Files
clang-p2996/mlir/lib/Conversion/GPUToNVVM/WmmaOpsToNvvm.cpp
Jeff Niu 5c5af910fe [mlir][LLVMIR] "Modernize" Insert/ExtractValueOp
This patch "modernizes" the LLVM `insertvalue` and `extractvalue`
operations to use DenseI64ArrayAttr, since they only require an array of
indices and previously there was confusion about whether to use i32 or
i64 arrays, and to use assembly format.

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D131537
2022-08-10 12:51:11 -04:00

369 lines
16 KiB
C++

//===------ WmmaOpsToNVVM.cpp - WMMA LD/ST/Compute to NVVM lowering -------===//
//
// 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 contains definitions of patterns to lower GPU Subgroup MMA ops to
// NVVM Dialect.
//
//===----------------------------------------------------------------------===//
#include "mlir/Conversion/GPUToNVVM/GPUToNVVMPass.h"
#include "mlir/Conversion/LLVMCommon/Pattern.h"
#include "mlir/Dialect/GPU/IR/GPUDialect.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/Dialect/LLVMIR/NVVMDialect.h"
#include "mlir/IR/TypeUtilities.h"
using namespace mlir;
namespace {
/// Checks if all the operands of the op being lowered are of LLVM Types. The
/// types are expected to be converted by the `LLVMTypeConverter` before the op
/// is actually lowered. If the type of an operands is not already converted it
/// hints a missing typeConversion and failure is returned in that case.
static LogicalResult areAllLLVMTypes(Operation *op, ValueRange operands,
ConversionPatternRewriter &rewriter) {
if (!llvm::all_of(operands, [](Value value) {
return LLVM::isCompatibleType(value.getType());
})) {
return rewriter.notifyMatchFailure(
op, "cannot convert if operands aren't of LLVM type.");
}
return success();
}
/// Error string to emit when an unimplemented WMMA variant is encountered.
static constexpr StringRef kInvalidCaseStr = "Unsupported WMMA variant.";
static NVVM::MMAFrag convertOperand(StringRef operandName) {
if (operandName.equals("AOp"))
return NVVM::MMAFrag::a;
if (operandName.equals("BOp"))
return NVVM::MMAFrag::b;
if (operandName.equals("COp"))
return NVVM::MMAFrag::c;
llvm_unreachable("Unknown operand name");
}
static NVVM::MMATypes getElementType(gpu::MMAMatrixType type) {
if (type.getElementType().isF16())
return NVVM::MMATypes::f16;
if (type.getElementType().isF32())
return type.getOperand().equals("COp") ? NVVM::MMATypes::f32
: NVVM::MMATypes::tf32;
llvm_unreachable("Unsupported type");
}
/// This class implements the conversion of GPU MMA loadOp to wmma.load op
/// in the NVVM dialect. The conversion not only emits the NVVM op but also
/// emits code that is necessary to store the data in the destination memref
/// after it has been loaded.
struct WmmaLoadOpToNVVMLowering
: public ConvertOpToLLVMPattern<gpu::SubgroupMmaLoadMatrixOp> {
using ConvertOpToLLVMPattern<
gpu::SubgroupMmaLoadMatrixOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(gpu::SubgroupMmaLoadMatrixOp subgroupMmaLoadMatrixOp,
OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
Operation *op = subgroupMmaLoadMatrixOp.getOperation();
if (failed(areAllLLVMTypes(op, adaptor.getOperands(), rewriter)))
return failure();
// Get the shape of the MMAMatrix type being returned. The shape will
// choose which intrinsic this op will be lowered to.
gpu::MMAMatrixType retType =
subgroupMmaLoadMatrixOp.res().getType().cast<gpu::MMAMatrixType>();
ArrayRef<int64_t> retTypeShape = retType.getShape();
int64_t m = 0;
int64_t n = 0;
int64_t k = 0;
NVVM::MMATypes eltype = getElementType(retType);
// NVVM intrinsics require to give mxnxk dimensions, infer the missing
// dimension based on the valid intrinsics available.
if (retType.getOperand().equals("AOp")) {
m = retTypeShape[0];
k = retTypeShape[1];
n = NVVM::WMMALoadOp::inferNDimension(m, k, eltype);
} else if (retType.getOperand().equals("BOp")) {
k = retTypeShape[0];
n = retTypeShape[1];
m = NVVM::WMMALoadOp::inferMDimension(k, n, eltype);
} else if (retType.getOperand().equals("COp")) {
m = retTypeShape[0];
n = retTypeShape[1];
k = NVVM::WMMALoadOp::inferKDimension(m, n, eltype);
}
NVVM::MMALayout layout = NVVM::MMALayout::row;
NVVM::MMAFrag frag = convertOperand(retType.getOperand());
// Check that there is an exisiting instruction for the combination we need.
if (NVVM::WMMALoadOp::getIntrinsicID(m, n, k, layout, eltype, frag) == 0)
return rewriter.notifyMatchFailure(op, kInvalidCaseStr);
Type resType = convertMMAToLLVMType(retType);
Location loc = op->getLoc();
// Create nvvm.mma_load op according to the operand types.
Value dataPtr = getStridedElementPtr(
loc, subgroupMmaLoadMatrixOp.srcMemref().getType().cast<MemRefType>(),
adaptor.srcMemref(), adaptor.indices(), rewriter);
Value leadingDim = rewriter.create<LLVM::ConstantOp>(
loc, rewriter.getI32Type(),
subgroupMmaLoadMatrixOp.leadDimensionAttr());
rewriter.replaceOpWithNewOp<NVVM::WMMALoadOp>(
op, resType, dataPtr, leadingDim, m, n, k, layout, eltype, frag);
return success();
}
};
/// This class implements the conversion of GPU MMA storeOp to wmma.store op
/// in the NVVM dialect. The conversion not only emits the NVVM op but also
/// emits code that is necessary to unpack the data in the source and
/// convert the data in the format that is needed by the NVVM op.
struct WmmaStoreOpToNVVMLowering
: public ConvertOpToLLVMPattern<gpu::SubgroupMmaStoreMatrixOp> {
using ConvertOpToLLVMPattern<
gpu::SubgroupMmaStoreMatrixOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(gpu::SubgroupMmaStoreMatrixOp subgroupMmaStoreMatrixOp,
OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
Operation *op = subgroupMmaStoreMatrixOp.getOperation();
if (failed(areAllLLVMTypes(op, adaptor.getOperands(), rewriter)))
return failure();
Location loc = op->getLoc();
SmallVector<Value, 4> storeOpOperands;
// Get the shape of the MMAMatrix type being stored. The shape will
// choose which intrinsic this op will be lowered to.
gpu::MMAMatrixType srcType =
subgroupMmaStoreMatrixOp.src().getType().cast<gpu::MMAMatrixType>();
ArrayRef<int64_t> srcTypeShape = srcType.getShape();
NVVM::MMALayout layout = NVVM::MMALayout::row;
NVVM::MMATypes eltype = getElementType(srcType);
int64_t m = srcTypeShape[0];
int64_t n = srcTypeShape[1];
int64_t k = NVVM::WMMAStoreOp::inferKDimension(m, n, eltype);
if (NVVM::WMMAStoreOp::getIntrinsicID(m, n, k, layout, eltype) == 0)
return rewriter.notifyMatchFailure(op, kInvalidCaseStr);
auto matrixType = adaptor.src().getType().cast<LLVM::LLVMStructType>();
for (unsigned i = 0, e = matrixType.getBody().size(); i < e; ++i) {
Value toUse =
rewriter.create<LLVM::ExtractValueOp>(loc, adaptor.src(), i);
storeOpOperands.push_back(toUse);
}
Value dataPtr = getStridedElementPtr(
loc, subgroupMmaStoreMatrixOp.dstMemref().getType().cast<MemRefType>(),
adaptor.dstMemref(), adaptor.indices(), rewriter);
Value leadingDim = rewriter.create<LLVM::ConstantOp>(
loc, rewriter.getI32Type(),
subgroupMmaStoreMatrixOp.leadDimensionAttr());
rewriter.replaceOpWithNewOp<NVVM::WMMAStoreOp>(
op, dataPtr, m, n, k, layout, eltype, storeOpOperands, leadingDim);
return success();
}
};
/// This class implements the conversion of GPU MMA computeOp to wmma.mma op
/// in the NVVM dialect.
struct WmmaMmaOpToNVVMLowering
: public ConvertOpToLLVMPattern<gpu::SubgroupMmaComputeOp> {
using ConvertOpToLLVMPattern<
gpu::SubgroupMmaComputeOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(gpu::SubgroupMmaComputeOp subgroupMmaComputeOp,
OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
Operation *op = subgroupMmaComputeOp.getOperation();
if (failed(areAllLLVMTypes(op, adaptor.getOperands(), rewriter)))
return failure();
Location loc = op->getLoc();
// The wmma.mma intrinsic in llvm requires the operands as individual
// values. So individual elements from the memrefs need to be extracted and
// then passed on to the intrinsic call. Emit llvm ops to extract individual
// values form lowered memrefs.
SmallVector<Value> unpackedOps;
auto unpackOp = [&](Value operand) {
auto structType = operand.getType().cast<LLVM::LLVMStructType>();
for (size_t i = 0, e = structType.getBody().size(); i < e; ++i) {
Value toUse = rewriter.create<LLVM::ExtractValueOp>(loc, operand, i);
unpackedOps.push_back(toUse);
}
};
// Get the shapes of the MMAMatrix type being used. The shapes will
// choose which intrinsic this op will be lowered to.
gpu::MMAMatrixType aType =
subgroupMmaComputeOp.opA().getType().cast<gpu::MMAMatrixType>();
ArrayRef<int64_t> aTypeShape = aType.getShape();
gpu::MMAMatrixType cType =
subgroupMmaComputeOp.opC().getType().cast<gpu::MMAMatrixType>();
ArrayRef<int64_t> cTypeShape = cType.getShape();
int64_t m = cTypeShape[0];
int64_t n = cTypeShape[1];
int64_t k = aTypeShape[1];
NVVM::MMALayout layout = NVVM::MMALayout::row;
NVVM::MMATypes sourceType = getElementType(aType);
NVVM::MMATypes destType = getElementType(cType);
if (NVVM::WMMAMmaOp::getIntrinsicID(m, n, k, layout, layout, sourceType,
destType) == 0)
return rewriter.notifyMatchFailure(op, kInvalidCaseStr);
unpackOp(adaptor.opA());
unpackOp(adaptor.opB());
unpackOp(adaptor.opC());
rewriter.replaceOpWithNewOp<NVVM::WMMAMmaOp>(
op, adaptor.opC().getType(), m, n, k, layout, layout, sourceType,
destType, unpackedOps);
return success();
}
};
/// Convert GPU MMA ConstantMatrixOp to a chain of InsertValueOp.
struct WmmaConstantOpToNVVMLowering
: public ConvertOpToLLVMPattern<gpu::SubgroupMmaConstantMatrixOp> {
using ConvertOpToLLVMPattern<
gpu::SubgroupMmaConstantMatrixOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(gpu::SubgroupMmaConstantMatrixOp subgroupMmaConstantOp,
OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
if (failed(areAllLLVMTypes(subgroupMmaConstantOp.getOperation(),
adaptor.getOperands(), rewriter)))
return failure();
Location loc = subgroupMmaConstantOp.getLoc();
Value cst = adaptor.getOperands()[0];
LLVM::LLVMStructType type = convertMMAToLLVMType(
subgroupMmaConstantOp.getType().cast<gpu::MMAMatrixType>());
// If the element type is a vector create a vector from the operand.
if (auto vecType = type.getBody()[0].dyn_cast<VectorType>()) {
Value vecCst = rewriter.create<LLVM::UndefOp>(loc, vecType);
for (int64_t vecEl = 0; vecEl < vecType.getNumElements(); vecEl++) {
Value idx = rewriter.create<LLVM::ConstantOp>(
loc, rewriter.getI32Type(), vecEl);
vecCst = rewriter.create<LLVM::InsertElementOp>(loc, vecType, vecCst,
cst, idx);
}
cst = vecCst;
}
Value matrixStruct = rewriter.create<LLVM::UndefOp>(loc, type);
for (size_t i : llvm::seq(size_t(0), type.getBody().size())) {
matrixStruct =
rewriter.create<LLVM::InsertValueOp>(loc, matrixStruct, cst, i);
}
rewriter.replaceOp(subgroupMmaConstantOp, matrixStruct);
return success();
}
};
static Value createMinMaxF(OpBuilder &builder, Location loc, Value lhs,
Value rhs, bool isMin) {
auto floatType = getElementTypeOrSelf(lhs.getType()).cast<FloatType>();
Type i1Type = builder.getI1Type();
if (auto vecType = lhs.getType().dyn_cast<VectorType>())
i1Type = VectorType::get(vecType.getShape(), i1Type);
Value cmp = builder.create<LLVM::FCmpOp>(
loc, i1Type, isMin ? LLVM::FCmpPredicate::olt : LLVM::FCmpPredicate::ogt,
lhs, rhs);
Value sel = builder.create<LLVM::SelectOp>(loc, cmp, lhs, rhs);
Value isNan = builder.create<LLVM::FCmpOp>(
loc, i1Type, LLVM::FCmpPredicate::uno, lhs, rhs);
Value nan = builder.create<LLVM::ConstantOp>(
loc, lhs.getType(),
builder.getFloatAttr(floatType,
APFloat::getQNaN(floatType.getFloatSemantics())));
return builder.create<LLVM::SelectOp>(loc, isNan, nan, sel);
}
static Value createScalarOp(OpBuilder &builder, Location loc,
gpu::MMAElementwiseOp op,
ArrayRef<Value> operands) {
switch (op) {
case gpu::MMAElementwiseOp::ADDF:
return builder.create<LLVM::FAddOp>(loc, operands[0].getType(), operands);
case gpu::MMAElementwiseOp::MULF:
return builder.create<LLVM::FMulOp>(loc, operands[0].getType(), operands);
case gpu::MMAElementwiseOp::DIVF:
return builder.create<LLVM::FDivOp>(loc, operands[0].getType(), operands);
case gpu::MMAElementwiseOp::MAXF:
return createMinMaxF(builder, loc, operands[0], operands[1],
/*isMin=*/false);
case gpu::MMAElementwiseOp::MINF:
return createMinMaxF(builder, loc, operands[0], operands[1],
/*isMin=*/true);
}
llvm_unreachable("unknown op");
}
/// Convert GPU MMA elementwise ops to extract + op + insert.
struct WmmaElementwiseOpToNVVMLowering
: public ConvertOpToLLVMPattern<gpu::SubgroupMmaElementwiseOp> {
using ConvertOpToLLVMPattern<
gpu::SubgroupMmaElementwiseOp>::ConvertOpToLLVMPattern;
LogicalResult
matchAndRewrite(gpu::SubgroupMmaElementwiseOp subgroupMmaElementwiseOp,
OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
if (failed(areAllLLVMTypes(subgroupMmaElementwiseOp.getOperation(),
adaptor.getOperands(), rewriter)))
return failure();
Location loc = subgroupMmaElementwiseOp.getLoc();
size_t numOperands = adaptor.getOperands().size();
LLVM::LLVMStructType destType = convertMMAToLLVMType(
subgroupMmaElementwiseOp.getType().cast<gpu::MMAMatrixType>());
Value matrixStruct = rewriter.create<LLVM::UndefOp>(loc, destType);
for (size_t i = 0, e = destType.getBody().size(); i < e; ++i) {
SmallVector<Value> extractedOperands;
for (size_t opIdx = 0; opIdx < numOperands; opIdx++) {
extractedOperands.push_back(rewriter.create<LLVM::ExtractValueOp>(
loc, adaptor.getOperands()[opIdx], i));
}
Value element =
createScalarOp(rewriter, loc, subgroupMmaElementwiseOp.operation(),
extractedOperands);
matrixStruct =
rewriter.create<LLVM::InsertValueOp>(loc, matrixStruct, element, i);
}
rewriter.replaceOp(subgroupMmaElementwiseOp, matrixStruct);
return success();
}
};
} // namespace
/// Return the LLVMStructureType corresponding to the MMAMatrixType `type`.
LLVM::LLVMStructType mlir::convertMMAToLLVMType(gpu::MMAMatrixType type) {
NVVM::MMAFrag frag = convertOperand(type.getOperand());
NVVM::MMATypes eltType = getElementType(type);
std::pair<Type, unsigned> typeInfo =
NVVM::inferMMAType(eltType, frag, type.getContext());
return LLVM::LLVMStructType::getLiteral(
type.getContext(), SmallVector<Type, 8>(typeInfo.second, typeInfo.first));
}
void mlir::populateGpuWMMAToNVVMConversionPatterns(
LLVMTypeConverter &converter, RewritePatternSet &patterns) {
patterns.add<WmmaLoadOpToNVVMLowering, WmmaMmaOpToNVVMLowering,
WmmaStoreOpToNVVMLowering, WmmaConstantOpToNVVMLowering,
WmmaElementwiseOpToNVVMLowering>(converter);
}