Files
clang-p2996/mlir/lib/Conversion/ArmSMEToLLVM/ArmSMEToLLVM.cpp
Benjamin Maxwell c93b45aaee [mlir][ArmSME] Reword in-memory tile warning (NFC) (#92415)
It did not make sense that this said "all tile operations will go
through memory". Only the operations where the warning is emitted will
go through memory. The message has been updated to reflect that.
2024-05-17 11:20:11 +01:00

990 lines
41 KiB
C++

//===- ArmSMEToLLVM.cpp - Convert ArmSME to LLVM dialect ------------------===//
//
// 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 lowering of ArmSME operations to LLVM intrinsics.
//
//===----------------------------------------------------------------------===//
#include "mlir/Conversion/ArmSMEToLLVM/ArmSMEToLLVM.h"
#include "mlir/Conversion/LLVMCommon/ConversionTarget.h"
#include "mlir/Conversion/LLVMCommon/Pattern.h"
#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/ArmSME/IR/ArmSME.h"
#include "mlir/Dialect/ArmSME/Transforms/Transforms.h"
#include "mlir/Dialect/ArmSME/Utils/Utils.h"
#include "mlir/Dialect/ControlFlow/IR/ControlFlowOps.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/Dialect/MemRef/IR/MemRef.h"
#include "mlir/Dialect/Vector/IR/VectorOps.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Transforms/DialectConversion.h"
namespace mlir {
#define GEN_PASS_DEF_CONVERTARMSMETOLLVM
#include "mlir/Conversion/Passes.h.inc"
} // namespace mlir
using namespace mlir;
namespace {
static constexpr StringLiteral kInMemoryTileIdAttr("arm_sme.in_memory_tile_id");
/// Helper to create an arm_sme.intr.ld1*.(horiz|vert)' intrinsic.
static Operation *createLoadTileSliceIntrinsic(
RewriterBase &rewriter, Location loc, arm_sme::ArmSMETileType type,
arm_sme::TileSliceLayout layout, Value maskOp, Value ptr,
IntegerAttr tileId, Value tileSliceI32) {
if (layout == arm_sme::TileSliceLayout::Horizontal) {
switch (type) {
case arm_sme::ArmSMETileType::ZAB:
return rewriter.create<arm_sme::aarch64_sme_ld1b_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAH:
return rewriter.create<arm_sme::aarch64_sme_ld1h_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAS:
return rewriter.create<arm_sme::aarch64_sme_ld1w_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAD:
return rewriter.create<arm_sme::aarch64_sme_ld1d_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAQ:
return rewriter.create<arm_sme::aarch64_sme_ld1q_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
}
} else {
switch (type) {
case arm_sme::ArmSMETileType::ZAB:
return rewriter.create<arm_sme::aarch64_sme_ld1b_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAH:
return rewriter.create<arm_sme::aarch64_sme_ld1h_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAS:
return rewriter.create<arm_sme::aarch64_sme_ld1w_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAD:
return rewriter.create<arm_sme::aarch64_sme_ld1d_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAQ:
return rewriter.create<arm_sme::aarch64_sme_ld1q_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
break;
}
}
}
/// Helper to create an arm_sme.intr.st1*.(horiz|vert)' intrinsic.
static Operation *createStoreTileSliceIntrinsic(
RewriterBase &rewriter, Location loc, arm_sme::ArmSMETileType type,
arm_sme::TileSliceLayout layout, Value maskOp, Value ptr,
IntegerAttr tileId, Value tileSliceI32) {
if (layout == arm_sme::TileSliceLayout::Horizontal) {
switch (type) {
case arm_sme::ArmSMETileType::ZAB:
return rewriter.create<arm_sme::aarch64_sme_st1b_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAH:
return rewriter.create<arm_sme::aarch64_sme_st1h_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAS:
return rewriter.create<arm_sme::aarch64_sme_st1w_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAD:
return rewriter.create<arm_sme::aarch64_sme_st1d_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAQ:
return rewriter.create<arm_sme::aarch64_sme_st1q_horiz>(
loc, maskOp, ptr, tileId, tileSliceI32);
}
} else {
switch (type) {
case arm_sme::ArmSMETileType::ZAB:
return rewriter.create<arm_sme::aarch64_sme_st1b_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAH:
return rewriter.create<arm_sme::aarch64_sme_st1h_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAS:
return rewriter.create<arm_sme::aarch64_sme_st1w_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAD:
return rewriter.create<arm_sme::aarch64_sme_st1d_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
case arm_sme::ArmSMETileType::ZAQ:
return rewriter.create<arm_sme::aarch64_sme_st1q_vert>(
loc, maskOp, ptr, tileId, tileSliceI32);
}
}
}
IntegerAttr getTileIdOrError(arm_sme::ArmSMETileOpInterface op) {
auto tileId = op.getTileId();
if (!tileId)
op.emitOpError(
"expected tile ID to be allocated before conversion to LLVM");
return tileId;
}
/// Creates an alloca matching the size of tile used by `tileOp`. The alloca is
/// placed in the first block of the function.
static memref::AllocaOp
createAllocaForTile(RewriterBase &rewriter, Location loc,
FunctionOpInterface func,
arm_sme::ArmSMETileOpInterface tileOp) {
RewriterBase::InsertionGuard g(rewriter);
// Move to the first operation in the function.
rewriter.setInsertionPointToStart(&func.getBlocks().front());
// Create an alloca matching the tile size of the `tileOp`.
auto vscale = rewriter.create<vector::VectorScaleOp>(loc);
auto tileElementType = tileOp.getTileType().getElementType();
auto memrefType = MemRefType::get(
{ShapedType::kDynamic, ShapedType::kDynamic}, tileElementType);
unsigned minElements = arm_sme::getSMETileSliceMinNumElts(tileElementType);
auto minElementsOp =
rewriter.create<arith::ConstantIndexOp>(loc, minElements);
auto vectorLen = rewriter.create<arith::MulIOp>(loc, vscale, minElementsOp);
auto alloca = rewriter.create<memref::AllocaOp>(
loc, memrefType, ValueRange{vectorLen, vectorLen});
return alloca;
}
/// Finds or creates an alloca for a spill of a tile.
static memref::AllocaOp getOrCreateAllocaForTile(
RewriterBase &rewriter, Location loc, FunctionOpInterface func,
arm_sme::ArmSMETileOpInterface tileOp, unsigned tileId) {
// Find an alloca at the top of the function tagged with a
// 'arm_sme.in_memory_tile_id' that matches `tileId`.
for (auto &op : func.getBlocks().front()) {
auto alloca = llvm::dyn_cast<memref::AllocaOp>(op);
if (!alloca)
continue;
auto inMemoryTileId = llvm::dyn_cast_or_null<IntegerAttr>(
alloca->getDiscardableAttr(kInMemoryTileIdAttr));
if (!inMemoryTileId)
continue;
if (inMemoryTileId.getInt() == tileId)
return alloca;
}
// Otherwise, create a new alloca:
auto alloca = createAllocaForTile(rewriter, loc, func, tileOp);
alloca->setDiscardableAttr(kInMemoryTileIdAttr,
rewriter.getI32IntegerAttr(tileId));
return alloca;
}
/// Very naive lowering of in-memory tiles (i.e. tiles that were not assigned a
/// hardware tile ID) to ArmSME intrinsics. Currently, this works by assigning
/// the op to tile 0, then emitting a full tile swap between ZA and memory
/// before + after the tile op.
///
/// Example:
///
/// // Note: <IN MEMORY TILE> = tile ID >= 16.
/// arm_sme.tile_op { tile_id = <IN MEMORY TILE> }
///
/// is converted to:
/// // At function entry:
/// %spill = memref.alloca ... : memref<?x?xty>
///
/// // Around op:
/// scf.for %slice_idx {
/// %slice_to_save = "arm_sme.intr.read.horiz" ... <{tile_id = 0 : i32}>
/// "arm_sme.intr.ld1h.horiz"(%spill, %slice_idx) <{tile_id = 0 : i32}>
/// vector.store %slice_to_save, %spill[%slice_idx, %c0]
/// }
/// arm_sme.tile_op { tile_id = 0 }
/// scf.for %slice_idx {
/// %slice_to_save = "arm_sme.intr.read.horiz" ... <{tile_id = 0 : i32}>
/// "arm_sme.intr.ld1h.horiz"(%spill, %slice_idx) <{tile_id = 0 : i32}>
/// vector.store %slice_to_save, %spill[%slice_idx, %c0]
/// }
///
/// Note that these spills/fills are not inserted earlier as concept of a
/// register, and the need to swap the contents, can't really be represented
/// correctly at a high level in MLIR.
///
/// TODO: Reduce the spills/reloads to single slices where possible (and omit
/// redundant reloads). This could be done via a method on the
/// `ArmSMETileOpInterface` which returns how the operation uses ZA. E.g.:
///
/// `tileOp.getZaUsage()` could return:
///
/// struct ArmSMEOpZAUsage {
/// enum class Kind {
/// TileRead, // Omit store after tile operation.
/// TileWrite, // Omit load before tile operation.
/// TileReadWrite, // Needs both tile load and store.
/// SliceRead, // Spill single slice and omit store after operation.
/// SliceWrite, // Spill single slice and omit load before operation.
/// SliceReadWrite // Spill single slice.
/// };
/// Value sliceIndex {};
/// TileSliceLayout sliceLayout { TileSliceLayout::Horizontal };
/// };
///
struct ConvertArmSMESpillsAndFillsToLLVM : public ConvertToLLVMPattern {
ConvertArmSMESpillsAndFillsToLLVM(StringRef rootOpName,
const LLVMTypeConverter &typeConverter,
PatternBenefit benefit)
: ConvertToLLVMPattern(rootOpName, &typeConverter.getContext(),
typeConverter, benefit) {}
LogicalResult
matchAndRewrite(Operation *op, ArrayRef<Value> operands,
ConversionPatternRewriter &rewriter) const override {
auto tileOp = cast<arm_sme::ArmSMETileOpInterface>(op);
// Tile has a real (hardware) tile. No spills/reloads required.
if (!tileOp.isInMemoryTile())
return failure();
tileOp->emitWarning(
"failed to allocate SME virtual tile to operation, tile value will go "
"through memory, expect degraded performance");
// Step 1. Create an alloca for the tile at the top of the function (if one
// does not already exist).
auto loc = tileOp.getLoc();
auto func = tileOp->getParentOfType<FunctionOpInterface>();
auto tileAlloca = getOrCreateAllocaForTile(rewriter, loc, func, tileOp,
tileOp.getTileId().getInt());
// Step 2. Assign the op a real tile ID.
// For simplicity, we always use tile 0 (which always exists).
auto zeroTileId = rewriter.getI32IntegerAttr(0);
rewriter.modifyOpInPlace(tileOp, [&] { tileOp.setTileId(zeroTileId); });
VectorType tileVectorType = tileOp.getTileType();
auto sliceType = VectorType::Builder(tileVectorType).dropDim(0);
auto swapInMemoryTileWithSMETileZero = [&] {
emitFullTileSwap(rewriter, loc, tileAlloca,
*arm_sme::getSMETileType(tileVectorType), sliceType,
zeroTileId);
};
// Step 3. Emit tile swaps before and after the op.
// TODO: Reduce the amount spilled to the amount of data the `tileOp`
// touches (i.e. a single tile slice).
{
rewriter.setInsertionPoint(op);
// Swap the contents of ZA and the in-memory tile before the op.
swapInMemoryTileWithSMETileZero();
rewriter.setInsertionPointAfter(op);
// Swap the tile back out to memory again after the op.
swapInMemoryTileWithSMETileZero();
}
return success();
}
/// Extracts a pointer to a slice of an in-memory tile.
Value getInMemoryTileSlicePtr(RewriterBase &rewriter, Location loc,
Value tileMemory, Value sliceIndex) const {
auto llvmType = getTypeConverter()->convertType(tileMemory.getType());
auto descriptor =
rewriter.create<UnrealizedConversionCastOp>(loc, llvmType, tileMemory);
auto zero = rewriter.create<arith::ConstantIntOp>(loc, 0, /*width=*/64);
auto sliceIndexI64 = rewriter.create<arith::IndexCastOp>(
loc, rewriter.getI64Type(), sliceIndex);
return getStridedElementPtr(
loc, llvm::cast<MemRefType>(tileMemory.getType()),
descriptor.getResult(0), {sliceIndexI64, zero},
static_cast<ConversionPatternRewriter &>(rewriter));
}
/// Emits an in-place swap of a slice of a tile in ZA and a slice of a
/// tile-sized memref (`tileAlloca`).
void emitSliceSwap(RewriterBase &rewriter, Location loc, Value tileAlloca,
arm_sme::ArmSMETileType tileType, VectorType sliceType,
IntegerAttr tileId, Value sliceIndex) const {
// Cast the slice index to an i32.
auto sliceIndexI32 = rewriter.create<arith::IndexCastOp>(
loc, rewriter.getI32Type(), sliceIndex);
// Create an all-true predicate for the slice.
auto predicateType = sliceType.clone(rewriter.getI1Type());
auto allTruePredicate = rewriter.create<arith::ConstantOp>(
loc, DenseElementsAttr::get(predicateType, true));
// Create padding vector (never used due to all-true predicate).
auto padVector = rewriter.create<LLVM::UndefOp>(loc, sliceType);
// Get a pointer to the current slice.
auto slicePtr =
getInMemoryTileSlicePtr(rewriter, loc, tileAlloca, sliceIndex);
// Read the value of the current slice from ZA.
auto currentTileSlice = rewriter.create<arm_sme::aarch64_sme_read_horiz>(
loc, sliceType, padVector, allTruePredicate, tileId, sliceIndexI32);
// Load the new tile slice back from memory into ZA.
createLoadTileSliceIntrinsic(
rewriter, loc, tileType, arm_sme::TileSliceLayout::Horizontal,
allTruePredicate, slicePtr, tileId, sliceIndexI32);
// Store the current tile slice to memory.
auto zero = rewriter.create<arith::ConstantIndexOp>(loc, 0);
rewriter.create<vector::StoreOp>(loc, currentTileSlice, tileAlloca,
ValueRange{sliceIndex, zero});
}
/// Emits a full in-place swap of the contents of a tile in ZA and a
/// tile-sized memref (`tileAlloca`).
void emitFullTileSwap(RewriterBase &rewriter, Location loc, Value tileAlloca,
arm_sme::ArmSMETileType tileType, VectorType sliceType,
IntegerAttr tileId) const {
RewriterBase::InsertionGuard guard(rewriter);
// Create an scf.for over all tile slices.
auto minNumElts =
rewriter.create<arith::ConstantIndexOp>(loc, sliceType.getDimSize(0));
auto lowerBound = rewriter.create<arith::ConstantIndexOp>(loc, 0);
auto upperBound = rewriter.create<arith::MulIOp>(
loc, minNumElts, rewriter.create<vector::VectorScaleOp>(loc));
auto step = rewriter.create<arith::ConstantIndexOp>(loc, 1);
auto forOp = rewriter.create<scf::ForOp>(loc, lowerBound, upperBound, step);
// Emit a swap for each tile slice.
rewriter.setInsertionPointToStart(forOp.getBody());
auto sliceIndex = forOp.getInductionVar();
emitSliceSwap(rewriter, loc, tileAlloca, tileType, sliceType, tileId,
sliceIndex);
}
};
enum class RequiresSpillsAndFills { Yes, No };
/// Base class for ArmSME to LLVM conversion patterns. By default, this adds
/// spills and fills around ArmSME ops that use in-memory tile IDs. This can be
/// disabled by setting the `requiresSpillsAndFills` template parameter to
/// `RequiresSpillsAndFills::No`.
template <typename SourceOp, RequiresSpillsAndFills requiresSpillsAndFills =
RequiresSpillsAndFills::Yes>
struct ConvertArmSMEOpToLLVMPattern : ConvertOpToLLVMPattern<SourceOp> {
using ArmSMEOp = SourceOp;
using ConvertOpToLLVMPattern<SourceOp>::ConvertOpToLLVMPattern;
static constexpr bool requiresSpillsAndFillsConversion() {
return requiresSpillsAndFills == RequiresSpillsAndFills::Yes;
}
};
template <typename Pattern>
static void addArmSMEConversionPattern(RewritePatternSet &patterns,
LLVMTypeConverter const &typeConverter) {
// Register spills/fills for ops that implement the
// `ArmSMETileOpInterface` and have `requiresSpillsAndFills` set to
// `RequiresSpillsAndFills::Yes`.
if constexpr (Pattern::requiresSpillsAndFillsConversion() &&
std::is_base_of_v<arm_sme::ArmSMETileOpInterface::Trait<
typename Pattern::ArmSMEOp>,
typename Pattern::ArmSMEOp>) {
// Add spill/fill conversions with a very high benefit to ensure
// they are lowered first.
patterns.add<ConvertArmSMESpillsAndFillsToLLVM>(
Pattern::ArmSMEOp::getOperationName(), typeConverter,
/*benefit=*/1337);
}
patterns.add<Pattern>(typeConverter);
}
/// Helper to register `ConvertArmSMEOpToLLVMPattern` patterns.
template <typename... Patterns>
static void
addArmSMEConversionPatterns(RewritePatternSet &patterns,
LLVMTypeConverter const &typeConverter) {
(addArmSMEConversionPattern<Patterns>(patterns, typeConverter), ...);
}
/// Lower 'arm_sme.zero' to SME intrinsics.
///
/// BEFORE:
/// ```mlir
/// %v = arm_sme.zero {tile_id = 0 : i32} : vector<[4]x[4]xi32>
/// ```
///
/// AFTER:
/// ```mlir
/// "arm_sme.intr.zero"() <{tile_mask = 17 : i32}> : () -> ()
/// %v = arm_sme.get_tile : vector<[4]x[4]xi32>
/// ```
///
/// The 'arm_sme.get_tile' (which models the return) will fold away once all
/// ArmSME ops have been converted to LLVM intrinsics.
struct ZeroOpConversion : public ConvertArmSMEOpToLLVMPattern<arm_sme::ZeroOp> {
using ConvertArmSMEOpToLLVMPattern::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(arm_sme::ZeroOp zero, OpAdaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto loc = zero.getLoc();
auto tileId = getTileIdOrError(zero);
if (!tileId)
return failure();
// Get the base mask for tile based on the element size.
// The base mask is just the mask to zero the first tile (of a size).
// These masks are derived from:
// https://developer.arm.com/documentation/ddi0602/2022-06/SME-Instructions/ZERO--Zero-a-list-of-64-bit-element-ZA-tiles-
arm_sme::ArmSMETileType tileType =
*arm_sme::getSMETileType(zero.getTileType());
auto baseMaskForSize = [&] {
switch (tileType) {
case arm_sme::ArmSMETileType::ZAB:
// Zeroing the 8-bit ZA0.B tile is equivalent to zeroing all eight
// 64-bit element tiles named ZA0.D to ZA7.D.
return 0b1111'1111;
case arm_sme::ArmSMETileType::ZAH:
// Zeroing the 16-bit ZA0.H tile is equivalent to zeroing 64-bit
// element tiles named ZA0.D, ZA2.D, ZA4.D, and ZA6.D. Shift this left
// once for ZA1.H.
return 0b0101'0101;
case arm_sme::ArmSMETileType::ZAS:
// Zeroing the 32-bit ZA0.S tile is equivalent to zeroing 64-bit
// element tiles named ZA0.D and ZA4.D.
// Shift left by 1, 2, or 3 respectively for ZA1.S, ZA2.S, ZA3.S.
return 0b0001'0001;
case arm_sme::ArmSMETileType::ZAD:
// Zeroing one of the a 64-bit tiles ZA0.D to ZA7.D just requires
// setting the bit for that tile.
return 0b0000'0001;
default:
llvm_unreachable("bad element size");
}
}();
// The actual mask is just the base mask shifted by the tile ID.
// This will be folded to a constant after tile allocation.
//
// The shift is just derived from the layout of the tiles, and that the tile
// ID is the index of the tile. For example, looking at the 32-bit ZAx.S
// tiles:
//
// ZA0.S = ZA0.D and ZA4.D
// * Tile ID -> 0
// * Mask -> 00010001 = (00010001 << 0)
// ZA1.S = ZA1.D and ZA5.D
// * Tile ID -> 1
// * Mask -> 00100010 = (00010001 << 1)
// ZA2.S = ZA2.D and ZA6.D
// * Tile ID -> 2
// * Mask -> 01000100 = (00010001 << 2)
// ZA3.S = ZA3.D and ZA7.D
// * Tile ID -> 3
// * Mask -> 10001000 = (00010001 << 3)
//
// This holds for all tile sizes.
int32_t zeroMask = baseMaskForSize << int32_t(tileId.getInt());
rewriter.create<arm_sme::aarch64_sme_zero>(
loc, rewriter.getI32IntegerAttr(zeroMask));
// Create a placeholder op to preserve dataflow.
rewriter.replaceOpWithNewOp<arm_sme::GetTileOp>(zero, zero.getVectorType());
return success();
}
};
/// Lower `arm_sme.load_tile_slice` to SME intrinsics.
struct LoadTileSliceConversion
: public ConvertArmSMEOpToLLVMPattern<arm_sme::LoadTileSliceOp> {
using ConvertArmSMEOpToLLVMPattern::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(arm_sme::LoadTileSliceOp loadTileSliceOp,
arm_sme::LoadTileSliceOp::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto loc = loadTileSliceOp.getLoc();
auto tileId = getTileIdOrError(loadTileSliceOp);
if (!tileId)
return failure();
Value ptr = this->getStridedElementPtr(loc, loadTileSliceOp.getMemRefType(),
adaptor.getBase(),
adaptor.getIndices(), rewriter);
auto tileSlice = loadTileSliceOp.getTileSliceIndex();
// Cast tile slice to i32 for intrinsic.
auto tileSliceI32 = rewriter.create<arith::IndexCastUIOp>(
loc, rewriter.getI32Type(), tileSlice);
// Create all active predicate mask.
auto maskOp = loadTileSliceOp.getMask();
auto tileVectorType = loadTileSliceOp.getVectorType();
arm_sme::ArmSMETileType tileType = *arm_sme::getSMETileType(tileVectorType);
arm_sme::TileSliceLayout layout = loadTileSliceOp.getLayout();
// Create 'arm_sme.intr.ld1*.(horiz|vert)' intrinsic to load ZA tile slice.
createLoadTileSliceIntrinsic(rewriter, loc, tileType, layout, maskOp, ptr,
tileId, tileSliceI32);
// The load intrinsics have no result, replace 'arm_sme.tile_load' with
// the input tile to preserve dataflow.
rewriter.replaceOp(loadTileSliceOp, loadTileSliceOp.getTile());
return success();
}
};
/// Lower for `arm_sme.store_tile_slice` to SME intrinsics.
struct StoreTileSliceConversion
: public ConvertArmSMEOpToLLVMPattern<arm_sme::StoreTileSliceOp> {
using ConvertArmSMEOpToLLVMPattern::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(arm_sme::StoreTileSliceOp storeTileSliceOp,
arm_sme::StoreTileSliceOp::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto loc = storeTileSliceOp.getLoc();
auto tileVectorType = storeTileSliceOp.getVectorType();
auto tileId = getTileIdOrError(storeTileSliceOp);
if (!tileId)
return failure();
// Create 'arm_sme.intr.st1*.horiz' intrinsic to store ZA tile slice.
Value ptr = this->getStridedElementPtr(
loc, storeTileSliceOp.getMemRefType(), adaptor.getBase(),
adaptor.getIndices(), rewriter);
auto tileSlice = storeTileSliceOp.getTileSliceIndex();
// Cast tile slice to i32 for intrinsic.
auto tileSliceI32 = rewriter.create<arith::IndexCastUIOp>(
loc, rewriter.getI32Type(), tileSlice);
auto maskOp = storeTileSliceOp.getMask();
arm_sme::TileSliceLayout layout = storeTileSliceOp.getLayout();
arm_sme::ArmSMETileType tileType = *arm_sme::getSMETileType(tileVectorType);
rewriter.replaceOp(storeTileSliceOp,
createStoreTileSliceIntrinsic(rewriter, loc, tileType,
layout, maskOp, ptr,
tileId, tileSliceI32));
return success();
}
};
/// Lower `arm_sme.move_vector_to_tile_slice` to SME intrinsics.
struct MoveVectorToTileSliceConversion
: public ConvertArmSMEOpToLLVMPattern<arm_sme::MoveVectorToTileSliceOp> {
using ConvertArmSMEOpToLLVMPattern::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(arm_sme::MoveVectorToTileSliceOp moveVectorToTileSliceOp,
arm_sme::MoveVectorToTileSliceOp::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto loc = moveVectorToTileSliceOp.getLoc();
auto tileType = moveVectorToTileSliceOp.getTileType();
auto tileId = getTileIdOrError(moveVectorToTileSliceOp);
if (!tileId)
return failure();
auto tileSlice = moveVectorToTileSliceOp.getTileSliceIndex();
// Cast tile slice from index to i32 for intrinsic.
auto tileSliceI32 = rewriter.create<arith::IndexCastUIOp>(
loc, rewriter.getI32Type(), tileSlice);
// Create all active predicate mask.
auto one = rewriter.create<arith::ConstantOp>(
loc, rewriter.getI1Type(),
rewriter.getIntegerAttr(rewriter.getI1Type(), 1));
auto predTy = VectorType::get(tileType.getShape()[0], rewriter.getI1Type(),
/*scalableDims=*/{true});
auto allActiveMask = rewriter.create<vector::SplatOp>(loc, predTy, one);
// Create 'arm_sme.intr.write.(horiz|vert)' to write vector to tile slice.
switch (moveVectorToTileSliceOp.getLayout()) {
case arm_sme::TileSliceLayout::Horizontal:
rewriter.create<arm_sme::aarch64_sme_write_horiz>(
loc, tileId, tileSliceI32, allActiveMask,
moveVectorToTileSliceOp.getVector());
break;
case arm_sme::TileSliceLayout::Vertical:
rewriter.create<arm_sme::aarch64_sme_write_vert>(
loc, tileId, tileSliceI32, allActiveMask,
moveVectorToTileSliceOp.getVector());
break;
}
// Intrinsic has no result, replace 'arm_sme.move_vector_to_tile_slice' with
// the input tile to preserve dataflow.
rewriter.replaceOp(moveVectorToTileSliceOp,
moveVectorToTileSliceOp.getTile());
return success();
}
};
/// Lower `arm_sme.move_tile_slice_to_vector` to SME intrinsics.
struct MoveTileSliceToVectorConversion
: public ConvertArmSMEOpToLLVMPattern<arm_sme::MoveTileSliceToVectorOp> {
using ConvertArmSMEOpToLLVMPattern::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(arm_sme::MoveTileSliceToVectorOp moveTileSliceToVector,
OpAdaptor,
ConversionPatternRewriter &rewriter) const override {
auto loc = moveTileSliceToVector.getLoc();
auto sliceType = moveTileSliceToVector.getSliceType();
auto sliceIndex = moveTileSliceToVector.getTileSliceIndex();
auto tileId = getTileIdOrError(moveTileSliceToVector);
if (!tileId)
return failure();
// Create an 'all true' predicate for the tile slice.
auto predicateType = sliceType.cloneWith({}, rewriter.getI1Type());
auto allTruePredicate = rewriter.create<arith::ConstantOp>(
loc, DenseElementsAttr::get(predicateType, true));
// Zero destination/fallback for tile slice extraction.
auto zeroVector = rewriter.create<arith::ConstantOp>(
loc, sliceType, rewriter.getZeroAttr(sliceType));
// Cast tile slice from index to i32 for intrinsic.
auto sliceIndexI32 = rewriter.create<arith::IndexCastOp>(
loc, rewriter.getI32Type(), sliceIndex);
// Create 'arm_sme.intr.read.(horiz|vert)' to extract the tile slice.
switch (moveTileSliceToVector.getLayout()) {
case arm_sme::TileSliceLayout::Horizontal:
rewriter.replaceOpWithNewOp<arm_sme::aarch64_sme_read_horiz>(
moveTileSliceToVector, sliceType, zeroVector, allTruePredicate,
tileId, sliceIndexI32);
break;
case arm_sme::TileSliceLayout::Vertical:
rewriter.replaceOpWithNewOp<arm_sme::aarch64_sme_read_vert>(
moveTileSliceToVector, sliceType, zeroVector, allTruePredicate,
tileId, sliceIndexI32);
break;
}
return success();
}
};
/// Lower `arm_sme.outerproduct` to SME MOPA intrinsics.
///
/// Example:
///
/// %0 = arm_sme.outerproduct %lhs, %rhs acc(%acc)
/// : vector<[4]xf32>, vector<[4]xf32>
///
/// is converted to:
///
/// "arm_sme.intr.mopa"(%ptrue_s, %ptrue_s, %lhs, %rhs) <{tile_id = 0 : i32}>
/// : (vector<[4]xi1>, vector<[4]xi1>, vector<[4]xf32>,
/// vector<[4]xf32>) -> ()
///
/// Currently only supports FMOPA and BFMOPA (non-widening).
struct OuterProductOpConversion
: public ConvertArmSMEOpToLLVMPattern<arm_sme::OuterProductOp> {
using ConvertArmSMEOpToLLVMPattern::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(arm_sme::OuterProductOp outerProductOp,
arm_sme::OuterProductOp::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto tileId = getTileIdOrError(outerProductOp);
if (!tileId)
return failure();
auto isSupportedType = [](VectorType vectorType) {
// TODO: the FP outer product instruction variants are predicated on
// different features [1]:
//
// * FMOPA (non-widening)
// * half-precision - +sme2p1,+sme-f16f16
// * single-precision - +sme
// * double-precision - +sme-f64f64
// * BFMOPA
// * half-precision - +sme2p1,+b16b16
//
// It should be possible to control lowering based on target features.
// [1]
// https://developer.arm.com/downloads/-/exploration-tools/feature-names-for-a-profile
if ((vectorType.getRank() != 2) || !vectorType.allDimsScalable())
return false;
auto elementType = vectorType.getElementType();
if (!elementType.isF16() && !elementType.isBF16() &&
!elementType.isF32() && !elementType.isF64())
return false;
unsigned minNumElts = arm_sme::MinStreamingVectorLengthInBits /
vectorType.getElementTypeBitWidth();
return vectorType.getShape() ==
ArrayRef<int64_t>({minNumElts, minNumElts});
};
// TODO: Support CombiningKind::Sub for outer products.
if (outerProductOp.getKind() != arm_sme::CombiningKind::Add)
return outerProductOp.emitError("unsupported kind");
auto resultVectorType = outerProductOp.getResultType();
if (!isSupportedType(resultVectorType))
return outerProductOp.emitError("unsupported type");
auto loc = outerProductOp.getLoc();
Value acc = outerProductOp.getAcc();
if (!acc) {
// Initalize accumulator with zero.
auto zero = rewriter.create<arm_sme::ZeroOp>(loc, resultVectorType);
zero.setTileId(tileId);
acc = zero;
}
Value lhsMask = outerProductOp.getLhsMask();
Value rhsMask = outerProductOp.getRhsMask();
if (!lhsMask || !rhsMask) {
auto predTy =
outerProductOp.getLhsType().cloneWith({}, rewriter.getI1Type());
Value allActiveMask = rewriter.create<arith::ConstantOp>(
loc, DenseElementsAttr::get(predTy, true));
lhsMask = allActiveMask;
rhsMask = allActiveMask;
}
// Create 'arm_sme.intr.mopa' outer product intrinsic.
rewriter.create<arm_sme::aarch64_sme_mopa>(loc, tileId, lhsMask, rhsMask,
outerProductOp.getLhs(),
outerProductOp.getRhs());
// The outerproduct intrinsics have no result, replace
// 'arm_sme.outerproduct' with the input tile to preserve dataflow.
rewriter.replaceOp(outerProductOp, acc);
return success();
}
};
/// Lower 2-way and 4-way widening outer products to intrinsics.
template <class OuterProductWideningOp, class OuterProductWideningIntrOp>
struct OuterProductWideningOpConversion
: public ConvertArmSMEOpToLLVMPattern<OuterProductWideningOp> {
using ConvertArmSMEOpToLLVMPattern<
OuterProductWideningOp>::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(OuterProductWideningOp op,
typename OuterProductWideningOp::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto tileId = getTileIdOrError(op);
if (!tileId)
return failure();
auto loc = op.getLoc();
Value acc = op.getAcc();
if (!acc) {
// Initalize accumulator with zero.
auto zero = rewriter.create<arm_sme::ZeroOp>(loc, op.getResultType());
zero.setTileId(tileId);
acc = zero;
}
Value lhsMask = op.getLhsMask();
Value rhsMask = op.getRhsMask();
if (!lhsMask || !rhsMask) {
auto predTy = op.getLhsType().cloneWith({}, rewriter.getI1Type());
Value allActiveMask = rewriter.create<arith::ConstantOp>(
loc, DenseElementsAttr::get(predTy, true));
lhsMask = allActiveMask;
rhsMask = allActiveMask;
}
rewriter.create<OuterProductWideningIntrOp>(
loc, tileId, lhsMask, rhsMask, adaptor.getLhs(), adaptor.getRhs());
// The outerproduct intrinsics have no result, replace
// 'arm_sme.outerproduct' with the input tile to preserve dataflow.
rewriter.replaceOp(op, acc);
return success();
}
};
/// Lower `arm_sme.streaming_vl` to SME CNTS intrinsics.
///
/// Example:
///
/// %0 = arm_sme.streaming_vl <half>
///
/// is converted to:
///
/// %cnt = "arm_sme.intr.cntsh"() : () -> i64
/// %0 = arith.index_cast %cnt : i64 to index
///
struct StreamingVLOpConversion
: public ConvertArmSMEOpToLLVMPattern<arm_sme::StreamingVLOp,
RequiresSpillsAndFills::No> {
using ConvertArmSMEOpToLLVMPattern::ConvertArmSMEOpToLLVMPattern;
LogicalResult
matchAndRewrite(arm_sme::StreamingVLOp streamingVlOp,
arm_sme::StreamingVLOp::Adaptor adaptor,
ConversionPatternRewriter &rewriter) const override {
auto loc = streamingVlOp.getLoc();
auto i64Type = rewriter.getI64Type();
auto *intrOp = [&]() -> Operation * {
switch (streamingVlOp.getTypeSize()) {
case arm_sme::TypeSize::Byte:
return rewriter.create<arm_sme::aarch64_sme_cntsb>(loc, i64Type);
case arm_sme::TypeSize::Half:
return rewriter.create<arm_sme::aarch64_sme_cntsh>(loc, i64Type);
case arm_sme::TypeSize::Word:
return rewriter.create<arm_sme::aarch64_sme_cntsw>(loc, i64Type);
case arm_sme::TypeSize::Double:
return rewriter.create<arm_sme::aarch64_sme_cntsd>(loc, i64Type);
}
}();
rewriter.replaceOpWithNewOp<arith::IndexCastOp>(
streamingVlOp, rewriter.getIndexType(), intrOp->getResult(0));
return success();
}
};
} // namespace
namespace {
struct ConvertArmSMEToLLVMPass
: public impl::ConvertArmSMEToLLVMBase<ConvertArmSMEToLLVMPass> {
ConvertArmSMEToLLVMPass(bool dumpTileLiveRanges) {
this->dumpTileLiveRanges = dumpTileLiveRanges;
}
void runOnOperation() override {
auto function = getOperation();
if (failed(arm_sme::allocateSMETiles(function, dumpTileLiveRanges)))
return signalPassFailure();
LLVMConversionTarget target(getContext());
RewritePatternSet patterns(&getContext());
LLVMTypeConverter converter(&getContext());
configureArmSMEToLLVMConversionLegality(target);
populateArmSMEToLLVMConversionPatterns(converter, patterns);
if (failed(applyPartialConversion(function, target, std::move(patterns))))
signalPassFailure();
// Walk the function and fail if there are unexpected operations on SME
// tile types after conversion.
function->walk([&](Operation *op) {
// These ops are legal post conversion, skip these.
if (isa<arm_sme::CopyTileOp, arm_sme::GetTileOp, cf::BranchOp>(op) ||
!op->isRegistered())
return;
auto isSMETileType = [](Type type) {
return arm_sme::isValidSMETileVectorType(type);
};
if (llvm::any_of(op->getResultTypes(), isSMETileType) ||
llvm::any_of(op->getOperandTypes(), isSMETileType)) {
op->emitOpError("unexpected operation with SME tile type after "
"conversion to LLVM");
signalPassFailure();
}
});
}
};
} // namespace
void mlir::configureArmSMEToLLVMConversionLegality(ConversionTarget &target) {
target.addIllegalDialect<arm_sme::ArmSMEDialect>();
target.addLegalOp<
arm_sme::aarch64_sme_zero, arm_sme::aarch64_sme_str,
arm_sme::aarch64_sme_ld1b_horiz, arm_sme::aarch64_sme_ld1h_horiz,
arm_sme::aarch64_sme_ld1w_horiz, arm_sme::aarch64_sme_ld1d_horiz,
arm_sme::aarch64_sme_ld1q_horiz, arm_sme::aarch64_sme_st1b_horiz,
arm_sme::aarch64_sme_st1h_horiz, arm_sme::aarch64_sme_st1w_horiz,
arm_sme::aarch64_sme_st1d_horiz, arm_sme::aarch64_sme_st1q_horiz,
arm_sme::aarch64_sme_ld1b_vert, arm_sme::aarch64_sme_ld1h_vert,
arm_sme::aarch64_sme_ld1w_vert, arm_sme::aarch64_sme_ld1d_vert,
arm_sme::aarch64_sme_ld1q_vert, arm_sme::aarch64_sme_st1b_vert,
arm_sme::aarch64_sme_st1h_vert, arm_sme::aarch64_sme_st1w_vert,
arm_sme::aarch64_sme_st1d_vert, arm_sme::aarch64_sme_st1q_vert,
arm_sme::aarch64_sme_read_horiz, arm_sme::aarch64_sme_read_vert,
arm_sme::aarch64_sme_write_horiz, arm_sme::aarch64_sme_write_vert,
arm_sme::aarch64_sme_mopa, arm_sme::aarch64_sme_mopa_wide,
arm_sme::aarch64_sme_mops_wide, arm_sme::aarch64_sme_smopa_wide,
arm_sme::aarch64_sme_smops_wide, arm_sme::aarch64_sme_umopa_wide,
arm_sme::aarch64_sme_umops_wide, arm_sme::aarch64_sme_smopa_za32,
arm_sme::aarch64_sme_smops_za32, arm_sme::aarch64_sme_umopa_za32,
arm_sme::aarch64_sme_umops_za32, arm_sme::aarch64_sme_sumopa_wide,
arm_sme::aarch64_sme_sumops_wide, arm_sme::aarch64_sme_usmopa_wide,
arm_sme::aarch64_sme_usmops_wide, arm_sme::aarch64_sme_cntsb,
arm_sme::aarch64_sme_cntsh, arm_sme::aarch64_sme_cntsw,
arm_sme::aarch64_sme_cntsd>();
target.addLegalDialect<arith::ArithDialect,
/* The following are used to lower tile spills/fills */
vector::VectorDialect, scf::SCFDialect,
memref::MemRefDialect>();
// Pseudo operations. These cannot be code-generated but may exist in the
// input IR, or be generated during the conversion. They need to be eliminated
// before the final conversion to LLVM IR (and likely will be due to DCE).
target.addLegalOp<arm_sme::GetTileOp, arm_sme::CopyTileOp,
UnrealizedConversionCastOp>();
}
void mlir::populateArmSMEToLLVMConversionPatterns(LLVMTypeConverter &converter,
RewritePatternSet &patterns) {
converter.addConversion([&](VectorType type) -> std::optional<Type> {
// There's no LLVM type for SME tiles, but after lowering to intrinsics all
// SME vector types should be eliminated.
if (arm_sme::isValidSMETileVectorType(type))
return type;
return std::nullopt;
});
addArmSMEConversionPatterns<
LoadTileSliceConversion, MoveTileSliceToVectorConversion,
MoveVectorToTileSliceConversion, StoreTileSliceConversion,
StreamingVLOpConversion, OuterProductOpConversion,
OuterProductWideningOpConversion<arm_sme::FMopa2WayOp,
arm_sme::aarch64_sme_mopa_wide>,
OuterProductWideningOpConversion<arm_sme::FMops2WayOp,
arm_sme::aarch64_sme_mops_wide>,
OuterProductWideningOpConversion<arm_sme::SMopa2WayOp,
arm_sme::aarch64_sme_smopa_za32>,
OuterProductWideningOpConversion<arm_sme::SMops2WayOp,
arm_sme::aarch64_sme_smops_za32>,
OuterProductWideningOpConversion<arm_sme::UMopa2WayOp,
arm_sme::aarch64_sme_umopa_za32>,
OuterProductWideningOpConversion<arm_sme::UMops2WayOp,
arm_sme::aarch64_sme_umops_za32>,
OuterProductWideningOpConversion<arm_sme::SMopa4WayOp,
arm_sme::aarch64_sme_smopa_wide>,
OuterProductWideningOpConversion<arm_sme::SMops4WayOp,
arm_sme::aarch64_sme_smops_wide>,
OuterProductWideningOpConversion<arm_sme::UMopa4WayOp,
arm_sme::aarch64_sme_umopa_wide>,
OuterProductWideningOpConversion<arm_sme::UMops4WayOp,
arm_sme::aarch64_sme_umops_wide>,
OuterProductWideningOpConversion<arm_sme::SuMopa4WayOp,
arm_sme::aarch64_sme_sumopa_wide>,
OuterProductWideningOpConversion<arm_sme::SuMops4WayOp,
arm_sme::aarch64_sme_sumops_wide>,
OuterProductWideningOpConversion<arm_sme::UsMopa4WayOp,
arm_sme::aarch64_sme_usmopa_wide>,
OuterProductWideningOpConversion<arm_sme::UsMops4WayOp,
arm_sme::aarch64_sme_usmops_wide>,
ZeroOpConversion>(patterns, converter);
}
std::unique_ptr<Pass>
mlir::createConvertArmSMEToLLVMPass(bool dumpTileLiveRanges) {
return std::make_unique<ConvertArmSMEToLLVMPass>(dumpTileLiveRanges);
}