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//===---- XeGPUUtils.cpp - MLIR Utilities for XeGPUOps ------------------===//
//
// Part of the MLIR 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 utility methods for working with the XeGPU dialect.
//
//===----------------------------------------------------------------------===//
#include "mlir/Dialect/XeGPU/Utils/XeGPUUtils.h"
#include "mlir/Dialect/GPU/IR/GPUDialect.h"
#include "mlir/Dialect/Index/IR/IndexOps.h"
#include "mlir/Dialect/LLVMIR/XeVMDialect.h"
#include "mlir/Dialect/SCF/Transforms/Patterns.h"
#include "mlir/Dialect/Utils/IndexingUtils.h"
#include "mlir/Dialect/XeGPU/IR/XeGPU.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/Operation.h"
#include "mlir/IR/ValueRange.h"
#include "mlir/Interfaces/LoopLikeInterface.h"
#include "mlir/Transforms/DialectConversion.h"
#include "llvm/Support/FormatVariadic.h"
#include <cstdint>
#include <numeric>
using namespace mlir;
/// convert ArrayRef<ValueRange> into SmallVector<Value>
SmallVector<Value> xegpu::flattenValues(ArrayRef<ValueRange> values) {
SmallVector<Value> result;
for (const auto &vals : values)
llvm::append_range(result, vals);
return result;
}
FailureOr<VectorType>
mlir::xegpu::getDistributedVectorType(xegpu::TensorDescType tdescTy) {
auto layout = llvm::dyn_cast_if_present<LayoutAttr>(tdescTy.getLayout());
// It only works for subgroup level layout, which only has lane_layout
// and lane_data, and is to distribute a SIMD code into SIMT code.
if (!layout || !layout.isForSubgroup())
return failure();
SmallVector<int64_t> laneData(layout.getLaneData().asArrayRef());
SmallVector<int64_t> laneLayout(layout.getLaneLayout().asArrayRef());
auto tdescShape = tdescTy.getShape();
auto elementType = tdescTy.getElementType();
// compute sgSize by multiply elements of laneLayout
// e.g. for 2D layout, sgSize = laneLayout[0] * laneLayout[1]
// e.g. for 1D layout, sgSize = laneLayout[0]
auto sgSize = std::accumulate(laneLayout.begin(), laneLayout.end(), 1,
std::multiplies<int64_t>());
// Case 1: regular loads/stores
auto scatterAttr = tdescTy.getEncodingOfType<ScatterTensorDescAttr>();
if (scatterAttr) {
auto chunkSize = scatterAttr.getChunkSize().getInt();
// Verify if the first dimension of the tensor descriptor shape is
// distributable.
assert(tdescShape[0] == laneLayout[0] &&
"tensor descriptor shape is not distributable");
return VectorType::get({chunkSize}, elementType);
}
// Case 2: block loads/stores
// Check if the tensor descriptor shape is distributable.
int64_t tensorSize = 1;
for (auto [tdescDim, laneDim, laneDataDim] :
llvm::zip_equal(tdescShape, laneLayout, laneData)) {
assert((tdescDim % (laneDim * laneDataDim) == 0) &&
"tensor descriptor shape is not distributable");
tensorSize *= tdescDim;
}
// tensorSize must be adjusted for array_length.
tensorSize *= tdescTy.getArrayLength();
return VectorType::get({tensorSize / sgSize}, elementType);
}
FailureOr<VectorType>
mlir::xegpu::getDistributedVectorType(VectorType originalType,
xegpu::LayoutAttr layout) {
int64_t rank = originalType.getRank();
// Distributed vector type is only supported for 1D, 2D and 3D vectors.
if (rank < 1 || rank > 3)
return failure();
ArrayRef<int64_t> shape = originalType.getShape();
// arrayLength is 1 for 1D and 2D vectors, and equal to the first dimension
// of the 3D vector.
int arrayLength = 1;
if (rank == 3) {
arrayLength = shape[0];
shape = shape.drop_front();
}
auto helperTdescTy = xegpu::TensorDescType::get(
shape, originalType.getElementType(), arrayLength,
/*boundary_check=*/true,
/*memory_space=*/xegpu::MemorySpace::Global, layout);
return xegpu::getDistributedVectorType(helperTdescTy);
}
std::string xegpu::getLayoutName(const OpOperand &operand) {
const StringRef prefix("layout_operand_");
unsigned idx = const_cast<OpOperand &>(operand).getOperandNumber();
return llvm::formatv("{0}{1}", prefix, idx).str();
}
std::string xegpu::getLayoutName(const OpResult result) {
const StringRef prefix = "layout_result_";
return llvm::formatv("{0}{1}", prefix, result.getResultNumber()).str();
}
xegpu::LayoutAttr xegpu::getLayoutAttr(const Value value) {
if (!value)
return nullptr;
if (auto tdescTy =
dyn_cast_if_present<xegpu::TensorDescType>(value.getType()))
return tdescTy.getLayoutAttr();
if (auto result = dyn_cast<OpResult>(value)) {
Operation *defOp = result.getDefiningOp();
assert(defOp && "result must have a defining op");
// For ConvertLayoutOp, the layout is stored in the targetLayoutAttr
if (auto convertOp = dyn_cast<xegpu::ConvertLayoutOp>(defOp))
return convertOp.getTargetLayoutAttr();
// for LoadNdOp, the layout is stored in the tensor descriptor
if (auto loadNd = dyn_cast<xegpu::LoadNdOp>(defOp))
return getLayoutAttr(loadNd.getTensorDesc());
std::string layoutName = getLayoutName(result);
if (defOp->hasAttr(layoutName))
return defOp->getAttrOfType<xegpu::LayoutAttr>(layoutName);
}
if (auto arg = dyn_cast<BlockArgument>(value)) {
auto parentOp = arg.getOwner()->getParentOp();
if (auto loop = dyn_cast<LoopLikeOpInterface>(parentOp)) {
OpOperand *tiedInit = loop.getTiedLoopInit(arg);
if (tiedInit)
return getLayoutAttr(tiedInit->get());
}
}
return nullptr;
}
xegpu::LayoutAttr xegpu::getLayoutAttr(const OpOperand &opr) {
Operation *op = opr.getOwner();
std::string layoutName = xegpu::getLayoutName(opr);
if (op->hasAttr(layoutName))
return op->getAttrOfType<xegpu::LayoutAttr>(layoutName);
return getLayoutAttr(opr.get());
}
template <typename T, typename>
void xegpu::setLayoutAttr(const T &operandOrResult, const LayoutAttr layout) {
Operation *owner = operandOrResult.getOwner();
std::string name = xegpu::getLayoutName(operandOrResult);
if (layout && !owner->hasAttrOfType<LayoutAttr>(name))
owner->setAttr(name, layout);
}
// Explicit instantiation for OpResult
template void
xegpu::setLayoutAttr<mlir::OpResult>(const mlir::OpResult &result,
const mlir::xegpu::LayoutAttr layout);
// Explicit instantiation for OpOperand
template void
xegpu::setLayoutAttr<mlir::OpOperand>(const mlir::OpOperand &operand,
const mlir::xegpu::LayoutAttr layout);
void xegpu::setLayoutAttrs(Operation *op,
function_ref<LayoutAttr(Value)> getLayoutImpl) {
op->walk([&](Operation *nestOp) {
for (OpOperand &opr : nestOp->getOpOperands()) {
auto layout = getLayoutImpl(opr.get());
setLayoutAttr(opr, layout);
}
for (OpResult result : nestOp->getOpResults()) {
auto layout = getLayoutImpl(result);
setLayoutAttr(result, layout);
}
});
}
template <typename T, typename>
void xegpu::removeLayoutAttr(const T &operandOrResult) {
Operation *owner = operandOrResult.getOwner();
std::string name = xegpu::getLayoutName(operandOrResult);
if (owner->hasAttrOfType<LayoutAttr>(name))
owner->removeAttr(name);
}
// Explicit instantiation for OpResult
template void
xegpu::removeLayoutAttr<mlir::OpResult>(const mlir::OpResult &result);
// Explicit instantiation for OpOperand
template void
xegpu::removeLayoutAttr<mlir::OpOperand>(const mlir::OpOperand &operand);
void xegpu::removeLayoutAttrs(Operation *op) {
op->walk([&](Operation *nestOp) {
for (OpOperand &opr : nestOp->getOpOperands())
removeLayoutAttr(opr);
for (OpResult result : nestOp->getOpResults())
removeLayoutAttr(result);
});
}
SmallVector<Value>
xegpu::extractVectorsWithShapeFromValue(OpBuilder &builder, Location loc,
Value value, ArrayRef<int64_t> shape) {
auto vecTy = dyn_cast<VectorType>(value.getType());
if (!vecTy)
return {value};
ArrayRef<int64_t> srcShape = vecTy.getShape();
if (!computeShapeRatio(srcShape, shape))
return {value};
SmallVector<Value> result;
for (SmallVector<int64_t> offsets : StaticTileOffsetRange(srcShape, shape)) {
SmallVector<int64_t> staticStrides(offsets.size(), 1);
result.push_back(vector::ExtractStridedSliceOp::create(
builder, loc, value, offsets, shape, staticStrides));
}
return result;
}
Value xegpu::createVectorWithShapeFromValues(OpBuilder &builder, Location loc,
ValueRange values,
ArrayRef<int64_t> shape) {
VectorType inputTy = dyn_cast<VectorType>(values[0].getType());
assert(llvm::all_of(values.getTypes(),
[&](Type type) { return type == inputTy; }) &&
"values must be of the same VectorType");
Type elemTy = inputTy.getElementType();
ArrayRef<int64_t> tileShape = inputTy.getShape();
VectorType resultTy = VectorType::get(shape, elemTy);
auto zeroAttr = builder.getZeroAttr(elemTy);
Value result = arith::ConstantOp::create(
builder, loc, resultTy, DenseElementsAttr::get(resultTy, zeroAttr));
for (auto [src, offsets] :
llvm::zip_equal(values, StaticTileOffsetRange(shape, tileShape))) {
SmallVector<int64_t> staticStrides(offsets.size(), 1);
result = vector::InsertStridedSliceOp::create(builder, loc, src, result,
offsets, staticStrides);
}
return result;
}
void xegpu::doSCFStructuralTypeConversionWithTensorType(
Operation *op, TypeConverter converter) {
MLIRContext *context = op->getContext();
auto materializeCast = [](OpBuilder &builder, Type type, ValueRange inputs,
Location loc) -> Value {
return UnrealizedConversionCastOp::create(builder, loc, type, inputs)
.getResult(0);
};
{ // convert VectorType to RankedTensorType for SCF Structural ops
TypeConverter converter;
converter.addConversion([](Type type) -> Type { return type; });
converter.addConversion([](VectorType type) -> Type {
return RankedTensorType::get(type.getShape(), type.getElementType());
});
converter.addSourceMaterialization(materializeCast);
converter.addTargetMaterialization(materializeCast);
mlir::ConversionTarget target(*context);
target.addLegalOp<UnrealizedConversionCastOp>();
mlir::RewritePatternSet patterns(context);
scf::populateSCFStructuralTypeConversionsAndLegality(converter, patterns,
target);
(void)mlir::applyPartialConversion(op, target, std::move(patterns));
}
{ // propagate the layout attribute to RankedTensorType by checking
// BuiltInUnrealizedCastOps
// for VectorType to RankedTensorType cast.
op->walk([](UnrealizedConversionCastOp castOp) {
if (castOp.getNumOperands() != 1 || castOp.getNumResults() != 1)
return WalkResult::skip();
Value input = castOp.getInputs()[0];
Value result = castOp.getResults()[0];
auto inputTy = dyn_cast<VectorType>(input.getType());
auto resultTy = dyn_cast<RankedTensorType>(result.getType());
// Only look at ops casting from VectorType to RankedTensorType
if (!inputTy || !resultTy)
return WalkResult::skip();
xegpu::LayoutAttr layout = xegpu::getLayoutAttr(input);
if (!layout)
return WalkResult::skip();
RankedTensorType newTy = resultTy.cloneWithEncoding(layout);
result.setType(newTy);
// update the arguments if user is a LoopLike op.
for (OpOperand &use : result.getUses()) {
if (auto loop = dyn_cast<LoopLikeOpInterface>(use.getOwner())) {
BlockArgument arg = loop.getTiedLoopRegionIterArg(&use);
arg.setType(newTy);
}
// whileOp has two regions, the BlockArgument of the after region
// is not exposed by LoopLikeOpInterface
if (auto whileOp = dyn_cast<scf::WhileOp>(use.getOwner())) {
unsigned idx = use.getOperandNumber();
BlockArgument arg = whileOp.getAfterArguments()[idx];
arg.setType(newTy);
}
}
return WalkResult::advance();
});
// using yieldOp as anchor to update the result type of its ParentOp
op->walk([](scf::YieldOp yieldOp) {
Operation *parentOp = yieldOp->getParentOp();
for (OpResult r : parentOp->getOpResults()) {
unsigned idx = r.getResultNumber();
Type resultTy = r.getType();
Type yieldTy = yieldOp.getResults()[idx].getType();
if (isa<RankedTensorType>(resultTy) && yieldTy != resultTy)
r.setType(yieldTy);
}
});
}
{ // perform the conversion from RankedTensorType to VectorType based on the
// LayoutAttr
// Handle the UnrealizedConversionCastOp introduced by the first step.
// For vector->RankedTensorType, it will simply forward the inputs.
// For RankedTensorType->vector, it will update the inputs with the
// one from the adaptor.
class UnrealizedConversionCastOpPattern
: public OpConversionPattern<mlir::UnrealizedConversionCastOp> {
using OpConversionPattern<
mlir::UnrealizedConversionCastOp>::OpConversionPattern;
mlir::LogicalResult
matchAndRewrite(mlir::UnrealizedConversionCastOp op,
OneToNOpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto inputs = op.getOperands();
auto outputs = op.getOutputs();
if (inputs.size() != 1 || outputs.size() != 1)
return failure();
auto inputTy = inputs[0].getType();
auto outputTy = outputs[0].getType();
if (isa<VectorType>(inputTy) && isa<RankedTensorType>(outputTy)) {
rewriter.replaceOpWithMultiple(op, adaptor.getInputs());
return success();
}
if (isa<RankedTensorType>(inputTy) && isa<VectorType>(outputTy)) {
SmallVector<Value> values = xegpu::flattenValues(adaptor.getInputs());
auto newOp = UnrealizedConversionCastOp::create(rewriter, op.getLoc(),
outputTy, values);
rewriter.replaceOp(op, newOp);
return success();
}
return failure();
}
};
converter.addSourceMaterialization(materializeCast);
converter.addTargetMaterialization([&](OpBuilder &builder, TypeRange type,
ValueRange inputs, Location loc) {
return UnrealizedConversionCastOp::create(builder, loc, type, inputs)
.getResults();
});
mlir::ConversionTarget target(*context);
target.addDynamicallyLegalOp<UnrealizedConversionCastOp>(
[](UnrealizedConversionCastOp op) {
auto isTensorTy = [](Type type) {
return isa<RankedTensorType>(type);
};
return llvm::none_of(op->getOperandTypes(), isTensorTy) &&
llvm::none_of(op->getResultTypes(), isTensorTy);
});
mlir::RewritePatternSet patterns(context);
patterns.insert<UnrealizedConversionCastOpPattern>(context);
scf::populateSCFStructuralTypeConversionsAndLegality(converter, patterns,
target);
(void)mlir::applyPartialConversion(op, target, std::move(patterns));
}
}
std::optional<std::string> xegpu::getChipStr(Operation *op) {
auto gpuModuleOp = op->getParentOfType<gpu::GPUModuleOp>();
if (!gpuModuleOp)
return std::nullopt;
auto targetAttrs = gpuModuleOp.getTargets();
if (targetAttrs) {
for (auto &attr : *targetAttrs) {
auto xevmAttr = llvm::dyn_cast<xevm::XeVMTargetAttr>(attr);
if (xevmAttr)
return xevmAttr.getChip().str();
}
}
return std::nullopt;
}
/// Generates element-wise addition ops of two arrays with automatic alignment.
/// When the input arrays have different sizes, the shorter array is
/// right-aligned with the longer array, and the unmatched leading elements from
/// the longer array are preserved unchanged. This is commonly used for offset
/// computation where higher-dimensional offsets need to be added to
/// lower-dimensional adjustments.
///
/// Example:
/// lhs = [l1, l2, l3], rhs = [r1, r2]
/// Result: [11, l2+r1, l3+r2]
SmallVector<OpFoldResult>
xegpu::addWithRightAligned(OpBuilder &builder, Location loc,
ArrayRef<OpFoldResult> lhs,
ArrayRef<OpFoldResult> rhs) {
// ensure a is longer than b
ArrayRef<OpFoldResult> a = lhs.size() >= rhs.size() ? lhs : rhs;
ArrayRef<OpFoldResult> b = lhs.size() >= rhs.size() ? rhs : lhs;
SmallVector<OpFoldResult> results(a.take_front(a.size() - b.size()));
a = a.slice(a.size() - b.size());
for (auto [l, r] : llvm::zip(a, b)) {
auto lval = getValueOrCreateConstantIndexOp(builder, loc, l);
auto rval = getValueOrCreateConstantIndexOp(builder, loc, r);
results.push_back(builder.createOrFold<index::AddOp>(loc, lval, rval));
}
return results;
return {};
}