llvm-project/mlir/lib/Dialect/SCF/TransformOps/SCFTransformOps.cpp

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10 KiB
C++

//===- SCFTransformOps.cpp - Implementation of SCF transformation ops -----===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/SCF/TransformOps/SCFTransformOps.h"
#include "mlir/Dialect/Affine/IR/AffineOps.h"
#include "mlir/Dialect/Affine/LoopUtils.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/SCF/IR/SCF.h"
#include "mlir/Dialect/SCF/Transforms/Patterns.h"
#include "mlir/Dialect/SCF/Transforms/Transforms.h"
#include "mlir/Dialect/SCF/Utils/Utils.h"
#include "mlir/Dialect/Transform/IR/TransformDialect.h"
#include "mlir/Dialect/Transform/IR/TransformInterfaces.h"
#include "mlir/Dialect/Transform/IR/TransformUtils.h"
#include "mlir/Dialect/Vector/IR/VectorOps.h"
using namespace mlir;
//===----------------------------------------------------------------------===//
// GetParentForOp
//===----------------------------------------------------------------------===//
DiagnosedSilenceableFailure
transform::GetParentForOp::apply(transform::TransformResults &results,
transform::TransformState &state) {
SetVector<Operation *> parents;
for (Operation *target : state.getPayloadOps(getTarget())) {
Operation *loop, *current = target;
for (unsigned i = 0, e = getNumLoops(); i < e; ++i) {
loop = getAffine()
? current->getParentOfType<AffineForOp>().getOperation()
: current->getParentOfType<scf::ForOp>().getOperation();
if (!loop) {
DiagnosedSilenceableFailure diag =
emitSilenceableError()
<< "could not find an '"
<< (getAffine() ? AffineForOp::getOperationName()
: scf::ForOp::getOperationName())
<< "' parent";
diag.attachNote(target->getLoc()) << "target op";
results.set(getResult().cast<OpResult>(), {});
return diag;
}
current = loop;
}
parents.insert(loop);
}
results.set(getResult().cast<OpResult>(), parents.getArrayRef());
return DiagnosedSilenceableFailure::success();
}
//===----------------------------------------------------------------------===//
// LoopOutlineOp
//===----------------------------------------------------------------------===//
/// Wraps the given operation `op` into an `scf.execute_region` operation. Uses
/// the provided rewriter for all operations to remain compatible with the
/// rewriting infra, as opposed to just splicing the op in place.
static scf::ExecuteRegionOp wrapInExecuteRegion(RewriterBase &b,
Operation *op) {
if (op->getNumRegions() != 1)
return nullptr;
OpBuilder::InsertionGuard g(b);
b.setInsertionPoint(op);
scf::ExecuteRegionOp executeRegionOp =
b.create<scf::ExecuteRegionOp>(op->getLoc(), op->getResultTypes());
{
OpBuilder::InsertionGuard g(b);
b.setInsertionPointToStart(&executeRegionOp.getRegion().emplaceBlock());
Operation *clonedOp = b.cloneWithoutRegions(*op);
Region &clonedRegion = clonedOp->getRegions().front();
assert(clonedRegion.empty() && "expected empty region");
b.inlineRegionBefore(op->getRegions().front(), clonedRegion,
clonedRegion.end());
b.create<scf::YieldOp>(op->getLoc(), clonedOp->getResults());
}
b.replaceOp(op, executeRegionOp.getResults());
return executeRegionOp;
}
DiagnosedSilenceableFailure
transform::LoopOutlineOp::apply(transform::TransformResults &results,
transform::TransformState &state) {
SmallVector<Operation *> transformed;
DenseMap<Operation *, SymbolTable> symbolTables;
for (Operation *target : state.getPayloadOps(getTarget())) {
Location location = target->getLoc();
Operation *symbolTableOp = SymbolTable::getNearestSymbolTable(target);
TrivialPatternRewriter rewriter(getContext());
scf::ExecuteRegionOp exec = wrapInExecuteRegion(rewriter, target);
if (!exec) {
DiagnosedSilenceableFailure diag = emitSilenceableError()
<< "failed to outline";
diag.attachNote(target->getLoc()) << "target op";
results.set(getTransformed().cast<OpResult>(), {});
return diag;
}
func::CallOp call;
FailureOr<func::FuncOp> outlined = outlineSingleBlockRegion(
rewriter, location, exec.getRegion(), getFuncName(), &call);
if (failed(outlined)) {
(void)reportUnknownTransformError(target);
return DiagnosedSilenceableFailure::definiteFailure();
}
if (symbolTableOp) {
SymbolTable &symbolTable =
symbolTables.try_emplace(symbolTableOp, symbolTableOp)
.first->getSecond();
symbolTable.insert(*outlined);
call.setCalleeAttr(FlatSymbolRefAttr::get(*outlined));
}
transformed.push_back(*outlined);
}
results.set(getTransformed().cast<OpResult>(), transformed);
return DiagnosedSilenceableFailure::success();
}
//===----------------------------------------------------------------------===//
// LoopPeelOp
//===----------------------------------------------------------------------===//
DiagnosedSilenceableFailure
transform::LoopPeelOp::applyToOne(scf::ForOp target,
SmallVector<Operation *> &results,
transform::TransformState &state) {
scf::ForOp result;
IRRewriter rewriter(target->getContext());
// This helper returns failure when peeling does not occur (i.e. when the IR
// is not modified). This is not a failure for the op as the postcondition:
// "the loop trip count is divisible by the step"
// is valid.
LogicalResult status =
scf::peelAndCanonicalizeForLoop(rewriter, target, result);
// TODO: Return both the peeled loop and the remainder loop.
results.push_back(failed(status) ? target : result);
return DiagnosedSilenceableFailure(success());
}
//===----------------------------------------------------------------------===//
// LoopPipelineOp
//===----------------------------------------------------------------------===//
/// Callback for PipeliningOption. Populates `schedule` with the mapping from an
/// operation to its logical time position given the iteration interval and the
/// read latency. The latter is only relevant for vector transfers.
static void
loopScheduling(scf::ForOp forOp,
std::vector<std::pair<Operation *, unsigned>> &schedule,
unsigned iterationInterval, unsigned readLatency) {
auto getLatency = [&](Operation *op) -> unsigned {
if (isa<vector::TransferReadOp>(op))
return readLatency;
return 1;
};
DenseMap<Operation *, unsigned> opCycles;
std::map<unsigned, std::vector<Operation *>> wrappedSchedule;
for (Operation &op : forOp.getBody()->getOperations()) {
if (isa<scf::YieldOp>(op))
continue;
unsigned earlyCycle = 0;
for (Value operand : op.getOperands()) {
Operation *def = operand.getDefiningOp();
if (!def)
continue;
earlyCycle = std::max(earlyCycle, opCycles[def] + getLatency(def));
}
opCycles[&op] = earlyCycle;
wrappedSchedule[earlyCycle % iterationInterval].push_back(&op);
}
for (const auto &it : wrappedSchedule) {
for (Operation *op : it.second) {
unsigned cycle = opCycles[op];
schedule.emplace_back(op, cycle / iterationInterval);
}
}
}
DiagnosedSilenceableFailure
transform::LoopPipelineOp::applyToOne(scf::ForOp target,
SmallVector<Operation *> &results,
transform::TransformState &state) {
scf::PipeliningOption options;
options.getScheduleFn =
[this](scf::ForOp forOp,
std::vector<std::pair<Operation *, unsigned>> &schedule) mutable {
loopScheduling(forOp, schedule, getIterationInterval(),
getReadLatency());
};
scf::ForLoopPipeliningPattern pattern(options, target->getContext());
TrivialPatternRewriter rewriter(getContext());
rewriter.setInsertionPoint(target);
FailureOr<scf::ForOp> patternResult =
pattern.returningMatchAndRewrite(target, rewriter);
if (succeeded(patternResult)) {
results.push_back(*patternResult);
return DiagnosedSilenceableFailure(success());
}
results.assign(1, nullptr);
return emitDefaultSilenceableFailure(target);
}
//===----------------------------------------------------------------------===//
// LoopUnrollOp
//===----------------------------------------------------------------------===//
DiagnosedSilenceableFailure
transform::LoopUnrollOp::applyToOne(Operation *op,
SmallVector<Operation *> &results,
transform::TransformState &state) {
LogicalResult result(failure());
if (scf::ForOp scfFor = dyn_cast<scf::ForOp>(op))
result = loopUnrollByFactor(scfFor, getFactor());
else if (AffineForOp affineFor = dyn_cast<AffineForOp>(op))
result = loopUnrollByFactor(affineFor, getFactor());
if (failed(result)) {
Diagnostic diag(op->getLoc(), DiagnosticSeverity::Note);
diag << "Op failed to unroll";
return DiagnosedSilenceableFailure::silenceableFailure(std::move(diag));
}
return DiagnosedSilenceableFailure(success());
}
//===----------------------------------------------------------------------===//
// Transform op registration
//===----------------------------------------------------------------------===//
namespace {
class SCFTransformDialectExtension
: public transform::TransformDialectExtension<
SCFTransformDialectExtension> {
public:
using Base::Base;
void init() {
declareGeneratedDialect<AffineDialect>();
declareGeneratedDialect<func::FuncDialect>();
registerTransformOps<
#define GET_OP_LIST
#include "mlir/Dialect/SCF/TransformOps/SCFTransformOps.cpp.inc"
>();
}
};
} // namespace
#define GET_OP_CLASSES
#include "mlir/Dialect/SCF/TransformOps/SCFTransformOps.cpp.inc"
void mlir::scf::registerTransformDialectExtension(DialectRegistry &registry) {
registry.addExtensions<SCFTransformDialectExtension>();
}