River Riddle ffde975e21 NFC: Move AffineOps dialect to the Dialect sub-directory.
PiperOrigin-RevId: 264482571
2019-08-20 15:36:39 -07:00

400 lines
16 KiB
C++

//===- LowerToLoops.cpp - conversion from Linalg library ops to loops------===//
//
// 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 "mlir/Dialect/AffineOps/AffineOps.h"
#include "mlir/Dialect/Linalg/IR/LinalgOps.h"
#include "mlir/Dialect/Linalg/IR/LinalgTypes.h"
#include "mlir/Dialect/Linalg/Passes.h"
#include "mlir/Dialect/Linalg/Utils/Intrinsics.h"
#include "mlir/Dialect/Linalg/Utils/Utils.h"
#include "mlir/Dialect/LoopOps/LoopOps.h"
#include "mlir/Dialect/StandardOps/Ops.h"
#include "mlir/EDSC/Helpers.h"
#include "mlir/IR/AffineExpr.h"
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/BlockAndValueMapping.h"
#include "mlir/IR/OpImplementation.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Support/LLVM.h"
#include "mlir/Support/STLExtras.h"
#include "mlir/Transforms/DialectConversion.h"
#include "mlir/Transforms/FoldUtils.h"
using namespace mlir;
using namespace mlir::edsc;
using namespace mlir::edsc::intrinsics;
using namespace mlir::linalg;
using namespace mlir::linalg::intrinsics;
using IndexedLinalgValue = TemplatedIndexedValue<linalg_load, linalg_store>;
using edsc::op::operator+;
using edsc::op::operator==;
static SmallVector<ValueHandle, 8>
foldedAffineApplies(OpBuilder &b, Location loc, AffineMap map,
ArrayRef<Value *> vals, OperationFolder &folder) {
assert(map.getNumSymbols() == 0);
assert(map.getNumInputs() == vals.size());
SmallVector<ValueHandle, 8> res;
res.reserve(map.getNumResults());
auto dims = map.getNumDims();
for (auto e : map.getResults()) {
auto exprMap = AffineMap::get(dims, 0, e);
SmallVector<Value *, 4> operands(vals.begin(), vals.end());
canonicalizeMapAndOperands(&exprMap, &operands);
res.push_back(affine_apply(folder, exprMap, operands));
}
return res;
}
static SmallVector<Value *, 4> permuteIvs(ArrayRef<Value *> ivs,
Optional<AffineMap> permutation,
OperationFolder &state) {
return permutation ? applyMapToValues(ScopedContext::getBuilder(),
ScopedContext::getLocation(),
permutation.getValue(), ivs, state)
: SmallVector<Value *, 4>(ivs.begin(), ivs.end());
}
// Creates a number of ranges equal to the number of results in `map`.
// The returned ranges correspond to the loop ranges, in the proper order, for
// which new loops will be created.
static SmallVector<Value *, 4> emitLoopRanges(OpBuilder &b, Location loc,
AffineMap map,
ArrayRef<Value *> allViewSizes,
OperationFolder &folder) {
// Apply `map` to get view sizes in loop order.
auto sizes = applyMapToValues(b, loc, map, allViewSizes, folder);
// Create a new range with the applied tile sizes.
ScopedContext scope(b, loc);
SmallVector<Value *, 4> res;
for (unsigned idx = 0, e = map.getNumResults(); idx < e; ++idx) {
res.push_back(range(constant_index(folder, 0), sizes[idx],
constant_index(folder, 1)));
}
return res;
}
template <typename LinalgOpType> class LinalgScopedEmitter {};
template <> class LinalgScopedEmitter<CopyOp> {
public:
static void emitScalarImplementation(ArrayRef<Value *> allIvs, CopyOp copyOp,
OperationFolder &folder) {
auto nPar = copyOp.getNumParallelLoops();
assert(nPar == allIvs.size());
auto inputIvs =
permuteIvs(allIvs.take_front(nPar), copyOp.inputPermutation(), folder);
auto outputIvs =
permuteIvs(allIvs.take_front(nPar), copyOp.outputPermutation(), folder);
SmallVector<IndexHandle, 8> iivs(inputIvs.begin(), inputIvs.end());
SmallVector<IndexHandle, 8> oivs(outputIvs.begin(), outputIvs.end());
IndexedLinalgValue O(copyOp.getOutput(0)), I(copyOp.getInput(0));
// Emit the proper scalar assignment, whether we are dealing with a 0-D or
// an n-D loop nest; with or without permutations.
// clang-format off
nPar > 0 ? O(oivs) = I(iivs) :
O() = I();
// clang-format on
}
};
template <> class LinalgScopedEmitter<FillOp> {
public:
static void emitScalarImplementation(ArrayRef<Value *> allIvs, FillOp fillOp,
OperationFolder &folder) {
auto nPar = fillOp.getNumParallelLoops();
assert(nPar == allIvs.size());
auto ivs =
SmallVector<IndexHandle, 4>(allIvs.begin(), allIvs.begin() + nPar);
IndexedLinalgValue O(fillOp.getOutput(0));
// Emit the proper scalar assignment, whether we are dealing with a 0-D or
// an n-D loop nest; with or without permutations.
nPar > 0 ? O(ivs) = ValueHandle(fillOp.getValue())
: O() = ValueHandle(fillOp.getValue());
}
};
template <> class LinalgScopedEmitter<DotOp> {
public:
static void emitScalarImplementation(ArrayRef<Value *> allIvs, DotOp dotOp,
OperationFolder &folder) {
assert(allIvs.size() == 1);
IndexHandle r_i(allIvs[0]);
IndexedLinalgValue A(dotOp.getInput(0)), B(dotOp.getInput(1)),
C(dotOp.getOutput(0));
// Emit scalar form.
C() = C() + A(r_i) * B(r_i);
}
};
template <> class LinalgScopedEmitter<MatvecOp> {
public:
static void emitScalarImplementation(ArrayRef<Value *> allIvs,
MatvecOp matvecOp,
OperationFolder &folder) {
assert(allIvs.size() == 2);
IndexHandle i(allIvs[0]), r_j(allIvs[1]);
IndexedLinalgValue A(matvecOp.getInput(0)), B(matvecOp.getInput(1)),
C(matvecOp.getOutput(0));
// Emit scalar form.
C(i) = C(i) + A(i, r_j) * B(r_j);
}
};
template <> class LinalgScopedEmitter<MatmulOp> {
public:
static void emitScalarImplementation(ArrayRef<Value *> allIvs,
MatmulOp matmulOp,
OperationFolder &folder) {
assert(allIvs.size() == 3);
IndexHandle i(allIvs[0]), j(allIvs[1]), r_k(allIvs[2]);
IndexedLinalgValue A(matmulOp.getInput(0)), B(matmulOp.getInput(1)),
C(matmulOp.getOutput(0));
// Emit scalar form.
C(i, j) = C(i, j) + A(i, r_k) * B(r_k, j);
}
};
template <> class LinalgScopedEmitter<ConvOp> {
public:
static void emitScalarImplementation(ArrayRef<Value *> allIvs, ConvOp convOp,
OperationFolder &folder) {
auto b = ScopedContext::getBuilder();
auto loc = ScopedContext::getLocation();
auto maps = loopToOperandRangesMaps(convOp);
SmallVector<ValueHandle, 8> fIdx(
foldedAffineApplies(b, loc, maps[0], allIvs, folder));
SmallVector<ValueHandle, 8> imIdx(
foldedAffineApplies(b, loc, maps[1], allIvs, folder));
SmallVector<ValueHandle, 8> oIdx(
foldedAffineApplies(b, loc, maps[2], allIvs, folder));
IndexedLinalgValue F(convOp.filter()), I(convOp.input()),
O(convOp.output());
// Emit scalar form.
O(oIdx) += F(fIdx) * I(imIdx);
}
};
// Emits the MLIR for the scalar part of the generic op by:
// 1. Emitting linalg_load and linalg_store ops for each input and output
// view in order. This is achieved by applying the appropriate input or
// output map to the enclosing induction variables.
// 2. Emitting a call to `op.fun()` that takes as arguments the scalars
// from point 1. above.
// 3. Emitting linalg_store to store the results of 2. to the output
// views.
//
// An example output may resemble:
//
// ```
// loop.for %i = %c0 to %0 step %c1 {
// loop.for %j = %c0 to %1 step %c1 {
// loop.for %k = %c0 to %4 step %c1 {
// %11 = linalg.load %arg0[%i, %j] : !linalg.view<?x?xf32>
// %12 = linalg.load %arg1[%i, %j, %k] : !linalg.view<?x?x?xf32>
// %13 = linalg.load %arg2[%i, %k, %j] : !linalg.view<?x?x?xf32>
// %14:2 = call @foo(%11, %12, %13) : (f32, f32, f32) -> (f32, f32)
// linalg.store %14#0, %arg1[%i, %j, %k] : !linalg.view<?x?x?xf32>
// linalg.store %14#1, %arg2[%i, %k, %j] : !linalg.view<?x?x?xf32>
// }
// }
// }
// ```
template <> class LinalgScopedEmitter<GenericOp> {
public:
static void emitScalarImplementation(ArrayRef<Value *> allIvs,
GenericOp genericOp,
OperationFolder &folder) {
auto b = ScopedContext::getBuilder();
auto loc = ScopedContext::getLocation();
using edsc::intrinsics::detail::ValueHandleArray;
unsigned nInputs = genericOp.getNumInputs();
unsigned nOutputs = genericOp.getNumOutputs();
SmallVector<Value *, 4> indexedValues(nInputs + nOutputs);
// 1.a. Emit linalg_load from input views.
for (unsigned i = 0, e = nInputs; i < e; ++i) {
ValueHandleArray indexing(foldedAffineApplies(
b, loc, genericOp.getInputIndexingMap(i), allIvs, folder));
indexedValues[i] = linalg_load(genericOp.getInput(i), indexing);
}
// 1.b. Emit linalg_load from output views.
for (unsigned i = 0, e = nOutputs; i < e; ++i) {
ValueHandleArray indexing(foldedAffineApplies(
b, loc, genericOp.getOutputIndexingMap(i), allIvs, folder));
indexedValues[nInputs + i] =
linalg_load(genericOp.getOutput(i), indexing);
}
auto funcOp = genericOp.getFunction();
if (funcOp) {
// 2. Emit call.
Operation *callOp = call(funcOp, indexedValues);
assert(callOp->getNumResults() == genericOp.getNumOutputs());
// 3. Emit linalg_store.
for (unsigned i = 0, e = nOutputs; i < e; ++i) {
ValueHandleArray indexing(foldedAffineApplies(
b, loc, genericOp.getOutputIndexingMap(i), allIvs, folder));
linalg_store(callOp->getResult(i), genericOp.getOutput(i), indexing);
}
} else {
// TODO(ntv): When a region inliner exists, use it.
// 2. Inline region, currently only works for a single basic block.
BlockAndValueMapping map;
auto &block = genericOp.region().front();
for (auto it : llvm::zip(block.getArguments(), indexedValues))
map.map(std::get<0>(it), std::get<1>(it));
for (auto &op : block) {
// Skip terminator.
if (&op == &block.back())
continue;
assert(op.getNumRegions() == 0);
auto *newOp = b.clone(op, map);
for (auto it : llvm::zip(op.getResults(), newOp->getResults()))
map.map(std::get<0>(it), std::get<1>(it));
}
// 3. Emit linalg_store.
auto *yieldOp = cast<YieldOp>(block.back()).getOperation();
assert(yieldOp->getNumOperands() == nOutputs);
for (unsigned i = 0, e = nOutputs; i < e; ++i) {
ValueHandleArray indexing(foldedAffineApplies(
b, loc, genericOp.getOutputIndexingMap(i), allIvs, folder));
linalg_store(map.lookup(yieldOp->getOperand(i)), genericOp.getOutput(i),
indexing);
}
}
}
};
template <typename ConcreteOp>
class LinalgRewritePattern : public RewritePattern {
public:
explicit LinalgRewritePattern(MLIRContext *context)
: RewritePattern(ConcreteOp::getOperationName(), /*benefit=*/1, context) {
}
PatternMatchResult matchAndRewrite(Operation *op,
PatternRewriter &rewriter) const override {
OpBuilder b(op);
ScopedContext scope(b, op->getLoc());
// The flattened loopToOperandRangesMaps is expected to be an invertible
// permutation map (which is asserted in the inverse calculation).
auto linalgOp = cast<ConcreteOp>(op);
auto invertedMap =
inversePermutation(concatAffineMaps(loopToOperandRangesMaps(linalgOp)));
if (!invertedMap) {
LinalgScopedEmitter<ConcreteOp>::emitScalarImplementation({}, linalgOp,
folder);
rewriter.replaceOp(op, {});
return matchSuccess();
}
auto nPar = linalgOp.getNumParallelLoops();
auto nRed = linalgOp.getNumReductionLoops();
auto nWin = linalgOp.getNumWindowLoops();
SmallVector<IndexHandle, 4> allIvs(nPar + nRed + nWin);
SmallVector<ValueHandle *, 4> allPIvs = makeIndexHandlePointers(allIvs);
auto pivs = MutableArrayRef<ValueHandle *>(allPIvs).take_front(nPar);
auto rivs = MutableArrayRef<ValueHandle *>(allPIvs)
.take_front(nPar + nRed)
.take_back(nRed);
auto wivs = MutableArrayRef<ValueHandle *>(allPIvs).take_back(nWin);
auto loopRanges =
emitLoopRanges(scope.getBuilder(), scope.getLocation(), invertedMap,
getViewSizes(linalgOp), folder);
assert(loopRanges.size() == pivs.size() + rivs.size() + wivs.size());
// clang-format off
ArrayRef<Value *> ranges(loopRanges);
LoopNestRangeBuilder(pivs, ranges.take_front(nPar))([&] {
LoopNestRangeBuilder(rivs, ranges.drop_back(nWin).take_back(nRed))([&] {
LoopNestRangeBuilder(wivs, ranges.take_back(wivs.size()))(
[&linalgOp, &allIvs, this] {
auto allIvValues = extractValues(allIvs);
LinalgScopedEmitter<ConcreteOp>::emitScalarImplementation(
allIvValues, linalgOp, folder);
});
});
});
// clang-format on
rewriter.replaceOp(op, {});
return matchSuccess();
}
mutable OperationFolder folder;
};
// Helper classes for type list expansion.
template <typename... LinalgOps> class ConversionList;
template <> class ConversionList<> {
public:
static void build(OwningRewritePatternList &patterns, MLIRContext *ctx) {}
};
template <typename ConcreteOp, typename... LinalgOps>
class ConversionList<ConcreteOp, LinalgOps...> {
public:
static void build(OwningRewritePatternList &patterns, MLIRContext *ctx) {
patterns.insert<LinalgRewritePattern<ConcreteOp>>(ctx);
ConversionList<LinalgOps...>::build(patterns, ctx);
}
};
/// Populate the given list with patterns that convert from Linalg to LLVM.
static void
populateLinalgToLoopRewritePatterns(OwningRewritePatternList &patterns,
MLIRContext *ctx) {
ConversionList<
#define GET_OP_LIST
#include "mlir/Dialect/Linalg/IR/LinalgLibraryOps.cpp.inc"
>::build(patterns, ctx);
}
namespace {
struct LowerLinalgToLoopsPass : public FunctionPass<LowerLinalgToLoopsPass> {
void runOnFunction();
};
} // namespace
void LowerLinalgToLoopsPass::runOnFunction() {
OwningRewritePatternList patterns;
populateLinalgToLoopRewritePatterns(patterns, &getContext());
ConversionTarget target(getContext());
target.addLegalDialect<AffineOpsDialect>();
target.addLegalDialect<loop::LoopOpsDialect>();
target.addLegalDialect<StandardOpsDialect>();
if (failed(applyPartialConversion(getFunction(), target, patterns))) {
signalPassFailure();
}
}
std::unique_ptr<FunctionPassBase> mlir::linalg::createLowerLinalgToLoopsPass() {
return std::make_unique<LowerLinalgToLoopsPass>();
}
static PassRegistration<LowerLinalgToLoopsPass>
pass("linalg-lower-to-loops",
"Lower the operations from the linalg dialect into loops");