Nicolas Vasilache 19e5b2bccb [mlir][Linalg] NFC - Simplify GenericNestLoop builder
Summary: This revision trims unnecessary complexity.

Differential Revision: https://reviews.llvm.org/D80290
2020-05-20 09:44:15 -04:00

798 lines
32 KiB
C++

//===- Loops.cpp - conversion from Linalg named and generic ops to loops --===//
//
// 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 "PassDetail.h"
#include "mlir/Dialect/Affine/EDSC/Intrinsics.h"
#include "mlir/Dialect/Linalg/EDSC/FoldedIntrinsics.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/Transforms/Transforms.h"
#include "mlir/Dialect/Linalg/Utils/Utils.h"
#include "mlir/Dialect/SCF/EDSC/Builders.h"
#include "mlir/Dialect/StandardOps/EDSC/Intrinsics.h"
#include "mlir/IR/AffineExpr.h"
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/BlockAndValueMapping.h"
#include "mlir/Support/LLVM.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 edsc::op::operator+;
static SmallVector<Value, 8> makeCanonicalAffineApplies(OpBuilder &b,
Location loc,
AffineMap map,
ArrayRef<Value> vals) {
if (map.isEmpty())
return {};
assert(map.getNumSymbols() == 0);
assert(map.getNumInputs() == vals.size());
SmallVector<Value, 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(exprMap, operands));
}
return res;
}
static SmallVector<Value, 4> permuteIvs(ArrayRef<Value> ivs,
Optional<AffineMap> permutation) {
return permutation ? applyMapToValues(ScopedContext::getBuilderRef(),
ScopedContext::getLocation(),
permutation.getValue(), ivs)
: 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<SubViewOp::Range, 4>
emitLoopRanges(OpBuilder &b, Location loc, AffineMap map,
ArrayRef<Value> allViewSizes) {
// Apply `map` to get view sizes in loop order.
auto sizes = applyMapToValues(b, loc, map, allViewSizes);
// Create a new range with the applied tile sizes.
ScopedContext scope(b, loc);
SmallVector<SubViewOp::Range, 4> res;
for (unsigned idx = 0, e = map.getNumResults(); idx < e; ++idx) {
res.push_back(SubViewOp::Range{std_constant_index(0), sizes[idx],
std_constant_index(1)});
}
return res;
}
template <typename IndexedValueType, typename OpType>
static void inlineRegionAndEmitStore(OpType op, ArrayRef<Value> indexedValues,
ArrayRef<SmallVector<Value, 8>> indexing,
ArrayRef<Value> outputBuffers) {
auto &b = ScopedContext::getBuilderRef();
auto &block = op.region().front();
BlockAndValueMapping map;
map.map(block.getArguments(), indexedValues);
for (auto &op : block.without_terminator()) {
assert(op.getNumRegions() == 0 && "expected a non-nested region");
auto *newOp = b.clone(op, map);
map.map(op.getResults(), newOp->getResults());
}
Operation &terminator = block.back();
assert(isa<YieldOp>(terminator) &&
"expected a yield op in the end of the region");
for (unsigned i = 0, e = terminator.getNumOperands(); i < e; ++i) {
IndexedValueType O(outputBuffers[i]);
O(indexing[i]) = map.lookupOrDefault(terminator.getOperand(i));
}
}
// Returns a pair that contains input indices and output indices of a
// SingleInputPoolingOp `op`.
struct InputAndOutputIndices {
SmallVector<Value, 8> inputs;
SmallVector<Value, 8> outputs;
};
template <typename SingleInputPoolingOp>
static InputAndOutputIndices getInputAndOutputIndices(ArrayRef<Value> allIvs,
SingleInputPoolingOp op) {
auto &b = ScopedContext::getBuilderRef();
auto loc = ScopedContext::getLocation();
auto mapsRange = op.indexing_maps().template getAsRange<AffineMapAttr>();
auto maps = llvm::to_vector<8>(
llvm::map_range(mapsRange, [](AffineMapAttr a) { return a.getValue(); }));
return InputAndOutputIndices{
makeCanonicalAffineApplies(b, loc, maps[0], allIvs),
makeCanonicalAffineApplies(b, loc, maps[2], allIvs)};
}
namespace {
/// Emits the MLIR for the scalar part of the generic op by:
/// 1. Emitting load 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 store ops to store the results of 2. to the output
/// views.
///
/// An example output may resemble:
///
/// ```
/// scf.for %i = %c0 to %0 step %c1 {
/// scf.for %j = %c0 to %1 step %c1 {
/// scf.for %k = %c0 to %4 step %c1 {
/// %11 = load %arg0[%i, %j] :
/// memref<?x?xf32, stride_specification>
/// %12 = load %arg1[%i, %j, %k] :
/// memref<?x?x?xf32, stride_specification>
/// %13 = load %arg2[%i, %k, %j] :
/// memref<?x?x?xf32, stride_specification>
/// %14:2 = call @foo(%11, %12, %13) : (f32, f32, f32) -> (f32, f32)
/// store %14#0, %arg1[%i, %j, %k] :
/// memref<?x?x?Xf32, stride_specification>
/// store %14#1, %arg2[%i, %k, %j] :
/// memref<?x?x?Xf32, stride_specification>
/// }
/// }
/// }
/// ```
template <typename IndexedValueType, typename LinalgOpType>
class LinalgScopedEmitter {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs,
LinalgOpType linalgOp) {
assert(linalgOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
auto &b = ScopedContext::getBuilderRef();
auto loc = ScopedContext::getLocation();
unsigned nInputs = linalgOp.getNumInputs();
unsigned nOutputs = linalgOp.getNumOutputs();
SmallVector<Value, 4> indexedValues;
indexedValues.reserve(nInputs + nOutputs);
// TODO(mravishankar): Avoid the loads if the corresponding argument of the
// region has no uses.
// 1.a. Emit load from input views.
for (unsigned i = 0; i < nInputs; ++i) {
auto indexing = makeCanonicalAffineApplies(
b, loc, linalgOp.getInputIndexingMap(i), allIvs);
// Passing through IndexedValueType emits the proper load operation.
indexedValues.push_back(IndexedValueType(linalgOp.getInput(i))(indexing));
}
// 1.b. Emit load from output views.
for (unsigned i = 0; i < nOutputs; ++i) {
auto indexing = makeCanonicalAffineApplies(
b, loc, linalgOp.getOutputIndexingMap(i), allIvs);
// Passing through IndexedValueType emits the proper load operation.
indexedValues.push_back(
IndexedValueType(linalgOp.getOutputBuffer(i))(indexing));
}
// TODO(ntv): When a region inliner exists, use it.
// 2. Inline region, currently only works for a single basic block.
// 3. Emit store.
SmallVector<SmallVector<Value, 8>, 8> indexing;
SmallVector<Value, 8> outputBuffers;
for (unsigned i = 0; i < nOutputs; ++i) {
indexing.push_back(makeCanonicalAffineApplies(
b, loc, linalgOp.getOutputIndexingMap(i), allIvs));
outputBuffers.push_back(linalgOp.getOutputBuffer(i));
}
inlineRegionAndEmitStore<IndexedValueType>(linalgOp, indexedValues,
indexing, outputBuffers);
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, CopyOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs, CopyOp copyOp) {
assert(copyOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
auto nPar = copyOp.getNumParallelLoops();
assert(nPar == allIvs.size());
auto inputIvs =
permuteIvs(allIvs.take_front(nPar), copyOp.inputPermutation());
auto outputIvs =
permuteIvs(allIvs.take_front(nPar), copyOp.outputPermutation());
SmallVector<Value, 8> iivs(inputIvs.begin(), inputIvs.end());
SmallVector<Value, 8> oivs(outputIvs.begin(), outputIvs.end());
IndexedValueType O(copyOp.getOutputBuffer(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 <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, FillOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs, FillOp fillOp) {
assert(fillOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
auto nPar = fillOp.getNumParallelLoops();
assert(nPar == allIvs.size());
auto ivs = SmallVector<Value, 4>(allIvs.begin(), allIvs.begin() + nPar);
IndexedValueType O(fillOp.getOutputBuffer(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) = fillOp.value() : O() = fillOp.value();
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, DotOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs, DotOp dotOp) {
assert(dotOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
assert(allIvs.size() == 1);
Value r_i(allIvs[0]);
IndexedValueType A(dotOp.getInput(0)), B(dotOp.getInput(1)),
C(dotOp.getOutputBuffer(0));
// Emit scalar form.
C() = C() + A(r_i) * B(r_i);
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, MatvecOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs,
MatvecOp matvecOp) {
assert(matvecOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
assert(allIvs.size() == 2);
Value i(allIvs[0]), r_j(allIvs[1]);
IndexedValueType A(matvecOp.getInput(0)), B(matvecOp.getInput(1)),
C(matvecOp.getOutputBuffer(0));
// Emit scalar form.
C(i) = C(i) + A(i, r_j) * B(r_j);
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, MatmulOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs,
MatmulOp matmulOp) {
assert(matmulOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
assert(allIvs.size() == 3);
Value i(allIvs[0]), j(allIvs[1]), r_k(allIvs[2]);
IndexedValueType A(matmulOp.getInput(0)), B(matmulOp.getInput(1)),
C(matmulOp.getOutputBuffer(0));
// Emit scalar form.
C(i, j) = C(i, j) + A(i, r_k) * B(r_k, j);
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, ConvOp> {
public:
/// Returns the input value of convOp. If the indices in `imIdx` is out of
/// boundary, returns 0 instead.
static Value getConvOpInput(ConvOp convOp, StdIndexedValue im,
MutableArrayRef<Value> imIdx) {
// TODO(ntv): add a level of indirection to linalg.generic.
if (!convOp.padding())
return im(imIdx);
auto *context = ScopedContext::getContext();
Value zeroIndex = std_constant_index(0);
SmallVector<Value, 8> conds;
SmallVector<Value, 8> clampedImIdx;
for (auto iter : llvm::enumerate(imIdx)) {
int idx = iter.index();
auto dim = iter.value();
// Only need to iterate over the window dimensions.
if (idx == 0 || idx == static_cast<int>(imIdx.size()) - 1) {
clampedImIdx.push_back(dim);
continue;
}
using edsc::op::operator<;
using edsc::op::operator>=;
using edsc::op::operator||;
Value leftOutOfBound = dim < zeroIndex;
if (conds.empty())
conds.push_back(leftOutOfBound);
else
conds.push_back(conds.back() || leftOutOfBound);
Value rightBound = std_dim(convOp.input(), idx);
conds.push_back(conds.back() || (dim >= rightBound));
// When padding is involved, the indices will only be shifted to negative,
// so having a max op is enough.
auto maxMap = AffineMap::get(/*dimCount=*/1, 0,
{getAffineDimExpr(/*position=*/0, context),
getAffineConstantExpr(0, context)},
context);
clampedImIdx.push_back(
affine_max(dim.getType(), maxMap, ValueRange{dim}));
}
auto &b = ScopedContext::getBuilderRef();
Type type = convOp.input().getType().cast<MemRefType>().getElementType();
Value zero = std_constant(type, b.getZeroAttr(type));
Value readInput = im(clampedImIdx);
return conds.empty() ? readInput
: (Value)std_select(conds.back(), zero, readInput);
}
static void emitScalarImplementation(ArrayRef<Value> allIvs, ConvOp convOp) {
assert(convOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
auto &b = ScopedContext::getBuilderRef();
auto loc = ScopedContext::getLocation();
auto mapsRange = convOp.indexing_maps().getAsRange<AffineMapAttr>();
auto maps = llvm::to_vector<8>(llvm::map_range(
mapsRange, [](AffineMapAttr a) { return a.getValue(); }));
SmallVector<Value, 8> fIdx(
makeCanonicalAffineApplies(b, loc, maps[0], allIvs));
SmallVector<Value, 8> imIdx(
makeCanonicalAffineApplies(b, loc, maps[1], allIvs));
SmallVector<Value, 8> oIdx(
makeCanonicalAffineApplies(b, loc, maps[2], allIvs));
// Padded conv involves an affine.max in the memory access which is not
// allowed by affine.load. Override to always use an StdIndexedValue.
StdIndexedValue I(convOp.input());
IndexedValueType F(convOp.filter()), O(convOp.output());
// Emit scalar form.
Value paddedInput = getConvOpInput(convOp, I, imIdx);
O(oIdx) += F(fIdx) * paddedInput;
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, PoolingMaxOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs,
PoolingMaxOp op) {
auto indices = getInputAndOutputIndices(allIvs, op);
// Emit scalar form.
Value lhs = std_load(op.output(), indices.outputs);
Value rhs = std_load(op.input(), indices.inputs);
using edsc::op::operator>;
Value maxValue = std_select(lhs > rhs, lhs, rhs);
std_store(maxValue, op.output(), indices.outputs);
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, PoolingMinOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs,
PoolingMinOp op) {
auto indices = getInputAndOutputIndices(allIvs, op);
// Emit scalar form.
Value lhs = std_load(op.output(), indices.outputs);
Value rhs = std_load(op.input(), indices.inputs);
using edsc::op::operator<;
Value minValue = std_select(lhs < rhs, lhs, rhs);
std_store(minValue, op.output(), indices.outputs);
}
};
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, PoolingSumOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs,
PoolingSumOp op) {
auto indices = getInputAndOutputIndices(allIvs, op);
IndexedValueType input(op.input()), output(op.output());
// Emit scalar form.
output(indices.outputs) += input(indices.inputs);
}
};
/// Emits the MLIR for the scalar part of the indexed generic op by:
/// 1. Emitting load 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 induction
/// variables and the scalars from point 1. above.
/// 3. Emitting store ops to store the results of 2. to the output views.
///
/// An example output may resemble:
///
/// ```
/// scf.for %i = %c0 to %0 step %c1 {
/// scf.for %j = %c0 to %1 step %c1 {
/// scf.for %k = %c0 to %4 step %c1 {
/// %11 = load %arg0[%i, %j] :
/// memref<?x?xf32, stride_specification>
/// %12 = load %arg1[%i, %j, %k] :
/// memref<?x?x?xf32, stride_specification>
/// %13 = load %arg2[%i, %k, %j] :
/// memref<?x?x?xf32, stride_specification>
/// %14:2 = call @foo(%i, %j, %k, %11, %12, %13) :
/// (index, index, index, f32, f32, f32) -> (f32, f32)
/// store %14#0, %arg1[%i, %j, %k] :
/// memref<?x?x?Xf32, stride_specification>
/// store %14#1, %arg2[%i, %k, %j] :
/// memref<?x?x?Xf32, stride_specification>
/// }
/// }
/// }
/// ```
template <typename IndexedValueType>
class LinalgScopedEmitter<IndexedValueType, IndexedGenericOp> {
public:
static void emitScalarImplementation(ArrayRef<Value> allIvs,
IndexedGenericOp indexedGenericOp) {
assert(indexedGenericOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
auto &b = ScopedContext::getBuilderRef();
auto loc = ScopedContext::getLocation();
unsigned nInputs = indexedGenericOp.getNumInputs();
unsigned nOutputs = indexedGenericOp.getNumOutputs();
unsigned nLoops = allIvs.size();
SmallVector<Value, 4> indexedValues;
indexedValues.reserve(nLoops + nInputs + nOutputs);
for (unsigned i = 0; i < nLoops; ++i)
indexedValues.push_back(allIvs[i]);
// TODO(mravishankar): Avoid the loads if the corresponding argument of the
// region has no uses.
// 1.a. Emit load from input views.
for (unsigned i = 0; i < nInputs; ++i) {
auto indexing = makeCanonicalAffineApplies(
b, loc, indexedGenericOp.getInputIndexingMap(i), allIvs);
// Pass input i through IndexedValueType emits the proper load operation.
indexedValues.push_back(
IndexedValueType(indexedGenericOp.getInput(i))(indexing));
}
// 1.b. Emit load from output views.
for (unsigned i = 0; i < nOutputs; ++i) {
auto indexing = makeCanonicalAffineApplies(
b, loc, indexedGenericOp.getOutputIndexingMap(i), allIvs);
// Pass output i through IndexedValueType emits the proper load operation.
indexedValues.push_back(
IndexedValueType(indexedGenericOp.getOutputBuffer(i))(indexing));
}
// TODO(ntv): When a region inliner exists, use it.
// 2. Inline region, currently only works for a single basic block.
// 3. Emit store.
SmallVector<SmallVector<Value, 8>, 8> indexing;
SmallVector<Value, 8> outputBuffers;
for (unsigned i = 0; i < nOutputs; ++i) {
indexing.push_back(makeCanonicalAffineApplies(
b, loc, indexedGenericOp.getOutputIndexingMap(i), allIvs));
outputBuffers.push_back(indexedGenericOp.getOutputBuffer(i));
}
inlineRegionAndEmitStore<IndexedValueType>(indexedGenericOp, indexedValues,
indexing, outputBuffers);
}
};
namespace {
/// Helper struct to generate the loop nest for the op. This factored out here
/// to be able to partially specialize this for different LoopTy.
template <typename LoopTy, typename ConcreteOpTy>
class GenerateLoopNest {
public:
using IndexedValueTy =
typename std::conditional<std::is_same<LoopTy, AffineForOp>::value,
AffineIndexedValue, StdIndexedValue>::type;
static void doit(ConcreteOpTy linalgOp, ArrayRef<SubViewOp::Range> loopRanges,
MutableArrayRef<Value> allIvs) {
GenericLoopNestRangeBuilder<LoopTy>(allIvs, loopRanges)([&] {
SmallVector<Value, 4> allIvValues(allIvs.begin(), allIvs.end());
LinalgScopedEmitter<IndexedValueTy,
ConcreteOpTy>::emitScalarImplementation(allIvValues,
linalgOp);
});
}
};
/// Generates loop nest using scf.parallel. scf.parallel is only used for the
/// outer parallel loops. All other loops are generated using scf.for
/// operation.
template <typename ConcreteOpTy>
class GenerateLoopNest<scf::ParallelOp, ConcreteOpTy> {
public:
using IndexedValueTy = StdIndexedValue;
static void doit(ConcreteOpTy linalgOp, ArrayRef<SubViewOp::Range> loopRanges,
MutableArrayRef<Value> allIvs) {
// Only generate scf.parallel for outer consecutive "parallel"
// iterator_types.
// TODO(ravishankarm): Generate scf.parallel for all "parallel" iterator
// types, not just the outer most ones. Also handle "reduction" iterator
// types.
auto nOuterPar = linalgOp.iterator_types()
.getValue()
.take_while([](Attribute attr) {
return attr.cast<StringAttr>().getValue() ==
getParallelIteratorTypeName();
})
.size();
// If there are no outer parallel loops, then number of loop ops is same as
// the number of loops, and they are all scf.for ops.
if (nOuterPar) {
GenericLoopNestRangeBuilder<scf::ParallelOp>(
allIvs.take_front(nOuterPar), loopRanges.take_front(nOuterPar))([&] {
GenericLoopNestRangeBuilder<scf::ForOp>(
allIvs.drop_front(nOuterPar),
loopRanges.drop_front(nOuterPar))([&] {
SmallVector<Value, 4> allIvValues(allIvs.begin(), allIvs.end());
LinalgScopedEmitter<StdIndexedValue, ConcreteOpTy>::
emitScalarImplementation(allIvValues, linalgOp);
});
});
} else {
// If there are no parallel loops then fallback to generating all scf.for
// operations.
GenericLoopNestRangeBuilder<scf::ForOp>(allIvs, loopRanges)([&] {
SmallVector<Value, 4> allIvValues(allIvs.begin(), allIvs.end());
LinalgScopedEmitter<StdIndexedValue,
ConcreteOpTy>::emitScalarImplementation(allIvValues,
linalgOp);
});
}
}
};
} // namespace
template <typename LoopTy, typename ConcreteOpTy>
Optional<LinalgLoops> linalgOpToLoopsImpl(Operation *op, OpBuilder &builder) {
using Impl = GenerateLoopNest<LoopTy, ConcreteOpTy>;
using IndexedValueTy =
typename GenerateLoopNest<LoopTy, ConcreteOpTy>::IndexedValueTy;
ScopedContext scope(builder, op->getLoc());
// The flattened loopToOperandRangesMaps is expected to be an invertible
// permutation map (which is asserted in the inverse calculation).
auto linalgOp = cast<ConcreteOpTy>(op);
assert(linalgOp.hasBufferSemantics() &&
"expected linalg op with buffer semantics");
auto nPar = linalgOp.getNumParallelLoops();
auto nRed = linalgOp.getNumReductionLoops();
auto nWin = linalgOp.getNumWindowLoops();
auto nLoops = nPar + nRed + nWin;
auto mapsRange =
linalgOp.indexing_maps().template getAsRange<AffineMapAttr>();
auto maps = llvm::to_vector<8>(
llvm::map_range(mapsRange, [](AffineMapAttr a) { return a.getValue(); }));
AffineMap invertedMap = inversePermutation(concatAffineMaps(maps));
if (!invertedMap)
return {};
if (invertedMap.isEmpty()) {
LinalgScopedEmitter<IndexedValueTy, ConcreteOpTy>::emitScalarImplementation(
{}, linalgOp);
return LinalgLoops();
}
SmallVector<Value, 4> allIvs(nLoops);
auto loopRanges =
emitLoopRanges(scope.getBuilderRef(), scope.getLocation(), invertedMap,
getViewSizes(builder, linalgOp));
assert(loopRanges.size() == allIvs.size());
Impl::doit(linalgOp, loopRanges, allIvs);
// Number of loop ops might be different from the number of ivs since some
// loops like affine.parallel and scf.parallel have multiple ivs.
llvm::SetVector<Operation *> loopSet;
for (Value iv : allIvs) {
if (!iv)
return {};
// The induction variable is a block argument of the entry block of the
// loop operation.
BlockArgument ivVal = iv.dyn_cast<BlockArgument>();
if (!ivVal)
return {};
loopSet.insert(ivVal.getOwner()->getParentOp());
}
LinalgLoops loops(loopSet.begin(), loopSet.end());
return loops;
}
template <typename LoopType, typename ConcreteOp>
class LinalgRewritePattern : public RewritePattern {
public:
explicit LinalgRewritePattern(MLIRContext *context)
: RewritePattern(ConcreteOp::getOperationName(), 1, context) {}
LogicalResult matchAndRewrite(Operation *op,
PatternRewriter &rewriter) const override {
if (!linalgOpToLoopsImpl<LoopType, ConcreteOp>(op, rewriter))
return failure();
rewriter.eraseOp(op);
return success();
}
};
/// Helper classes for type list expansion.
template <typename LoopType, typename... LinalgOps>
class RewritePatternList;
template <typename LoopType>
class RewritePatternList<LoopType> {
public:
static void build(OwningRewritePatternList &patterns, MLIRContext *ctx) {}
};
template <typename LoopType, typename ConcreteOp, typename... LinalgOps>
class RewritePatternList<LoopType, ConcreteOp, LinalgOps...> {
public:
static void build(OwningRewritePatternList &patterns, MLIRContext *ctx) {
patterns.insert<LinalgRewritePattern<LoopType, ConcreteOp>>(ctx);
RewritePatternList<LoopType, LinalgOps...>::build(patterns, ctx);
}
};
/// Populate the given list with patterns that convert from Linalg to loops.
template <typename LoopType>
void FillRewritePatterns(OwningRewritePatternList &patterns, MLIRContext *ctx) {
RewritePatternList<LoopType,
#define GET_OP_LIST
#include "mlir/Dialect/Linalg/IR/LinalgStructuredOps.cpp.inc"
>::build(patterns, ctx);
}
/// Local folding pattern for AffineApplyOp that we can apply greedily.
/// This replaces AffineApplyOp by the proper value in cases where the
/// associated map is trivial.
/// A trivial map here is defined as a map with a single result and either:
/// 1. Zero operand + returns a single AffineConstantExpr
/// 2. One operand + returns a single AffineDimExpr
/// 3. One operand + returns a single AffineSymbolExpr
//
/// In the first case, the AffineApplyOp is replaced by a new constant. In the
/// other cases, it is replaced by its unique operand.
struct FoldAffineOp : public RewritePattern {
FoldAffineOp(MLIRContext *context)
: RewritePattern(AffineApplyOp::getOperationName(), 0, context) {}
LogicalResult matchAndRewrite(Operation *op,
PatternRewriter &rewriter) const override {
AffineApplyOp affineApplyOp = cast<AffineApplyOp>(op);
auto map = affineApplyOp.getAffineMap();
if (map.getNumResults() != 1 || map.getNumInputs() > 1)
return failure();
AffineExpr expr = map.getResult(0);
if (map.getNumInputs() == 0) {
if (auto val = expr.dyn_cast<AffineConstantExpr>()) {
rewriter.replaceOpWithNewOp<ConstantIndexOp>(op, val.getValue());
return success();
}
return failure();
}
if (expr.dyn_cast<AffineDimExpr>() || expr.dyn_cast<AffineSymbolExpr>()) {
rewriter.replaceOp(op, op->getOperand(0));
return success();
}
return failure();
}
};
} // namespace
template <typename LoopType>
static void lowerLinalgToLoopsImpl(Operation *op, MLIRContext *context) {
OwningRewritePatternList patterns;
// Canonicalization and folding patterns applied greedily allow cleaning up
// the emitted IR on the fly.
// TODO(ntv) fold view and subview ops?
FillRewritePatterns<LoopType>(patterns, context);
DimOp::getCanonicalizationPatterns(patterns, context);
AffineApplyOp::getCanonicalizationPatterns(patterns, context);
patterns.insert<FoldAffineOp>(context);
// Just apply the patterns greedily.
applyPatternsAndFoldGreedily(op, patterns);
}
namespace {
struct LowerToAffineLoops
: public LinalgLowerToAffineLoopsBase<LowerToAffineLoops> {
void runOnFunction() override {
lowerLinalgToLoopsImpl<AffineForOp>(getFunction(), &getContext());
}
};
struct LowerToLoops : public LinalgLowerToLoopsBase<LowerToLoops> {
void runOnFunction() override {
lowerLinalgToLoopsImpl<scf::ForOp>(getFunction(), &getContext());
}
};
struct LowerToParallelLoops
: public LinalgLowerToParallelLoopsBase<LowerToParallelLoops> {
void runOnFunction() override {
lowerLinalgToLoopsImpl<scf::ParallelOp>(getFunction(), &getContext());
}
};
} // namespace
std::unique_ptr<OperationPass<FuncOp>> mlir::createConvertLinalgToLoopsPass() {
return std::make_unique<LowerToLoops>();
}
std::unique_ptr<OperationPass<FuncOp>>
mlir::createConvertLinalgToParallelLoopsPass() {
return std::make_unique<LowerToParallelLoops>();
}
std::unique_ptr<OperationPass<FuncOp>>
mlir::createConvertLinalgToAffineLoopsPass() {
return std::make_unique<LowerToAffineLoops>();
}
/// Emits a loop nest with the proper body for `op`.
template <typename LoopTy, typename ConcreteOp>
Optional<LinalgLoops> mlir::linalg::linalgLowerOpToLoops(OpBuilder &builder,
Operation *op) {
return linalgOpToLoopsImpl<LoopTy, ConcreteOp>(op, builder);
}
/// Emits a loop nest of `scf.for` with the proper body for `op`.
template <typename ConcreteOp>
LogicalResult mlir::linalg::linalgOpToLoops(OpBuilder &builder, Operation *op) {
Optional<LinalgLoops> loops =
linalgLowerOpToLoops<scf::ForOp, ConcreteOp>(builder, op);
return loops ? success() : failure();
}
/// Emits a loop nest of `affine.for` with the proper body for `op`.
template <typename ConcreteOp>
LogicalResult mlir::linalg::linalgOpToAffineLoops(OpBuilder &builder,
Operation *op) {
Optional<LinalgLoops> loops =
linalgLowerOpToLoops<AffineForOp, ConcreteOp>(builder, op);
return loops ? success() : failure();
}
/// Emits a loop nest of `scf.parallel` with the proper body for `op`.
template <typename ConcreteOp>
LogicalResult mlir::linalg::linalgOpToParallelLoops(OpBuilder &builder,
Operation *op) {
Optional<LinalgLoops> loops =
linalgLowerOpToLoops<scf::ParallelOp, ConcreteOp>(builder, op);
return loops ? success() : failure();
}
// TODO Need to make these instantiations more future-proof to avoid the need to
// update as soon as we add new ops.
#define INSTANTIATE_LINALG_OP_TO_LOOPS(OP_TYPE) \
template LogicalResult mlir::linalg::linalgOpToLoops<OP_TYPE>( \
OpBuilder & builder, Operation * op); \
template LogicalResult mlir::linalg::linalgOpToAffineLoops<OP_TYPE>( \
OpBuilder & builder, Operation * op); \
template LogicalResult mlir::linalg::linalgOpToParallelLoops<OP_TYPE>( \
OpBuilder & builder, Operation * op); \
template Optional<LinalgLoops> \
mlir::linalg::linalgLowerOpToLoops<scf::ParallelOp, OP_TYPE>( \
OpBuilder & builder, Operation * op);
INSTANTIATE_LINALG_OP_TO_LOOPS(CopyOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(FillOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(DotOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(MatvecOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(MatmulOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(ConvOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(PoolingMaxOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(PoolingMinOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(PoolingSumOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(GenericOp)
INSTANTIATE_LINALG_OP_TO_LOOPS(IndexedGenericOp)