llvm-project/mlir/lib/Dialect/Linalg/Transforms/CodegenStrategy.cpp

111 lines
4.8 KiB
C++

//===- CodegenStrategy.cpp - Linalg programmable codegen strategy ---------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements logic and helpers to expose Linalg transforms as
// composable rewrite patterns through a programmable CodegenStrategy object.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/Linalg/Transforms/CodegenStrategy.h"
#include "mlir/Dialect/Linalg/Transforms/Hoisting.h"
#include "mlir/Dialect/Vector/VectorOps.h"
#include "mlir/Dialect/Vector/VectorTransforms.h"
#include "mlir/Pass/PassManager.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
#include "mlir/Transforms/LoopUtils.h"
#include "mlir/Transforms/Passes.h"
using namespace mlir;
using namespace mlir::linalg;
#define DEBUG_TYPE "linalg-codegen-strategy"
void mlir::linalg::CodegenStrategy::transform(FuncOp func) const {
MLIRContext *context = func.getContext();
// Emplace patterns one at a time while also maintaining a simple chained
// state transition.
unsigned stepCount = 0;
SmallVector<FrozenRewritePatternSet, 4> stage1Patterns;
auto zeroState = Identifier::get(std::to_string(stepCount), context);
auto currentState = zeroState;
for (const std::unique_ptr<Transformation> &t : transformationSequence) {
auto nextState = Identifier::get(std::to_string(++stepCount), context);
auto marker = (currentState == zeroState)
? linalg::LinalgTransformationFilter(
t->filter, ArrayRef<Identifier>{}, nextState)
: linalg::LinalgTransformationFilter(
t->filter, currentState, nextState);
stage1Patterns.emplace_back(t->buildRewritePatterns(context, marker));
currentState = nextState;
}
RewritePatternSet stage2Patterns =
linalg::getLinalgTilingCanonicalizationPatterns(context);
stage2Patterns.add<AffineMinSCFCanonicalizationPattern>(context);
auto stage3Transforms = [&](Operation *op) {
// Some of these may be too aggressive as a stage 3 that is applied on each
// stage 1 application and may have to be split out to post staged patterns
// application (in which case they could just be passes, TBD).
if (lateCodegenStrategyOptions.enableLICM) {
op->walk([&](LoopLikeOpInterface loopLike) {
LLVM_DEBUG(loopLike.print(llvm::dbgs() << "\nOriginal loop:\n"));
if (failed(moveLoopInvariantCode(loopLike)))
llvm_unreachable("unexpected LICM failure");
});
}
promoteSingleIterationLoops(cast<FuncOp>(op));
if (lateCodegenStrategyOptions.enableHoistRedundantVectorTransfers)
hoistRedundantVectorTransfers(cast<FuncOp>(op));
if (lateCodegenStrategyOptions.enableHoistRedundantVectorTransfersOnTensor)
hoistRedundantVectorTransfersOnTensor(cast<FuncOp>(op));
return success();
};
(void)linalg::applyStagedPatterns(
func, stage1Patterns, std::move(stage2Patterns), stage3Transforms);
//===--------------------------------------------------------------------===//
// Post staged patterns transforms
//===--------------------------------------------------------------------===//
// Programmatic splitting of slow/fast path vector transfers.
if (lateCodegenStrategyOptions.enableVectorTransferPartialRewrite) {
RewritePatternSet patterns(context);
patterns.add<vector::VectorTransferFullPartialRewriter>(
context, vectorTransformsOptions);
(void)applyPatternsAndFoldGreedily(func, std::move(patterns));
}
// Programmatic controlled lowering of vector.contract only.
if (lateCodegenStrategyOptions.enableVectorContractLowering) {
RewritePatternSet vectorContractLoweringPatterns(context);
vectorContractLoweringPatterns
.add<ContractionOpToOuterProductOpLowering,
ContractionOpToMatmulOpLowering, ContractionOpLowering>(
vectorTransformsOptions, context);
vector::populateVectorTransferPermutationMapLoweringPatterns(
vectorContractLoweringPatterns);
(void)applyPatternsAndFoldGreedily(
func, std::move(vectorContractLoweringPatterns));
}
// Programmatic controlled lowering of vector.transfer only.
if (lateCodegenStrategyOptions.enableVectorToSCFConversion) {
RewritePatternSet vectorToLoopsPatterns(context);
populateVectorToSCFConversionPatterns(vectorToLoopsPatterns,
vectorToSCFOptions);
(void)applyPatternsAndFoldGreedily(func, std::move(vectorToLoopsPatterns));
}
// Ensure we drop the marker in the end.
func.walk([](LinalgOp op) {
op->removeAttr(LinalgTransforms::kLinalgTransformMarker);
});
}