// ```
-
-using namespace mlir;
-using vector::VectorTransferReadOp;
-using vector::VectorTransferWriteOp;
-
-#define DEBUG_TYPE "affine-lower-vector-transfers"
-
-namespace {
-
+///
+/// In the future, clipping should not be the only way and instead we should
+/// load vectors + mask them. Similarly on the write side, load/mask/store for
+/// implementing RMW behavior.
+///
 /// Lowers VectorTransferOp into a combination of:
 ///   1. local memory allocation;
 ///   2. perfect loop nest over:
@@ -359,26 +356,12 @@ VectorTransferRewriter<VectorTransferWriteOp>::matchAndRewrite(
   rewriter.eraseOp(op);
   return matchSuccess();
 }
+} // namespace
 
-struct LowerVectorTransfersPass
-    : public FunctionPass<LowerVectorTransfersPass> {
-  void runOnFunction() override {
-    OwningRewritePatternList patterns;
-    auto *context = &getContext();
+/// Populate the given list with patterns that convert from Vector to LLVM.
+void mlir::populateVectorToAffineLoopsConversionPatterns(
+    MLIRContext *context, OwningRewritePatternList &patterns) {
   patterns.insert<VectorTransferRewriter<vector::VectorTransferReadOp>,
                   VectorTransferRewriter<vector::VectorTransferWriteOp>>(
       context);
-    applyPatternsGreedily(getFunction(), patterns);
-  }
-};
-
-} // end anonymous namespace
-
-std::unique_ptr<OpPassBase<FuncOp>> mlir::createLowerVectorTransfersPass() {
-  return std::make_unique<LowerVectorTransfersPass>();
 }
-
-static PassRegistration<LowerVectorTransfersPass>
-    pass("affine-lower-vector-transfers",
-         "Materializes vector transfer ops to a "
-         "proper abstraction for the hardware");

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

@@ -19,7 +19,7 @@
 #include "mlir/Conversion/LoopToStandard/ConvertLoopToStandard.h"
 #include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVM.h"
 #include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVMPass.h"
-#include "mlir/Conversion/VectorToLLVM/VectorToLLVM.h"
+#include "mlir/Conversion/VectorConversions/VectorConversions.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/Dialect/Linalg/IR/LinalgOps.h"
 #include "mlir/Dialect/Linalg/IR/LinalgTypes.h"

mlir/lib/Transforms/CMakeLists.txt

@@ -13,7 +13,6 @@ add_llvm_library(MLIRTransforms
   LoopTiling.cpp
   LoopUnrollAndJam.cpp
   LoopUnroll.cpp
-  LowerVectorTransfers.cpp
   MaterializeVectors.cpp
   MemRefDataFlowOpt.cpp
   PipelineDataTransfer.cpp

mlir/test/Conversion/VectorConversions/lower_vector_transfers.mlir

@@ -1,4 +1,4 @@
-// RUN: mlir-opt %s -affine-lower-vector-transfers | FileCheck %s
+// RUN: mlir-opt %s -test-affine-lower-vector-transfers | FileCheck %s
 
 // CHECK: #[[ADD:map[0-9]+]] = (d0, d1) -> (d0 + d1)
 // CHECK: #[[SUB:map[0-9]+]] = ()[s0] -> (s0 - 1)

mlir/test/lib/Transforms/CMakeLists.txt

@@ -5,6 +5,7 @@ add_llvm_library(MLIRTestTransforms
   TestInlining.cpp
   TestLoopMapping.cpp
   TestLoopParametricTiling.cpp
+  TestLowerVectorTransfers.cpp
   TestOpaqueLoc.cpp
   TestMemRefStrideCalculation.cpp
   TestVectorizationUtils.cpp

mlir/test/lib/Transforms/TestLowerVectorTransfers.cpp

@@ -0,0 +1,44 @@
+//===- TestLowerVectorTransfers.cpp - Test VectorTransfers lowering -------===//
+//
+// Copyright 2019 The MLIR Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// =============================================================================
+
+#include <type_traits>
+
+#include "mlir/Conversion/VectorConversions/VectorConversions.h"
+#include "mlir/IR/PatternMatch.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Transforms/Passes.h"
+
+using namespace mlir;
+
+namespace {
+
+struct TestLowerVectorTransfersPass
+    : public FunctionPass<TestLowerVectorTransfersPass> {
+  void runOnFunction() override {
+    OwningRewritePatternList patterns;
+    auto *context = &getContext();
+    populateVectorToAffineLoopsConversionPatterns(context, patterns);
+    applyPatternsGreedily(getFunction(), patterns);
+  }
+};
+
+} // end anonymous namespace
+
+static PassRegistration<TestLowerVectorTransfersPass>
+    pass("test-affine-lower-vector-transfers",
+         "Materializes vector transfer ops to a "
+         "proper abstraction for the hardware");