llvm-project/mlir/lib/Dialect/Utils/ReshapeOpsUtils.cpp
2022-06-25 11:55:57 -07:00

273 lines
10 KiB
C++

//===- ReshapeOpsUtils.cpp - Utilities used by structured 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/Utils/ReshapeOpsUtils.h"
#include "mlir/IR/AffineMap.h"
#include "mlir/IR/Builders.h"
#include <numeric>
using namespace mlir;
Optional<SmallVector<ReassociationIndices>>
mlir::getReassociationIndicesForReshape(ShapedType sourceType,
ShapedType targetType) {
if (sourceType.getRank() > targetType.getRank())
return getReassociationIndicesForCollapse(sourceType.getShape(),
targetType.getShape());
if (sourceType.getRank() < targetType.getRank())
return getReassociationIndicesForCollapse(targetType.getShape(),
sourceType.getShape());
return llvm::None;
}
Optional<SmallVector<ReassociationIndices>>
mlir::getReassociationIndicesForCollapse(ArrayRef<int64_t> sourceShape,
ArrayRef<int64_t> targetShape) {
if (sourceShape.size() <= targetShape.size())
return llvm::None;
unsigned sourceDim = 0;
SmallVector<ReassociationIndices> reassociationMap;
reassociationMap.reserve(targetShape.size());
ReassociationIndices currIndices;
int64_t prodOfCollapsedDims = 1;
while (sourceDim < sourceShape.size()) {
unsigned targetDim = reassociationMap.size();
// If we have mapped all the target dimensions stop and handle the remaining
// tail of size-1 dimensions explictly.
if (targetDim == targetShape.size())
break;
int64_t currTargetShape = targetShape[targetDim];
while (sourceShape[sourceDim] != ShapedType::kDynamicSize &&
prodOfCollapsedDims * sourceShape[sourceDim] < currTargetShape &&
sourceDim < sourceShape.size()) {
prodOfCollapsedDims *= sourceShape[sourceDim];
currIndices.push_back(sourceDim++);
}
// If the current expanded dimension is dynamic, then the collapsed
// dimensions should also be dynamic and product of all previous unprocessed
// dimensions of the expanded shape should be 1.
if (sourceShape[sourceDim] == ShapedType::kDynamicSize &&
(currTargetShape != ShapedType::kDynamicSize ||
prodOfCollapsedDims != 1))
return llvm::None;
// If the collapsed dim is dynamic, the current expanded dim should also
// be dynamic.
if (currTargetShape == ShapedType::kDynamicSize &&
sourceShape[sourceDim] != ShapedType::kDynamicSize)
return llvm::None;
// For static shapes, if the product of dimensions of the expanded shape
// should match the collapsed dimension shape.
if (prodOfCollapsedDims * sourceShape[sourceDim] != currTargetShape)
return llvm::None;
currIndices.push_back(sourceDim++);
reassociationMap.emplace_back(ReassociationIndices{});
std::swap(reassociationMap.back(), currIndices);
prodOfCollapsedDims = 1;
}
// All the dimensions in the target must have been processed.
if (reassociationMap.size() != targetShape.size())
return llvm::None;
// Process any remaining entries in the source shape. They all need to be
// 1 or dynamic.
for (; sourceDim < sourceShape.size(); sourceDim++) {
if (sourceShape[sourceDim] != ShapedType::kDynamicSize &&
sourceShape[sourceDim] != 1)
return llvm::None;
// The map is empty when the target type is a scalar.
if (!reassociationMap.empty())
reassociationMap.back().push_back(sourceDim);
}
return reassociationMap;
}
Optional<SmallVector<ReassociationIndices>> mlir::composeReassociationIndices(
ArrayRef<ReassociationIndices> producerReassociations,
ArrayRef<ReassociationIndices> consumerReassociations,
MLIRContext *context) {
SmallVector<ReassociationIndices> composedIndices;
// Make the producer the larger sized vector. If they are of same size, the
// resulting reshape is not a supported reshape op.
if (producerReassociations.size() == consumerReassociations.size())
return llvm::None;
if (producerReassociations.size() < consumerReassociations.size())
std::swap(producerReassociations, consumerReassociations);
// Handle the corner case of the result being a rank 0 shaped type. Return an
// empty reassociation.
if (consumerReassociations.empty())
return composedIndices;
size_t consumerDims = std::accumulate(
consumerReassociations.begin(), consumerReassociations.end(), 0,
[](size_t all, ReassociationIndicesRef indices) {
return all + indices.size();
});
if (producerReassociations.size() != consumerDims)
return llvm::None;
for (ReassociationIndicesRef consumerIndices : consumerReassociations) {
ReassociationIndices reassociations;
for (int64_t consumerIndex : consumerIndices) {
llvm::append_range(reassociations, producerReassociations[consumerIndex]);
}
composedIndices.push_back(std::move(reassociations));
}
return composedIndices;
}
SmallVector<SmallVector<AffineExpr, 2>, 2>
mlir::convertReassociationIndicesToExprs(
MLIRContext *context, ArrayRef<ReassociationIndices> reassociationIndices) {
SmallVector<SmallVector<AffineExpr, 2>, 2> reassociationMaps;
for (const auto &indices : reassociationIndices) {
SmallVector<AffineExpr, 2> reassociationMap;
reassociationMap.reserve(indices.size());
for (int64_t index : indices)
reassociationMap.push_back(mlir::getAffineDimExpr(index, context));
reassociationMaps.push_back(std::move(reassociationMap));
}
return reassociationMaps;
}
template <typename AffineExprTy>
unsigned getMaxPosOfType(ArrayRef<ReassociationExprs> exprArrays) {
unsigned pos = 0;
for (const auto &exprs : exprArrays) {
for (auto expr : exprs) {
expr.walk([&pos](AffineExpr e) {
if (auto d = e.dyn_cast<AffineExprTy>())
pos = std::max(pos, d.getPosition());
});
}
}
return pos;
}
ArrayAttr mlir::getReassociationIndicesAttribute(
OpBuilder &b, ArrayRef<ReassociationIndices> reassociation) {
SmallVector<Attribute, 4> reassociationAttr =
llvm::to_vector<4>(llvm::map_range(
reassociation, [&](const ReassociationIndices &indices) -> Attribute {
return b.getI64ArrayAttr(indices).cast<Attribute>();
}));
return b.getArrayAttr(reassociationAttr);
}
SmallVector<ReassociationIndices, 2> mlir::convertReassociationMapsToIndices(
OpBuilder &b, ArrayRef<ReassociationExprs> reassociationExprs) {
SmallVector<ReassociationIndices, 2> reassociationIndices;
for (const auto &exprs : reassociationExprs) {
ReassociationIndices indices;
indices.reserve(exprs.size());
for (const auto &expr : exprs)
indices.push_back(expr.cast<AffineDimExpr>().getPosition());
reassociationIndices.push_back(indices);
}
return reassociationIndices;
}
SmallVector<AffineMap, 4>
mlir::getSymbolLessAffineMaps(ArrayRef<ReassociationExprs> reassociation) {
unsigned maxDim = getMaxPosOfType<AffineDimExpr>(reassociation);
assert(getMaxPosOfType<AffineSymbolExpr>(reassociation) == 0 &&
"Expected symbol-less expressions");
SmallVector<AffineMap, 4> maps;
maps.reserve(reassociation.size());
for (const auto &exprs : reassociation) {
assert(!exprs.empty());
maps.push_back(AffineMap::get(maxDim + 1, 0, exprs, exprs[0].getContext()));
}
return maps;
}
bool mlir::isReassociationValid(ArrayRef<AffineMap> reassociation,
int *invalidIndex) {
if (reassociation.empty())
return true;
unsigned nDims = reassociation[0].getNumDims();
unsigned nextExpectedDim = 0;
for (const auto &it : llvm::enumerate(reassociation)) {
auto m = it.value();
if (m.getNumDims() != nDims || m.getNumSymbols() != 0) {
if (invalidIndex)
*invalidIndex = it.index();
return false;
}
for (auto e : m.getResults()) {
auto d = e.dyn_cast<AffineDimExpr>();
if (!d || d.getPosition() != nextExpectedDim++) {
if (invalidIndex)
*invalidIndex = it.index();
return false;
}
}
}
if (nextExpectedDim != nDims) {
if (invalidIndex)
*invalidIndex = reassociation.size() - 1;
return false;
}
return true;
}
LogicalResult mlir::reshapeLikeShapesAreCompatible(
function_ref<LogicalResult(const Twine &)> emitError,
ArrayRef<int64_t> collapsedShape, ArrayRef<int64_t> expandedShape,
ArrayRef<ReassociationIndices> reassociationMaps, bool isExpandingReshape) {
unsigned expandedDimStart = 0;
for (const auto &map : llvm::enumerate(reassociationMaps)) {
Optional<int64_t> dynamicShape;
int64_t linearizedStaticShape = 1;
for (const auto &dim : llvm::enumerate(
expandedShape.slice(expandedDimStart, map.value().size()))) {
if (ShapedType::isDynamic(dim.value())) {
if (isExpandingReshape && dynamicShape) {
return emitError("invalid to have a single dimension (" +
Twine(map.index()) +
") expanded into multiple dynamic dims (" +
Twine(expandedDimStart + dynamicShape.value()) +
"," + Twine(expandedDimStart + dim.index()) + ")");
}
dynamicShape = dim.index();
} else {
linearizedStaticShape *= dim.value();
}
}
if (dynamicShape) {
if (!ShapedType::isDynamic(collapsedShape[map.index()])) {
return emitError(
"expected dimension " + Twine(map.index()) +
" of collapsed type to be dynamic since one or more of the "
"corresponding dimensions in the expanded type is dynamic");
}
} else {
if (collapsedShape[map.index()] != linearizedStaticShape) {
return emitError("expected dimension " + Twine(map.index()) +
" of collapsed type to be static value of " +
Twine(linearizedStaticShape));
}
}
expandedDimStart += map.value().size();
}
return success();
}
bool mlir::hasNonIdentityLayout(Type type) {
if (auto memrefType = type.dyn_cast<MemRefType>())
return !memrefType.getLayout().isIdentity();
return false;
}