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//===- Vectorization.cpp - Implementation of linalg Vectorization ---------===//
//
// 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 the linalg dialect Vectorization transformations.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/Linalg/Analysis/DependenceAnalysis.h"
#include "mlir/Dialect/Linalg/IR/LinalgOps.h"
#include "mlir/Dialect/Linalg/Transforms/Transforms.h"
#include "mlir/Dialect/Linalg/Utils/Utils.h"
#include "mlir/Dialect/StandardOps/EDSC/Intrinsics.h"
#include "mlir/Dialect/Utils/StructuredOpsUtils.h"
#include "mlir/Dialect/Vector/EDSC/Intrinsics.h"
#include "mlir/Dialect/Vector/VectorOps.h"
#include "mlir/IR/AffineExpr.h"
#include "mlir/IR/Matchers.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Support/LLVM.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <type_traits>
using namespace mlir;
using namespace mlir::edsc;
using namespace mlir::edsc::intrinsics;
using namespace mlir::linalg;
using llvm::dbgs;
#define DEBUG_TYPE "linalg-vectorization"
static bool hasMultiplyAddBody(Region &r) {
if (!llvm::hasSingleElement(r))
return false;
if (!llvm::hasNItems(r.front().begin(), r.front().end(), 3))
return false;
using mlir::matchers::m_Val;
auto a = m_Val(r.getArgument(0));
auto b = m_Val(r.getArgument(1));
auto c = m_Val(r.getArgument(2));
// TODO: Update this detection once we have matcher support for specifying
// that any permutation of operands matches.
auto pattern1 = m_Op<linalg::YieldOp>(m_Op<AddFOp>(m_Op<MulFOp>(a, b), c));
auto pattern2 = m_Op<linalg::YieldOp>(m_Op<AddFOp>(c, m_Op<MulFOp>(a, b)));
auto pattern3 = m_Op<linalg::YieldOp>(m_Op<AddFOp>(m_Op<MulFOp>(b, a), c));
auto pattern4 = m_Op<linalg::YieldOp>(m_Op<AddFOp>(c, m_Op<MulFOp>(b, a)));
auto pattern5 = m_Op<linalg::YieldOp>(m_Op<AddIOp>(m_Op<MulIOp>(a, b), c));
auto pattern6 = m_Op<linalg::YieldOp>(m_Op<AddIOp>(c, m_Op<MulIOp>(a, b)));
auto pattern7 = m_Op<linalg::YieldOp>(m_Op<AddIOp>(m_Op<MulIOp>(b, a), c));
auto pattern8 = m_Op<linalg::YieldOp>(m_Op<AddIOp>(c, m_Op<MulIOp>(b, a)));
return pattern1.match(&r.front().back()) ||
pattern2.match(&r.front().back()) ||
pattern3.match(&r.front().back()) ||
pattern4.match(&r.front().back()) ||
pattern5.match(&r.front().back()) ||
pattern6.match(&r.front().back()) ||
pattern7.match(&r.front().back()) || pattern8.match(&r.front().back());
}
// TODO: Should be Tablegen'd from a single source that generates the op itself.
static LogicalResult isContraction(Operation *op) {
// TODO: interface for named ops.
if (isa<linalg::BatchMatmulOp, linalg::MatmulOp, linalg::MatvecOp,
linalg::DotOp>(op))
return success();
auto genericOp = dyn_cast<linalg::GenericOp>(op);
if (!genericOp)
return failure();
auto mapRange = genericOp.indexing_maps().getAsValueRange<AffineMapAttr>();
return success(
genericOp.getNumInputs() == 2 && genericOp.getNumOutputs() == 1 &&
llvm::all_of(mapRange,
[](AffineMap m) { return m.isProjectedPermutation(); }) &&
hasMultiplyAddBody(genericOp.region()));
}
LogicalResult mlir::linalg::vectorizeLinalgOpPrecondition(Operation *op) {
auto linalgOp = cast<linalg::LinalgOp>(op);
// All types must be static shape to go to vector.
for (Value operand : linalgOp.getInputsAndOutputBuffers())
if (!operand.getType().cast<ShapedType>().hasStaticShape())
return failure();
for (Type outputTensorType : linalgOp.getOutputTensorTypes())
if (!outputTensorType.cast<ShapedType>().hasStaticShape())
return failure();
if (isa<linalg::FillOp, linalg::CopyOp>(op))
return success();
return isContraction(op);
}
void mlir::linalg::vectorizeLinalgOp(OpBuilder &builder, Operation *op) {
assert(succeeded(vectorizeLinalgOpPrecondition(op)));
StringRef dbgPref = "\n[" DEBUG_TYPE "]: ";
(void)dbgPref;
edsc::ScopedContext scope(builder, op->getLoc());
if (auto fillOp = dyn_cast<linalg::FillOp>(op)) {
// Vectorize fill as a vector.broadcast.
LLVM_DEBUG(dbgs() << dbgPref
<< "Rewrite linalg.fill as vector.broadcast: " << *op);
Value memref = vector_type_cast(fillOp.getOutputBuffer(0));
Value dst = std_load(memref);
Value res = vector_broadcast(dst.getType(), fillOp.value());
std_store(res, memref);
return;
}
// In the case of 0-D memrefs, return null and special case to scalar load or
// store later.
auto extractVectorTypeFromScalarView = [](Value v) {
MemRefType mt = v.getType().cast<MemRefType>();
return mt.getShape().empty()
? VectorType()
: VectorType::get(mt.getShape(), mt.getElementType());
};
if (auto copyOp = dyn_cast<linalg::CopyOp>(op)) {
// Vectorize copy as a vector.transfer_read+vector.transfer_write.
LLVM_DEBUG(dbgs() << dbgPref
<< "Rewrite linalg.copy as vector.transfer_read + "
"vector.transfer_write: "
<< *op);
Value zero = std_constant_index(0);
Value viewInput = copyOp.input();
Value viewOutput = copyOp.output();
Value vector;
if (VectorType inputType = extractVectorTypeFromScalarView(viewInput)) {
SmallVector<Value, 4> indicesInput(inputType.getRank(), zero);
if (copyOp.inputPermutation())
vector = vector_transfer_read(
extractVectorTypeFromScalarView(viewInput), viewInput, indicesInput,
copyOp.inputPermutation().getValue());
else
vector =
vector_transfer_read(extractVectorTypeFromScalarView(viewInput),
viewInput, indicesInput);
} else {
vector = std_load(viewInput).value;
}
if (VectorType outputType = extractVectorTypeFromScalarView(viewOutput)) {
SmallVector<Value, 4> indicesOutput(outputType.getRank(), zero);
if (copyOp.outputPermutation())
vector_transfer_write(vector, viewOutput, indicesOutput,
copyOp.outputPermutation().getValue());
else
vector_transfer_write(vector, viewOutput, indicesOutput);
} else {
std_store(vector, viewOutput);
}
return;
}
assert(succeeded(isContraction(op)) && "Expected contraction");
// Vectorize other ops as vector contraction.
// TODO: interface.
LLVM_DEBUG(dbgs() << dbgPref
<< "Rewrite linalg op as vector.contract: " << *op);
auto linalgOp = cast<linalg::LinalgOp>(op);
Value viewA = linalgOp.getInput(0);
Value viewB = linalgOp.getInput(1);
Value viewC = linalgOp.getOutputBuffer(0);
VectorType vtA = extractVectorTypeFromScalarView(viewA);
VectorType vtB = extractVectorTypeFromScalarView(viewB);
VectorType vtC = extractVectorTypeFromScalarView(viewC);
Value zero = std_constant_index(0);
SmallVector<Value, 4> indicesA, indicesB, indicesC;
if (vtA)
indicesA = SmallVector<Value, 4>(vtA.getRank(), zero);
if (vtB)
indicesB = SmallVector<Value, 4>(vtB.getRank(), zero);
if (vtC)
indicesC = SmallVector<Value, 4>(vtC.getRank(), zero);
Value a = vtA ? vector_transfer_read(vtA, viewA, indicesA).value
: std_load(viewA, indicesA).value;
Value b = vtB ? vector_transfer_read(vtB, viewB, indicesB).value
: std_load(viewB, indicesB).value;
Value c = vtC ? vector_transfer_read(vtC, viewC, indicesC).value
: std_load(viewC, indicesC).value;
Value res = vector_contract(a, b, c, linalgOp.indexing_maps(),
linalgOp.iterator_types());
if (vtC)
vector_transfer_write(res, viewC, indicesC);
else
std_store(res, viewC, indicesC);
}
/// Check whether there is any interleaved use of any `values` between `firstOp`
/// and `secondOp`. Conservatively return `true` if any op or value is in a
/// different block.
static bool mayExistInterleavedUses(Operation *firstOp, Operation *secondOp,
ValueRange values) {
StringRef dbgPref = "\n[" DEBUG_TYPE "]: ";
(void)dbgPref;
if (firstOp->getBlock() != secondOp->getBlock() ||
!firstOp->isBeforeInBlock(secondOp)) {
LLVM_DEBUG(llvm::dbgs()
<< dbgPref << "interleavedUses precondition failed, firstOp: "
<< *firstOp << ", second op: " << *secondOp);
return true;
}
for (auto v : values) {
for (auto &u : v.getUses()) {
Operation *owner = u.getOwner();
if (owner == firstOp || owner == secondOp)
continue;
// TODO: this is too conservative, use dominance info in the future.
if (owner->getBlock() == firstOp->getBlock() &&
(owner->isBeforeInBlock(firstOp) || secondOp->isBeforeInBlock(owner)))
continue;
LLVM_DEBUG(llvm::dbgs()
<< dbgPref << " found interleaved op " << *owner
<< ", firstOp: " << *firstOp << ", second op: " << *secondOp);
return true;
}
}
return false;
}
/// Return the unique subview use of `v` if it is indeed unique, null otherwise.
static SubViewOp getSubViewUseIfUnique(Value v) {
SubViewOp subViewOp;
for (auto &u : v.getUses()) {
if (auto newSubViewOp = dyn_cast<SubViewOp>(u.getOwner())) {
if (subViewOp)
return SubViewOp();
subViewOp = newSubViewOp;
}
}
return subViewOp;
}
/// TODO: use interfaces, side-effects and aliasing analysis as appropriate,
/// when available.
LogicalResult LinalgCopyVTRForwardingPattern::matchAndRewrite(
vector::TransferReadOp xferOp, PatternRewriter &rewriter) const {
// Transfer into `view`.
Value viewOrAlloc = xferOp.memref();
if (!viewOrAlloc.getDefiningOp<ViewOp>() &&
!viewOrAlloc.getDefiningOp<AllocOp>())
return failure();
StringRef dbgPref = "\n[" DEBUG_TYPE "]: VTRForwarding: ";
(void)dbgPref;
LLVM_DEBUG(llvm::dbgs() << dbgPref << viewOrAlloc);
// Ensure there is exactly one subview of `viewOrAlloc` defining `subView`.
SubViewOp subViewOp = getSubViewUseIfUnique(viewOrAlloc);
if (!subViewOp)
return failure();
Value subView = subViewOp.getResult();
LLVM_DEBUG(llvm::dbgs() << dbgPref << "with subView " << subView);
// Find the copy into `subView` without interleaved uses.
CopyOp copyOp;
for (auto &u : subView.getUses()) {
if (auto newCopyOp = dyn_cast<CopyOp>(u.getOwner())) {
if (newCopyOp.getOutputBuffer(0) != subView)
continue;
LLVM_DEBUG(llvm::dbgs() << dbgPref << "copy candidate " << *newCopyOp);
if (mayExistInterleavedUses(newCopyOp, xferOp, {viewOrAlloc, subView}))
continue;
copyOp = newCopyOp;
break;
}
}
if (!copyOp)
return failure();
LLVM_DEBUG(llvm::dbgs() << dbgPref << "with copy " << *copyOp);
// Find the fill into `viewOrAlloc` without interleaved uses before the copy.
FillOp maybeFillOp;
for (auto &u : viewOrAlloc.getUses()) {
if (auto newFillOp = dyn_cast<FillOp>(u.getOwner())) {
if (newFillOp.getOutputBuffer(0) != viewOrAlloc)
continue;
LLVM_DEBUG(llvm::dbgs() << dbgPref << "fill candidate " << *newFillOp);
if (mayExistInterleavedUses(newFillOp, copyOp, {viewOrAlloc, subView}))
continue;
maybeFillOp = newFillOp;
break;
}
}
// Ensure padding matches.
if (maybeFillOp && xferOp.padding() != maybeFillOp.value())
return failure();
if (maybeFillOp)
LLVM_DEBUG(llvm::dbgs() << dbgPref << "with maybeFillOp " << *maybeFillOp);
// `in` is the subview that linalg.copy reads. Replace it.
Value in = copyOp.getInput(0);
// linalg.copy + linalg.fill can be used to create a padded local buffer.
// The `masked` attribute is only valid on this padded buffer.
// When forwarding to vector.transfer_read, the attribute must be reset
// conservatively.
Value res = rewriter.create<vector::TransferReadOp>(
xferOp.getLoc(), xferOp.getVectorType(), in, xferOp.indices(),
xferOp.permutation_map(), xferOp.padding(), ArrayAttr());
if (maybeFillOp)
rewriter.eraseOp(maybeFillOp);
rewriter.eraseOp(copyOp);
rewriter.replaceOp(xferOp, res);
return success();
}
/// TODO: use interfaces, side-effects and aliasing analysis as appropriate,
/// when available.
LogicalResult LinalgCopyVTWForwardingPattern::matchAndRewrite(
vector::TransferWriteOp xferOp, PatternRewriter &rewriter) const {
// Transfer into `viewOrAlloc`.
Value viewOrAlloc = xferOp.memref();
if (!viewOrAlloc.getDefiningOp<ViewOp>() &&
!viewOrAlloc.getDefiningOp<AllocOp>())
return failure();
// Ensure there is exactly one subview of `viewOrAlloc` defining `subView`.
SubViewOp subViewOp = getSubViewUseIfUnique(viewOrAlloc);
if (!subViewOp)
return failure();
Value subView = subViewOp.getResult();
// Find the copy from `subView` without interleaved uses.
CopyOp copyOp;
for (auto &u : subViewOp.getResult().getUses()) {
if (auto newCopyOp = dyn_cast<CopyOp>(u.getOwner())) {
if (newCopyOp.getInput(0) != subView)
continue;
if (mayExistInterleavedUses(xferOp, newCopyOp, {viewOrAlloc, subView}))
continue;
copyOp = newCopyOp;
break;
}
}
if (!copyOp)
return failure();
// `out` is the subview copied into that we replace.
Value out = copyOp.getOutputBuffer(0);
// Forward vector.transfer into copy.
// linalg.copy + linalg.fill can be used to create a padded local buffer.
// The `masked` attribute is only valid on this padded buffer.
// When forwarding to vector.transfer_write, the attribute must be reset
// conservatively.
rewriter.create<vector::TransferWriteOp>(
xferOp.getLoc(), xferOp.vector(), out, xferOp.indices(),
xferOp.permutation_map(), ArrayAttr());
rewriter.eraseOp(copyOp);
rewriter.eraseOp(xferOp);
return success();
}
template <class ConvOp, int N>
LogicalResult ConvOpVectorization<ConvOp, N>::matchAndRewrite(
ConvOp op, PatternRewriter &rewriter) const {
const unsigned dimSize = 3;
Location loc = op.getLoc();
MLIRContext *context = op.getContext();
edsc::ScopedContext scope(rewriter, loc);
ShapedType inShapeType = op.getInputShapedType(0);
ShapedType kShapeType = op.getInputShapedType(1);
ArrayRef<int64_t> inShape = inShapeType.getShape();
ArrayRef<int64_t> kShape = kShapeType.getShape();
if (!inShapeType.hasStaticShape() || !kShapeType.hasStaticShape())
return failure();
SmallVector<AffineExpr, 4> mapping;
// Fail to apply when the size of not vectorized dimension is not 1 or
// when the size of vectorized dimension is not dimSize.
for (unsigned i = 0; i < N; i++) {
if (!mask[i] && (inShape[i] != 1 || kShape[i] != 1))
return failure();
if (mask[i] && (inShape[i] != dimSize || kShape[i] != dimSize))
return failure();
if (mask[i])
mapping.push_back(getAffineDimExpr(i, context));
}
Value input = op.getInput(0);
Value kernel = op.getInput(1);
Value output = op.getOutputBuffer(0);
unsigned rank = inShapeType.getRank();
unsigned numDims = mapping.size();
Type elemType = inShapeType.getElementType();
auto map = AffineMap::get(rank, 0, mapping, context);
SmallVector<Value, 4> zeros(rank, std_constant_index(0));
auto vecType =
VectorType::get(SmallVector<int64_t, 4>(numDims, dimSize), elemType);
auto inputVec = vector_transfer_read(vecType, input, zeros, map);
auto kernelVec = vector_transfer_read(vecType, kernel, zeros, map);
auto acc = std_constant(elemType, rewriter.getZeroAttr(elemType));
std::array<AffineMap, 3> indexingMaps{
AffineMap::getMultiDimIdentityMap(numDims, context),
AffineMap::getMultiDimIdentityMap(numDims, context),
AffineMap::get(numDims, 0, {}, context)};
std::vector<StringRef> iteratorTypes(numDims, "reduction");
auto result = rewriter.create<vector::ContractionOp>(
loc, inputVec, kernelVec, acc,
rewriter.getAffineMapArrayAttr(indexingMaps),
rewriter.getStrArrayAttr(iteratorTypes));
rewriter.create<StoreOp>(loc, result, output, ValueRange(zeros));
rewriter.eraseOp(op);
return success();
}
void mlir::linalg::populateConvVectorizationPatterns(
MLIRContext *context, OwningRewritePatternList &patterns) {
patterns.insert<ConvOpVectorization<linalg::ConvWOp, 1>>(
context, SmallVector<bool, 4>{true});
patterns.insert<ConvOpVectorization<linalg::ConvNWCOp, 3>>(
context, SmallVector<bool, 4>{false, true, true});
patterns.insert<ConvOpVectorization<linalg::ConvNCWOp, 3>>(
context, SmallVector<bool, 4>{false, true, true});
patterns.insert<ConvOpVectorization<linalg::ConvHWOp, 2>>(
context, SmallVector<bool, 4>{true, true});
patterns.insert<ConvOpVectorization<linalg::ConvNHWCOp, 4>>(
context, SmallVector<bool, 4>{false, true, true, true});
patterns.insert<ConvOpVectorization<linalg::ConvNCHWOp, 4>>(
context, SmallVector<bool, 4>{false, true, true, true});
patterns.insert<ConvOpVectorization<linalg::ConvDHWOp, 3>>(
context, SmallVector<bool, 4>{true, true, true});
patterns.insert<ConvOpVectorization<linalg::ConvNDHWCOp, 5>>(
context, SmallVector<bool, 4>{false, true, true, true, true});
patterns.insert<ConvOpVectorization<linalg::ConvNCDHWOp, 5>>(
context, SmallVector<bool, 4>{false, true, true, true, true});
}