FuncOp has been moved to the `func` namespace for a little over a month, the using directive can be dropped now.
413 lines
15 KiB
C++
413 lines
15 KiB
C++
//===- Bufferize.cpp - Bufferization utilities ----------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "PassDetail.h"
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#include "mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h"
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#include "mlir/Dialect/Bufferization/IR/Bufferization.h"
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#include "mlir/Dialect/Bufferization/Transforms/Bufferize.h"
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#include "mlir/Dialect/Bufferization/Transforms/OneShotAnalysis.h"
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#include "mlir/Dialect/Bufferization/Transforms/Passes.h"
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#include "mlir/Dialect/Func/IR/FuncOps.h"
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#include "mlir/IR/Operation.h"
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#include "mlir/Pass/PassManager.h"
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#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
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#include "mlir/Transforms/Passes.h"
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using namespace mlir;
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using namespace mlir::bufferization;
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//===----------------------------------------------------------------------===//
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// BufferizeTypeConverter
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//===----------------------------------------------------------------------===//
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static Value materializeToTensor(OpBuilder &builder, TensorType type,
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ValueRange inputs, Location loc) {
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assert(inputs.size() == 1);
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assert(inputs[0].getType().isa<BaseMemRefType>());
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return builder.create<bufferization::ToTensorOp>(loc, type, inputs[0]);
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}
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/// Registers conversions into BufferizeTypeConverter
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BufferizeTypeConverter::BufferizeTypeConverter() {
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// Keep all types unchanged.
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addConversion([](Type type) { return type; });
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// Convert RankedTensorType to MemRefType.
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addConversion([](RankedTensorType type) -> Type {
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return MemRefType::get(type.getShape(), type.getElementType());
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});
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// Convert UnrankedTensorType to UnrankedMemRefType.
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addConversion([](UnrankedTensorType type) -> Type {
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return UnrankedMemRefType::get(type.getElementType(), 0);
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});
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addArgumentMaterialization(materializeToTensor);
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addSourceMaterialization(materializeToTensor);
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addTargetMaterialization([](OpBuilder &builder, BaseMemRefType type,
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ValueRange inputs, Location loc) -> Value {
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assert(inputs.size() == 1 && "expected exactly one input");
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if (auto inputType = inputs[0].getType().dyn_cast<MemRefType>()) {
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// MemRef to MemRef cast.
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assert(inputType != type && "expected different types");
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// Unranked to ranked and ranked to unranked casts must be explicit.
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auto rankedDestType = type.dyn_cast<MemRefType>();
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if (!rankedDestType)
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return nullptr;
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FailureOr<Value> replacement =
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castOrReallocMemRefValue(builder, inputs[0], rankedDestType);
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if (failed(replacement))
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return nullptr;
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return *replacement;
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}
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if (inputs[0].getType().isa<TensorType>()) {
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// Tensor to MemRef cast.
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return builder.create<bufferization::ToMemrefOp>(loc, type, inputs[0]);
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}
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llvm_unreachable("only tensor/memref input types supported");
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});
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}
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void mlir::bufferization::populateBufferizeMaterializationLegality(
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ConversionTarget &target) {
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target.addLegalOp<bufferization::ToTensorOp, bufferization::ToMemrefOp>();
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}
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namespace {
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// In a finalizing bufferize conversion, we know that all tensors have been
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// converted to memrefs, thus, this op becomes an identity.
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class BufferizeToTensorOp
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: public OpConversionPattern<bufferization::ToTensorOp> {
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public:
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using OpConversionPattern::OpConversionPattern;
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LogicalResult
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matchAndRewrite(bufferization::ToTensorOp op, OpAdaptor adaptor,
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ConversionPatternRewriter &rewriter) const override {
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rewriter.replaceOp(op, adaptor.memref());
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return success();
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}
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};
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} // namespace
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namespace {
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// In a finalizing bufferize conversion, we know that all tensors have been
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// converted to memrefs, thus, this op becomes an identity.
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class BufferizeToMemrefOp
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: public OpConversionPattern<bufferization::ToMemrefOp> {
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public:
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using OpConversionPattern::OpConversionPattern;
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LogicalResult
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matchAndRewrite(bufferization::ToMemrefOp op, OpAdaptor adaptor,
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ConversionPatternRewriter &rewriter) const override {
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rewriter.replaceOp(op, adaptor.tensor());
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return success();
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}
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};
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} // namespace
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void mlir::bufferization::populateEliminateBufferizeMaterializationsPatterns(
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BufferizeTypeConverter &typeConverter, RewritePatternSet &patterns) {
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patterns.add<BufferizeToTensorOp, BufferizeToMemrefOp>(typeConverter,
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patterns.getContext());
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}
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namespace {
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struct FinalizingBufferizePass
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: public FinalizingBufferizeBase<FinalizingBufferizePass> {
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using FinalizingBufferizeBase<
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FinalizingBufferizePass>::FinalizingBufferizeBase;
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void runOnOperation() override {
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auto func = getOperation();
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auto *context = &getContext();
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BufferizeTypeConverter typeConverter;
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RewritePatternSet patterns(context);
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ConversionTarget target(*context);
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populateEliminateBufferizeMaterializationsPatterns(typeConverter, patterns);
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// If all result types are legal, and all block arguments are legal (ensured
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// by func conversion above), then all types in the program are legal.
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//
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// We also check that the operand types are legal to avoid creating invalid
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// IR. For example, this prevents
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// populateEliminateBufferizeMaterializationsPatterns from updating the
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// types of the operands to a return op without updating the enclosing
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// function.
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target.markUnknownOpDynamicallyLegal(
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[&](Operation *op) { return typeConverter.isLegal(op); });
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if (failed(applyFullConversion(func, target, std::move(patterns))))
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signalPassFailure();
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}
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};
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struct OneShotBufferizePass
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: public OneShotBufferizeBase<OneShotBufferizePass> {
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OneShotBufferizePass() : OneShotBufferizeBase<OneShotBufferizePass>() {}
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explicit OneShotBufferizePass(const OneShotBufferizationOptions &options)
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: options(options) {}
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void getDependentDialects(DialectRegistry ®istry) const override {
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registry
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.insert<bufferization::BufferizationDialect, memref::MemRefDialect>();
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registerAllocationOpInterfaceExternalModels(registry);
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}
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void runOnOperation() override {
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OneShotBufferizationOptions opt;
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if (!options) {
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// Make new bufferization options if none were provided when creating the
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// pass.
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opt.allowReturnAllocs = allowReturnAllocs;
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opt.allowUnknownOps = allowUnknownOps;
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opt.analysisFuzzerSeed = analysisFuzzerSeed;
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opt.createDeallocs = createDeallocs;
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opt.fullyDynamicLayoutMaps = fullyDynamicLayoutMaps;
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opt.printConflicts = printConflicts;
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opt.testAnalysisOnly = testAnalysisOnly;
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BufferizationOptions::OpFilterEntry::FilterFn filterFn =
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[&](Operation *op) {
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// Disallow non-func dialect ops. I.e., no ops related to function
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// calls.
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if (isa<func::FuncDialect>(op->getDialect()))
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return false;
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// Filter may be specified via options.
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if (this->dialectFilter.hasValue())
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return llvm::find(this->dialectFilter,
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op->getDialect()->getNamespace()) !=
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this->dialectFilter.end();
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// No filter specified: All other ops are allowed.
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return true;
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};
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opt.allowOperationInFilter(filterFn);
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} else {
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opt = *options;
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}
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ModuleOp moduleOp = getOperation();
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if (failed(runOneShotBufferize(moduleOp, opt))) {
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signalPassFailure();
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return;
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}
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if (opt.testAnalysisOnly)
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return;
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OpPassManager cleanupPipeline("builtin.module");
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cleanupPipeline.addPass(createCanonicalizerPass());
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cleanupPipeline.addPass(createCSEPass());
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cleanupPipeline.addPass(createLoopInvariantCodeMotionPass());
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(void)runPipeline(cleanupPipeline, moduleOp);
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}
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private:
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llvm::Optional<OneShotBufferizationOptions> options;
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};
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} // namespace
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std::unique_ptr<Pass> mlir::bufferization::createOneShotBufferizePass() {
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return std::make_unique<OneShotBufferizePass>();
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}
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std::unique_ptr<Pass> mlir::bufferization::createOneShotBufferizePass(
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const OneShotBufferizationOptions &options) {
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return std::make_unique<OneShotBufferizePass>(options);
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}
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std::unique_ptr<OperationPass<func::FuncOp>>
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mlir::bufferization::createFinalizingBufferizePass() {
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return std::make_unique<FinalizingBufferizePass>();
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}
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//===----------------------------------------------------------------------===//
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// BufferizableOpInterface-based Bufferization
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//===----------------------------------------------------------------------===//
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static bool isaTensor(Type t) { return t.isa<TensorType>(); }
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/// Return true if the given op has a tensor result or a tensor operand.
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static bool hasTensorSemantics(Operation *op) {
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bool hasTensorResult = any_of(op->getResultTypes(), isaTensor);
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bool hasTensorOperand = any_of(op->getOperandTypes(), isaTensor);
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return hasTensorResult || hasTensorOperand;
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}
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/// Rewrite pattern that bufferizes bufferizable ops.
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struct BufferizationPattern
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: public OpInterfaceRewritePattern<BufferizableOpInterface> {
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BufferizationPattern(MLIRContext *context, BufferizationState &state,
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PatternBenefit benefit = 1)
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: OpInterfaceRewritePattern<BufferizableOpInterface>(context, benefit),
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state(&state) {}
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LogicalResult matchAndRewrite(BufferizableOpInterface bufferizableOp,
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PatternRewriter &rewriter) const override {
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const BufferizationOptions &options = state->getOptions();
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// No tensors => no buffers.
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if (!hasTensorSemantics(bufferizableOp.getOperation()))
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return failure();
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if (!options.isOpAllowed(bufferizableOp.getOperation()))
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return failure();
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return bufferizableOp.bufferize(rewriter, *state);
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}
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private:
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BufferizationState *const state;
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};
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/// Check the result of bufferization. Return an error if an op was not
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/// bufferized, unless partial bufferization is allowed.
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static LogicalResult
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checkBufferizationResult(Operation *op, const BufferizationOptions &options) {
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if (!options.allowUnknownOps) {
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// Check if all ops were bufferized.
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LogicalResult status = success();
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op->walk([&](Operation *op) {
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if (!hasTensorSemantics(op))
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return WalkResult::advance();
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// Bufferization dialect ops will canonicalize away if all other ops are
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// bufferized.
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if (isa<bufferization::ToMemrefOp, bufferization::ToTensorOp>(op))
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return WalkResult::advance();
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// Ops that are not in the allow list can be ignored.
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if (!options.isOpAllowed(op))
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return WalkResult::advance();
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// Ops without any uses and no side effects will fold away.
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if (op->getUses().empty() && MemoryEffectOpInterface::hasNoEffect(op))
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return WalkResult::advance();
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status = op->emitError("op was not bufferized");
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return WalkResult::interrupt();
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});
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if (failed(status))
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return status;
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}
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return success();
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}
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LogicalResult
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bufferization::finalizeBuffers(Operation *op,
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const BufferizationOptions &options) {
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// Hoist buffers.
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if (failed(hoistBufferAllocations(op, options)))
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return failure();
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// Deallocate buffers that escape block boundaries ("leaking buffers") with
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// the buffer deallocation pass.
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bool hasLeakingAlloc = false;
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if (failed(createAllocDeallocOps(op, options, /*onlyLeakingAllocs=*/true,
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&hasLeakingAlloc)))
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return failure();
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if (options.createDeallocs && hasLeakingAlloc &&
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failed(deallocateBuffers(op)))
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return failure();
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// Deallocate all remaining buffers at the end of the block.
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if (failed(createAllocDeallocOps(op, options)))
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return failure();
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return success();
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}
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LogicalResult bufferization::bufferizeOp(Operation *op,
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const AnalysisState &analysisState) {
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BufferizationState bufferizationState(analysisState);
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if (failed(bufferizeOp(op, bufferizationState)))
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return failure();
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if (failed(finalizeBuffers(op, analysisState.getOptions())))
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return failure();
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return success();
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}
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LogicalResult
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bufferization::bufferizeOp(Operation *op,
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BufferizationState &bufferizationState) {
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// Bufferize the op and its nested ops.
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RewritePatternSet patterns(op->getContext());
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patterns.add<BufferizationPattern>(patterns.getContext(), bufferizationState);
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// Bufferize ops top-to-bottom. When creating a new op, we should ideally
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// know the exact memref type of all operands. Otherwise, we have to use a
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// memref type with a fully dynamic layout map, which has to canonicalize
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// away. This is less efficient.
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//
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// Note: If "fullyDynamicLayoutMaps = false", we may have to insert buffer
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// copies to fold ("finalize") to_memref(to_tensor(x)) ops with non-cast-
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// compatible layout maps when doing a traversal other than top-to-bottom.
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// There are currently no canonicalization patterns to fold these away.
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GreedyRewriteConfig config;
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config.useTopDownTraversal = true;
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// TODO: Perform a preorder walk instead of the greedy pattern rewriter. This
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// would be more efficient because every bufferization pattern is guaranteed
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// to apply only a single time (otherwise, an assertion would be triggered).
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// However, there are restrictions wrt. erasing ops during a preorder walk,
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// which would likely require a larger refactoring.
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if (failed(applyPatternsAndFoldGreedily(op, std::move(patterns), config)))
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return failure();
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if (failed(checkBufferizationResult(op, bufferizationState.getOptions())))
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return failure();
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return success();
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}
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namespace {
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/// This a "no analysis, always copy" AnalysisState. In the absence of an
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/// analysis, a buffer must be copied each time it is written to. Therefore, all
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/// OpOperands that bufferize to a memory write must bufferize out-of-place.
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class AlwaysCopyAnalysisState : public AnalysisState {
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public:
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AlwaysCopyAnalysisState(const BufferizationOptions &options)
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: AnalysisState(options) {}
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AlwaysCopyAnalysisState(const AlwaysCopyAnalysisState &) = delete;
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virtual ~AlwaysCopyAnalysisState() = default;
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/// Return `true` if the given OpResult has been decided to bufferize inplace.
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bool isInPlace(OpOperand &opOperand) const override {
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// OpOperands that bufferize to a memory write are out-of-place, i.e., an
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// alloc and copy is inserted.
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return !bufferizesToMemoryWrite(opOperand);
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}
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/// Return true if `v1` and `v2` bufferize to equivalent buffers.
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bool areEquivalentBufferizedValues(Value v1, Value v2) const override {
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// There is no analysis, so we do not know if the values are equivalent. The
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// conservative answer is "false".
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return false;
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}
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};
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} // namespace
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LogicalResult bufferization::bufferizeOp(Operation *op,
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const BufferizationOptions &options) {
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AlwaysCopyAnalysisState state(options);
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return bufferizeOp(op, state);
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}
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BufferizationOptions bufferization::getPartialBufferizationOptions() {
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BufferizationOptions options;
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options.allowUnknownOps = true;
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options.createDeallocs = false;
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options.fullyDynamicLayoutMaps = false;
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return options;
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}
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