Files
clang-p2996/mlir/lib/Dialect/Linalg/Transforms/InlineScalarOperands.cpp
Jacques Pienaar 09dfc5713d [mlir] Enable decoupling two kinds of greedy behavior. (#104649)
The greedy rewriter is used in many different flows and it has a lot of
convenience (work list management, debugging actions, tracing, etc). But
it combines two kinds of greedy behavior 1) how ops are matched, 2)
folding wherever it can.

These are independent forms of greedy and leads to inefficiency. E.g.,
cases where one need to create different phases in lowering and is
required to applying patterns in specific order split across different
passes. Using the driver one ends up needlessly retrying folding/having
multiple rounds of folding attempts, where one final run would have
sufficed.

Of course folks can locally avoid this behavior by just building their
own, but this is also a common requested feature that folks keep on
working around locally in suboptimal ways.

For downstream users, there should be no behavioral change. Updating
from the deprecated should just be a find and replace (e.g., `find ./
-type f -exec sed -i
's|applyPatternsAndFoldGreedily|applyPatternsGreedily|g' {} \;` variety)
as the API arguments hasn't changed between the two.
2024-12-20 08:15:48 -08:00

120 lines
4.4 KiB
C++

//===- InlineScalarOperands.cpp - Pass to inline scalar operands =============//
//
// 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 patterns/pass to inline scalar operands into a generic
// operation. A scalar operand is an operand whose indexing map has a constant
// rhs.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/Linalg/Passes.h"
#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/Linalg/IR/Linalg.h"
#include "mlir/Dialect/Linalg/Transforms/Transforms.h"
#include "mlir/IR/AffineExpr.h"
#include "mlir/IR/AffineMap.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
namespace mlir {
#define GEN_PASS_DEF_LINALGINLINESCALAROPERANDSPASS
#include "mlir/Dialect/Linalg/Passes.h.inc"
} // namespace mlir
using namespace mlir;
using namespace mlir::linalg;
namespace {
struct InlineScalarOperands : public OpRewritePattern<GenericOp> {
using OpRewritePattern<GenericOp>::OpRewritePattern;
LogicalResult matchAndRewrite(GenericOp genericOp,
PatternRewriter &rewriter) const override {
if (!genericOp.hasPureTensorSemantics())
return failure();
SmallVector<size_t> scalarOperands;
SmallVector<AffineMap> newIndexingMaps;
SmallVector<Value> newOperands;
for (OpOperand *opOperand : genericOp.getDpsInputOperands()) {
AffineMap map = genericOp.getMatchingIndexingMap(opOperand);
if (genericOp.isDpsInput(opOperand) && map.isConstant()) {
scalarOperands.emplace_back(opOperand->getOperandNumber());
} else {
newIndexingMaps.emplace_back(map);
newOperands.emplace_back(opOperand->get());
}
}
if (scalarOperands.empty())
return failure();
for (OpOperand &opOperand : genericOp.getDpsInitsMutable())
newIndexingMaps.emplace_back(
genericOp.getMatchingIndexingMap(&opOperand));
Location loc = genericOp->getLoc();
SmallVector<Value> outputOperands = genericOp.getOutputs();
auto newOp = rewriter.create<GenericOp>(
loc, genericOp->getResultTypes(), newOperands, outputOperands,
newIndexingMaps, genericOp.getIteratorTypesArray());
rewriter.cloneRegionBefore(genericOp.getRegion(), newOp.getRegion(),
newOp.getRegion().begin());
Block *body = newOp.getBody();
PatternRewriter::InsertionGuard guard(rewriter);
rewriter.setInsertionPointToStart(body);
for (auto idx : llvm::reverse(scalarOperands)) {
OpOperand *opOperand = genericOp.getDpsInputOperand(idx);
AffineMap map = genericOp.getMatchingIndexingMap(opOperand);
SmallVector<int64_t> indices = map.getConstantResults();
SmallVector<Value> indicesValues;
for (auto idx : indices)
indicesValues.emplace_back(
rewriter.create<arith::ConstantIndexOp>(loc, idx));
Value scalarValue = opOperand->get();
if (isa<RankedTensorType>(scalarValue.getType())) {
scalarValue =
rewriter.create<tensor::ExtractOp>(loc, scalarValue, indicesValues);
}
body->getArgument(idx).replaceAllUsesWith(scalarValue);
body->eraseArgument(idx);
}
rewriter.replaceOp(genericOp, newOp->getResults());
return success();
}
};
} // namespace
/// Patterns that are used to inline constant operands into linalg generic
/// ops.
void mlir::linalg::populateInlineConstantOperandsPatterns(
RewritePatternSet &patterns) {
auto *context = patterns.getContext();
patterns.add<InlineScalarOperands>(context);
}
namespace {
/// Pass that removes unit-extent dims within generic ops.
struct LinalgInlineScalarOperandsPass
: public impl::LinalgInlineScalarOperandsPassBase<
LinalgInlineScalarOperandsPass> {
using impl::LinalgInlineScalarOperandsPassBase<
LinalgInlineScalarOperandsPass>::LinalgInlineScalarOperandsPassBase;
void runOnOperation() override {
Operation *op = getOperation();
MLIRContext &ctx = getContext();
RewritePatternSet patterns(&ctx);
populateInlineConstantOperandsPatterns(patterns);
(void)applyPatternsGreedily(op, std::move(patterns));
}
};
} // namespace