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llvm-mirror/lib/Transforms/Vectorize/SLPVectorizer.cpp
Alexey Bataev 48b45a5713 [SLP]Merge reorder and reuse shuffles. 
It is possible to merge reuse and reorder shuffles and reduce the total
cost of the vectorization tree/number of final instructions.

Differential Revision: https://reviews.llvm.org/D94992
2021-03-02 06:39:47 -08:00

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//===- SLPVectorizer.cpp - A bottom up SLP Vectorizer ---------------------===//
//
// 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 pass implements the Bottom Up SLP vectorizer. It detects consecutive
// stores that can be put together into vector-stores. Next, it attempts to
// construct vectorizable tree using the use-def chains. If a profitable tree
// was found, the SLP vectorizer performs vectorization on the tree.
//
// The pass is inspired by the work described in the paper:
// "Loop-Aware SLP in GCC" by Ira Rosen, Dorit Nuzman, Ayal Zaks.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Vectorize/SLPVectorizer.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallBitVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/iterator.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CodeMetrics.h"
#include "llvm/Analysis/DemandedBits.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/IVDescriptors.h"
#include "llvm/Analysis/LoopAccessAnalysis.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/VectorUtils.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/NoFolder.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/IR/Verifier.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DOTGraphTraits.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/InstructionCost.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/InjectTLIMappings.h"
#include "llvm/Transforms/Utils/LoopUtils.h"
#include "llvm/Transforms/Vectorize.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <memory>
#include <set>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace llvm;
using namespace llvm::PatternMatch;
using namespace slpvectorizer;
#define SV_NAME "slp-vectorizer"
#define DEBUG_TYPE "SLP"
STATISTIC(NumVectorInstructions, "Number of vector instructions generated");
cl::opt<bool> RunSLPVectorization("vectorize-slp", cl::init(true), cl::Hidden,
cl::desc("Run the SLP vectorization passes"));
static cl::opt<int>
SLPCostThreshold("slp-threshold", cl::init(0), cl::Hidden,
cl::desc("Only vectorize if you gain more than this "
"number "));
static cl::opt<bool>
ShouldVectorizeHor("slp-vectorize-hor", cl::init(true), cl::Hidden,
cl::desc("Attempt to vectorize horizontal reductions"));
static cl::opt<bool> ShouldStartVectorizeHorAtStore(
"slp-vectorize-hor-store", cl::init(false), cl::Hidden,
cl::desc(
"Attempt to vectorize horizontal reductions feeding into a store"));
static cl::opt<int>
MaxVectorRegSizeOption("slp-max-reg-size", cl::init(128), cl::Hidden,
cl::desc("Attempt to vectorize for this register size in bits"));
static cl::opt<unsigned>
MaxVFOption("slp-max-vf", cl::init(0), cl::Hidden,
cl::desc("Maximum SLP vectorization factor (0=unlimited)"));
static cl::opt<int>
MaxStoreLookup("slp-max-store-lookup", cl::init(32), cl::Hidden,
cl::desc("Maximum depth of the lookup for consecutive stores."));
/// Limits the size of scheduling regions in a block.
/// It avoid long compile times for _very_ large blocks where vector
/// instructions are spread over a wide range.
/// This limit is way higher than needed by real-world functions.
static cl::opt<int>
ScheduleRegionSizeBudget("slp-schedule-budget", cl::init(100000), cl::Hidden,
cl::desc("Limit the size of the SLP scheduling region per block"));
static cl::opt<int> MinVectorRegSizeOption(
"slp-min-reg-size", cl::init(128), cl::Hidden,
cl::desc("Attempt to vectorize for this register size in bits"));
static cl::opt<unsigned> RecursionMaxDepth(
"slp-recursion-max-depth", cl::init(12), cl::Hidden,
cl::desc("Limit the recursion depth when building a vectorizable tree"));
static cl::opt<unsigned> MinTreeSize(
"slp-min-tree-size", cl::init(3), cl::Hidden,
cl::desc("Only vectorize small trees if they are fully vectorizable"));
// The maximum depth that the look-ahead score heuristic will explore.
// The higher this value, the higher the compilation time overhead.
static cl::opt<int> LookAheadMaxDepth(
"slp-max-look-ahead-depth", cl::init(2), cl::Hidden,
cl::desc("The maximum look-ahead depth for operand reordering scores"));
// The Look-ahead heuristic goes through the users of the bundle to calculate
// the users cost in getExternalUsesCost(). To avoid compilation time increase
// we limit the number of users visited to this value.
static cl::opt<unsigned> LookAheadUsersBudget(
"slp-look-ahead-users-budget", cl::init(2), cl::Hidden,
cl::desc("The maximum number of users to visit while visiting the "
"predecessors. This prevents compilation time increase."));
static cl::opt<bool>
ViewSLPTree("view-slp-tree", cl::Hidden,
cl::desc("Display the SLP trees with Graphviz"));
// Limit the number of alias checks. The limit is chosen so that
// it has no negative effect on the llvm benchmarks.
static const unsigned AliasedCheckLimit = 10;
// Another limit for the alias checks: The maximum distance between load/store
// instructions where alias checks are done.
// This limit is useful for very large basic blocks.
static const unsigned MaxMemDepDistance = 160;
/// If the ScheduleRegionSizeBudget is exhausted, we allow small scheduling
/// regions to be handled.
static const int MinScheduleRegionSize = 16;
/// Predicate for the element types that the SLP vectorizer supports.
///
/// The most important thing to filter here are types which are invalid in LLVM
/// vectors. We also filter target specific types which have absolutely no
/// meaningful vectorization path such as x86_fp80 and ppc_f128. This just
/// avoids spending time checking the cost model and realizing that they will
/// be inevitably scalarized.
static bool isValidElementType(Type *Ty) {
return VectorType::isValidElementType(Ty) && !Ty->isX86_FP80Ty() &&
!Ty->isPPC_FP128Ty();
}
/// \returns true if all of the instructions in \p VL are in the same block or
/// false otherwise.
static bool allSameBlock(ArrayRef<Value *> VL) {
Instruction *I0 = dyn_cast<Instruction>(VL[0]);
if (!I0)
return false;
BasicBlock *BB = I0->getParent();
for (int I = 1, E = VL.size(); I < E; I++) {
auto *II = dyn_cast<Instruction>(VL[I]);
if (!II)
return false;
if (BB != II->getParent())
return false;
}
return true;
}
/// \returns True if all of the values in \p VL are constants (but not
/// globals/constant expressions).
static bool allConstant(ArrayRef<Value *> VL) {
// Constant expressions and globals can't be vectorized like normal integer/FP
// constants.
for (Value *i : VL)
if (!isa<Constant>(i) || isa<ConstantExpr>(i) || isa<GlobalValue>(i))
return false;
return true;
}
/// \returns True if all of the values in \p VL are identical.
static bool isSplat(ArrayRef<Value *> VL) {
for (unsigned i = 1, e = VL.size(); i < e; ++i)
if (VL[i] != VL[0])
return false;
return true;
}
/// \returns True if \p I is commutative, handles CmpInst and BinaryOperator.
static bool isCommutative(Instruction *I) {
if (auto *Cmp = dyn_cast<CmpInst>(I))
return Cmp->isCommutative();
if (auto *BO = dyn_cast<BinaryOperator>(I))
return BO->isCommutative();
// TODO: This should check for generic Instruction::isCommutative(), but
// we need to confirm that the caller code correctly handles Intrinsics
// for example (does not have 2 operands).
return false;
}
/// Checks if the vector of instructions can be represented as a shuffle, like:
/// %x0 = extractelement <4 x i8> %x, i32 0
/// %x3 = extractelement <4 x i8> %x, i32 3
/// %y1 = extractelement <4 x i8> %y, i32 1
/// %y2 = extractelement <4 x i8> %y, i32 2
/// %x0x0 = mul i8 %x0, %x0
/// %x3x3 = mul i8 %x3, %x3
/// %y1y1 = mul i8 %y1, %y1
/// %y2y2 = mul i8 %y2, %y2
/// %ins1 = insertelement <4 x i8> poison, i8 %x0x0, i32 0
/// %ins2 = insertelement <4 x i8> %ins1, i8 %x3x3, i32 1
/// %ins3 = insertelement <4 x i8> %ins2, i8 %y1y1, i32 2
/// %ins4 = insertelement <4 x i8> %ins3, i8 %y2y2, i32 3
/// ret <4 x i8> %ins4
/// can be transformed into:
/// %1 = shufflevector <4 x i8> %x, <4 x i8> %y, <4 x i32> <i32 0, i32 3, i32 5,
/// i32 6>
/// %2 = mul <4 x i8> %1, %1
/// ret <4 x i8> %2
/// We convert this initially to something like:
/// %x0 = extractelement <4 x i8> %x, i32 0
/// %x3 = extractelement <4 x i8> %x, i32 3
/// %y1 = extractelement <4 x i8> %y, i32 1
/// %y2 = extractelement <4 x i8> %y, i32 2
/// %1 = insertelement <4 x i8> poison, i8 %x0, i32 0
/// %2 = insertelement <4 x i8> %1, i8 %x3, i32 1
/// %3 = insertelement <4 x i8> %2, i8 %y1, i32 2
/// %4 = insertelement <4 x i8> %3, i8 %y2, i32 3
/// %5 = mul <4 x i8> %4, %4
/// %6 = extractelement <4 x i8> %5, i32 0
/// %ins1 = insertelement <4 x i8> poison, i8 %6, i32 0
/// %7 = extractelement <4 x i8> %5, i32 1
/// %ins2 = insertelement <4 x i8> %ins1, i8 %7, i32 1
/// %8 = extractelement <4 x i8> %5, i32 2
/// %ins3 = insertelement <4 x i8> %ins2, i8 %8, i32 2
/// %9 = extractelement <4 x i8> %5, i32 3
/// %ins4 = insertelement <4 x i8> %ins3, i8 %9, i32 3
/// ret <4 x i8> %ins4
/// InstCombiner transforms this into a shuffle and vector mul
/// TODO: Can we split off and reuse the shuffle mask detection from
/// TargetTransformInfo::getInstructionThroughput?
static Optional<TargetTransformInfo::ShuffleKind>
isShuffle(ArrayRef<Value *> VL) {
auto *EI0 = cast<ExtractElementInst>(VL[0]);
unsigned Size =
cast<FixedVectorType>(EI0->getVectorOperandType())->getNumElements();
Value *Vec1 = nullptr;
Value *Vec2 = nullptr;
enum ShuffleMode { Unknown, Select, Permute };
ShuffleMode CommonShuffleMode = Unknown;
for (unsigned I = 0, E = VL.size(); I < E; ++I) {
auto *EI = cast<ExtractElementInst>(VL[I]);
auto *Vec = EI->getVectorOperand();
// All vector operands must have the same number of vector elements.
if (cast<FixedVectorType>(Vec->getType())->getNumElements() != Size)
return None;
auto *Idx = dyn_cast<ConstantInt>(EI->getIndexOperand());
if (!Idx)
return None;
// Undefined behavior if Idx is negative or >= Size.
if (Idx->getValue().uge(Size))
continue;
unsigned IntIdx = Idx->getValue().getZExtValue();
// We can extractelement from undef or poison vector.
if (isa<UndefValue>(Vec))
continue;
// For correct shuffling we have to have at most 2 different vector operands
// in all extractelement instructions.
if (!Vec1 || Vec1 == Vec)
Vec1 = Vec;
else if (!Vec2 || Vec2 == Vec)
Vec2 = Vec;
else
return None;
if (CommonShuffleMode == Permute)
continue;
// If the extract index is not the same as the operation number, it is a
// permutation.
if (IntIdx != I) {
CommonShuffleMode = Permute;
continue;
}
CommonShuffleMode = Select;
}
// If we're not crossing lanes in different vectors, consider it as blending.
if (CommonShuffleMode == Select && Vec2)
return TargetTransformInfo::SK_Select;
// If Vec2 was never used, we have a permutation of a single vector, otherwise
// we have permutation of 2 vectors.
return Vec2 ? TargetTransformInfo::SK_PermuteTwoSrc
: TargetTransformInfo::SK_PermuteSingleSrc;
}
namespace {
/// Main data required for vectorization of instructions.
struct InstructionsState {
/// The very first instruction in the list with the main opcode.
Value *OpValue = nullptr;
/// The main/alternate instruction.
Instruction *MainOp = nullptr;
Instruction *AltOp = nullptr;
/// The main/alternate opcodes for the list of instructions.
unsigned getOpcode() const {
return MainOp ? MainOp->getOpcode() : 0;
}
unsigned getAltOpcode() const {
return AltOp ? AltOp->getOpcode() : 0;
}
/// Some of the instructions in the list have alternate opcodes.
bool isAltShuffle() const { return getOpcode() != getAltOpcode(); }
bool isOpcodeOrAlt(Instruction *I) const {
unsigned CheckedOpcode = I->getOpcode();
return getOpcode() == CheckedOpcode || getAltOpcode() == CheckedOpcode;
}
InstructionsState() = delete;
InstructionsState(Value *OpValue, Instruction *MainOp, Instruction *AltOp)
: OpValue(OpValue), MainOp(MainOp), AltOp(AltOp) {}
};
} // end anonymous namespace
/// Chooses the correct key for scheduling data. If \p Op has the same (or
/// alternate) opcode as \p OpValue, the key is \p Op. Otherwise the key is \p
/// OpValue.
static Value *isOneOf(const InstructionsState &S, Value *Op) {
auto *I = dyn_cast<Instruction>(Op);
if (I && S.isOpcodeOrAlt(I))
return Op;
return S.OpValue;
}
/// \returns true if \p Opcode is allowed as part of of the main/alternate
/// instruction for SLP vectorization.
///
/// Example of unsupported opcode is SDIV that can potentially cause UB if the
/// "shuffled out" lane would result in division by zero.
static bool isValidForAlternation(unsigned Opcode) {
if (Instruction::isIntDivRem(Opcode))
return false;
return true;
}
/// \returns analysis of the Instructions in \p VL described in
/// InstructionsState, the Opcode that we suppose the whole list
/// could be vectorized even if its structure is diverse.
static InstructionsState getSameOpcode(ArrayRef<Value *> VL,
unsigned BaseIndex = 0) {
// Make sure these are all Instructions.
if (llvm::any_of(VL, [](Value *V) { return !isa<Instruction>(V); }))
return InstructionsState(VL[BaseIndex], nullptr, nullptr);
bool IsCastOp = isa<CastInst>(VL[BaseIndex]);
bool IsBinOp = isa<BinaryOperator>(VL[BaseIndex]);
unsigned Opcode = cast<Instruction>(VL[BaseIndex])->getOpcode();
unsigned AltOpcode = Opcode;
unsigned AltIndex = BaseIndex;
// Check for one alternate opcode from another BinaryOperator.
// TODO - generalize to support all operators (types, calls etc.).
for (int Cnt = 0, E = VL.size(); Cnt < E; Cnt++) {
unsigned InstOpcode = cast<Instruction>(VL[Cnt])->getOpcode();
if (IsBinOp && isa<BinaryOperator>(VL[Cnt])) {
if (InstOpcode == Opcode || InstOpcode == AltOpcode)
continue;
if (Opcode == AltOpcode && isValidForAlternation(InstOpcode) &&
isValidForAlternation(Opcode)) {
AltOpcode = InstOpcode;
AltIndex = Cnt;
continue;
}
} else if (IsCastOp && isa<CastInst>(VL[Cnt])) {
Type *Ty0 = cast<Instruction>(VL[BaseIndex])->getOperand(0)->getType();
Type *Ty1 = cast<Instruction>(VL[Cnt])->getOperand(0)->getType();
if (Ty0 == Ty1) {
if (InstOpcode == Opcode || InstOpcode == AltOpcode)
continue;
if (Opcode == AltOpcode) {
assert(isValidForAlternation(Opcode) &&
isValidForAlternation(InstOpcode) &&
"Cast isn't safe for alternation, logic needs to be updated!");
AltOpcode = InstOpcode;
AltIndex = Cnt;
continue;
}
}
} else if (InstOpcode == Opcode || InstOpcode == AltOpcode)
continue;
return InstructionsState(VL[BaseIndex], nullptr, nullptr);
}
return InstructionsState(VL[BaseIndex], cast<Instruction>(VL[BaseIndex]),
cast<Instruction>(VL[AltIndex]));
}
/// \returns true if all of the values in \p VL have the same type or false
/// otherwise.
static bool allSameType(ArrayRef<Value *> VL) {
Type *Ty = VL[0]->getType();
for (int i = 1, e = VL.size(); i < e; i++)
if (VL[i]->getType() != Ty)
return false;
return true;
}
/// \returns True if Extract{Value,Element} instruction extracts element Idx.
static Optional<unsigned> getExtractIndex(Instruction *E) {
unsigned Opcode = E->getOpcode();
assert((Opcode == Instruction::ExtractElement ||
Opcode == Instruction::ExtractValue) &&
"Expected extractelement or extractvalue instruction.");
if (Opcode == Instruction::ExtractElement) {
auto *CI = dyn_cast<ConstantInt>(E->getOperand(1));
if (!CI)
return None;
return CI->getZExtValue();
}
ExtractValueInst *EI = cast<ExtractValueInst>(E);
if (EI->getNumIndices() != 1)
return None;
return *EI->idx_begin();
}
/// \returns True if in-tree use also needs extract. This refers to
/// possible scalar operand in vectorized instruction.
static bool InTreeUserNeedToExtract(Value *Scalar, Instruction *UserInst,
TargetLibraryInfo *TLI) {
unsigned Opcode = UserInst->getOpcode();
switch (Opcode) {
case Instruction::Load: {
LoadInst *LI = cast<LoadInst>(UserInst);
return (LI->getPointerOperand() == Scalar);
}
case Instruction::Store: {
StoreInst *SI = cast<StoreInst>(UserInst);
return (SI->getPointerOperand() == Scalar);
}
case Instruction::Call: {
CallInst *CI = cast<CallInst>(UserInst);
Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
for (unsigned i = 0, e = CI->getNumArgOperands(); i != e; ++i) {
if (hasVectorInstrinsicScalarOpd(ID, i))
return (CI->getArgOperand(i) == Scalar);
}
LLVM_FALLTHROUGH;
}
default:
return false;
}
}
/// \returns the AA location that is being access by the instruction.
static MemoryLocation getLocation(Instruction *I, AAResults *AA) {
if (StoreInst *SI = dyn_cast<StoreInst>(I))
return MemoryLocation::get(SI);
if (LoadInst *LI = dyn_cast<LoadInst>(I))
return MemoryLocation::get(LI);
return MemoryLocation();
}
/// \returns True if the instruction is not a volatile or atomic load/store.
static bool isSimple(Instruction *I) {
if (LoadInst *LI = dyn_cast<LoadInst>(I))
return LI->isSimple();
if (StoreInst *SI = dyn_cast<StoreInst>(I))
return SI->isSimple();
if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I))
return !MI->isVolatile();
return true;
}
namespace llvm {
static void inversePermutation(ArrayRef<unsigned> Indices,
SmallVectorImpl<int> &Mask) {
Mask.clear();
const unsigned E = Indices.size();
Mask.resize(E, E + 1);
for (unsigned I = 0; I < E; ++I)
Mask[Indices[I]] = I;
}
namespace slpvectorizer {
/// Bottom Up SLP Vectorizer.
class BoUpSLP {
struct TreeEntry;
struct ScheduleData;
public:
using ValueList = SmallVector<Value *, 8>;
using InstrList = SmallVector<Instruction *, 16>;
using ValueSet = SmallPtrSet<Value *, 16>;
using StoreList = SmallVector<StoreInst *, 8>;
using ExtraValueToDebugLocsMap =
MapVector<Value *, SmallVector<Instruction *, 2>>;
using OrdersType = SmallVector<unsigned, 4>;
BoUpSLP(Function *Func, ScalarEvolution *Se, TargetTransformInfo *Tti,
TargetLibraryInfo *TLi, AAResults *Aa, LoopInfo *Li,
DominatorTree *Dt, AssumptionCache *AC, DemandedBits *DB,
const DataLayout *DL, OptimizationRemarkEmitter *ORE)
: F(Func), SE(Se), TTI(Tti), TLI(TLi), AA(Aa), LI(Li), DT(Dt), AC(AC),
DB(DB), DL(DL), ORE(ORE), Builder(Se->getContext()) {
CodeMetrics::collectEphemeralValues(F, AC, EphValues);
// Use the vector register size specified by the target unless overridden
// by a command-line option.
// TODO: It would be better to limit the vectorization factor based on
// data type rather than just register size. For example, x86 AVX has
// 256-bit registers, but it does not support integer operations
// at that width (that requires AVX2).
if (MaxVectorRegSizeOption.getNumOccurrences())
MaxVecRegSize = MaxVectorRegSizeOption;
else
MaxVecRegSize = TTI->getRegisterBitWidth(true);
if (MinVectorRegSizeOption.getNumOccurrences())
MinVecRegSize = MinVectorRegSizeOption;
else
MinVecRegSize = TTI->getMinVectorRegisterBitWidth();
}
/// Vectorize the tree that starts with the elements in \p VL.
/// Returns the vectorized root.
Value *vectorizeTree();
/// Vectorize the tree but with the list of externally used values \p
/// ExternallyUsedValues. Values in this MapVector can be replaced but the
/// generated extractvalue instructions.
Value *vectorizeTree(ExtraValueToDebugLocsMap &ExternallyUsedValues);
/// \returns the cost incurred by unwanted spills and fills, caused by
/// holding live values over call sites.
InstructionCost getSpillCost() const;
/// \returns the vectorization cost of the subtree that starts at \p VL.
/// A negative number means that this is profitable.
InstructionCost getTreeCost();
/// Construct a vectorizable tree that starts at \p Roots, ignoring users for
/// the purpose of scheduling and extraction in the \p UserIgnoreLst.
void buildTree(ArrayRef<Value *> Roots,
ArrayRef<Value *> UserIgnoreLst = None);
/// Construct a vectorizable tree that starts at \p Roots, ignoring users for
/// the purpose of scheduling and extraction in the \p UserIgnoreLst taking
/// into account (and updating it, if required) list of externally used
/// values stored in \p ExternallyUsedValues.
void buildTree(ArrayRef<Value *> Roots,
ExtraValueToDebugLocsMap &ExternallyUsedValues,
ArrayRef<Value *> UserIgnoreLst = None);
/// Clear the internal data structures that are created by 'buildTree'.
void deleteTree() {
VectorizableTree.clear();
ScalarToTreeEntry.clear();
MustGather.clear();
ExternalUses.clear();
NumOpsWantToKeepOrder.clear();
NumOpsWantToKeepOriginalOrder = 0;
for (auto &Iter : BlocksSchedules) {
BlockScheduling *BS = Iter.second.get();
BS->clear();
}
MinBWs.clear();
}
unsigned getTreeSize() const { return VectorizableTree.size(); }
/// Perform LICM and CSE on the newly generated gather sequences.
void optimizeGatherSequence();
/// \returns The best order of instructions for vectorization.
Optional<ArrayRef<unsigned>> bestOrder() const {
assert(llvm::all_of(
NumOpsWantToKeepOrder,
[this](const decltype(NumOpsWantToKeepOrder)::value_type &D) {
return D.getFirst().size() ==
VectorizableTree[0]->Scalars.size();
}) &&
"All orders must have the same size as number of instructions in "
"tree node.");
auto I = std::max_element(
NumOpsWantToKeepOrder.begin(), NumOpsWantToKeepOrder.end(),
[](const decltype(NumOpsWantToKeepOrder)::value_type &D1,
const decltype(NumOpsWantToKeepOrder)::value_type &D2) {
return D1.second < D2.second;
});
if (I == NumOpsWantToKeepOrder.end() ||
I->getSecond() <= NumOpsWantToKeepOriginalOrder)
return None;
return makeArrayRef(I->getFirst());
}
/// Builds the correct order for root instructions.
/// If some leaves have the same instructions to be vectorized, we may
/// incorrectly evaluate the best order for the root node (it is built for the
/// vector of instructions without repeated instructions and, thus, has less
/// elements than the root node). This function builds the correct order for
/// the root node.
/// For example, if the root node is \<a+b, a+c, a+d, f+e\>, then the leaves
/// are \<a, a, a, f\> and \<b, c, d, e\>. When we try to vectorize the first
/// leaf, it will be shrink to \<a, b\>. If instructions in this leaf should
/// be reordered, the best order will be \<1, 0\>. We need to extend this
/// order for the root node. For the root node this order should look like
/// \<3, 0, 1, 2\>. This function extends the order for the reused
/// instructions.
void findRootOrder(OrdersType &Order) {
// If the leaf has the same number of instructions to vectorize as the root
// - order must be set already.
unsigned RootSize = VectorizableTree[0]->Scalars.size();
if (Order.size() == RootSize)
return;
SmallVector<unsigned, 4> RealOrder(Order.size());
std::swap(Order, RealOrder);
SmallVector<int, 4> Mask;
inversePermutation(RealOrder, Mask);
Order.assign(Mask.begin(), Mask.end());
// The leaf has less number of instructions - need to find the true order of
// the root.
// Scan the nodes starting from the leaf back to the root.
const TreeEntry *PNode = VectorizableTree.back().get();
SmallVector<const TreeEntry *, 4> Nodes(1, PNode);
SmallPtrSet<const TreeEntry *, 4> Visited;
while (!Nodes.empty() && Order.size() != RootSize) {
const TreeEntry *PNode = Nodes.pop_back_val();
if (!Visited.insert(PNode).second)
continue;
const TreeEntry &Node = *PNode;
for (const EdgeInfo &EI : Node.UserTreeIndices)
if (EI.UserTE)
Nodes.push_back(EI.UserTE);
if (Node.ReuseShuffleIndices.empty())
continue;
// Build the order for the parent node.
OrdersType NewOrder(Node.ReuseShuffleIndices.size(), RootSize);
SmallVector<unsigned, 4> OrderCounter(Order.size(), 0);
// The algorithm of the order extension is:
// 1. Calculate the number of the same instructions for the order.
// 2. Calculate the index of the new order: total number of instructions
// with order less than the order of the current instruction + reuse
// number of the current instruction.
// 3. The new order is just the index of the instruction in the original
// vector of the instructions.
for (unsigned I : Node.ReuseShuffleIndices)
++OrderCounter[Order[I]];
SmallVector<unsigned, 4> CurrentCounter(Order.size(), 0);
for (unsigned I = 0, E = Node.ReuseShuffleIndices.size(); I < E; ++I) {
unsigned ReusedIdx = Node.ReuseShuffleIndices[I];
unsigned OrderIdx = Order[ReusedIdx];
unsigned NewIdx = 0;
for (unsigned J = 0; J < OrderIdx; ++J)
NewIdx += OrderCounter[J];
NewIdx += CurrentCounter[OrderIdx];
++CurrentCounter[OrderIdx];
assert(NewOrder[NewIdx] == RootSize &&
"The order index should not be written already.");
NewOrder[NewIdx] = I;
}
std::swap(Order, NewOrder);
}
assert(Order.size() == RootSize &&
"Root node is expected or the size of the order must be the same as "
"the number of elements in the root node.");
assert(llvm::all_of(Order,
[RootSize](unsigned Val) { return Val != RootSize; }) &&
"All indices must be initialized");
}
/// \return The vector element size in bits to use when vectorizing the
/// expression tree ending at \p V. If V is a store, the size is the width of
/// the stored value. Otherwise, the size is the width of the largest loaded
/// value reaching V. This method is used by the vectorizer to calculate
/// vectorization factors.
unsigned getVectorElementSize(Value *V);
/// Compute the minimum type sizes required to represent the entries in a
/// vectorizable tree.
void computeMinimumValueSizes();
// \returns maximum vector register size as set by TTI or overridden by cl::opt.
unsigned getMaxVecRegSize() const {
return MaxVecRegSize;
}
// \returns minimum vector register size as set by cl::opt.
unsigned getMinVecRegSize() const {
return MinVecRegSize;
}
unsigned getMaximumVF(unsigned ElemWidth, unsigned Opcode) const {
unsigned MaxVF = MaxVFOption.getNumOccurrences() ?
MaxVFOption : TTI->getMaximumVF(ElemWidth, Opcode);
return MaxVF ? MaxVF : UINT_MAX;
}
/// Check if homogeneous aggregate is isomorphic to some VectorType.
/// Accepts homogeneous multidimensional aggregate of scalars/vectors like
/// {[4 x i16], [4 x i16]}, { <2 x float>, <2 x float> },
/// {{{i16, i16}, {i16, i16}}, {{i16, i16}, {i16, i16}}} and so on.
///
/// \returns number of elements in vector if isomorphism exists, 0 otherwise.
unsigned canMapToVector(Type *T, const DataLayout &DL) const;
/// \returns True if the VectorizableTree is both tiny and not fully
/// vectorizable. We do not vectorize such trees.
bool isTreeTinyAndNotFullyVectorizable() const;
/// Assume that a legal-sized 'or'-reduction of shifted/zexted loaded values
/// can be load combined in the backend. Load combining may not be allowed in
/// the IR optimizer, so we do not want to alter the pattern. For example,
/// partially transforming a scalar bswap() pattern into vector code is
/// effectively impossible for the backend to undo.
/// TODO: If load combining is allowed in the IR optimizer, this analysis
/// may not be necessary.
bool isLoadCombineReductionCandidate(RecurKind RdxKind) const;
/// Assume that a vector of stores of bitwise-or/shifted/zexted loaded values
/// can be load combined in the backend. Load combining may not be allowed in
/// the IR optimizer, so we do not want to alter the pattern. For example,
/// partially transforming a scalar bswap() pattern into vector code is
/// effectively impossible for the backend to undo.
/// TODO: If load combining is allowed in the IR optimizer, this analysis
/// may not be necessary.
bool isLoadCombineCandidate() const;
OptimizationRemarkEmitter *getORE() { return ORE; }
/// This structure holds any data we need about the edges being traversed
/// during buildTree_rec(). We keep track of:
/// (i) the user TreeEntry index, and
/// (ii) the index of the edge.
struct EdgeInfo {
EdgeInfo() = default;
EdgeInfo(TreeEntry *UserTE, unsigned EdgeIdx)
: UserTE(UserTE), EdgeIdx(EdgeIdx) {}
/// The user TreeEntry.
TreeEntry *UserTE = nullptr;
/// The operand index of the use.
unsigned EdgeIdx = UINT_MAX;
#ifndef NDEBUG
friend inline raw_ostream &operator<<(raw_ostream &OS,
const BoUpSLP::EdgeInfo &EI) {
EI.dump(OS);
return OS;
}
/// Debug print.
void dump(raw_ostream &OS) const {
OS << "{User:" << (UserTE ? std::to_string(UserTE->Idx) : "null")
<< " EdgeIdx:" << EdgeIdx << "}";
}
LLVM_DUMP_METHOD void dump() const { dump(dbgs()); }
#endif
};
/// A helper data structure to hold the operands of a vector of instructions.
/// This supports a fixed vector length for all operand vectors.
class VLOperands {
/// For each operand we need (i) the value, and (ii) the opcode that it
/// would be attached to if the expression was in a left-linearized form.
/// This is required to avoid illegal operand reordering.
/// For example:
/// \verbatim
/// 0 Op1
/// |/
/// Op1 Op2 Linearized + Op2
/// \ / ----------> |/
/// - -
///
/// Op1 - Op2 (0 + Op1) - Op2
/// \endverbatim
///
/// Value Op1 is attached to a '+' operation, and Op2 to a '-'.
///
/// Another way to think of this is to track all the operations across the
/// path from the operand all the way to the root of the tree and to
/// calculate the operation that corresponds to this path. For example, the
/// path from Op2 to the root crosses the RHS of the '-', therefore the
/// corresponding operation is a '-' (which matches the one in the
/// linearized tree, as shown above).
///
/// For lack of a better term, we refer to this operation as Accumulated
/// Path Operation (APO).
struct OperandData {
OperandData() = default;
OperandData(Value *V, bool APO, bool IsUsed)
: V(V), APO(APO), IsUsed(IsUsed) {}
/// The operand value.
Value *V = nullptr;
/// TreeEntries only allow a single opcode, or an alternate sequence of
/// them (e.g, +, -). Therefore, we can safely use a boolean value for the
/// APO. It is set to 'true' if 'V' is attached to an inverse operation
/// in the left-linearized form (e.g., Sub/Div), and 'false' otherwise
/// (e.g., Add/Mul)
bool APO = false;
/// Helper data for the reordering function.
bool IsUsed = false;
};
/// During operand reordering, we are trying to select the operand at lane
/// that matches best with the operand at the neighboring lane. Our
/// selection is based on the type of value we are looking for. For example,
/// if the neighboring lane has a load, we need to look for a load that is
/// accessing a consecutive address. These strategies are summarized in the
/// 'ReorderingMode' enumerator.
enum class ReorderingMode {
Load, ///< Matching loads to consecutive memory addresses
Opcode, ///< Matching instructions based on opcode (same or alternate)
Constant, ///< Matching constants
Splat, ///< Matching the same instruction multiple times (broadcast)
Failed, ///< We failed to create a vectorizable group
};
using OperandDataVec = SmallVector<OperandData, 2>;
/// A vector of operand vectors.
SmallVector<OperandDataVec, 4> OpsVec;
const DataLayout &DL;
ScalarEvolution &SE;
const BoUpSLP &R;
/// \returns the operand data at \p OpIdx and \p Lane.
OperandData &getData(unsigned OpIdx, unsigned Lane) {
return OpsVec[OpIdx][Lane];
}
/// \returns the operand data at \p OpIdx and \p Lane. Const version.
const OperandData &getData(unsigned OpIdx, unsigned Lane) const {
return OpsVec[OpIdx][Lane];
}
/// Clears the used flag for all entries.
void clearUsed() {
for (unsigned OpIdx = 0, NumOperands = getNumOperands();
OpIdx != NumOperands; ++OpIdx)
for (unsigned Lane = 0, NumLanes = getNumLanes(); Lane != NumLanes;
++Lane)
OpsVec[OpIdx][Lane].IsUsed = false;
}
/// Swap the operand at \p OpIdx1 with that one at \p OpIdx2.
void swap(unsigned OpIdx1, unsigned OpIdx2, unsigned Lane) {
std::swap(OpsVec[OpIdx1][Lane], OpsVec[OpIdx2][Lane]);
}
// The hard-coded scores listed here are not very important. When computing
// the scores of matching one sub-tree with another, we are basically
// counting the number of values that are matching. So even if all scores
// are set to 1, we would still get a decent matching result.
// However, sometimes we have to break ties. For example we may have to
// choose between matching loads vs matching opcodes. This is what these
// scores are helping us with: they provide the order of preference.
/// Loads from consecutive memory addresses, e.g. load(A[i]), load(A[i+1]).
static const int ScoreConsecutiveLoads = 3;
/// ExtractElementInst from same vector and consecutive indexes.
static const int ScoreConsecutiveExtracts = 3;
/// Constants.
static const int ScoreConstants = 2;
/// Instructions with the same opcode.
static const int ScoreSameOpcode = 2;
/// Instructions with alt opcodes (e.g, add + sub).
static const int ScoreAltOpcodes = 1;
/// Identical instructions (a.k.a. splat or broadcast).
static const int ScoreSplat = 1;
/// Matching with an undef is preferable to failing.
static const int ScoreUndef = 1;
/// Score for failing to find a decent match.
static const int ScoreFail = 0;
/// User exteranl to the vectorized code.
static const int ExternalUseCost = 1;
/// The user is internal but in a different lane.
static const int UserInDiffLaneCost = ExternalUseCost;
/// \returns the score of placing \p V1 and \p V2 in consecutive lanes.
static int getShallowScore(Value *V1, Value *V2, const DataLayout &DL,
ScalarEvolution &SE) {
auto *LI1 = dyn_cast<LoadInst>(V1);
auto *LI2 = dyn_cast<LoadInst>(V2);
if (LI1 && LI2)
return isConsecutiveAccess(LI1, LI2, DL, SE)
? VLOperands::ScoreConsecutiveLoads
: VLOperands::ScoreFail;
auto *C1 = dyn_cast<Constant>(V1);
auto *C2 = dyn_cast<Constant>(V2);
if (C1 && C2)
return VLOperands::ScoreConstants;
// Extracts from consecutive indexes of the same vector better score as
// the extracts could be optimized away.
Value *EV;
ConstantInt *Ex1Idx, *Ex2Idx;
if (match(V1, m_ExtractElt(m_Value(EV), m_ConstantInt(Ex1Idx))) &&
match(V2, m_ExtractElt(m_Deferred(EV), m_ConstantInt(Ex2Idx))) &&
Ex1Idx->getZExtValue() + 1 == Ex2Idx->getZExtValue())
return VLOperands::ScoreConsecutiveExtracts;
auto *I1 = dyn_cast<Instruction>(V1);
auto *I2 = dyn_cast<Instruction>(V2);
if (I1 && I2) {
if (I1 == I2)
return VLOperands::ScoreSplat;
InstructionsState S = getSameOpcode({I1, I2});
// Note: Only consider instructions with <= 2 operands to avoid
// complexity explosion.
if (S.getOpcode() && S.MainOp->getNumOperands() <= 2)
return S.isAltShuffle() ? VLOperands::ScoreAltOpcodes
: VLOperands::ScoreSameOpcode;
}
if (isa<UndefValue>(V2))
return VLOperands::ScoreUndef;
return VLOperands::ScoreFail;
}
/// Holds the values and their lane that are taking part in the look-ahead
/// score calculation. This is used in the external uses cost calculation.
SmallDenseMap<Value *, int> InLookAheadValues;
/// \Returns the additinal cost due to uses of \p LHS and \p RHS that are
/// either external to the vectorized code, or require shuffling.
int getExternalUsesCost(const std::pair<Value *, int> &LHS,
const std::pair<Value *, int> &RHS) {
int Cost = 0;
std::array<std::pair<Value *, int>, 2> Values = {{LHS, RHS}};
for (int Idx = 0, IdxE = Values.size(); Idx != IdxE; ++Idx) {
Value *V = Values[Idx].first;
if (isa<Constant>(V)) {
// Since this is a function pass, it doesn't make semantic sense to
// walk the users of a subclass of Constant. The users could be in
// another function, or even another module that happens to be in
// the same LLVMContext.
continue;
}
// Calculate the absolute lane, using the minimum relative lane of LHS
// and RHS as base and Idx as the offset.
int Ln = std::min(LHS.second, RHS.second) + Idx;
assert(Ln >= 0 && "Bad lane calculation");
unsigned UsersBudget = LookAheadUsersBudget;
for (User *U : V->users()) {
if (const TreeEntry *UserTE = R.getTreeEntry(U)) {
// The user is in the VectorizableTree. Check if we need to insert.
auto It = llvm::find(UserTE->Scalars, U);
assert(It != UserTE->Scalars.end() && "U is in UserTE");
int UserLn = std::distance(UserTE->Scalars.begin(), It);
assert(UserLn >= 0 && "Bad lane");
if (UserLn != Ln)
Cost += UserInDiffLaneCost;
} else {
// Check if the user is in the look-ahead code.
auto It2 = InLookAheadValues.find(U);
if (It2 != InLookAheadValues.end()) {
// The user is in the look-ahead code. Check the lane.
if (It2->second != Ln)
Cost += UserInDiffLaneCost;
} else {
// The user is neither in SLP tree nor in the look-ahead code.
Cost += ExternalUseCost;
}
}
// Limit the number of visited uses to cap compilation time.
if (--UsersBudget == 0)
break;
}
}
return Cost;
}
/// Go through the operands of \p LHS and \p RHS recursively until \p
/// MaxLevel, and return the cummulative score. For example:
/// \verbatim
/// A[0] B[0] A[1] B[1] C[0] D[0] B[1] A[1]
/// \ / \ / \ / \ /
/// + + + +
/// G1 G2 G3 G4
/// \endverbatim
/// The getScoreAtLevelRec(G1, G2) function will try to match the nodes at
/// each level recursively, accumulating the score. It starts from matching
/// the additions at level 0, then moves on to the loads (level 1). The
/// score of G1 and G2 is higher than G1 and G3, because {A[0],A[1]} and
/// {B[0],B[1]} match with VLOperands::ScoreConsecutiveLoads, while
/// {A[0],C[0]} has a score of VLOperands::ScoreFail.
/// Please note that the order of the operands does not matter, as we
/// evaluate the score of all profitable combinations of operands. In
/// other words the score of G1 and G4 is the same as G1 and G2. This
/// heuristic is based on ideas described in:
/// Look-ahead SLP: Auto-vectorization in the presence of commutative
/// operations, CGO 2018 by Vasileios Porpodas, Rodrigo C. O. Rocha,
/// Luís F. W. Góes
int getScoreAtLevelRec(const std::pair<Value *, int> &LHS,
const std::pair<Value *, int> &RHS, int CurrLevel,
int MaxLevel) {
Value *V1 = LHS.first;
Value *V2 = RHS.first;
// Get the shallow score of V1 and V2.
int ShallowScoreAtThisLevel =
std::max((int)ScoreFail, getShallowScore(V1, V2, DL, SE) -
getExternalUsesCost(LHS, RHS));
int Lane1 = LHS.second;
int Lane2 = RHS.second;
// If reached MaxLevel,
// or if V1 and V2 are not instructions,
// or if they are SPLAT,
// or if they are not consecutive, early return the current cost.
auto *I1 = dyn_cast<Instruction>(V1);
auto *I2 = dyn_cast<Instruction>(V2);
if (CurrLevel == MaxLevel || !(I1 && I2) || I1 == I2 ||
ShallowScoreAtThisLevel == VLOperands::ScoreFail ||
(isa<LoadInst>(I1) && isa<LoadInst>(I2) && ShallowScoreAtThisLevel))
return ShallowScoreAtThisLevel;
assert(I1 && I2 && "Should have early exited.");
// Keep track of in-tree values for determining the external-use cost.
InLookAheadValues[V1] = Lane1;
InLookAheadValues[V2] = Lane2;
// Contains the I2 operand indexes that got matched with I1 operands.
SmallSet<unsigned, 4> Op2Used;
// Recursion towards the operands of I1 and I2. We are trying all possbile
// operand pairs, and keeping track of the best score.
for (unsigned OpIdx1 = 0, NumOperands1 = I1->getNumOperands();
OpIdx1 != NumOperands1; ++OpIdx1) {
// Try to pair op1I with the best operand of I2.
int MaxTmpScore = 0;
unsigned MaxOpIdx2 = 0;
bool FoundBest = false;
// If I2 is commutative try all combinations.
unsigned FromIdx = isCommutative(I2) ? 0 : OpIdx1;
unsigned ToIdx = isCommutative(I2)
? I2->getNumOperands()
: std::min(I2->getNumOperands(), OpIdx1 + 1);
assert(FromIdx <= ToIdx && "Bad index");
for (unsigned OpIdx2 = FromIdx; OpIdx2 != ToIdx; ++OpIdx2) {
// Skip operands already paired with OpIdx1.
if (Op2Used.count(OpIdx2))
continue;
// Recursively calculate the cost at each level
int TmpScore = getScoreAtLevelRec({I1->getOperand(OpIdx1), Lane1},
{I2->getOperand(OpIdx2), Lane2},
CurrLevel + 1, MaxLevel);
// Look for the best score.
if (TmpScore > VLOperands::ScoreFail && TmpScore > MaxTmpScore) {
MaxTmpScore = TmpScore;
MaxOpIdx2 = OpIdx2;
FoundBest = true;
}
}
if (FoundBest) {
// Pair {OpIdx1, MaxOpIdx2} was found to be best. Never revisit it.
Op2Used.insert(MaxOpIdx2);
ShallowScoreAtThisLevel += MaxTmpScore;
}
}
return ShallowScoreAtThisLevel;
}
/// \Returns the look-ahead score, which tells us how much the sub-trees
/// rooted at \p LHS and \p RHS match, the more they match the higher the
/// score. This helps break ties in an informed way when we cannot decide on
/// the order of the operands by just considering the immediate
/// predecessors.
int getLookAheadScore(const std::pair<Value *, int> &LHS,
const std::pair<Value *, int> &RHS) {
InLookAheadValues.clear();
return getScoreAtLevelRec(LHS, RHS, 1, LookAheadMaxDepth);
}
// Search all operands in Ops[*][Lane] for the one that matches best
// Ops[OpIdx][LastLane] and return its opreand index.
// If no good match can be found, return None.
Optional<unsigned>
getBestOperand(unsigned OpIdx, int Lane, int LastLane,
ArrayRef<ReorderingMode> ReorderingModes) {
unsigned NumOperands = getNumOperands();
// The operand of the previous lane at OpIdx.
Value *OpLastLane = getData(OpIdx, LastLane).V;
// Our strategy mode for OpIdx.
ReorderingMode RMode = ReorderingModes[OpIdx];
// The linearized opcode of the operand at OpIdx, Lane.
bool OpIdxAPO = getData(OpIdx, Lane).APO;
// The best operand index and its score.
// Sometimes we have more than one option (e.g., Opcode and Undefs), so we
// are using the score to differentiate between the two.
struct BestOpData {
Optional<unsigned> Idx = None;
unsigned Score = 0;
} BestOp;
// Iterate through all unused operands and look for the best.
for (unsigned Idx = 0; Idx != NumOperands; ++Idx) {
// Get the operand at Idx and Lane.
OperandData &OpData = getData(Idx, Lane);
Value *Op = OpData.V;
bool OpAPO = OpData.APO;
// Skip already selected operands.
if (OpData.IsUsed)
continue;
// Skip if we are trying to move the operand to a position with a
// different opcode in the linearized tree form. This would break the
// semantics.
if (OpAPO != OpIdxAPO)
continue;
// Look for an operand that matches the current mode.
switch (RMode) {
case ReorderingMode::Load:
case ReorderingMode::Constant:
case ReorderingMode::Opcode: {
bool LeftToRight = Lane > LastLane;
Value *OpLeft = (LeftToRight) ? OpLastLane : Op;
Value *OpRight = (LeftToRight) ? Op : OpLastLane;
unsigned Score =
getLookAheadScore({OpLeft, LastLane}, {OpRight, Lane});
if (Score > BestOp.Score) {
BestOp.Idx = Idx;
BestOp.Score = Score;
}
break;
}
case ReorderingMode::Splat:
if (Op == OpLastLane)
BestOp.Idx = Idx;
break;
case ReorderingMode::Failed:
return None;
}
}
if (BestOp.Idx) {
getData(BestOp.Idx.getValue(), Lane).IsUsed = true;
return BestOp.Idx;
}
// If we could not find a good match return None.
return None;
}
/// Helper for reorderOperandVecs. \Returns the lane that we should start
/// reordering from. This is the one which has the least number of operands
/// that can freely move about.
unsigned getBestLaneToStartReordering() const {
unsigned BestLane = 0;
unsigned Min = UINT_MAX;
for (unsigned Lane = 0, NumLanes = getNumLanes(); Lane != NumLanes;
++Lane) {
unsigned NumFreeOps = getMaxNumOperandsThatCanBeReordered(Lane);
if (NumFreeOps < Min) {
Min = NumFreeOps;
BestLane = Lane;
}
}
return BestLane;
}
/// \Returns the maximum number of operands that are allowed to be reordered
/// for \p Lane. This is used as a heuristic for selecting the first lane to
/// start operand reordering.
unsigned getMaxNumOperandsThatCanBeReordered(unsigned Lane) const {
unsigned CntTrue = 0;
unsigned NumOperands = getNumOperands();
// Operands with the same APO can be reordered. We therefore need to count
// how many of them we have for each APO, like this: Cnt[APO] = x.
// Since we only have two APOs, namely true and false, we can avoid using
// a map. Instead we can simply count the number of operands that
// correspond to one of them (in this case the 'true' APO), and calculate
// the other by subtracting it from the total number of operands.
for (unsigned OpIdx = 0; OpIdx != NumOperands; ++OpIdx)
if (getData(OpIdx, Lane).APO)
++CntTrue;
unsigned CntFalse = NumOperands - CntTrue;
return std::max(CntTrue, CntFalse);
}
/// Go through the instructions in VL and append their operands.
void appendOperandsOfVL(ArrayRef<Value *> VL) {
assert(!VL.empty() && "Bad VL");
assert((empty() || VL.size() == getNumLanes()) &&
"Expected same number of lanes");
assert(isa<Instruction>(VL[0]) && "Expected instruction");
unsigned NumOperands = cast<Instruction>(VL[0])->getNumOperands();
OpsVec.resize(NumOperands);
unsigned NumLanes = VL.size();
for (unsigned OpIdx = 0; OpIdx != NumOperands; ++OpIdx) {
OpsVec[OpIdx].resize(NumLanes);
for (unsigned Lane = 0; Lane != NumLanes; ++Lane) {
assert(isa<Instruction>(VL[Lane]) && "Expected instruction");
// Our tree has just 3 nodes: the root and two operands.
// It is therefore trivial to get the APO. We only need to check the
// opcode of VL[Lane] and whether the operand at OpIdx is the LHS or
// RHS operand. The LHS operand of both add and sub is never attached
// to an inversese operation in the linearized form, therefore its APO
// is false. The RHS is true only if VL[Lane] is an inverse operation.
// Since operand reordering is performed on groups of commutative
// operations or alternating sequences (e.g., +, -), we can safely
// tell the inverse operations by checking commutativity.
bool IsInverseOperation = !isCommutative(cast<Instruction>(VL[Lane]));
bool APO = (OpIdx == 0) ? false : IsInverseOperation;
OpsVec[OpIdx][Lane] = {cast<Instruction>(VL[Lane])->getOperand(OpIdx),
APO, false};
}
}
}
/// \returns the number of operands.
unsigned getNumOperands() const { return OpsVec.size(); }
/// \returns the number of lanes.
unsigned getNumLanes() const { return OpsVec[0].size(); }
/// \returns the operand value at \p OpIdx and \p Lane.
Value *getValue(unsigned OpIdx, unsigned Lane) const {
return getData(OpIdx, Lane).V;
}
/// \returns true if the data structure is empty.
bool empty() const { return OpsVec.empty(); }
/// Clears the data.
void clear() { OpsVec.clear(); }
/// \Returns true if there are enough operands identical to \p Op to fill
/// the whole vector.
/// Note: This modifies the 'IsUsed' flag, so a cleanUsed() must follow.
bool shouldBroadcast(Value *Op, unsigned OpIdx, unsigned Lane) {
bool OpAPO = getData(OpIdx, Lane).APO;
for (unsigned Ln = 0, Lns = getNumLanes(); Ln != Lns; ++Ln) {
if (Ln == Lane)
continue;
// This is set to true if we found a candidate for broadcast at Lane.
bool FoundCandidate = false;
for (unsigned OpI = 0, OpE = getNumOperands(); OpI != OpE; ++OpI) {
OperandData &Data = getData(OpI, Ln);
if (Data.APO != OpAPO || Data.IsUsed)
continue;
if (Data.V == Op) {
FoundCandidate = true;
Data.IsUsed = true;
break;
}
}
if (!FoundCandidate)
return false;
}
return true;
}
public:
/// Initialize with all the operands of the instruction vector \p RootVL.
VLOperands(ArrayRef<Value *> RootVL, const DataLayout &DL,
ScalarEvolution &SE, const BoUpSLP &R)
: DL(DL), SE(SE), R(R) {
// Append all the operands of RootVL.
appendOperandsOfVL(RootVL);
}
/// \Returns a value vector with the operands across all lanes for the
/// opearnd at \p OpIdx.
ValueList getVL(unsigned OpIdx) const {
ValueList OpVL(OpsVec[OpIdx].size());
assert(OpsVec[OpIdx].size() == getNumLanes() &&
"Expected same num of lanes across all operands");
for (unsigned Lane = 0, Lanes = getNumLanes(); Lane != Lanes; ++Lane)
OpVL[Lane] = OpsVec[OpIdx][Lane].V;
return OpVL;
}
// Performs operand reordering for 2 or more operands.
// The original operands are in OrigOps[OpIdx][Lane].
// The reordered operands are returned in 'SortedOps[OpIdx][Lane]'.
void reorder() {
unsigned NumOperands = getNumOperands();
unsigned NumLanes = getNumLanes();
// Each operand has its own mode. We are using this mode to help us select
// the instructions for each lane, so that they match best with the ones
// we have selected so far.
SmallVector<ReorderingMode, 2> ReorderingModes(NumOperands);
// This is a greedy single-pass algorithm. We are going over each lane
// once and deciding on the best order right away with no back-tracking.
// However, in order to increase its effectiveness, we start with the lane
// that has operands that can move the least. For example, given the
// following lanes:
// Lane 0 : A[0] = B[0] + C[0] // Visited 3rd
// Lane 1 : A[1] = C[1] - B[1] // Visited 1st
// Lane 2 : A[2] = B[2] + C[2] // Visited 2nd
// Lane 3 : A[3] = C[3] - B[3] // Visited 4th
// we will start at Lane 1, since the operands of the subtraction cannot
// be reordered. Then we will visit the rest of the lanes in a circular
// fashion. That is, Lanes 2, then Lane 0, and finally Lane 3.
// Find the first lane that we will start our search from.
unsigned FirstLane = getBestLaneToStartReordering();
// Initialize the modes.
for (unsigned OpIdx = 0; OpIdx != NumOperands; ++OpIdx) {
Value *OpLane0 = getValue(OpIdx, FirstLane);
// Keep track if we have instructions with all the same opcode on one
// side.
if (isa<LoadInst>(OpLane0))
ReorderingModes[OpIdx] = ReorderingMode::Load;
else if (isa<Instruction>(OpLane0)) {
// Check if OpLane0 should be broadcast.
if (shouldBroadcast(OpLane0, OpIdx, FirstLane))
ReorderingModes[OpIdx] = ReorderingMode::Splat;
else
ReorderingModes[OpIdx] = ReorderingMode::Opcode;
}
else if (isa<Constant>(OpLane0))
ReorderingModes[OpIdx] = ReorderingMode::Constant;
else if (isa<Argument>(OpLane0))
// Our best hope is a Splat. It may save some cost in some cases.
ReorderingModes[OpIdx] = ReorderingMode::Splat;
else
// NOTE: This should be unreachable.
ReorderingModes[OpIdx] = ReorderingMode::Failed;
}
// If the initial strategy fails for any of the operand indexes, then we
// perform reordering again in a second pass. This helps avoid assigning
// high priority to the failed strategy, and should improve reordering for
// the non-failed operand indexes.
for (int Pass = 0; Pass != 2; ++Pass) {
// Skip the second pass if the first pass did not fail.
bool StrategyFailed = false;
// Mark all operand data as free to use.
clearUsed();
// We keep the original operand order for the FirstLane, so reorder the
// rest of the lanes. We are visiting the nodes in a circular fashion,
// using FirstLane as the center point and increasing the radius
// distance.
for (unsigned Distance = 1; Distance != NumLanes; ++Distance) {
// Visit the lane on the right and then the lane on the left.
for (int Direction : {+1, -1}) {
int Lane = FirstLane + Direction * Distance;
if (Lane < 0 || Lane >= (int)NumLanes)
continue;
int LastLane = Lane - Direction;
assert(LastLane >= 0 && LastLane < (int)NumLanes &&
"Out of bounds");
// Look for a good match for each operand.
for (unsigned OpIdx = 0; OpIdx != NumOperands; ++OpIdx) {
// Search for the operand that matches SortedOps[OpIdx][Lane-1].
Optional<unsigned> BestIdx =
getBestOperand(OpIdx, Lane, LastLane, ReorderingModes);
// By not selecting a value, we allow the operands that follow to
// select a better matching value. We will get a non-null value in
// the next run of getBestOperand().
if (BestIdx) {
// Swap the current operand with the one returned by
// getBestOperand().
swap(OpIdx, BestIdx.getValue(), Lane);
} else {
// We failed to find a best operand, set mode to 'Failed'.
ReorderingModes[OpIdx] = ReorderingMode::Failed;
// Enable the second pass.
StrategyFailed = true;
}
}
}
}
// Skip second pass if the strategy did not fail.
if (!StrategyFailed)
break;
}
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD static StringRef getModeStr(ReorderingMode RMode) {
switch (RMode) {
case ReorderingMode::Load:
return "Load";
case ReorderingMode::Opcode:
return "Opcode";
case ReorderingMode::Constant:
return "Constant";
case ReorderingMode::Splat:
return "Splat";
case ReorderingMode::Failed:
return "Failed";
}
llvm_unreachable("Unimplemented Reordering Type");
}
LLVM_DUMP_METHOD static raw_ostream &printMode(ReorderingMode RMode,
raw_ostream &OS) {
return OS << getModeStr(RMode);
}
/// Debug print.
LLVM_DUMP_METHOD static void dumpMode(ReorderingMode RMode) {
printMode(RMode, dbgs());
}
friend raw_ostream &operator<<(raw_ostream &OS, ReorderingMode RMode) {
return printMode(RMode, OS);
}
LLVM_DUMP_METHOD raw_ostream &print(raw_ostream &OS) const {
const unsigned Indent = 2;
unsigned Cnt = 0;
for (const OperandDataVec &OpDataVec : OpsVec) {
OS << "Operand " << Cnt++ << "\n";
for (const OperandData &OpData : OpDataVec) {
OS.indent(Indent) << "{";
if (Value *V = OpData.V)
OS << *V;
else
OS << "null";
OS << ", APO:" << OpData.APO << "}\n";
}
OS << "\n";
}
return OS;
}
/// Debug print.
LLVM_DUMP_METHOD void dump() const { print(dbgs()); }
#endif
};
/// Checks if the instruction is marked for deletion.
bool isDeleted(Instruction *I) const { return DeletedInstructions.count(I); }
/// Marks values operands for later deletion by replacing them with Undefs.
void eraseInstructions(ArrayRef<Value *> AV);
~BoUpSLP();
private:
/// Checks if all users of \p I are the part of the vectorization tree.
bool areAllUsersVectorized(Instruction *I) const;
/// \returns the cost of the vectorizable entry.
InstructionCost getEntryCost(TreeEntry *E);
/// This is the recursive part of buildTree.
void buildTree_rec(ArrayRef<Value *> Roots, unsigned Depth,
const EdgeInfo &EI);
/// \returns true if the ExtractElement/ExtractValue instructions in \p VL can
/// be vectorized to use the original vector (or aggregate "bitcast" to a
/// vector) and sets \p CurrentOrder to the identity permutation; otherwise
/// returns false, setting \p CurrentOrder to either an empty vector or a
/// non-identity permutation that allows to reuse extract instructions.
bool canReuseExtract(ArrayRef<Value *> VL, Value *OpValue,
SmallVectorImpl<unsigned> &CurrentOrder) const;
/// Vectorize a single entry in the tree.
Value *vectorizeTree(TreeEntry *E);
/// Vectorize a single entry in the tree, starting in \p VL.
Value *vectorizeTree(ArrayRef<Value *> VL);
/// \returns the scalarization cost for this type. Scalarization in this
/// context means the creation of vectors from a group of scalars.
InstructionCost
getGatherCost(FixedVectorType *Ty,
const DenseSet<unsigned> &ShuffledIndices) const;
/// \returns the scalarization cost for this list of values. Assuming that
/// this subtree gets vectorized, we may need to extract the values from the
/// roots. This method calculates the cost of extracting the values.
InstructionCost getGatherCost(ArrayRef<Value *> VL) const;
/// Set the Builder insert point to one after the last instruction in
/// the bundle
void setInsertPointAfterBundle(TreeEntry *E);
/// \returns a vector from a collection of scalars in \p VL.
Value *gather(ArrayRef<Value *> VL);
/// \returns whether the VectorizableTree is fully vectorizable and will
/// be beneficial even the tree height is tiny.
bool isFullyVectorizableTinyTree() const;
/// Reorder commutative or alt operands to get better probability of
/// generating vectorized code.
static void reorderInputsAccordingToOpcode(ArrayRef<Value *> VL,
SmallVectorImpl<Value *> &Left,
SmallVectorImpl<Value *> &Right,
const DataLayout &DL,
ScalarEvolution &SE,
const BoUpSLP &R);
struct TreeEntry {
using VecTreeTy = SmallVector<std::unique_ptr<TreeEntry>, 8>;
TreeEntry(VecTreeTy &Container) : Container(Container) {}
/// \returns true if the scalars in VL are equal to this entry.
bool isSame(ArrayRef<Value *> VL) const {
if (VL.size() == Scalars.size())
return std::equal(VL.begin(), VL.end(), Scalars.begin());
return VL.size() == ReuseShuffleIndices.size() &&
std::equal(
VL.begin(), VL.end(), ReuseShuffleIndices.begin(),
[this](Value *V, int Idx) { return V == Scalars[Idx]; });
}
/// A vector of scalars.
ValueList Scalars;
/// The Scalars are vectorized into this value. It is initialized to Null.
Value *VectorizedValue = nullptr;
/// Do we need to gather this sequence or vectorize it
/// (either with vector instruction or with scatter/gather
/// intrinsics for store/load)?
enum EntryState { Vectorize, ScatterVectorize, NeedToGather };
EntryState State;
/// Does this sequence require some shuffling?
SmallVector<int, 4> ReuseShuffleIndices;
/// Does this entry require reordering?
SmallVector<unsigned, 4> ReorderIndices;
/// Points back to the VectorizableTree.
///
/// Only used for Graphviz right now. Unfortunately GraphTrait::NodeRef has
/// to be a pointer and needs to be able to initialize the child iterator.
/// Thus we need a reference back to the container to translate the indices
/// to entries.
VecTreeTy &Container;
/// The TreeEntry index containing the user of this entry. We can actually
/// have multiple users so the data structure is not truly a tree.
SmallVector<EdgeInfo, 1> UserTreeIndices;
/// The index of this treeEntry in VectorizableTree.
int Idx = -1;
private:
/// The operands of each instruction in each lane Operands[op_index][lane].
/// Note: This helps avoid the replication of the code that performs the
/// reordering of operands during buildTree_rec() and vectorizeTree().
SmallVector<ValueList, 2> Operands;
/// The main/alternate instruction.
Instruction *MainOp = nullptr;
Instruction *AltOp = nullptr;
public:
/// Set this bundle's \p OpIdx'th operand to \p OpVL.
void setOperand(unsigned OpIdx, ArrayRef<Value *> OpVL) {
if (Operands.size() < OpIdx + 1)
Operands.resize(OpIdx + 1);
assert(Operands[OpIdx].size() == 0 && "Already resized?");
Operands[OpIdx].resize(Scalars.size());
for (unsigned Lane = 0, E = Scalars.size(); Lane != E; ++Lane)
Operands[OpIdx][Lane] = OpVL[Lane];
}
/// Set the operands of this bundle in their original order.
void setOperandsInOrder() {
assert(Operands.empty() && "Already initialized?");
auto *I0 = cast<Instruction>(Scalars[0]);
Operands.resize(I0->getNumOperands());
unsigned NumLanes = Scalars.size();
for (unsigned OpIdx = 0, NumOperands = I0->getNumOperands();
OpIdx != NumOperands; ++OpIdx) {
Operands[OpIdx].resize(NumLanes);
for (unsigned Lane = 0; Lane != NumLanes; ++Lane) {
auto *I = cast<Instruction>(Scalars[Lane]);
assert(I->getNumOperands() == NumOperands &&
"Expected same number of operands");
Operands[OpIdx][Lane] = I->getOperand(OpIdx);
}
}
}
/// \returns the \p OpIdx operand of this TreeEntry.
ValueList &getOperand(unsigned OpIdx) {
assert(OpIdx < Operands.size() && "Off bounds");
return Operands[OpIdx];
}
/// \returns the number of operands.
unsigned getNumOperands() const { return Operands.size(); }
/// \return the single \p OpIdx operand.
Value *getSingleOperand(unsigned OpIdx) const {
assert(OpIdx < Operands.size() && "Off bounds");
assert(!Operands[OpIdx].empty() && "No operand available");
return Operands[OpIdx][0];
}
/// Some of the instructions in the list have alternate opcodes.
bool isAltShuffle() const {
return getOpcode() != getAltOpcode();
}
bool isOpcodeOrAlt(Instruction *I) const {
unsigned CheckedOpcode = I->getOpcode();
return (getOpcode() == CheckedOpcode ||
getAltOpcode() == CheckedOpcode);
}
/// Chooses the correct key for scheduling data. If \p Op has the same (or
/// alternate) opcode as \p OpValue, the key is \p Op. Otherwise the key is
/// \p OpValue.
Value *isOneOf(Value *Op) const {
auto *I = dyn_cast<Instruction>(Op);
if (I && isOpcodeOrAlt(I))
return Op;
return MainOp;
}
void setOperations(const InstructionsState &S) {
MainOp = S.MainOp;
AltOp = S.AltOp;
}
Instruction *getMainOp() const {
return MainOp;
}
Instruction *getAltOp() const {
return AltOp;
}
/// The main/alternate opcodes for the list of instructions.
unsigned getOpcode() const {
return MainOp ? MainOp->getOpcode() : 0;
}
unsigned getAltOpcode() const {
return AltOp ? AltOp->getOpcode() : 0;
}
/// Update operations state of this entry if reorder occurred.
bool updateStateIfReorder() {
if (ReorderIndices.empty())
return false;
InstructionsState S = getSameOpcode(Scalars, ReorderIndices.front());
setOperations(S);
return true;
}
#ifndef NDEBUG
/// Debug printer.
LLVM_DUMP_METHOD void dump() const {
dbgs() << Idx << ".\n";
for (unsigned OpI = 0, OpE = Operands.size(); OpI != OpE; ++OpI) {
dbgs() << "Operand " << OpI << ":\n";
for (const Value *V : Operands[OpI])
dbgs().indent(2) << *V << "\n";
}
dbgs() << "Scalars: \n";
for (Value *V : Scalars)
dbgs().indent(2) << *V << "\n";
dbgs() << "State: ";
switch (State) {
case Vectorize:
dbgs() << "Vectorize\n";
break;
case ScatterVectorize:
dbgs() << "ScatterVectorize\n";
break;
case NeedToGather:
dbgs() << "NeedToGather\n";
break;
}
dbgs() << "MainOp: ";
if (MainOp)
dbgs() << *MainOp << "\n";
else
dbgs() << "NULL\n";
dbgs() << "AltOp: ";
if (AltOp)
dbgs() << *AltOp << "\n";
else
dbgs() << "NULL\n";
dbgs() << "VectorizedValue: ";
if (VectorizedValue)
dbgs() << *VectorizedValue << "\n";
else
dbgs() << "NULL\n";
dbgs() << "ReuseShuffleIndices: ";
if (ReuseShuffleIndices.empty())
dbgs() << "Empty";
else
for (unsigned ReuseIdx : ReuseShuffleIndices)
dbgs() << ReuseIdx << ", ";
dbgs() << "\n";
dbgs() << "ReorderIndices: ";
for (unsigned ReorderIdx : ReorderIndices)
dbgs() << ReorderIdx << ", ";
dbgs() << "\n";
dbgs() << "UserTreeIndices: ";
for (const auto &EInfo : UserTreeIndices)
dbgs() << EInfo << ", ";
dbgs() << "\n";
}
#endif
};
#ifndef NDEBUG
void dumpTreeCosts(TreeEntry *E, InstructionCost ReuseShuffleCost,
InstructionCost VecCost,
InstructionCost ScalarCost) const {
dbgs() << "SLP: Calculated costs for Tree:\n"; E->dump();
dbgs() << "SLP: Costs:\n";
dbgs() << "SLP: ReuseShuffleCost = " << ReuseShuffleCost << "\n";
dbgs() << "SLP: VectorCost = " << VecCost << "\n";
dbgs() << "SLP: ScalarCost = " << ScalarCost << "\n";
dbgs() << "SLP: ReuseShuffleCost + VecCost - ScalarCost = " <<
ReuseShuffleCost + VecCost - ScalarCost << "\n";
}
#endif
/// Create a new VectorizableTree entry.
TreeEntry *newTreeEntry(ArrayRef<Value *> VL, Optional<ScheduleData *> Bundle,
const InstructionsState &S,
const EdgeInfo &UserTreeIdx,
ArrayRef<unsigned> ReuseShuffleIndices = None,
ArrayRef<unsigned> ReorderIndices = None) {
TreeEntry::EntryState EntryState =
Bundle ? TreeEntry::Vectorize : TreeEntry::NeedToGather;
return newTreeEntry(VL, EntryState, Bundle, S, UserTreeIdx,
ReuseShuffleIndices, ReorderIndices);
}
TreeEntry *newTreeEntry(ArrayRef<Value *> VL,
TreeEntry::EntryState EntryState,
Optional<ScheduleData *> Bundle,
const InstructionsState &S,
const EdgeInfo &UserTreeIdx,
ArrayRef<unsigned> ReuseShuffleIndices = None,
ArrayRef<unsigned> ReorderIndices = None) {
assert(((!Bundle && EntryState == TreeEntry::NeedToGather) ||
(Bundle && EntryState != TreeEntry::NeedToGather)) &&
"Need to vectorize gather entry?");
VectorizableTree.push_back(std::make_unique<TreeEntry>(VectorizableTree));
TreeEntry *Last = VectorizableTree.back().get();
Last->Idx = VectorizableTree.size() - 1;
Last->Scalars.insert(Last->Scalars.begin(), VL.begin(), VL.end());
Last->State = EntryState;
Last->ReuseShuffleIndices.append(ReuseShuffleIndices.begin(),
ReuseShuffleIndices.end());
Last->ReorderIndices.append(ReorderIndices.begin(), ReorderIndices.end());
Last->setOperations(S);
if (Last->State != TreeEntry::NeedToGather) {
for (Value *V : VL) {
assert(!getTreeEntry(V) && "Scalar already in tree!");
ScalarToTreeEntry[V] = Last;
}
// Update the scheduler bundle to point to this TreeEntry.
unsigned Lane = 0;
for (ScheduleData *BundleMember = Bundle.getValue(); BundleMember;
BundleMember = BundleMember->NextInBundle) {
BundleMember->TE = Last;
BundleMember->Lane = Lane;
++Lane;
}
assert((!Bundle.getValue() || Lane == VL.size()) &&
"Bundle and VL out of sync");
} else {
MustGather.insert(VL.begin(), VL.end());
}
if (UserTreeIdx.UserTE)
Last->UserTreeIndices.push_back(UserTreeIdx);
return Last;
}
/// -- Vectorization State --
/// Holds all of the tree entries.
TreeEntry::VecTreeTy VectorizableTree;
#ifndef NDEBUG
/// Debug printer.
LLVM_DUMP_METHOD void dumpVectorizableTree() const {
for (unsigned Id = 0, IdE = VectorizableTree.size(); Id != IdE; ++Id) {
VectorizableTree[Id]->dump();
dbgs() << "\n";
}
}
#endif
TreeEntry *getTreeEntry(Value *V) { return ScalarToTreeEntry.lookup(V); }
const TreeEntry *getTreeEntry(Value *V) const {
return ScalarToTreeEntry.lookup(V);
}
/// Maps a specific scalar to its tree entry.
SmallDenseMap<Value*, TreeEntry *> ScalarToTreeEntry;
/// Maps a value to the proposed vectorizable size.
SmallDenseMap<Value *, unsigned> InstrElementSize;
/// A list of scalars that we found that we need to keep as scalars.
ValueSet MustGather;
/// This POD struct describes one external user in the vectorized tree.
struct ExternalUser {
ExternalUser(Value *S, llvm::User *U, int L)
: Scalar(S), User(U), Lane(L) {}
// Which scalar in our function.
Value *Scalar;
// Which user that uses the scalar.
llvm::User *User;
// Which lane does the scalar belong to.
int Lane;
};
using UserList = SmallVector<ExternalUser, 16>;
/// Checks if two instructions may access the same memory.
///
/// \p Loc1 is the location of \p Inst1. It is passed explicitly because it
/// is invariant in the calling loop.
bool isAliased(const MemoryLocation &Loc1, Instruction *Inst1,
Instruction *Inst2) {
// First check if the result is already in the cache.
AliasCacheKey key = std::make_pair(Inst1, Inst2);
Optional<bool> &result = AliasCache[key];
if (result.hasValue()) {
return result.getValue();
}
MemoryLocation Loc2 = getLocation(Inst2, AA);
bool aliased = true;
if (Loc1.Ptr && Loc2.Ptr && isSimple(Inst1) && isSimple(Inst2)) {
// Do the alias check.
aliased = AA->alias(Loc1, Loc2);
}
// Store the result in the cache.
result = aliased;
return aliased;
}
using AliasCacheKey = std::pair<Instruction *, Instruction *>;
/// Cache for alias results.
/// TODO: consider moving this to the AliasAnalysis itself.
DenseMap<AliasCacheKey, Optional<bool>> AliasCache;
/// Removes an instruction from its block and eventually deletes it.
/// It's like Instruction::eraseFromParent() except that the actual deletion
/// is delayed until BoUpSLP is destructed.
/// This is required to ensure that there are no incorrect collisions in the
/// AliasCache, which can happen if a new instruction is allocated at the
/// same address as a previously deleted instruction.
void eraseInstruction(Instruction *I, bool ReplaceOpsWithUndef = false) {
auto It = DeletedInstructions.try_emplace(I, ReplaceOpsWithUndef).first;
It->getSecond() = It->getSecond() && ReplaceOpsWithUndef;
}
/// Temporary store for deleted instructions. Instructions will be deleted
/// eventually when the BoUpSLP is destructed.
DenseMap<Instruction *, bool> DeletedInstructions;
/// A list of values that need to extracted out of the tree.
/// This list holds pairs of (Internal Scalar : External User). External User
/// can be nullptr, it means that this Internal Scalar will be used later,
/// after vectorization.
UserList ExternalUses;
/// Values used only by @llvm.assume calls.
SmallPtrSet<const Value *, 32> EphValues;
/// Holds all of the instructions that we gathered.
SetVector<Instruction *> GatherSeq;
/// A list of blocks that we are going to CSE.
SetVector<BasicBlock *> CSEBlocks;
/// Contains all scheduling relevant data for an instruction.
/// A ScheduleData either represents a single instruction or a member of an
/// instruction bundle (= a group of instructions which is combined into a
/// vector instruction).
struct ScheduleData {
// The initial value for the dependency counters. It means that the
// dependencies are not calculated yet.
enum { InvalidDeps = -1 };
ScheduleData() = default;
void init(int BlockSchedulingRegionID, Value *OpVal) {
FirstInBundle = this;
NextInBundle = nullptr;
NextLoadStore = nullptr;
IsScheduled = false;
SchedulingRegionID = BlockSchedulingRegionID;
UnscheduledDepsInBundle = UnscheduledDeps;
clearDependencies();
OpValue = OpVal;
TE = nullptr;
Lane = -1;
}
/// Returns true if the dependency information has been calculated.
bool hasValidDependencies() const { return Dependencies != InvalidDeps; }
/// Returns true for single instructions and for bundle representatives
/// (= the head of a bundle).
bool isSchedulingEntity() const { return FirstInBundle == this; }
/// Returns true if it represents an instruction bundle and not only a
/// single instruction.
bool isPartOfBundle() const {
return NextInBundle != nullptr || FirstInBundle != this;
}
/// Returns true if it is ready for scheduling, i.e. it has no more
/// unscheduled depending instructions/bundles.
bool isReady() const {
assert(isSchedulingEntity() &&
"can't consider non-scheduling entity for ready list");
return UnscheduledDepsInBundle == 0 && !IsScheduled;
}
/// Modifies the number of unscheduled dependencies, also updating it for
/// the whole bundle.
int incrementUnscheduledDeps(int Incr) {
UnscheduledDeps += Incr;
return FirstInBundle->UnscheduledDepsInBundle += Incr;
}
/// Sets the number of unscheduled dependencies to the number of
/// dependencies.
void resetUnscheduledDeps() {
incrementUnscheduledDeps(Dependencies - UnscheduledDeps);
}
/// Clears all dependency information.
void clearDependencies() {
Dependencies = InvalidDeps;
resetUnscheduledDeps();
MemoryDependencies.clear();
}
void dump(raw_ostream &os) const {
if (!isSchedulingEntity()) {
os << "/ " << *Inst;
} else if (NextInBundle) {
os << '[' << *Inst;
ScheduleData *SD = NextInBundle;
while (SD) {
os << ';' << *SD->Inst;
SD = SD->NextInBundle;
}
os << ']';
} else {
os << *Inst;
}
}
Instruction *Inst = nullptr;
/// Points to the head in an instruction bundle (and always to this for
/// single instructions).
ScheduleData *FirstInBundle = nullptr;
/// Single linked list of all instructions in a bundle. Null if it is a
/// single instruction.
ScheduleData *NextInBundle = nullptr;
/// Single linked list of all memory instructions (e.g. load, store, call)
/// in the block - until the end of the scheduling region.
ScheduleData *NextLoadStore = nullptr;
/// The dependent memory instructions.
/// This list is derived on demand in calculateDependencies().
SmallVector<ScheduleData *, 4> MemoryDependencies;
/// This ScheduleData is in the current scheduling region if this matches
/// the current SchedulingRegionID of BlockScheduling.
int SchedulingRegionID = 0;
/// Used for getting a "good" final ordering of instructions.
int SchedulingPriority = 0;
/// The number of dependencies. Constitutes of the number of users of the
/// instruction plus the number of dependent memory instructions (if any).
/// This value is calculated on demand.
/// If InvalidDeps, the number of dependencies is not calculated yet.
int Dependencies = InvalidDeps;
/// The number of dependencies minus the number of dependencies of scheduled
/// instructions. As soon as this is zero, the instruction/bundle gets ready
/// for scheduling.
/// Note that this is negative as long as Dependencies is not calculated.
int UnscheduledDeps = InvalidDeps;
/// The sum of UnscheduledDeps in a bundle. Equals to UnscheduledDeps for
/// single instructions.
int UnscheduledDepsInBundle = InvalidDeps;
/// True if this instruction is scheduled (or considered as scheduled in the
/// dry-run).
bool IsScheduled = false;
/// Opcode of the current instruction in the schedule data.
Value *OpValue = nullptr;
/// The TreeEntry that this instruction corresponds to.
TreeEntry *TE = nullptr;
/// The lane of this node in the TreeEntry.
int Lane = -1;
};
#ifndef NDEBUG
friend inline raw_ostream &operator<<(raw_ostream &os,
const BoUpSLP::ScheduleData &SD) {
SD.dump(os);
return os;
}
#endif
friend struct GraphTraits<BoUpSLP *>;
friend struct DOTGraphTraits<BoUpSLP *>;
/// Contains all scheduling data for a basic block.
struct BlockScheduling {
BlockScheduling(BasicBlock *BB)
: BB(BB), ChunkSize(BB->size()), ChunkPos(ChunkSize) {}
void clear() {
ReadyInsts.clear();
ScheduleStart = nullptr;
ScheduleEnd = nullptr;
FirstLoadStoreInRegion = nullptr;
LastLoadStoreInRegion = nullptr;
// Reduce the maximum schedule region size by the size of the
// previous scheduling run.
ScheduleRegionSizeLimit -= ScheduleRegionSize;
if (ScheduleRegionSizeLimit < MinScheduleRegionSize)
ScheduleRegionSizeLimit = MinScheduleRegionSize;
ScheduleRegionSize = 0;
// Make a new scheduling region, i.e. all existing ScheduleData is not
// in the new region yet.
++SchedulingRegionID;
}
ScheduleData *getScheduleData(Value *V) {
ScheduleData *SD = ScheduleDataMap[V];
if (SD && SD->SchedulingRegionID == SchedulingRegionID)
return SD;
return nullptr;
}
ScheduleData *getScheduleData(Value *V, Value *Key) {
if (V == Key)
return getScheduleData(V);
auto I = ExtraScheduleDataMap.find(V);
if (I != ExtraScheduleDataMap.end()) {
ScheduleData *SD = I->second[Key];
if (SD && SD->SchedulingRegionID == SchedulingRegionID)
return SD;
}
return nullptr;
}
bool isInSchedulingRegion(ScheduleData *SD) const {
return SD->SchedulingRegionID == SchedulingRegionID;
}
/// Marks an instruction as scheduled and puts all dependent ready
/// instructions into the ready-list.
template <typename ReadyListType>
void schedule(ScheduleData *SD, ReadyListType &ReadyList) {
SD->IsScheduled = true;
LLVM_DEBUG(dbgs() << "SLP: schedule " << *SD << "\n");
ScheduleData *BundleMember = SD;
while (BundleMember) {
if (BundleMember->Inst != BundleMember->OpValue) {
BundleMember = BundleMember->NextInBundle;
continue;
}
// Handle the def-use chain dependencies.
// Decrement the unscheduled counter and insert to ready list if ready.
auto &&DecrUnsched = [this, &ReadyList](Instruction *I) {
doForAllOpcodes(I, [&ReadyList](ScheduleData *OpDef) {
if (OpDef && OpDef->hasValidDependencies() &&
OpDef->incrementUnscheduledDeps(-1) == 0) {
// There are no more unscheduled dependencies after
// decrementing, so we can put the dependent instruction
// into the ready list.
ScheduleData *DepBundle = OpDef->FirstInBundle;
assert(!DepBundle->IsScheduled &&
"already scheduled bundle gets ready");
ReadyList.insert(DepBundle);
LLVM_DEBUG(dbgs()
<< "SLP: gets ready (def): " << *DepBundle << "\n");
}
});
};
// If BundleMember is a vector bundle, its operands may have been
// reordered duiring buildTree(). We therefore need to get its operands
// through the TreeEntry.
if (TreeEntry *TE = BundleMember->TE) {
int Lane = BundleMember->Lane;
assert(Lane >= 0 && "Lane not set");
// Since vectorization tree is being built recursively this assertion
// ensures that the tree entry has all operands set before reaching
// this code. Couple of exceptions known at the moment are extracts
// where their second (immediate) operand is not added. Since
// immediates do not affect scheduler behavior this is considered
// okay.
auto *In = TE->getMainOp();
assert(In &&
(isa<ExtractValueInst>(In) || isa<ExtractElementInst>(In) ||
In->getNumOperands() == TE->getNumOperands()) &&
"Missed TreeEntry operands?");
(void)In; // fake use to avoid build failure when assertions disabled
for (unsigned OpIdx = 0, NumOperands = TE->getNumOperands();
OpIdx != NumOperands; ++OpIdx)
if (auto *I = dyn_cast<Instruction>(TE->getOperand(OpIdx)[Lane]))
DecrUnsched(I);
} else {
// If BundleMember is a stand-alone instruction, no operand reordering
// has taken place, so we directly access its operands.
for (Use &U : BundleMember->Inst->operands())
if (auto *I = dyn_cast<Instruction>(U.get()))
DecrUnsched(I);
}
// Handle the memory dependencies.
for (ScheduleData *MemoryDepSD : BundleMember->MemoryDependencies) {
if (MemoryDepSD->incrementUnscheduledDeps(-1) == 0) {
// There are no more unscheduled dependencies after decrementing,
// so we can put the dependent instruction into the ready list.
ScheduleData *DepBundle = MemoryDepSD->FirstInBundle;
assert(!DepBundle->IsScheduled &&
"already scheduled bundle gets ready");
ReadyList.insert(DepBundle);
LLVM_DEBUG(dbgs()
<< "SLP: gets ready (mem): " << *DepBundle << "\n");
}
}
BundleMember = BundleMember->NextInBundle;
}
}
void doForAllOpcodes(Value *V,
function_ref<void(ScheduleData *SD)> Action) {
if (ScheduleData *SD = getScheduleData(V))
Action(SD);
auto I = ExtraScheduleDataMap.find(V);
if (I != ExtraScheduleDataMap.end())
for (auto &P : I->second)
if (P.second->SchedulingRegionID == SchedulingRegionID)
Action(P.second);
}
/// Put all instructions into the ReadyList which are ready for scheduling.
template <typename ReadyListType>
void initialFillReadyList(ReadyListType &ReadyList) {
for (auto *I = ScheduleStart; I != ScheduleEnd; I = I->getNextNode()) {
doForAllOpcodes(I, [&](ScheduleData *SD) {
if (SD->isSchedulingEntity() && SD->isReady()) {
ReadyList.insert(SD);
LLVM_DEBUG(dbgs()
<< "SLP: initially in ready list: " << *I << "\n");
}
});
}
}
/// Checks if a bundle of instructions can be scheduled, i.e. has no
/// cyclic dependencies. This is only a dry-run, no instructions are
/// actually moved at this stage.
/// \returns the scheduling bundle. The returned Optional value is non-None
/// if \p VL is allowed to be scheduled.
Optional<ScheduleData *>
tryScheduleBundle(ArrayRef<Value *> VL, BoUpSLP *SLP,
const InstructionsState &S);
/// Un-bundles a group of instructions.
void cancelScheduling(ArrayRef<Value *> VL, Value *OpValue);
/// Allocates schedule data chunk.
ScheduleData *allocateScheduleDataChunks();
/// Extends the scheduling region so that V is inside the region.
/// \returns true if the region size is within the limit.
bool extendSchedulingRegion(Value *V, const InstructionsState &S);
/// Initialize the ScheduleData structures for new instructions in the
/// scheduling region.
void initScheduleData(Instruction *FromI, Instruction *ToI,
ScheduleData *PrevLoadStore,
ScheduleData *NextLoadStore);
/// Updates the dependency information of a bundle and of all instructions/
/// bundles which depend on the original bundle.
void calculateDependencies(ScheduleData *SD, bool InsertInReadyList,
BoUpSLP *SLP);
/// Sets all instruction in the scheduling region to un-scheduled.
void resetSchedule();
BasicBlock *BB;
/// Simple memory allocation for ScheduleData.
std::vector<std::unique_ptr<ScheduleData[]>> ScheduleDataChunks;
/// The size of a ScheduleData array in ScheduleDataChunks.
int ChunkSize;
/// The allocator position in the current chunk, which is the last entry
/// of ScheduleDataChunks.
int ChunkPos;
/// Attaches ScheduleData to Instruction.
/// Note that the mapping survives during all vectorization iterations, i.e.
/// ScheduleData structures are recycled.
DenseMap<Value *, ScheduleData *> ScheduleDataMap;
/// Attaches ScheduleData to Instruction with the leading key.
DenseMap<Value *, SmallDenseMap<Value *, ScheduleData *>>
ExtraScheduleDataMap;
struct ReadyList : SmallVector<ScheduleData *, 8> {
void insert(ScheduleData *SD) { push_back(SD); }
};
/// The ready-list for scheduling (only used for the dry-run).
ReadyList ReadyInsts;
/// The first instruction of the scheduling region.
Instruction *ScheduleStart = nullptr;
/// The first instruction _after_ the scheduling region.
Instruction *ScheduleEnd = nullptr;
/// The first memory accessing instruction in the scheduling region
/// (can be null).
ScheduleData *FirstLoadStoreInRegion = nullptr;
/// The last memory accessing instruction in the scheduling region
/// (can be null).
ScheduleData *LastLoadStoreInRegion = nullptr;
/// The current size of the scheduling region.
int ScheduleRegionSize = 0;
/// The maximum size allowed for the scheduling region.
int ScheduleRegionSizeLimit = ScheduleRegionSizeBudget;
/// The ID of the scheduling region. For a new vectorization iteration this
/// is incremented which "removes" all ScheduleData from the region.
// Make sure that the initial SchedulingRegionID is greater than the
// initial SchedulingRegionID in ScheduleData (which is 0).
int SchedulingRegionID = 1;
};
/// Attaches the BlockScheduling structures to basic blocks.
MapVector<BasicBlock *, std::unique_ptr<BlockScheduling>> BlocksSchedules;
/// Performs the "real" scheduling. Done before vectorization is actually
/// performed in a basic block.
void scheduleBlock(BlockScheduling *BS);
/// List of users to ignore during scheduling and that don't need extracting.
ArrayRef<Value *> UserIgnoreList;
/// A DenseMapInfo implementation for holding DenseMaps and DenseSets of
/// sorted SmallVectors of unsigned.
struct OrdersTypeDenseMapInfo {
static OrdersType getEmptyKey() {
OrdersType V;
V.push_back(~1U);
return V;
}
static OrdersType getTombstoneKey() {
OrdersType V;
V.push_back(~2U);
return V;
}
static unsigned getHashValue(const OrdersType &V) {
return static_cast<unsigned>(hash_combine_range(V.begin(), V.end()));
}
static bool isEqual(const OrdersType &LHS, const OrdersType &RHS) {
return LHS == RHS;
}
};
/// Contains orders of operations along with the number of bundles that have
/// operations in this order. It stores only those orders that require
/// reordering, if reordering is not required it is counted using \a
/// NumOpsWantToKeepOriginalOrder.
DenseMap<OrdersType, unsigned, OrdersTypeDenseMapInfo> NumOpsWantToKeepOrder;
/// Number of bundles that do not require reordering.
unsigned NumOpsWantToKeepOriginalOrder = 0;
// Analysis and block reference.
Function *F;
ScalarEvolution *SE;
TargetTransformInfo *TTI;
TargetLibraryInfo *TLI;
AAResults *AA;
LoopInfo *LI;
DominatorTree *DT;
AssumptionCache *AC;
DemandedBits *DB;
const DataLayout *DL;
OptimizationRemarkEmitter *ORE;
unsigned MaxVecRegSize; // This is set by TTI or overridden by cl::opt.
unsigned MinVecRegSize; // Set by cl::opt (default: 128).
/// Instruction builder to construct the vectorized tree.
IRBuilder<> Builder;
/// A map of scalar integer values to the smallest bit width with which they
/// can legally be represented. The values map to (width, signed) pairs,
/// where "width" indicates the minimum bit width and "signed" is True if the
/// value must be signed-extended, rather than zero-extended, back to its
/// original width.
MapVector<Value *, std::pair<uint64_t, bool>> MinBWs;
};
} // end namespace slpvectorizer
template <> struct GraphTraits<BoUpSLP *> {
using TreeEntry = BoUpSLP::TreeEntry;
/// NodeRef has to be a pointer per the GraphWriter.
using NodeRef = TreeEntry *;
using ContainerTy = BoUpSLP::TreeEntry::VecTreeTy;
/// Add the VectorizableTree to the index iterator to be able to return
/// TreeEntry pointers.
struct ChildIteratorType
: public iterator_adaptor_base<
ChildIteratorType, SmallVector<BoUpSLP::EdgeInfo, 1>::iterator> {
ContainerTy &VectorizableTree;
ChildIteratorType(SmallVector<BoUpSLP::EdgeInfo, 1>::iterator W,
ContainerTy &VT)
: ChildIteratorType::iterator_adaptor_base(W), VectorizableTree(VT) {}
NodeRef operator*() { return I->UserTE; }
};
static NodeRef getEntryNode(BoUpSLP &R) {
return R.VectorizableTree[0].get();
}
static ChildIteratorType child_begin(NodeRef N) {
return {N->UserTreeIndices.begin(), N->Container};
}
static ChildIteratorType child_end(NodeRef N) {
return {N->UserTreeIndices.end(), N->Container};
}
/// For the node iterator we just need to turn the TreeEntry iterator into a
/// TreeEntry* iterator so that it dereferences to NodeRef.
class nodes_iterator {
using ItTy = ContainerTy::iterator;
ItTy It;
public:
nodes_iterator(const ItTy &It2) : It(It2) {}
NodeRef operator*() { return It->get(); }
nodes_iterator operator++() {
++It;
return *this;
}
bool operator!=(const nodes_iterator &N2) const { return N2.It != It; }
};
static nodes_iterator nodes_begin(BoUpSLP *R) {
return nodes_iterator(R->VectorizableTree.begin());
}
static nodes_iterator nodes_end(BoUpSLP *R) {
return nodes_iterator(R->VectorizableTree.end());
}
static unsigned size(BoUpSLP *R) { return R->VectorizableTree.size(); }
};
template <> struct DOTGraphTraits<BoUpSLP *> : public DefaultDOTGraphTraits {
using TreeEntry = BoUpSLP::TreeEntry;
DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
std::string getNodeLabel(const TreeEntry *Entry, const BoUpSLP *R) {
std::string Str;
raw_string_ostream OS(Str);
if (isSplat(Entry->Scalars)) {
OS << "<splat> " << *Entry->Scalars[0];
return Str;
}
for (auto V : Entry->Scalars) {
OS << *V;
if (llvm::any_of(R->ExternalUses, [&](const BoUpSLP::ExternalUser &EU) {
return EU.Scalar == V;
}))
OS << " <extract>";
OS << "\n";
}
return Str;
}
static std::string getNodeAttributes(const TreeEntry *Entry,
const BoUpSLP *) {
if (Entry->State == TreeEntry::NeedToGather)
return "color=red";
return "";
}
};
} // end namespace llvm
BoUpSLP::~BoUpSLP() {
for (const auto &Pair : DeletedInstructions) {
// Replace operands of ignored instructions with Undefs in case if they were
// marked for deletion.
if (Pair.getSecond()) {
Value *Undef = UndefValue::get(Pair.getFirst()->getType());
Pair.getFirst()->replaceAllUsesWith(Undef);
}
Pair.getFirst()->dropAllReferences();
}
for (const auto &Pair : DeletedInstructions) {
assert(Pair.getFirst()->use_empty() &&
"trying to erase instruction with users.");
Pair.getFirst()->eraseFromParent();
}
#ifdef EXPENSIVE_CHECKS
// If we could guarantee that this call is not extremely slow, we could
// remove the ifdef limitation (see PR47712).
assert(!verifyFunction(*F, &dbgs()));
#endif
}
void BoUpSLP::eraseInstructions(ArrayRef<Value *> AV) {
for (auto *V : AV) {
if (auto *I = dyn_cast<Instruction>(V))
eraseInstruction(I, /*ReplaceOpsWithUndef=*/true);
};
}
void BoUpSLP::buildTree(ArrayRef<Value *> Roots,
ArrayRef<Value *> UserIgnoreLst) {
ExtraValueToDebugLocsMap ExternallyUsedValues;
buildTree(Roots, ExternallyUsedValues, UserIgnoreLst);
}
void BoUpSLP::buildTree(ArrayRef<Value *> Roots,
ExtraValueToDebugLocsMap &ExternallyUsedValues,
ArrayRef<Value *> UserIgnoreLst) {
deleteTree();
UserIgnoreList = UserIgnoreLst;
if (!allSameType(Roots))
return;
buildTree_rec(Roots, 0, EdgeInfo());
// Collect the values that we need to extract from the tree.
for (auto &TEPtr : VectorizableTree) {
TreeEntry *Entry = TEPtr.get();
// No need to handle users of gathered values.
if (Entry->State == TreeEntry::NeedToGather)
continue;
// For each lane:
for (int Lane = 0, LE = Entry->Scalars.size(); Lane != LE; ++Lane) {
Value *Scalar = Entry->Scalars[Lane];
int FoundLane = Lane;
if (!Entry->ReuseShuffleIndices.empty()) {
FoundLane =
std::distance(Entry->ReuseShuffleIndices.begin(),
llvm::find(Entry->ReuseShuffleIndices, FoundLane));
}
// Check if the scalar is externally used as an extra arg.
auto ExtI = ExternallyUsedValues.find(Scalar);
if (ExtI != ExternallyUsedValues.end()) {
LLVM_DEBUG(dbgs() << "SLP: Need to extract: Extra arg from lane "
<< Lane << " from " << *Scalar << ".\n");
ExternalUses.emplace_back(Scalar, nullptr, FoundLane);
}
for (User *U : Scalar->users()) {
LLVM_DEBUG(dbgs() << "SLP: Checking user:" << *U << ".\n");
Instruction *UserInst = dyn_cast<Instruction>(U);
if (!UserInst)
continue;
// Skip in-tree scalars that become vectors
if (TreeEntry *UseEntry = getTreeEntry(U)) {
Value *UseScalar = UseEntry->Scalars[0];
// Some in-tree scalars will remain as scalar in vectorized
// instructions. If that is the case, the one in Lane 0 will
// be used.
if (UseScalar != U ||
UseEntry->State == TreeEntry::ScatterVectorize ||
!InTreeUserNeedToExtract(Scalar, UserInst, TLI)) {
LLVM_DEBUG(dbgs() << "SLP: \tInternal user will be removed:" << *U
<< ".\n");
assert(UseEntry->State != TreeEntry::NeedToGather && "Bad state");
continue;
}
}
// Ignore users in the user ignore list.
if (is_contained(UserIgnoreList, UserInst))
continue;
LLVM_DEBUG(dbgs() << "SLP: Need to extract:" << *U << " from lane "
<< Lane << " from " << *Scalar << ".\n");
ExternalUses.push_back(ExternalUser(Scalar, U, FoundLane));
}
}
}
}
void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth,
const EdgeInfo &UserTreeIdx) {
assert((allConstant(VL) || allSameType(VL)) && "Invalid types!");
InstructionsState S = getSameOpcode(VL);
if (Depth == RecursionMaxDepth) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to max recursion depth.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
// Don't handle vectors.
if (S.OpValue->getType()->isVectorTy()) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to vector type.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
if (StoreInst *SI = dyn_cast<StoreInst>(S.OpValue))
if (SI->getValueOperand()->getType()->isVectorTy()) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to store vector type.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
// If all of the operands are identical or constant we have a simple solution.
if (allConstant(VL) || isSplat(VL) || !allSameBlock(VL) || !S.getOpcode()) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to C,S,B,O. \n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
// We now know that this is a vector of instructions of the same type from
// the same block.
// Don't vectorize ephemeral values.
for (Value *V : VL) {
if (EphValues.count(V)) {
LLVM_DEBUG(dbgs() << "SLP: The instruction (" << *V
<< ") is ephemeral.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
}
// Check if this is a duplicate of another entry.
if (TreeEntry *E = getTreeEntry(S.OpValue)) {
LLVM_DEBUG(dbgs() << "SLP: \tChecking bundle: " << *S.OpValue << ".\n");
if (!E->isSame(VL)) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to partial overlap.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
// Record the reuse of the tree node. FIXME, currently this is only used to
// properly draw the graph rather than for the actual vectorization.
E->UserTreeIndices.push_back(UserTreeIdx);
LLVM_DEBUG(dbgs() << "SLP: Perfect diamond merge at " << *S.OpValue
<< ".\n");
return;
}
// Check that none of the instructions in the bundle are already in the tree.
for (Value *V : VL) {
auto *I = dyn_cast<Instruction>(V);
if (!I)
continue;
if (getTreeEntry(I)) {
LLVM_DEBUG(dbgs() << "SLP: The instruction (" << *V
<< ") is already in tree.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
}
// If any of the scalars is marked as a value that needs to stay scalar, then
// we need to gather the scalars.
// The reduction nodes (stored in UserIgnoreList) also should stay scalar.
for (Value *V : VL) {
if (MustGather.count(V) || is_contained(UserIgnoreList, V)) {
LLVM_DEBUG(dbgs() << "SLP: Gathering due to gathered scalar.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
}
// Check that all of the users of the scalars that we want to vectorize are
// schedulable.
auto *VL0 = cast<Instruction>(S.OpValue);
BasicBlock *BB = VL0->getParent();
if (!DT->isReachableFromEntry(BB)) {
// Don't go into unreachable blocks. They may contain instructions with
// dependency cycles which confuse the final scheduling.
LLVM_DEBUG(dbgs() << "SLP: bundle in unreachable block.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
// Check that every instruction appears once in this bundle.
SmallVector<unsigned, 4> ReuseShuffleIndicies;
SmallVector<Value *, 4> UniqueValues;
DenseMap<Value *, unsigned> UniquePositions;
for (Value *V : VL) {
auto Res = UniquePositions.try_emplace(V, UniqueValues.size());
ReuseShuffleIndicies.emplace_back(Res.first->second);
if (Res.second)
UniqueValues.emplace_back(V);
}
size_t NumUniqueScalarValues = UniqueValues.size();
if (NumUniqueScalarValues == VL.size()) {
ReuseShuffleIndicies.clear();
} else {
LLVM_DEBUG(dbgs() << "SLP: Shuffle for reused scalars.\n");
if (NumUniqueScalarValues <= 1 ||
!llvm::isPowerOf2_32(NumUniqueScalarValues)) {
LLVM_DEBUG(dbgs() << "SLP: Scalar used twice in bundle.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx);
return;
}
VL = UniqueValues;
}
auto &BSRef = BlocksSchedules[BB];
if (!BSRef)
BSRef = std::make_unique<BlockScheduling>(BB);
BlockScheduling &BS = *BSRef.get();
Optional<ScheduleData *> Bundle = BS.tryScheduleBundle(VL, this, S);
if (!Bundle) {
LLVM_DEBUG(dbgs() << "SLP: We are not able to schedule this bundle!\n");
assert((!BS.getScheduleData(VL0) ||
!BS.getScheduleData(VL0)->isPartOfBundle()) &&
"tryScheduleBundle should cancelScheduling on failure");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
return;
}
LLVM_DEBUG(dbgs() << "SLP: We are able to schedule this bundle.\n");
unsigned ShuffleOrOp = S.isAltShuffle() ?
(unsigned) Instruction::ShuffleVector : S.getOpcode();
switch (ShuffleOrOp) {
case Instruction::PHI: {
auto *PH = cast<PHINode>(VL0);
// Check for terminator values (e.g. invoke).
for (Value *V : VL)
for (unsigned I = 0, E = PH->getNumIncomingValues(); I < E; ++I) {
Instruction *Term = dyn_cast<Instruction>(
cast<PHINode>(V)->getIncomingValueForBlock(
PH->getIncomingBlock(I)));
if (Term && Term->isTerminator()) {
LLVM_DEBUG(dbgs()
<< "SLP: Need to swizzle PHINodes (terminator use).\n");
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
return;
}
}
TreeEntry *TE =
newTreeEntry(VL, Bundle, S, UserTreeIdx, ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: added a vector of PHINodes.\n");
// Keeps the reordered operands to avoid code duplication.
SmallVector<ValueList, 2> OperandsVec;
for (unsigned I = 0, E = PH->getNumIncomingValues(); I < E; ++I) {
ValueList Operands;
// Prepare the operand vector.
for (Value *V : VL)
Operands.push_back(cast<PHINode>(V)->getIncomingValueForBlock(
PH->getIncomingBlock(I)));
TE->setOperand(I, Operands);
OperandsVec.push_back(Operands);
}
for (unsigned OpIdx = 0, OpE = OperandsVec.size(); OpIdx != OpE; ++OpIdx)
buildTree_rec(OperandsVec[OpIdx], Depth + 1, {TE, OpIdx});
return;
}
case Instruction::ExtractValue:
case Instruction::ExtractElement: {
OrdersType CurrentOrder;
bool Reuse = canReuseExtract(VL, VL0, CurrentOrder);
if (Reuse) {
LLVM_DEBUG(dbgs() << "SLP: Reusing or shuffling extract sequence.\n");
++NumOpsWantToKeepOriginalOrder;
newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
// This is a special case, as it does not gather, but at the same time
// we are not extending buildTree_rec() towards the operands.
ValueList Op0;
Op0.assign(VL.size(), VL0->getOperand(0));
VectorizableTree.back()->setOperand(0, Op0);
return;
}
if (!CurrentOrder.empty()) {
LLVM_DEBUG({
dbgs() << "SLP: Reusing or shuffling of reordered extract sequence "
"with order";
for (unsigned Idx : CurrentOrder)
dbgs() << " " << Idx;
dbgs() << "\n";
});
// Insert new order with initial value 0, if it does not exist,
// otherwise return the iterator to the existing one.
newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies, CurrentOrder);
findRootOrder(CurrentOrder);
++NumOpsWantToKeepOrder[CurrentOrder];
// This is a special case, as it does not gather, but at the same time
// we are not extending buildTree_rec() towards the operands.
ValueList Op0;
Op0.assign(VL.size(), VL0->getOperand(0));
VectorizableTree.back()->setOperand(0, Op0);
return;
}
LLVM_DEBUG(dbgs() << "SLP: Gather extract sequence.\n");
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
BS.cancelScheduling(VL, VL0);
return;
}
case Instruction::Load: {
// Check that a vectorized load would load the same memory as a scalar
// load. For example, we don't want to vectorize loads that are smaller
// than 8-bit. Even though we have a packed struct {<i2, i2, i2, i2>} LLVM
// treats loading/storing it as an i8 struct. If we vectorize loads/stores
// from such a struct, we read/write packed bits disagreeing with the
// unvectorized version.
Type *ScalarTy = VL0->getType();
if (DL->getTypeSizeInBits(ScalarTy) !=
DL->getTypeAllocSizeInBits(ScalarTy)) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: Gathering loads of non-packed type.\n");
return;
}
// Make sure all loads in the bundle are simple - we can't vectorize
// atomic or volatile loads.
SmallVector<Value *, 4> PointerOps(VL.size());
auto POIter = PointerOps.begin();
for (Value *V : VL) {
auto *L = cast<LoadInst>(V);
if (!L->isSimple()) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: Gathering non-simple loads.\n");
return;
}
*POIter = L->getPointerOperand();
++POIter;
}
OrdersType CurrentOrder;
// Check the order of pointer operands.
if (llvm::sortPtrAccesses(PointerOps, *DL, *SE, CurrentOrder)) {
Value *Ptr0;
Value *PtrN;
if (CurrentOrder.empty()) {
Ptr0 = PointerOps.front();
PtrN = PointerOps.back();
} else {
Ptr0 = PointerOps[CurrentOrder.front()];
PtrN = PointerOps[CurrentOrder.back()];
}
const SCEV *Scev0 = SE->getSCEV(Ptr0);
const SCEV *ScevN = SE->getSCEV(PtrN);
const auto *Diff =
dyn_cast<SCEVConstant>(SE->getMinusSCEV(ScevN, Scev0));
uint64_t Size = DL->getTypeAllocSize(ScalarTy);
// Check that the sorted loads are consecutive.
if (Diff && Diff->getAPInt() == (VL.size() - 1) * Size) {
if (CurrentOrder.empty()) {
// Original loads are consecutive and does not require reordering.
++NumOpsWantToKeepOriginalOrder;
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S,
UserTreeIdx, ReuseShuffleIndicies);
TE->setOperandsInOrder();
LLVM_DEBUG(dbgs() << "SLP: added a vector of loads.\n");
} else {
// Need to reorder.
TreeEntry *TE =
newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies, CurrentOrder);
TE->setOperandsInOrder();
LLVM_DEBUG(dbgs() << "SLP: added a vector of jumbled loads.\n");
findRootOrder(CurrentOrder);
++NumOpsWantToKeepOrder[CurrentOrder];
}
return;
}
// Vectorizing non-consecutive loads with `llvm.masked.gather`.
TreeEntry *TE = newTreeEntry(VL, TreeEntry::ScatterVectorize, Bundle, S,
UserTreeIdx, ReuseShuffleIndicies);
TE->setOperandsInOrder();
buildTree_rec(PointerOps, Depth + 1, {TE, 0});
LLVM_DEBUG(dbgs() << "SLP: added a vector of non-consecutive loads.\n");
return;
}
LLVM_DEBUG(dbgs() << "SLP: Gathering non-consecutive loads.\n");
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
return;
}
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::FPExt:
case Instruction::PtrToInt:
case Instruction::IntToPtr:
case Instruction::SIToFP:
case Instruction::UIToFP:
case Instruction::Trunc:
case Instruction::FPTrunc:
case Instruction::BitCast: {
Type *SrcTy = VL0->getOperand(0)->getType();
for (Value *V : VL) {
Type *Ty = cast<Instruction>(V)->getOperand(0)->getType();
if (Ty != SrcTy || !isValidElementType(Ty)) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs()
<< "SLP: Gathering casts with different src types.\n");
return;
}
}
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: added a vector of casts.\n");
TE->setOperandsInOrder();
for (unsigned i = 0, e = VL0->getNumOperands(); i < e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (Value *V : VL)
Operands.push_back(cast<Instruction>(V)->getOperand(i));
buildTree_rec(Operands, Depth + 1, {TE, i});
}
return;
}
case Instruction::ICmp:
case Instruction::FCmp: {
// Check that all of the compares have the same predicate.
CmpInst::Predicate P0 = cast<CmpInst>(VL0)->getPredicate();
CmpInst::Predicate SwapP0 = CmpInst::getSwappedPredicate(P0);
Type *ComparedTy = VL0->getOperand(0)->getType();
for (Value *V : VL) {
CmpInst *Cmp = cast<CmpInst>(V);
if ((Cmp->getPredicate() != P0 && Cmp->getPredicate() != SwapP0) ||
Cmp->getOperand(0)->getType() != ComparedTy) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs()
<< "SLP: Gathering cmp with different predicate.\n");
return;
}
}
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: added a vector of compares.\n");
ValueList Left, Right;
if (cast<CmpInst>(VL0)->isCommutative()) {
// Commutative predicate - collect + sort operands of the instructions
// so that each side is more likely to have the same opcode.
assert(P0 == SwapP0 && "Commutative Predicate mismatch");
reorderInputsAccordingToOpcode(VL, Left, Right, *DL, *SE, *this);
} else {
// Collect operands - commute if it uses the swapped predicate.
for (Value *V : VL) {
auto *Cmp = cast<CmpInst>(V);
Value *LHS = Cmp->getOperand(0);
Value *RHS = Cmp->getOperand(1);
if (Cmp->getPredicate() != P0)
std::swap(LHS, RHS);
Left.push_back(LHS);
Right.push_back(RHS);
}
}
TE->setOperand(0, Left);
TE->setOperand(1, Right);
buildTree_rec(Left, Depth + 1, {TE, 0});
buildTree_rec(Right, Depth + 1, {TE, 1});
return;
}
case Instruction::Select:
case Instruction::FNeg:
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::FDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::FRem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: added a vector of un/bin op.\n");
// Sort operands of the instructions so that each side is more likely to
// have the same opcode.
if (isa<BinaryOperator>(VL0) && VL0->isCommutative()) {
ValueList Left, Right;
reorderInputsAccordingToOpcode(VL, Left, Right, *DL, *SE, *this);
TE->setOperand(0, Left);
TE->setOperand(1, Right);
buildTree_rec(Left, Depth + 1, {TE, 0});
buildTree_rec(Right, Depth + 1, {TE, 1});
return;
}
TE->setOperandsInOrder();
for (unsigned i = 0, e = VL0->getNumOperands(); i < e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (Value *V : VL)
Operands.push_back(cast<Instruction>(V)->getOperand(i));
buildTree_rec(Operands, Depth + 1, {TE, i});
}
return;
}
case Instruction::GetElementPtr: {
// We don't combine GEPs with complicated (nested) indexing.
for (Value *V : VL) {
if (cast<Instruction>(V)->getNumOperands() != 2) {
LLVM_DEBUG(dbgs() << "SLP: not-vectorizable GEP (nested indexes).\n");
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
return;
}
}
// We can't combine several GEPs into one vector if they operate on
// different types.
Type *Ty0 = VL0->getOperand(0)->getType();
for (Value *V : VL) {
Type *CurTy = cast<Instruction>(V)->getOperand(0)->getType();
if (Ty0 != CurTy) {
LLVM_DEBUG(dbgs()
<< "SLP: not-vectorizable GEP (different types).\n");
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
return;
}
}
// We don't combine GEPs with non-constant indexes.
Type *Ty1 = VL0->getOperand(1)->getType();
for (Value *V : VL) {
auto Op = cast<Instruction>(V)->getOperand(1);
if (!isa<ConstantInt>(Op) ||
(Op->getType() != Ty1 &&
Op->getType()->getScalarSizeInBits() >
DL->getIndexSizeInBits(
V->getType()->getPointerAddressSpace()))) {
LLVM_DEBUG(dbgs()
<< "SLP: not-vectorizable GEP (non-constant indexes).\n");
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
return;
}
}
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: added a vector of GEPs.\n");
TE->setOperandsInOrder();
for (unsigned i = 0, e = 2; i < e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (Value *V : VL)
Operands.push_back(cast<Instruction>(V)->getOperand(i));
buildTree_rec(Operands, Depth + 1, {TE, i});
}
return;
}
case Instruction::Store: {
// Check if the stores are consecutive or if we need to swizzle them.
llvm::Type *ScalarTy = cast<StoreInst>(VL0)->getValueOperand()->getType();
// Avoid types that are padded when being allocated as scalars, while
// being packed together in a vector (such as i1).
if (DL->getTypeSizeInBits(ScalarTy) !=
DL->getTypeAllocSizeInBits(ScalarTy)) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: Gathering stores of non-packed type.\n");
return;
}
// Make sure all stores in the bundle are simple - we can't vectorize
// atomic or volatile stores.
SmallVector<Value *, 4> PointerOps(VL.size());
ValueList Operands(VL.size());
auto POIter = PointerOps.begin();
auto OIter = Operands.begin();
for (Value *V : VL) {
auto *SI = cast<StoreInst>(V);
if (!SI->isSimple()) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: Gathering non-simple stores.\n");
return;
}
*POIter = SI->getPointerOperand();
*OIter = SI->getValueOperand();
++POIter;
++OIter;
}
OrdersType CurrentOrder;
// Check the order of pointer operands.
if (llvm::sortPtrAccesses(PointerOps, *DL, *SE, CurrentOrder)) {
Value *Ptr0;
Value *PtrN;
if (CurrentOrder.empty()) {
Ptr0 = PointerOps.front();
PtrN = PointerOps.back();
} else {
Ptr0 = PointerOps[CurrentOrder.front()];
PtrN = PointerOps[CurrentOrder.back()];
}
const SCEV *Scev0 = SE->getSCEV(Ptr0);
const SCEV *ScevN = SE->getSCEV(PtrN);
const auto *Diff =
dyn_cast<SCEVConstant>(SE->getMinusSCEV(ScevN, Scev0));
uint64_t Size = DL->getTypeAllocSize(ScalarTy);
// Check that the sorted pointer operands are consecutive.
if (Diff && Diff->getAPInt() == (VL.size() - 1) * Size) {
if (CurrentOrder.empty()) {
// Original stores are consecutive and does not require reordering.
++NumOpsWantToKeepOriginalOrder;
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S,
UserTreeIdx, ReuseShuffleIndicies);
TE->setOperandsInOrder();
buildTree_rec(Operands, Depth + 1, {TE, 0});
LLVM_DEBUG(dbgs() << "SLP: added a vector of stores.\n");
} else {
TreeEntry *TE =
newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies, CurrentOrder);
TE->setOperandsInOrder();
buildTree_rec(Operands, Depth + 1, {TE, 0});
LLVM_DEBUG(dbgs() << "SLP: added a vector of jumbled stores.\n");
findRootOrder(CurrentOrder);
++NumOpsWantToKeepOrder[CurrentOrder];
}
return;
}
}
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: Non-consecutive store.\n");
return;
}
case Instruction::Call: {
// Check if the calls are all to the same vectorizable intrinsic or
// library function.
CallInst *CI = cast<CallInst>(VL0);
Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
VFShape Shape = VFShape::get(
*CI, ElementCount::getFixed(static_cast<unsigned int>(VL.size())),
false /*HasGlobalPred*/);
Function *VecFunc = VFDatabase(*CI).getVectorizedFunction(Shape);
if (!VecFunc && !isTriviallyVectorizable(ID)) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: Non-vectorizable call.\n");
return;
}
Function *F = CI->getCalledFunction();
unsigned NumArgs = CI->getNumArgOperands();
SmallVector<Value*, 4> ScalarArgs(NumArgs, nullptr);
for (unsigned j = 0; j != NumArgs; ++j)
if (hasVectorInstrinsicScalarOpd(ID, j))
ScalarArgs[j] = CI->getArgOperand(j);
for (Value *V : VL) {
CallInst *CI2 = dyn_cast<CallInst>(V);
if (!CI2 || CI2->getCalledFunction() != F ||
getVectorIntrinsicIDForCall(CI2, TLI) != ID ||
(VecFunc &&
VecFunc != VFDatabase(*CI2).getVectorizedFunction(Shape)) ||
!CI->hasIdenticalOperandBundleSchema(*CI2)) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: mismatched calls:" << *CI << "!=" << *V
<< "\n");
return;
}
// Some intrinsics have scalar arguments and should be same in order for
// them to be vectorized.
for (unsigned j = 0; j != NumArgs; ++j) {
if (hasVectorInstrinsicScalarOpd(ID, j)) {
Value *A1J = CI2->getArgOperand(j);
if (ScalarArgs[j] != A1J) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: mismatched arguments in call:" << *CI
<< " argument " << ScalarArgs[j] << "!=" << A1J
<< "\n");
return;
}
}
}
// Verify that the bundle operands are identical between the two calls.
if (CI->hasOperandBundles() &&
!std::equal(CI->op_begin() + CI->getBundleOperandsStartIndex(),
CI->op_begin() + CI->getBundleOperandsEndIndex(),
CI2->op_begin() + CI2->getBundleOperandsStartIndex())) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: mismatched bundle operands in calls:"
<< *CI << "!=" << *V << '\n');
return;
}
}
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
TE->setOperandsInOrder();
for (unsigned i = 0, e = CI->getNumArgOperands(); i != e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (Value *V : VL) {
auto *CI2 = cast<CallInst>(V);
Operands.push_back(CI2->getArgOperand(i));
}
buildTree_rec(Operands, Depth + 1, {TE, i});
}
return;
}
case Instruction::ShuffleVector: {
// If this is not an alternate sequence of opcode like add-sub
// then do not vectorize this instruction.
if (!S.isAltShuffle()) {
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: ShuffleVector are not vectorized.\n");
return;
}
TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: added a ShuffleVector op.\n");
// Reorder operands if reordering would enable vectorization.
if (isa<BinaryOperator>(VL0)) {
ValueList Left, Right;
reorderInputsAccordingToOpcode(VL, Left, Right, *DL, *SE, *this);
TE->setOperand(0, Left);
TE->setOperand(1, Right);
buildTree_rec(Left, Depth + 1, {TE, 0});
buildTree_rec(Right, Depth + 1, {TE, 1});
return;
}
TE->setOperandsInOrder();
for (unsigned i = 0, e = VL0->getNumOperands(); i < e; ++i) {
ValueList Operands;
// Prepare the operand vector.
for (Value *V : VL)
Operands.push_back(cast<Instruction>(V)->getOperand(i));
buildTree_rec(Operands, Depth + 1, {TE, i});
}
return;
}
default:
BS.cancelScheduling(VL, VL0);
newTreeEntry(VL, None /*not vectorized*/, S, UserTreeIdx,
ReuseShuffleIndicies);
LLVM_DEBUG(dbgs() << "SLP: Gathering unknown instruction.\n");
return;
}
}
unsigned BoUpSLP::canMapToVector(Type *T, const DataLayout &DL) const {
unsigned N = 1;
Type *EltTy = T;
while (isa<StructType>(EltTy) || isa<ArrayType>(EltTy) ||
isa<VectorType>(EltTy)) {
if (auto *ST = dyn_cast<StructType>(EltTy)) {
// Check that struct is homogeneous.
for (const auto *Ty : ST->elements())
if (Ty != *ST->element_begin())
return 0;
N *= ST->getNumElements();
EltTy = *ST->element_begin();
} else if (auto *AT = dyn_cast<ArrayType>(EltTy)) {
N *= AT->getNumElements();
EltTy = AT->getElementType();
} else {
auto *VT = cast<FixedVectorType>(EltTy);
N *= VT->getNumElements();
EltTy = VT->getElementType();
}
}
if (!isValidElementType(EltTy))
return 0;
uint64_t VTSize = DL.getTypeStoreSizeInBits(FixedVectorType::get(EltTy, N));
if (VTSize < MinVecRegSize || VTSize > MaxVecRegSize || VTSize != DL.getTypeStoreSizeInBits(T))
return 0;
return N;
}
bool BoUpSLP::canReuseExtract(ArrayRef<Value *> VL, Value *OpValue,
SmallVectorImpl<unsigned> &CurrentOrder) const {
Instruction *E0 = cast<Instruction>(OpValue);
assert(E0->getOpcode() == Instruction::ExtractElement ||
E0->getOpcode() == Instruction::ExtractValue);
assert(E0->getOpcode() == getSameOpcode(VL).getOpcode() && "Invalid opcode");
// Check if all of the extracts come from the same vector and from the
// correct offset.
Value *Vec = E0->getOperand(0);
CurrentOrder.clear();
// We have to extract from a vector/aggregate with the same number of elements.
unsigned NElts;
if (E0->getOpcode() == Instruction::ExtractValue) {
const DataLayout &DL = E0->getModule()->getDataLayout();
NElts = canMapToVector(Vec->getType(), DL);
if (!NElts)
return false;
// Check if load can be rewritten as load of vector.
LoadInst *LI = dyn_cast<LoadInst>(Vec);
if (!LI || !LI->isSimple() || !LI->hasNUses(VL.size()))
return false;
} else {
NElts = cast<FixedVectorType>(Vec->getType())->getNumElements();
}
if (NElts != VL.size())
return false;
// Check that all of the indices extract from the correct offset.
bool ShouldKeepOrder = true;
unsigned E = VL.size();
// Assign to all items the initial value E + 1 so we can check if the extract
// instruction index was used already.
// Also, later we can check that all the indices are used and we have a
// consecutive access in the extract instructions, by checking that no
// element of CurrentOrder still has value E + 1.
CurrentOrder.assign(E, E + 1);
unsigned I = 0;
for (; I < E; ++I) {
auto *Inst = cast<Instruction>(VL[I]);
if (Inst->getOperand(0) != Vec)
break;
Optional<unsigned> Idx = getExtractIndex(Inst);
if (!Idx)
break;
const unsigned ExtIdx = *Idx;
if (ExtIdx != I) {
if (ExtIdx >= E || CurrentOrder[ExtIdx] != E + 1)
break;
ShouldKeepOrder = false;
CurrentOrder[ExtIdx] = I;
} else {
if (CurrentOrder[I] != E + 1)
break;
CurrentOrder[I] = I;
}
}
if (I < E) {
CurrentOrder.clear();
return false;
}
return ShouldKeepOrder;
}
bool BoUpSLP::areAllUsersVectorized(Instruction *I) const {
return I->hasOneUse() || llvm::all_of(I->users(), [this](User *U) {
return ScalarToTreeEntry.count(U) > 0;
});
}
static std::pair<InstructionCost, InstructionCost>
getVectorCallCosts(CallInst *CI, FixedVectorType *VecTy,
TargetTransformInfo *TTI, TargetLibraryInfo *TLI) {
Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
// Calculate the cost of the scalar and vector calls.
SmallVector<Type *, 4> VecTys;
for (Use &Arg : CI->args())
VecTys.push_back(
FixedVectorType::get(Arg->getType(), VecTy->getNumElements()));
FastMathFlags FMF;
if (auto *FPCI = dyn_cast<FPMathOperator>(CI))
FMF = FPCI->getFastMathFlags();
SmallVector<const Value *> Arguments(CI->arg_begin(), CI->arg_end());
IntrinsicCostAttributes CostAttrs(ID, VecTy, Arguments, VecTys, FMF,
dyn_cast<IntrinsicInst>(CI));
auto IntrinsicCost =
TTI->getIntrinsicInstrCost(CostAttrs, TTI::TCK_RecipThroughput);
auto Shape = VFShape::get(*CI, ElementCount::getFixed(static_cast<unsigned>(
VecTy->getNumElements())),
false /*HasGlobalPred*/);
Function *VecFunc = VFDatabase(*CI).getVectorizedFunction(Shape);
auto LibCost = IntrinsicCost;
if (!CI->isNoBuiltin() && VecFunc) {
// Calculate the cost of the vector library call.
// If the corresponding vector call is cheaper, return its cost.
LibCost = TTI->getCallInstrCost(nullptr, VecTy, VecTys,
TTI::TCK_RecipThroughput);
}
return {IntrinsicCost, LibCost};
}
InstructionCost BoUpSLP::getEntryCost(TreeEntry *E) {
ArrayRef<Value*> VL = E->Scalars;
Type *ScalarTy = VL[0]->getType();
if (StoreInst *SI = dyn_cast<StoreInst>(VL[0]))
ScalarTy = SI->getValueOperand()->getType();
else if (CmpInst *CI = dyn_cast<CmpInst>(VL[0]))
ScalarTy = CI->getOperand(0)->getType();
auto *VecTy = FixedVectorType::get(ScalarTy, VL.size());
TTI::TargetCostKind CostKind = TTI::TCK_RecipThroughput;
// If we have computed a smaller type for the expression, update VecTy so
// that the costs will be accurate.
if (MinBWs.count(VL[0]))
VecTy = FixedVectorType::get(
IntegerType::get(F->getContext(), MinBWs[VL[0]].first), VL.size());
unsigned ReuseShuffleNumbers = E->ReuseShuffleIndices.size();
bool NeedToShuffleReuses = !E->ReuseShuffleIndices.empty();
InstructionCost ReuseShuffleCost = 0;
if (NeedToShuffleReuses) {
ReuseShuffleCost =
TTI->getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc, VecTy);
}
if (E->State == TreeEntry::NeedToGather) {
if (allConstant(VL))
return 0;
if (isSplat(VL)) {
return ReuseShuffleCost +
TTI->getShuffleCost(TargetTransformInfo::SK_Broadcast, VecTy, 0);
}
if (E->getOpcode() == Instruction::ExtractElement &&
allSameType(VL) && allSameBlock(VL)) {
Optional<TargetTransformInfo::ShuffleKind> ShuffleKind = isShuffle(VL);
if (ShuffleKind.hasValue()) {
InstructionCost Cost =
TTI->getShuffleCost(ShuffleKind.getValue(), VecTy);
for (auto *V : VL) {
// If all users of instruction are going to be vectorized and this
// instruction itself is not going to be vectorized, consider this
// instruction as dead and remove its cost from the final cost of the
// vectorized tree.
if (areAllUsersVectorized(cast<Instruction>(V)) &&
!ScalarToTreeEntry.count(V)) {
auto *IO = cast<ConstantInt>(
cast<ExtractElementInst>(V)->getIndexOperand());
Cost -= TTI->getVectorInstrCost(Instruction::ExtractElement, VecTy,
IO->getZExtValue());
}
}
return ReuseShuffleCost + Cost;
}
}
return ReuseShuffleCost + getGatherCost(VL);
}
assert((E->State == TreeEntry::Vectorize ||
E->State == TreeEntry::ScatterVectorize) &&
"Unhandled state");
assert(E->getOpcode() && allSameType(VL) && allSameBlock(VL) && "Invalid VL");
Instruction *VL0 = E->getMainOp();
unsigned ShuffleOrOp =
E->isAltShuffle() ? (unsigned)Instruction::ShuffleVector : E->getOpcode();
switch (ShuffleOrOp) {
case Instruction::PHI:
return 0;
case Instruction::ExtractValue:
case Instruction::ExtractElement: {
// The common cost of removal ExtractElement/ExtractValue instructions +
// the cost of shuffles, if required to resuffle the original vector.
InstructionCost CommonCost = 0;
if (NeedToShuffleReuses) {
unsigned Idx = 0;
for (unsigned I : E->ReuseShuffleIndices) {
if (ShuffleOrOp == Instruction::ExtractElement) {
auto *IO = cast<ConstantInt>(
cast<ExtractElementInst>(VL[I])->getIndexOperand());
Idx = IO->getZExtValue();
ReuseShuffleCost -= TTI->getVectorInstrCost(
Instruction::ExtractElement, VecTy, Idx);
} else {
ReuseShuffleCost -= TTI->getVectorInstrCost(
Instruction::ExtractElement, VecTy, Idx);
++Idx;
}
}
Idx = ReuseShuffleNumbers;
for (Value *V : VL) {
if (ShuffleOrOp == Instruction::ExtractElement) {
auto *IO = cast<ConstantInt>(
cast<ExtractElementInst>(V)->getIndexOperand());
Idx = IO->getZExtValue();
} else {
--Idx;
}
ReuseShuffleCost +=
TTI->getVectorInstrCost(Instruction::ExtractElement, VecTy, Idx);
}
CommonCost = ReuseShuffleCost;
} else if (!E->ReorderIndices.empty()) {
CommonCost = TTI->getShuffleCost(
TargetTransformInfo::SK_PermuteSingleSrc, VecTy);
}
for (unsigned I = 0, E = VL.size(); I < E; ++I) {
Instruction *EI = cast<Instruction>(VL[I]);
// If all users are going to be vectorized, instruction can be
// considered as dead.
// The same, if have only one user, it will be vectorized for sure.
if (areAllUsersVectorized(EI)) {
// Take credit for instruction that will become dead.
if (EI->hasOneUse()) {
Instruction *Ext = EI->user_back();
if ((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&
all_of(Ext->users(),
[](User *U) { return isa<GetElementPtrInst>(U); })) {
// Use getExtractWithExtendCost() to calculate the cost of
// extractelement/ext pair.
CommonCost -= TTI->getExtractWithExtendCost(
Ext->getOpcode(), Ext->getType(), VecTy, I);
// Add back the cost of s|zext which is subtracted separately.
CommonCost += TTI->getCastInstrCost(
Ext->getOpcode(), Ext->getType(), EI->getType(),
TTI::getCastContextHint(Ext), CostKind, Ext);
continue;
}
}
CommonCost -=
TTI->getVectorInstrCost(Instruction::ExtractElement, VecTy, I);
}
}
return CommonCost;
}
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::FPExt:
case Instruction::PtrToInt:
case Instruction::IntToPtr:
case Instruction::SIToFP:
case Instruction::UIToFP:
case Instruction::Trunc:
case Instruction::FPTrunc:
case Instruction::BitCast: {
Type *SrcTy = VL0->getOperand(0)->getType();
InstructionCost ScalarEltCost =
TTI->getCastInstrCost(E->getOpcode(), ScalarTy, SrcTy,
TTI::getCastContextHint(VL0), CostKind, VL0);
if (NeedToShuffleReuses) {
ReuseShuffleCost -= (ReuseShuffleNumbers - VL.size()) * ScalarEltCost;
}
// Calculate the cost of this instruction.
InstructionCost ScalarCost = VL.size() * ScalarEltCost;
auto *SrcVecTy = FixedVectorType::get(SrcTy, VL.size());
InstructionCost VecCost = 0;
// Check if the values are candidates to demote.
if (!MinBWs.count(VL0) || VecTy != SrcVecTy) {
VecCost =
ReuseShuffleCost +
TTI->getCastInstrCost(E->getOpcode(), VecTy, SrcVecTy,
TTI::getCastContextHint(VL0), CostKind, VL0);
}
LLVM_DEBUG(dumpTreeCosts(E, ReuseShuffleCost, VecCost, ScalarCost));
return VecCost - ScalarCost;
}
case Instruction::FCmp:
case Instruction::ICmp:
case Instruction::Select: {
// Calculate the cost of this instruction.
InstructionCost ScalarEltCost =
TTI->getCmpSelInstrCost(E->getOpcode(), ScalarTy, Builder.getInt1Ty(),
CmpInst::BAD_ICMP_PREDICATE, CostKind, VL0);
if (NeedToShuffleReuses) {
ReuseShuffleCost -= (ReuseShuffleNumbers - VL.size()) * ScalarEltCost;
}
auto *MaskTy = FixedVectorType::get(Builder.getInt1Ty(), VL.size());
InstructionCost ScalarCost = VecTy->getNumElements() * ScalarEltCost;
// Check if all entries in VL are either compares or selects with compares
// as condition that have the same predicates.
CmpInst::Predicate VecPred = CmpInst::BAD_ICMP_PREDICATE;
bool First = true;
for (auto *V : VL) {
CmpInst::Predicate CurrentPred;
auto MatchCmp = m_Cmp(CurrentPred, m_Value(), m_Value());
if ((!match(V, m_Select(MatchCmp, m_Value(), m_Value())) &&
!match(V, MatchCmp)) ||
(!First && VecPred != CurrentPred)) {
VecPred = CmpInst::BAD_ICMP_PREDICATE;
break;
}
First = false;
VecPred = CurrentPred;
}
InstructionCost VecCost = TTI->getCmpSelInstrCost(
E->getOpcode(), VecTy, MaskTy, VecPred, CostKind, VL0);
// Check if it is possible and profitable to use min/max for selects in
// VL.
//
auto IntrinsicAndUse = canConvertToMinOrMaxIntrinsic(VL);
if (IntrinsicAndUse.first != Intrinsic::not_intrinsic) {
IntrinsicCostAttributes CostAttrs(IntrinsicAndUse.first, VecTy,
{VecTy, VecTy});
InstructionCost IntrinsicCost =
TTI->getIntrinsicInstrCost(CostAttrs, CostKind);
// If the selects are the only uses of the compares, they will be dead
// and we can adjust the cost by removing their cost.
if (IntrinsicAndUse.second)
IntrinsicCost -=
TTI->getCmpSelInstrCost(Instruction::ICmp, VecTy, MaskTy,
CmpInst::BAD_ICMP_PREDICATE, CostKind);
VecCost = std::min(VecCost, IntrinsicCost);
}
LLVM_DEBUG(dumpTreeCosts(E, ReuseShuffleCost, VecCost, ScalarCost));
return ReuseShuffleCost + VecCost - ScalarCost;
}
case Instruction::FNeg:
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::FDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::FRem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
// Certain instructions can be cheaper to vectorize if they have a
// constant second vector operand.
TargetTransformInfo::OperandValueKind Op1VK =
TargetTransformInfo::OK_AnyValue;
TargetTransformInfo::OperandValueKind Op2VK =
TargetTransformInfo::OK_UniformConstantValue;
TargetTransformInfo::OperandValueProperties Op1VP =
TargetTransformInfo::OP_None;
TargetTransformInfo::OperandValueProperties Op2VP =
TargetTransformInfo::OP_PowerOf2;
// If all operands are exactly the same ConstantInt then set the
// operand kind to OK_UniformConstantValue.
// If instead not all operands are constants, then set the operand kind
// to OK_AnyValue. If all operands are constants but not the same,
// then set the operand kind to OK_NonUniformConstantValue.
ConstantInt *CInt0 = nullptr;
for (unsigned i = 0, e = VL.size(); i < e; ++i) {
const Instruction *I = cast<Instruction>(VL[i]);
unsigned OpIdx = isa<BinaryOperator>(I) ? 1 : 0;
ConstantInt *CInt = dyn_cast<ConstantInt>(I->getOperand(OpIdx));
if (!CInt) {
Op2VK = TargetTransformInfo::OK_AnyValue;
Op2VP = TargetTransformInfo::OP_None;
break;
}
if (Op2VP == TargetTransformInfo::OP_PowerOf2 &&
!CInt->getValue().isPowerOf2())
Op2VP = TargetTransformInfo::OP_None;
if (i == 0) {
CInt0 = CInt;
continue;
}
if (CInt0 != CInt)
Op2VK = TargetTransformInfo::OK_NonUniformConstantValue;
}
SmallVector<const Value *, 4> Operands(VL0->operand_values());
InstructionCost ScalarEltCost =
TTI->getArithmeticInstrCost(E->getOpcode(), ScalarTy, CostKind, Op1VK,
Op2VK, Op1VP, Op2VP, Operands, VL0);
if (NeedToShuffleReuses) {
ReuseShuffleCost -= (ReuseShuffleNumbers - VL.size()) * ScalarEltCost;
}
InstructionCost ScalarCost = VecTy->getNumElements() * ScalarEltCost;
InstructionCost VecCost =
TTI->getArithmeticInstrCost(E->getOpcode(), VecTy, CostKind, Op1VK,
Op2VK, Op1VP, Op2VP, Operands, VL0);
LLVM_DEBUG(dumpTreeCosts(E, ReuseShuffleCost, VecCost, ScalarCost));
return ReuseShuffleCost + VecCost - ScalarCost;
}
case Instruction::GetElementPtr: {
TargetTransformInfo::OperandValueKind Op1VK =
TargetTransformInfo::OK_AnyValue;
TargetTransformInfo::OperandValueKind Op2VK =
TargetTransformInfo::OK_UniformConstantValue;
InstructionCost ScalarEltCost = TTI->getArithmeticInstrCost(
Instruction::Add, ScalarTy, CostKind, Op1VK, Op2VK);
if (NeedToShuffleReuses) {
ReuseShuffleCost -= (ReuseShuffleNumbers - VL.size()) * ScalarEltCost;
}
InstructionCost ScalarCost = VecTy->getNumElements() * ScalarEltCost;
InstructionCost VecCost = TTI->getArithmeticInstrCost(
Instruction::Add, VecTy, CostKind, Op1VK, Op2VK);
LLVM_DEBUG(dumpTreeCosts(E, ReuseShuffleCost, VecCost, ScalarCost));
return ReuseShuffleCost + VecCost - ScalarCost;
}
case Instruction::Load: {
// Cost of wide load - cost of scalar loads.
Align alignment = cast<LoadInst>(VL0)->getAlign();
InstructionCost ScalarEltCost = TTI->getMemoryOpCost(
Instruction::Load, ScalarTy, alignment, 0, CostKind, VL0);
if (NeedToShuffleReuses) {
ReuseShuffleCost -= (ReuseShuffleNumbers - VL.size()) * ScalarEltCost;
}
InstructionCost ScalarLdCost = VecTy->getNumElements() * ScalarEltCost;
InstructionCost VecLdCost;
if (E->State == TreeEntry::Vectorize) {
VecLdCost = TTI->getMemoryOpCost(Instruction::Load, VecTy, alignment, 0,
CostKind, VL0);
} else {
assert(E->State == TreeEntry::ScatterVectorize && "Unknown EntryState");
VecLdCost = TTI->getGatherScatterOpCost(
Instruction::Load, VecTy, cast<LoadInst>(VL0)->getPointerOperand(),
/*VariableMask=*/false, alignment, CostKind, VL0);
}
if (!NeedToShuffleReuses && !E->ReorderIndices.empty())
VecLdCost += TTI->getShuffleCost(
TargetTransformInfo::SK_PermuteSingleSrc, VecTy);
LLVM_DEBUG(dumpTreeCosts(E, ReuseShuffleCost, VecLdCost, ScalarLdCost));
return ReuseShuffleCost + VecLdCost - ScalarLdCost;
}
case Instruction::Store: {
// We know that we can merge the stores. Calculate the cost.
bool IsReorder = !E->ReorderIndices.empty();
auto *SI =
cast<StoreInst>(IsReorder ? VL[E->ReorderIndices.front()] : VL0);
Align Alignment = SI->getAlign();
InstructionCost ScalarEltCost = TTI->getMemoryOpCost(
Instruction::Store, ScalarTy, Alignment, 0, CostKind, VL0);
InstructionCost ScalarStCost = VecTy->getNumElements() * ScalarEltCost;
InstructionCost VecStCost = TTI->getMemoryOpCost(
Instruction::Store, VecTy, Alignment, 0, CostKind, VL0);
if (IsReorder)
VecStCost += TTI->getShuffleCost(
TargetTransformInfo::SK_PermuteSingleSrc, VecTy);
LLVM_DEBUG(dumpTreeCosts(E, ReuseShuffleCost, VecStCost, ScalarStCost));
return VecStCost - ScalarStCost;
}
case Instruction::Call: {
CallInst *CI = cast<CallInst>(VL0);
Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
// Calculate the cost of the scalar and vector calls.
IntrinsicCostAttributes CostAttrs(ID, *CI, 1);
InstructionCost ScalarEltCost =
TTI->getIntrinsicInstrCost(CostAttrs, CostKind);
if (NeedToShuffleReuses) {
ReuseShuffleCost -= (ReuseShuffleNumbers - VL.size()) * ScalarEltCost;
}
InstructionCost ScalarCallCost = VecTy->getNumElements() * ScalarEltCost;
auto VecCallCosts = getVectorCallCosts(CI, VecTy, TTI, TLI);
InstructionCost VecCallCost =
std::min(VecCallCosts.first, VecCallCosts.second);
LLVM_DEBUG(dbgs() << "SLP: Call cost " << VecCallCost - ScalarCallCost
<< " (" << VecCallCost << "-" << ScalarCallCost << ")"
<< " for " << *CI << "\n");
return ReuseShuffleCost + VecCallCost - ScalarCallCost;
}
case Instruction::ShuffleVector: {
assert(E->isAltShuffle() &&
((Instruction::isBinaryOp(E->getOpcode()) &&
Instruction::isBinaryOp(E->getAltOpcode())) ||
(Instruction::isCast(E->getOpcode()) &&
Instruction::isCast(E->getAltOpcode()))) &&
"Invalid Shuffle Vector Operand");
InstructionCost ScalarCost = 0;
if (NeedToShuffleReuses) {
for (unsigned Idx : E->ReuseShuffleIndices) {
Instruction *I = cast<Instruction>(VL[Idx]);
ReuseShuffleCost -= TTI->getInstructionCost(I, CostKind);
}
for (Value *V : VL) {
Instruction *I = cast<Instruction>(V);
ReuseShuffleCost += TTI->getInstructionCost(I, CostKind);
}
}
for (Value *V : VL) {
Instruction *I = cast<Instruction>(V);
assert(E->isOpcodeOrAlt(I) && "Unexpected main/alternate opcode");
ScalarCost += TTI->getInstructionCost(I, CostKind);
}
// VecCost is equal to sum of the cost of creating 2 vectors
// and the cost of creating shuffle.
InstructionCost VecCost = 0;
if (Instruction::isBinaryOp(E->getOpcode())) {
VecCost = TTI->getArithmeticInstrCost(E->getOpcode(), VecTy, CostKind);
VecCost += TTI->getArithmeticInstrCost(E->getAltOpcode(), VecTy,
CostKind);
} else {
Type *Src0SclTy = E->getMainOp()->getOperand(0)->getType();
Type *Src1SclTy = E->getAltOp()->getOperand(0)->getType();
auto *Src0Ty = FixedVectorType::get(Src0SclTy, VL.size());
auto *Src1Ty = FixedVectorType::get(Src1SclTy, VL.size());
VecCost = TTI->getCastInstrCost(E->getOpcode(), VecTy, Src0Ty,
TTI::CastContextHint::None, CostKind);
VecCost += TTI->getCastInstrCost(E->getAltOpcode(), VecTy, Src1Ty,
TTI::CastContextHint::None, CostKind);
}
VecCost += TTI->getShuffleCost(TargetTransformInfo::SK_Select, VecTy, 0);
LLVM_DEBUG(dumpTreeCosts(E, ReuseShuffleCost, VecCost, ScalarCost));
return ReuseShuffleCost + VecCost - ScalarCost;
}
default:
llvm_unreachable("Unknown instruction");
}
}
bool BoUpSLP::isFullyVectorizableTinyTree() const {
LLVM_DEBUG(dbgs() << "SLP: Check whether the tree with height "
<< VectorizableTree.size() << " is fully vectorizable .\n");
// We only handle trees of heights 1 and 2.
if (VectorizableTree.size() == 1 &&
VectorizableTree[0]->State == TreeEntry::Vectorize)
return true;
if (VectorizableTree.size() != 2)
return false;
// Handle splat and all-constants stores.
if (VectorizableTree[0]->State == TreeEntry::Vectorize &&
(allConstant(VectorizableTree[1]->Scalars) ||
isSplat(VectorizableTree[1]->Scalars)))
return true;
// Gathering cost would be too much for tiny trees.
if (VectorizableTree[0]->State == TreeEntry::NeedToGather ||
VectorizableTree[1]->State == TreeEntry::NeedToGather)
return false;
return true;
}
static bool isLoadCombineCandidateImpl(Value *Root, unsigned NumElts,
TargetTransformInfo *TTI) {
// Look past the root to find a source value. Arbitrarily follow the
// path through operand 0 of any 'or'. Also, peek through optional
// shift-left-by-multiple-of-8-bits.
Value *ZextLoad = Root;
const APInt *ShAmtC;
while (!isa<ConstantExpr>(ZextLoad) &&
(match(ZextLoad, m_Or(m_Value(), m_Value())) ||
(match(ZextLoad, m_Shl(m_Value(), m_APInt(ShAmtC))) &&
ShAmtC->urem(8) == 0)))
ZextLoad = cast<BinaryOperator>(ZextLoad)->getOperand(0);
// Check if the input is an extended load of the required or/shift expression.
Value *LoadPtr;
if (ZextLoad == Root || !match(ZextLoad, m_ZExt(m_Load(m_Value(LoadPtr)))))
return false;
// Require that the total load bit width is a legal integer type.
// For example, <8 x i8> --> i64 is a legal integer on a 64-bit target.
// But <16 x i8> --> i128 is not, so the backend probably can't reduce it.
Type *SrcTy = LoadPtr->getType()->getPointerElementType();
unsigned LoadBitWidth = SrcTy->getIntegerBitWidth() * NumElts;
if (!TTI->isTypeLegal(IntegerType::get(Root->getContext(), LoadBitWidth)))
return false;
// Everything matched - assume that we can fold the whole sequence using
// load combining.
LLVM_DEBUG(dbgs() << "SLP: Assume load combining for tree starting at "
<< *(cast<Instruction>(Root)) << "\n");
return true;
}
bool BoUpSLP::isLoadCombineReductionCandidate(RecurKind RdxKind) const {
if (RdxKind != RecurKind::Or)
return false;
unsigned NumElts = VectorizableTree[0]->Scalars.size();
Value *FirstReduced = VectorizableTree[0]->Scalars[0];
return isLoadCombineCandidateImpl(FirstReduced, NumElts, TTI);
}
bool BoUpSLP::isLoadCombineCandidate() const {
// Peek through a final sequence of stores and check if all operations are
// likely to be load-combined.
unsigned NumElts = VectorizableTree[0]->Scalars.size();
for (Value *Scalar : VectorizableTree[0]->Scalars) {
Value *X;
if (!match(Scalar, m_Store(m_Value(X), m_Value())) ||
!isLoadCombineCandidateImpl(X, NumElts, TTI))
return false;
}
return true;
}
bool BoUpSLP::isTreeTinyAndNotFullyVectorizable() const {
// We can vectorize the tree if its size is greater than or equal to the
// minimum size specified by the MinTreeSize command line option.
if (VectorizableTree.size() >= MinTreeSize)
return false;
// If we have a tiny tree (a tree whose size is less than MinTreeSize), we
// can vectorize it if we can prove it fully vectorizable.
if (isFullyVectorizableTinyTree())
return false;
assert(VectorizableTree.empty()
? ExternalUses.empty()
: true && "We shouldn't have any external users");
// Otherwise, we can't vectorize the tree. It is both tiny and not fully
// vectorizable.
return true;
}
InstructionCost BoUpSLP::getSpillCost() const {
// Walk from the bottom of the tree to the top, tracking which values are
// live. When we see a call instruction that is not part of our tree,
// query TTI to see if there is a cost to keeping values live over it
// (for example, if spills and fills are required).
unsigned BundleWidth = VectorizableTree.front()->Scalars.size();
InstructionCost Cost = 0;
SmallPtrSet<Instruction*, 4> LiveValues;
Instruction *PrevInst = nullptr;
// The entries in VectorizableTree are not necessarily ordered by their
// position in basic blocks. Collect them and order them by dominance so later
// instructions are guaranteed to be visited first. For instructions in
// different basic blocks, we only scan to the beginning of the block, so
// their order does not matter, as long as all instructions in a basic block
// are grouped together. Using dominance ensures a deterministic order.
SmallVector<Instruction *, 16> OrderedScalars;
for (const auto &TEPtr : VectorizableTree) {
Instruction *Inst = dyn_cast<Instruction>(TEPtr->Scalars[0]);
if (!Inst)
continue;
OrderedScalars.push_back(Inst);
}
llvm::stable_sort(OrderedScalars, [this](Instruction *A, Instruction *B) {
return DT->dominates(B, A);
});
for (Instruction *Inst : OrderedScalars) {
if (!PrevInst) {
PrevInst = Inst;
continue;
}
// Update LiveValues.
LiveValues.erase(PrevInst);
for (auto &J : PrevInst->operands()) {
if (isa<Instruction>(&*J) && getTreeEntry(&*J))
LiveValues.insert(cast<Instruction>(&*J));
}
LLVM_DEBUG({
dbgs() << "SLP: #LV: " << LiveValues.size();
for (auto *X : LiveValues)
dbgs() << " " << X->getName();
dbgs() << ", Looking at ";
Inst->dump();
});
// Now find the sequence of instructions between PrevInst and Inst.
unsigned NumCalls = 0;
BasicBlock::reverse_iterator InstIt = ++Inst->getIterator().getReverse(),
PrevInstIt =
PrevInst->getIterator().getReverse();
while (InstIt != PrevInstIt) {
if (PrevInstIt == PrevInst->getParent()->rend()) {
PrevInstIt = Inst->getParent()->rbegin();
continue;
}
// Debug information does not impact spill cost.
if ((isa<CallInst>(&*PrevInstIt) &&
!isa<DbgInfoIntrinsic>(&*PrevInstIt)) &&
&*PrevInstIt != PrevInst)
NumCalls++;
++PrevInstIt;
}
if (NumCalls) {
SmallVector<Type*, 4> V;
for (auto *II : LiveValues)
V.push_back(FixedVectorType::get(II->getType(), BundleWidth));
Cost += NumCalls * TTI->getCostOfKeepingLiveOverCall(V);
}
PrevInst = Inst;
}
return Cost;
}
InstructionCost BoUpSLP::getTreeCost() {
InstructionCost Cost = 0;
LLVM_DEBUG(dbgs() << "SLP: Calculating cost for tree of size "
<< VectorizableTree.size() << ".\n");
unsigned BundleWidth = VectorizableTree[0]->Scalars.size();
for (unsigned I = 0, E = VectorizableTree.size(); I < E; ++I) {
TreeEntry &TE = *VectorizableTree[I].get();
// We create duplicate tree entries for gather sequences that have multiple
// uses. However, we should not compute the cost of duplicate sequences.
// For example, if we have a build vector (i.e., insertelement sequence)
// that is used by more than one vector instruction, we only need to
// compute the cost of the insertelement instructions once. The redundant
// instructions will be eliminated by CSE.
//
// We should consider not creating duplicate tree entries for gather
// sequences, and instead add additional edges to the tree representing
// their uses. Since such an approach results in fewer total entries,
// existing heuristics based on tree size may yield different results.
//
if (TE.State == TreeEntry::NeedToGather &&
std::any_of(std::next(VectorizableTree.begin(), I + 1),
VectorizableTree.end(),
[TE](const std::unique_ptr<TreeEntry> &EntryPtr) {
return EntryPtr->State == TreeEntry::NeedToGather &&
EntryPtr->isSame(TE.Scalars);
}))
continue;
InstructionCost C = getEntryCost(&TE);
Cost += C;
LLVM_DEBUG(dbgs() << "SLP: Adding cost " << C
<< " for bundle that starts with " << *TE.Scalars[0]
<< ".\n"
<< "SLP: Current total cost = " << Cost << "\n");
}
SmallPtrSet<Value *, 16> ExtractCostCalculated;
InstructionCost ExtractCost = 0;
for (ExternalUser &EU : ExternalUses) {
// We only add extract cost once for the same scalar.
if (!ExtractCostCalculated.insert(EU.Scalar).second)
continue;
// Uses by ephemeral values are free (because the ephemeral value will be
// removed prior to code generation, and so the extraction will be
// removed as well).
if (EphValues.count(EU.User))
continue;
// If we plan to rewrite the tree in a smaller type, we will need to sign
// extend the extracted value back to the original type. Here, we account
// for the extract and the added cost of the sign extend if needed.
auto *VecTy = FixedVectorType::get(EU.Scalar->getType(), BundleWidth);
auto *ScalarRoot = VectorizableTree[0]->Scalars[0];
if (MinBWs.count(ScalarRoot)) {
auto *MinTy = IntegerType::get(F->getContext(), MinBWs[ScalarRoot].first);
auto Extend =
MinBWs[ScalarRoot].second ? Instruction::SExt : Instruction::ZExt;
VecTy = FixedVectorType::get(MinTy, BundleWidth);
ExtractCost += TTI->getExtractWithExtendCost(Extend, EU.Scalar->getType(),
VecTy, EU.Lane);
} else {
ExtractCost +=
TTI->getVectorInstrCost(Instruction::ExtractElement, VecTy, EU.Lane);
}
}
InstructionCost SpillCost = getSpillCost();
Cost += SpillCost + ExtractCost;
#ifndef NDEBUG
SmallString<256> Str;
{
raw_svector_ostream OS(Str);
OS << "SLP: Spill Cost = " << SpillCost << ".\n"
<< "SLP: Extract Cost = " << ExtractCost << ".\n"
<< "SLP: Total Cost = " << Cost << ".\n";
}
LLVM_DEBUG(dbgs() << Str);
if (ViewSLPTree)
ViewGraph(this, "SLP" + F->getName(), false, Str);
#endif
return Cost;
}
InstructionCost
BoUpSLP::getGatherCost(FixedVectorType *Ty,
const DenseSet<unsigned> &ShuffledIndices) const {
unsigned NumElts = Ty->getNumElements();
APInt DemandedElts = APInt::getNullValue(NumElts);
for (unsigned I = 0; I < NumElts; ++I)
if (!ShuffledIndices.count(I))
DemandedElts.setBit(I);
InstructionCost Cost =
TTI->getScalarizationOverhead(Ty, DemandedElts, /*Insert*/ true,
/*Extract*/ false);
if (!ShuffledIndices.empty())
Cost += TTI->getShuffleCost(TargetTransformInfo::SK_PermuteSingleSrc, Ty);
return Cost;
}
InstructionCost BoUpSLP::getGatherCost(ArrayRef<Value *> VL) const {
// Find the type of the operands in VL.
Type *ScalarTy = VL[0]->getType();
if (StoreInst *SI = dyn_cast<StoreInst>(VL[0]))
ScalarTy = SI->getValueOperand()->getType();
auto *VecTy = FixedVectorType::get(ScalarTy, VL.size());
// Find the cost of inserting/extracting values from the vector.
// Check if the same elements are inserted several times and count them as
// shuffle candidates.
DenseSet<unsigned> ShuffledElements;
DenseSet<Value *> UniqueElements;
// Iterate in reverse order to consider insert elements with the high cost.
for (unsigned I = VL.size(); I > 0; --I) {
unsigned Idx = I - 1;
if (!UniqueElements.insert(VL[Idx]).second)
ShuffledElements.insert(Idx);
}
return getGatherCost(VecTy, ShuffledElements);
}
// Perform operand reordering on the instructions in VL and return the reordered
// operands in Left and Right.
void BoUpSLP::reorderInputsAccordingToOpcode(ArrayRef<Value *> VL,
SmallVectorImpl<Value *> &Left,
SmallVectorImpl<Value *> &Right,
const DataLayout &DL,
ScalarEvolution &SE,
const BoUpSLP &R) {
if (VL.empty())
return;
VLOperands Ops(VL, DL, SE, R);
// Reorder the operands in place.
Ops.reorder();
Left = Ops.getVL(0);
Right = Ops.getVL(1);
}
void BoUpSLP::setInsertPointAfterBundle(TreeEntry *E) {
// Get the basic block this bundle is in. All instructions in the bundle
// should be in this block.
auto *Front = E->getMainOp();
auto *BB = Front->getParent();
assert(llvm::all_of(E->Scalars, [=](Value *V) -> bool {
auto *I = cast<Instruction>(V);
return !E->isOpcodeOrAlt(I) || I->getParent() == BB;
}));
// The last instruction in the bundle in program order.
Instruction *LastInst = nullptr;
// Find the last instruction. The common case should be that BB has been
// scheduled, and the last instruction is VL.back(). So we start with
// VL.back() and iterate over schedule data until we reach the end of the
// bundle. The end of the bundle is marked by null ScheduleData.
if (BlocksSchedules.count(BB)) {
auto *Bundle =
BlocksSchedules[BB]->getScheduleData(E->isOneOf(E->Scalars.back()));
if (Bundle && Bundle->isPartOfBundle())
for (; Bundle; Bundle = Bundle->NextInBundle)
if (Bundle->OpValue == Bundle->Inst)
LastInst = Bundle->Inst;
}
// LastInst can still be null at this point if there's either not an entry
// for BB in BlocksSchedules or there's no ScheduleData available for
// VL.back(). This can be the case if buildTree_rec aborts for various
// reasons (e.g., the maximum recursion depth is reached, the maximum region
// size is reached, etc.). ScheduleData is initialized in the scheduling
// "dry-run".
//
// If this happens, we can still find the last instruction by brute force. We
// iterate forwards from Front (inclusive) until we either see all
// instructions in the bundle or reach the end of the block. If Front is the
// last instruction in program order, LastInst will be set to Front, and we
// will visit all the remaining instructions in the block.
//
// One of the reasons we exit early from buildTree_rec is to place an upper
// bound on compile-time. Thus, taking an additional compile-time hit here is
// not ideal. However, this should be exceedingly rare since it requires that
// we both exit early from buildTree_rec and that the bundle be out-of-order
// (causing us to iterate all the way to the end of the block).
if (!LastInst) {
SmallPtrSet<Value *, 16> Bundle(E->Scalars.begin(), E->Scalars.end());
for (auto &I : make_range(BasicBlock::iterator(Front), BB->end())) {
if (Bundle.erase(&I) && E->isOpcodeOrAlt(&I))
LastInst = &I;
if (Bundle.empty())
break;
}
}
assert(LastInst && "Failed to find last instruction in bundle");
// Set the insertion point after the last instruction in the bundle. Set the
// debug location to Front.
Builder.SetInsertPoint(BB, ++LastInst->getIterator());
Builder.SetCurrentDebugLocation(Front->getDebugLoc());
}
Value *BoUpSLP::gather(ArrayRef<Value *> VL) {
Value *Val0 =
isa<StoreInst>(VL[0]) ? cast<StoreInst>(VL[0])->getValueOperand() : VL[0];
FixedVectorType *VecTy = FixedVectorType::get(Val0->getType(), VL.size());
Value *Vec = PoisonValue::get(VecTy);
unsigned InsIndex = 0;
for (Value *Val : VL) {
Vec = Builder.CreateInsertElement(Vec, Val, Builder.getInt32(InsIndex++));
auto *InsElt = dyn_cast<InsertElementInst>(Vec);
if (!InsElt)
continue;
GatherSeq.insert(InsElt);
CSEBlocks.insert(InsElt->getParent());
// Add to our 'need-to-extract' list.
if (TreeEntry *Entry = getTreeEntry(Val)) {
// Find which lane we need to extract.
unsigned FoundLane = std::distance(Entry->Scalars.begin(),
find(Entry->Scalars, Val));
assert(FoundLane < Entry->Scalars.size() && "Couldn't find extract lane");
if (!Entry->ReuseShuffleIndices.empty()) {
FoundLane = std::distance(Entry->ReuseShuffleIndices.begin(),
find(Entry->ReuseShuffleIndices, FoundLane));
}
ExternalUses.push_back(ExternalUser(Val, InsElt, FoundLane));
}
}
return Vec;
}
Value *BoUpSLP::vectorizeTree(ArrayRef<Value *> VL) {
InstructionsState S = getSameOpcode(VL);
if (S.getOpcode()) {
if (TreeEntry *E = getTreeEntry(S.OpValue)) {
if (E->isSame(VL)) {
Value *V = vectorizeTree(E);
if (VL.size() == E->Scalars.size() && !E->ReuseShuffleIndices.empty()) {
// Reshuffle to get only unique values.
// If some of the scalars are duplicated in the vectorization tree
// entry, we do not vectorize them but instead generate a mask for the
// reuses. But if there are several users of the same entry, they may
// have different vectorization factors. This is especially important
// for PHI nodes. In this case, we need to adapt the resulting
// instruction for the user vectorization factor and have to reshuffle
// it again to take only unique elements of the vector. Without this
// code the function incorrectly returns reduced vector instruction
// with the same elements, not with the unique ones.
// block:
// %phi = phi <2 x > { .., %entry} {%shuffle, %block}
// %2 = shuffle <2 x > %phi, %poison, <4 x > <0, 0, 1, 1>
// ... (use %2)
// %shuffle = shuffle <2 x> %2, poison, <2 x> {0, 2}
// br %block
SmallVector<int, 4> UniqueIdxs;
SmallSet<int, 4> UsedIdxs;
int Pos = 0;
for (int Idx : E->ReuseShuffleIndices) {
if (UsedIdxs.insert(Idx).second)
UniqueIdxs.emplace_back(Pos);
++Pos;
}
V = Builder.CreateShuffleVector(V, UniqueIdxs, "shrink.shuffle");
}
return V;
}
}
}
// Check that every instruction appears once in this bundle.
SmallVector<int, 4> ReuseShuffleIndicies;
SmallVector<Value *, 4> UniqueValues;
if (VL.size() > 2) {
DenseMap<Value *, unsigned> UniquePositions;
for (Value *V : VL) {
auto Res = UniquePositions.try_emplace(V, UniqueValues.size());
ReuseShuffleIndicies.emplace_back(Res.first->second);
if (Res.second || isa<Constant>(V))
UniqueValues.emplace_back(V);
}
// Do not shuffle single element or if number of unique values is not power
// of 2.
if (UniqueValues.size() == VL.size() || UniqueValues.size() <= 1 ||
!llvm::isPowerOf2_32(UniqueValues.size()))
ReuseShuffleIndicies.clear();
else
VL = UniqueValues;
}
Value *Vec = gather(VL);
if (!ReuseShuffleIndicies.empty()) {
Vec = Builder.CreateShuffleVector(Vec, ReuseShuffleIndicies, "shuffle");
if (auto *I = dyn_cast<Instruction>(Vec)) {
GatherSeq.insert(I);
CSEBlocks.insert(I->getParent());
}
}
return Vec;
}
namespace {
/// Merges shuffle masks and emits final shuffle instruction, if required.
class ShuffleInstructionBuilder {
IRBuilderBase &Builder;
bool IsFinalized = false;
SmallVector<int, 4> Mask;
public:
ShuffleInstructionBuilder(IRBuilderBase &Builder) : Builder(Builder) {}
/// Adds a mask, inverting it before applying.
void addInversedMask(ArrayRef<unsigned> SubMask) {
if (SubMask.empty())
return;
SmallVector<int, 4> NewMask;
inversePermutation(SubMask, NewMask);
addMask(NewMask);
}
/// Functions adds masks, merging them into single one.
void addMask(ArrayRef<unsigned> SubMask) {
SmallVector<int, 4> NewMask(SubMask.begin(), SubMask.end());
addMask(NewMask);
}
void addMask(ArrayRef<int> SubMask) {
if (SubMask.empty())
return;
if (Mask.empty()) {
Mask.append(SubMask.begin(), SubMask.end());
return;
}
SmallVector<int, 4> NewMask(SubMask.size(), SubMask.size());
int TermValue = std::min(Mask.size(), SubMask.size());
for (int I = 0, E = SubMask.size(); I < E; ++I) {
if (SubMask[I] >= TermValue || Mask[SubMask[I]] >= TermValue) {
NewMask[I] = E;
continue;
}
NewMask[I] = Mask[SubMask[I]];
}
Mask.swap(NewMask);
}
Value *finalize(Value *V) {
IsFinalized = true;
if (Mask.empty())
return V;
return Builder.CreateShuffleVector(V, Mask, "shuffle");
}
~ShuffleInstructionBuilder() {
assert((IsFinalized || Mask.empty()) &&
"Shuffle construction must be finalized.");
}
};
} // namespace
Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
IRBuilder<>::InsertPointGuard Guard(Builder);
if (E->VectorizedValue) {
LLVM_DEBUG(dbgs() << "SLP: Diamond merged for " << *E->Scalars[0] << ".\n");
return E->VectorizedValue;
}
ShuffleInstructionBuilder ShuffleBuilder(Builder);
bool NeedToShuffleReuses = !E->ReuseShuffleIndices.empty();
if (E->State == TreeEntry::NeedToGather) {
setInsertPointAfterBundle(E);
Value *Vec = gather(E->Scalars);
if (NeedToShuffleReuses) {
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
Vec = ShuffleBuilder.finalize(Vec);
if (auto *I = dyn_cast<Instruction>(Vec)) {
GatherSeq.insert(I);
CSEBlocks.insert(I->getParent());
}
}
E->VectorizedValue = Vec;
return Vec;
}
assert((E->State == TreeEntry::Vectorize ||
E->State == TreeEntry::ScatterVectorize) &&
"Unhandled state");
unsigned ShuffleOrOp =
E->isAltShuffle() ? (unsigned)Instruction::ShuffleVector : E->getOpcode();
Instruction *VL0 = E->getMainOp();
Type *ScalarTy = VL0->getType();
if (auto *Store = dyn_cast<StoreInst>(VL0))
ScalarTy = Store->getValueOperand()->getType();
auto *VecTy = FixedVectorType::get(ScalarTy, E->Scalars.size());
switch (ShuffleOrOp) {
case Instruction::PHI: {
auto *PH = cast<PHINode>(VL0);
Builder.SetInsertPoint(PH->getParent()->getFirstNonPHI());
Builder.SetCurrentDebugLocation(PH->getDebugLoc());
PHINode *NewPhi = Builder.CreatePHI(VecTy, PH->getNumIncomingValues());
Value *V = NewPhi;
if (NeedToShuffleReuses)
V = Builder.CreateShuffleVector(V, E->ReuseShuffleIndices, "shuffle");
E->VectorizedValue = V;
// PHINodes may have multiple entries from the same block. We want to
// visit every block once.
SmallPtrSet<BasicBlock*, 4> VisitedBBs;
for (unsigned i = 0, e = PH->getNumIncomingValues(); i < e; ++i) {
ValueList Operands;
BasicBlock *IBB = PH->getIncomingBlock(i);
if (!VisitedBBs.insert(IBB).second) {
NewPhi->addIncoming(NewPhi->getIncomingValueForBlock(IBB), IBB);
continue;
}
Builder.SetInsertPoint(IBB->getTerminator());
Builder.SetCurrentDebugLocation(PH->getDebugLoc());
Value *Vec = vectorizeTree(E->getOperand(i));
NewPhi->addIncoming(Vec, IBB);
}
assert(NewPhi->getNumIncomingValues() == PH->getNumIncomingValues() &&
"Invalid number of incoming values");
return V;
}
case Instruction::ExtractElement: {
Value *V = E->getSingleOperand(0);
Builder.SetInsertPoint(VL0);
ShuffleBuilder.addInversedMask(E->ReorderIndices);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
return V;
}
case Instruction::ExtractValue: {
auto *LI = cast<LoadInst>(E->getSingleOperand(0));
Builder.SetInsertPoint(LI);
auto *PtrTy = PointerType::get(VecTy, LI->getPointerAddressSpace());
Value *Ptr = Builder.CreateBitCast(LI->getOperand(0), PtrTy);
LoadInst *V = Builder.CreateAlignedLoad(VecTy, Ptr, LI->getAlign());
Value *NewV = propagateMetadata(V, E->Scalars);
ShuffleBuilder.addInversedMask(E->ReorderIndices);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
NewV = ShuffleBuilder.finalize(NewV);
E->VectorizedValue = NewV;
return NewV;
}
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::FPExt:
case Instruction::PtrToInt:
case Instruction::IntToPtr:
case Instruction::SIToFP:
case Instruction::UIToFP:
case Instruction::Trunc:
case Instruction::FPTrunc:
case Instruction::BitCast: {
setInsertPointAfterBundle(E);
Value *InVec = vectorizeTree(E->getOperand(0));
if (E->VectorizedValue) {
LLVM_DEBUG(dbgs() << "SLP: Diamond merged for " << *VL0 << ".\n");
return E->VectorizedValue;
}
auto *CI = cast<CastInst>(VL0);
Value *V = Builder.CreateCast(CI->getOpcode(), InVec, VecTy);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::FCmp:
case Instruction::ICmp: {
setInsertPointAfterBundle(E);
Value *L = vectorizeTree(E->getOperand(0));
Value *R = vectorizeTree(E->getOperand(1));
if (E->VectorizedValue) {
LLVM_DEBUG(dbgs() << "SLP: Diamond merged for " << *VL0 << ".\n");
return E->VectorizedValue;
}
CmpInst::Predicate P0 = cast<CmpInst>(VL0)->getPredicate();
Value *V = Builder.CreateCmp(P0, L, R);
propagateIRFlags(V, E->Scalars, VL0);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::Select: {
setInsertPointAfterBundle(E);
Value *Cond = vectorizeTree(E->getOperand(0));
Value *True = vectorizeTree(E->getOperand(1));
Value *False = vectorizeTree(E->getOperand(2));
if (E->VectorizedValue) {
LLVM_DEBUG(dbgs() << "SLP: Diamond merged for " << *VL0 << ".\n");
return E->VectorizedValue;
}
Value *V = Builder.CreateSelect(Cond, True, False);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::FNeg: {
setInsertPointAfterBundle(E);
Value *Op = vectorizeTree(E->getOperand(0));
if (E->VectorizedValue) {
LLVM_DEBUG(dbgs() << "SLP: Diamond merged for " << *VL0 << ".\n");
return E->VectorizedValue;
}
Value *V = Builder.CreateUnOp(
static_cast<Instruction::UnaryOps>(E->getOpcode()), Op);
propagateIRFlags(V, E->Scalars, VL0);
if (auto *I = dyn_cast<Instruction>(V))
V = propagateMetadata(I, E->Scalars);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
case Instruction::FSub:
case Instruction::Mul:
case Instruction::FMul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::FDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::FRem:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
setInsertPointAfterBundle(E);
Value *LHS = vectorizeTree(E->getOperand(0));
Value *RHS = vectorizeTree(E->getOperand(1));
if (E->VectorizedValue) {
LLVM_DEBUG(dbgs() << "SLP: Diamond merged for " << *VL0 << ".\n");
return E->VectorizedValue;
}
Value *V = Builder.CreateBinOp(
static_cast<Instruction::BinaryOps>(E->getOpcode()), LHS,
RHS);
propagateIRFlags(V, E->Scalars, VL0);
if (auto *I = dyn_cast<Instruction>(V))
V = propagateMetadata(I, E->Scalars);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::Load: {
// Loads are inserted at the head of the tree because we don't want to
// sink them all the way down past store instructions.
bool IsReorder = E->updateStateIfReorder();
if (IsReorder)
VL0 = E->getMainOp();
setInsertPointAfterBundle(E);
LoadInst *LI = cast<LoadInst>(VL0);
Instruction *NewLI;
unsigned AS = LI->getPointerAddressSpace();
Value *PO = LI->getPointerOperand();
if (E->State == TreeEntry::Vectorize) {
Value *VecPtr = Builder.CreateBitCast(PO, VecTy->getPointerTo(AS));
// The pointer operand uses an in-tree scalar so we add the new BitCast
// to ExternalUses list to make sure that an extract will be generated
// in the future.
if (getTreeEntry(PO))
ExternalUses.emplace_back(PO, cast<User>(VecPtr), 0);
NewLI = Builder.CreateAlignedLoad(VecTy, VecPtr, LI->getAlign());
} else {
assert(E->State == TreeEntry::ScatterVectorize && "Unhandled state");
Value *VecPtr = vectorizeTree(E->getOperand(0));
// Use the minimum alignment of the gathered loads.
Align CommonAlignment = LI->getAlign();
for (Value *V : E->Scalars)
CommonAlignment =
commonAlignment(CommonAlignment, cast<LoadInst>(V)->getAlign());
NewLI = Builder.CreateMaskedGather(VecPtr, CommonAlignment);
}
Value *V = propagateMetadata(NewLI, E->Scalars);
ShuffleBuilder.addInversedMask(E->ReorderIndices);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::Store: {
bool IsReorder = !E->ReorderIndices.empty();
auto *SI = cast<StoreInst>(
IsReorder ? E->Scalars[E->ReorderIndices.front()] : VL0);
unsigned AS = SI->getPointerAddressSpace();
setInsertPointAfterBundle(E);
Value *VecValue = vectorizeTree(E->getOperand(0));
ShuffleBuilder.addMask(E->ReorderIndices);
VecValue = ShuffleBuilder.finalize(VecValue);
Value *ScalarPtr = SI->getPointerOperand();
Value *VecPtr = Builder.CreateBitCast(
ScalarPtr, VecValue->getType()->getPointerTo(AS));
StoreInst *ST = Builder.CreateAlignedStore(VecValue, VecPtr,
SI->getAlign());
// The pointer operand uses an in-tree scalar, so add the new BitCast to
// ExternalUses to make sure that an extract will be generated in the
// future.
if (getTreeEntry(ScalarPtr))
ExternalUses.push_back(ExternalUser(ScalarPtr, cast<User>(VecPtr), 0));
Value *V = propagateMetadata(ST, E->Scalars);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::GetElementPtr: {
setInsertPointAfterBundle(E);
Value *Op0 = vectorizeTree(E->getOperand(0));
std::vector<Value *> OpVecs;
for (int j = 1, e = cast<GetElementPtrInst>(VL0)->getNumOperands(); j < e;
++j) {
ValueList &VL = E->getOperand(j);
// Need to cast all elements to the same type before vectorization to
// avoid crash.
Type *VL0Ty = VL0->getOperand(j)->getType();
Type *Ty = llvm::all_of(
VL, [VL0Ty](Value *V) { return VL0Ty == V->getType(); })
? VL0Ty
: DL->getIndexType(cast<GetElementPtrInst>(VL0)
->getPointerOperandType()
->getScalarType());
for (Value *&V : VL) {
auto *CI = cast<ConstantInt>(V);
V = ConstantExpr::getIntegerCast(CI, Ty,
CI->getValue().isSignBitSet());
}
Value *OpVec = vectorizeTree(VL);
OpVecs.push_back(OpVec);
}
Value *V = Builder.CreateGEP(
cast<GetElementPtrInst>(VL0)->getSourceElementType(), Op0, OpVecs);
if (Instruction *I = dyn_cast<Instruction>(V))
V = propagateMetadata(I, E->Scalars);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::Call: {
CallInst *CI = cast<CallInst>(VL0);
setInsertPointAfterBundle(E);
Intrinsic::ID IID = Intrinsic::not_intrinsic;
if (Function *FI = CI->getCalledFunction())
IID = FI->getIntrinsicID();
Intrinsic::ID ID = getVectorIntrinsicIDForCall(CI, TLI);
auto VecCallCosts = getVectorCallCosts(CI, VecTy, TTI, TLI);
bool UseIntrinsic = ID != Intrinsic::not_intrinsic &&
VecCallCosts.first <= VecCallCosts.second;
Value *ScalarArg = nullptr;
std::vector<Value *> OpVecs;
for (int j = 0, e = CI->getNumArgOperands(); j < e; ++j) {
ValueList OpVL;
// Some intrinsics have scalar arguments. This argument should not be
// vectorized.
if (UseIntrinsic && hasVectorInstrinsicScalarOpd(IID, j)) {
CallInst *CEI = cast<CallInst>(VL0);
ScalarArg = CEI->getArgOperand(j);
OpVecs.push_back(CEI->getArgOperand(j));
continue;
}
Value *OpVec = vectorizeTree(E->getOperand(j));
LLVM_DEBUG(dbgs() << "SLP: OpVec[" << j << "]: " << *OpVec << "\n");
OpVecs.push_back(OpVec);
}
Function *CF;
if (!UseIntrinsic) {
VFShape Shape =
VFShape::get(*CI, ElementCount::getFixed(static_cast<unsigned>(
VecTy->getNumElements())),
false /*HasGlobalPred*/);
CF = VFDatabase(*CI).getVectorizedFunction(Shape);
} else {
Type *Tys[] = {FixedVectorType::get(CI->getType(), E->Scalars.size())};
CF = Intrinsic::getDeclaration(F->getParent(), ID, Tys);
}
SmallVector<OperandBundleDef, 1> OpBundles;
CI->getOperandBundlesAsDefs(OpBundles);
Value *V = Builder.CreateCall(CF, OpVecs, OpBundles);
// The scalar argument uses an in-tree scalar so we add the new vectorized
// call to ExternalUses list to make sure that an extract will be
// generated in the future.
if (ScalarArg && getTreeEntry(ScalarArg))
ExternalUses.push_back(ExternalUser(ScalarArg, cast<User>(V), 0));
propagateIRFlags(V, E->Scalars, VL0);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
case Instruction::ShuffleVector: {
assert(E->isAltShuffle() &&
((Instruction::isBinaryOp(E->getOpcode()) &&
Instruction::isBinaryOp(E->getAltOpcode())) ||
(Instruction::isCast(E->getOpcode()) &&
Instruction::isCast(E->getAltOpcode()))) &&
"Invalid Shuffle Vector Operand");
Value *LHS = nullptr, *RHS = nullptr;
if (Instruction::isBinaryOp(E->getOpcode())) {
setInsertPointAfterBundle(E);
LHS = vectorizeTree(E->getOperand(0));
RHS = vectorizeTree(E->getOperand(1));
} else {
setInsertPointAfterBundle(E);
LHS = vectorizeTree(E->getOperand(0));
}
if (E->VectorizedValue) {
LLVM_DEBUG(dbgs() << "SLP: Diamond merged for " << *VL0 << ".\n");
return E->VectorizedValue;
}
Value *V0, *V1;
if (Instruction::isBinaryOp(E->getOpcode())) {
V0 = Builder.CreateBinOp(
static_cast<Instruction::BinaryOps>(E->getOpcode()), LHS, RHS);
V1 = Builder.CreateBinOp(
static_cast<Instruction::BinaryOps>(E->getAltOpcode()), LHS, RHS);
} else {
V0 = Builder.CreateCast(
static_cast<Instruction::CastOps>(E->getOpcode()), LHS, VecTy);
V1 = Builder.CreateCast(
static_cast<Instruction::CastOps>(E->getAltOpcode()), LHS, VecTy);
}
// Create shuffle to take alternate operations from the vector.
// Also, gather up main and alt scalar ops to propagate IR flags to
// each vector operation.
ValueList OpScalars, AltScalars;
unsigned e = E->Scalars.size();
SmallVector<int, 8> Mask(e);
for (unsigned i = 0; i < e; ++i) {
auto *OpInst = cast<Instruction>(E->Scalars[i]);
assert(E->isOpcodeOrAlt(OpInst) && "Unexpected main/alternate opcode");
if (OpInst->getOpcode() == E->getAltOpcode()) {
Mask[i] = e + i;
AltScalars.push_back(E->Scalars[i]);
} else {
Mask[i] = i;
OpScalars.push_back(E->Scalars[i]);
}
}
propagateIRFlags(V0, OpScalars);
propagateIRFlags(V1, AltScalars);
Value *V = Builder.CreateShuffleVector(V0, V1, Mask);
if (Instruction *I = dyn_cast<Instruction>(V))
V = propagateMetadata(I, E->Scalars);
ShuffleBuilder.addMask(E->ReuseShuffleIndices);
V = ShuffleBuilder.finalize(V);
E->VectorizedValue = V;
++NumVectorInstructions;
return V;
}
default:
llvm_unreachable("unknown inst");
}
return nullptr;
}
Value *BoUpSLP::vectorizeTree() {
ExtraValueToDebugLocsMap ExternallyUsedValues;
return vectorizeTree(ExternallyUsedValues);
}
Value *
BoUpSLP::vectorizeTree(ExtraValueToDebugLocsMap &ExternallyUsedValues) {
// All blocks must be scheduled before any instructions are inserted.
for (auto &BSIter : BlocksSchedules) {
scheduleBlock(BSIter.second.get());
}
Builder.SetInsertPoint(&F->getEntryBlock().front());
auto *VectorRoot = vectorizeTree(VectorizableTree[0].get());
// If the vectorized tree can be rewritten in a smaller type, we truncate the
// vectorized root. InstCombine will then rewrite the entire expression. We
// sign extend the extracted values below.
auto *ScalarRoot = VectorizableTree[0]->Scalars[0];
if (MinBWs.count(ScalarRoot)) {
if (auto *I = dyn_cast<Instruction>(VectorRoot))
Builder.SetInsertPoint(&*++BasicBlock::iterator(I));
auto BundleWidth = VectorizableTree[0]->Scalars.size();
auto *MinTy = IntegerType::get(F->getContext(), MinBWs[ScalarRoot].first);
auto *VecTy = FixedVectorType::get(MinTy, BundleWidth);
auto *Trunc = Builder.CreateTrunc(VectorRoot, VecTy);
VectorizableTree[0]->VectorizedValue = Trunc;
}
LLVM_DEBUG(dbgs() << "SLP: Extracting " << ExternalUses.size()
<< " values .\n");
// If necessary, sign-extend or zero-extend ScalarRoot to the larger type
// specified by ScalarType.
auto extend = [&](Value *ScalarRoot, Value *Ex, Type *ScalarType) {
if (!MinBWs.count(ScalarRoot))
return Ex;
if (MinBWs[ScalarRoot].second)
return Builder.CreateSExt(Ex, ScalarType);
return Builder.CreateZExt(Ex, ScalarType);
};
// Extract all of the elements with the external uses.
for (const auto &ExternalUse : ExternalUses) {
Value *Scalar = ExternalUse.Scalar;
llvm::User *User = ExternalUse.User;
// Skip users that we already RAUW. This happens when one instruction
// has multiple uses of the same value.
if (User && !is_contained(Scalar->users(), User))
continue;
TreeEntry *E = getTreeEntry(Scalar);
assert(E && "Invalid scalar");
assert(E->State != TreeEntry::NeedToGather &&
"Extracting from a gather list");
Value *Vec = E->VectorizedValue;
assert(Vec && "Can't find vectorizable value");
Value *Lane = Builder.getInt32(ExternalUse.Lane);
// If User == nullptr, the Scalar is used as extra arg. Generate
// ExtractElement instruction and update the record for this scalar in
// ExternallyUsedValues.
if (!User) {
assert(ExternallyUsedValues.count(Scalar) &&
"Scalar with nullptr as an external user must be registered in "
"ExternallyUsedValues map");
if (auto *VecI = dyn_cast<Instruction>(Vec)) {
Builder.SetInsertPoint(VecI->getParent(),
std::next(VecI->getIterator()));
} else {
Builder.SetInsertPoint(&F->getEntryBlock().front());
}
Value *Ex = Builder.CreateExtractElement(Vec, Lane);
Ex = extend(ScalarRoot, Ex, Scalar->getType());
CSEBlocks.insert(cast<Instruction>(Scalar)->getParent());
auto &Locs = ExternallyUsedValues[Scalar];
ExternallyUsedValues.insert({Ex, Locs});
ExternallyUsedValues.erase(Scalar);
// Required to update internally referenced instructions.
Scalar->replaceAllUsesWith(Ex);
continue;
}
// Generate extracts for out-of-tree users.
// Find the insertion point for the extractelement lane.
if (auto *VecI = dyn_cast<Instruction>(Vec)) {
if (PHINode *PH = dyn_cast<PHINode>(User)) {
for (int i = 0, e = PH->getNumIncomingValues(); i != e; ++i) {
if (PH->getIncomingValue(i) == Scalar) {
Instruction *IncomingTerminator =
PH->getIncomingBlock(i)->getTerminator();
if (isa<CatchSwitchInst>(IncomingTerminator)) {
Builder.SetInsertPoint(VecI->getParent(),
std::next(VecI->getIterator()));
} else {
Builder.SetInsertPoint(PH->getIncomingBlock(i)->getTerminator());
}
Value *Ex = Builder.CreateExtractElement(Vec, Lane);
Ex = extend(ScalarRoot, Ex, Scalar->getType());
CSEBlocks.insert(PH->getIncomingBlock(i));
PH->setOperand(i, Ex);
}
}
} else {
Builder.SetInsertPoint(cast<Instruction>(User));
Value *Ex = Builder.CreateExtractElement(Vec, Lane);
Ex = extend(ScalarRoot, Ex, Scalar->getType());
CSEBlocks.insert(cast<Instruction>(User)->getParent());
User->replaceUsesOfWith(Scalar, Ex);
}
} else {
Builder.SetInsertPoint(&F->getEntryBlock().front());
Value *Ex = Builder.CreateExtractElement(Vec, Lane);
Ex = extend(ScalarRoot, Ex, Scalar->getType());
CSEBlocks.insert(&F->getEntryBlock());
User->replaceUsesOfWith(Scalar, Ex);
}
LLVM_DEBUG(dbgs() << "SLP: Replaced:" << *User << ".\n");
}
// For each vectorized value:
for (auto &TEPtr : VectorizableTree) {
TreeEntry *Entry = TEPtr.get();
// No need to handle users of gathered values.
if (Entry->State == TreeEntry::NeedToGather)
continue;
assert(Entry->VectorizedValue && "Can't find vectorizable value");
// For each lane:
for (int Lane = 0, LE = Entry->Scalars.size(); Lane != LE; ++Lane) {
Value *Scalar = Entry->Scalars[Lane];
#ifndef NDEBUG
Type *Ty = Scalar->getType();
if (!Ty->isVoidTy()) {
for (User *U : Scalar->users()) {
LLVM_DEBUG(dbgs() << "SLP: \tvalidating user:" << *U << ".\n");
// It is legal to delete users in the ignorelist.
assert((getTreeEntry(U) || is_contained(UserIgnoreList, U)) &&
"Deleting out-of-tree value");
}
}
#endif
LLVM_DEBUG(dbgs() << "SLP: \tErasing scalar:" << *Scalar << ".\n");
eraseInstruction(cast<Instruction>(Scalar));
}
}
Builder.ClearInsertionPoint();
InstrElementSize.clear();
return VectorizableTree[0]->VectorizedValue;
}
void BoUpSLP::optimizeGatherSequence() {
LLVM_DEBUG(dbgs() << "SLP: Optimizing " << GatherSeq.size()
<< " gather sequences instructions.\n");
// LICM InsertElementInst sequences.
for (Instruction *I : GatherSeq) {
if (isDeleted(I))
continue;
// Check if this block is inside a loop.
Loop *L = LI->getLoopFor(I->getParent());
if (!L)
continue;
// Check if it has a preheader.
BasicBlock *PreHeader = L->getLoopPreheader();
if (!PreHeader)
continue;
// If the vector or the element that we insert into it are
// instructions that are defined in this basic block then we can't
// hoist this instruction.
auto *Op0 = dyn_cast<Instruction>(I->getOperand(0));
auto *Op1 = dyn_cast<Instruction>(I->getOperand(1));
if (Op0 && L->contains(Op0))
continue;
if (Op1 && L->contains(Op1))
continue;
// We can hoist this instruction. Move it to the pre-header.
I->moveBefore(PreHeader->getTerminator());
}
// Make a list of all reachable blocks in our CSE queue.
SmallVector<const DomTreeNode *, 8> CSEWorkList;
CSEWorkList.reserve(CSEBlocks.size());
for (BasicBlock *BB : CSEBlocks)
if (DomTreeNode *N = DT->getNode(BB)) {
assert(DT->isReachableFromEntry(N));
CSEWorkList.push_back(N);
}
// Sort blocks by domination. This ensures we visit a block after all blocks
// dominating it are visited.
llvm::stable_sort(CSEWorkList,
[this](const DomTreeNode *A, const DomTreeNode *B) {
return DT->properlyDominates(A, B);
});
// Perform O(N^2) search over the gather sequences and merge identical
// instructions. TODO: We can further optimize this scan if we split the
// instructions into different buckets based on the insert lane.
SmallVector<Instruction *, 16> Visited;
for (auto I = CSEWorkList.begin(), E = CSEWorkList.end(); I != E; ++I) {
assert(*I &&
(I == CSEWorkList.begin() || !DT->dominates(*I, *std::prev(I))) &&
"Worklist not sorted properly!");
BasicBlock *BB = (*I)->getBlock();
// For all instructions in blocks containing gather sequences:
for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e;) {
Instruction *In = &*it++;
if (isDeleted(In))
continue;
if (!isa<InsertElementInst>(In) && !isa<ExtractElementInst>(In))
continue;
// Check if we can replace this instruction with any of the
// visited instructions.
for (Instruction *v : Visited) {
if (In->isIdenticalTo(v) &&
DT->dominates(v->getParent(), In->getParent())) {
In->replaceAllUsesWith(v);
eraseInstruction(In);
In = nullptr;
break;
}
}
if (In) {
assert(!is_contained(Visited, In));
Visited.push_back(In);
}
}
}
CSEBlocks.clear();
GatherSeq.clear();
}
// Groups the instructions to a bundle (which is then a single scheduling entity)
// and schedules instructions until the bundle gets ready.
Optional<BoUpSLP::ScheduleData *>
BoUpSLP::BlockScheduling::tryScheduleBundle(ArrayRef<Value *> VL, BoUpSLP *SLP,
const InstructionsState &S) {
if (isa<PHINode>(S.OpValue))
return nullptr;
// Initialize the instruction bundle.
Instruction *OldScheduleEnd = ScheduleEnd;
ScheduleData *PrevInBundle = nullptr;
ScheduleData *Bundle = nullptr;
bool ReSchedule = false;
LLVM_DEBUG(dbgs() << "SLP: bundle: " << *S.OpValue << "\n");
// Make sure that the scheduling region contains all
// instructions of the bundle.
for (Value *V : VL) {
if (!extendSchedulingRegion(V, S))
return None;
}
for (Value *V : VL) {
ScheduleData *BundleMember = getScheduleData(V);
assert(BundleMember &&
"no ScheduleData for bundle member (maybe not in same basic block)");
if (BundleMember->IsScheduled) {
// A bundle member was scheduled as single instruction before and now
// needs to be scheduled as part of the bundle. We just get rid of the
// existing schedule.
LLVM_DEBUG(dbgs() << "SLP: reset schedule because " << *BundleMember
<< " was already scheduled\n");
ReSchedule = true;
}
assert(BundleMember->isSchedulingEntity() &&
"bundle member already part of other bundle");
if (PrevInBundle) {
PrevInBundle->NextInBundle = BundleMember;
} else {
Bundle = BundleMember;
}
BundleMember->UnscheduledDepsInBundle = 0;
Bundle->UnscheduledDepsInBundle += BundleMember->UnscheduledDeps;
// Group the instructions to a bundle.
BundleMember->FirstInBundle = Bundle;
PrevInBundle = BundleMember;
}
if (ScheduleEnd != OldScheduleEnd) {
// The scheduling region got new instructions at the lower end (or it is a
// new region for the first bundle). This makes it necessary to
// recalculate all dependencies.
// It is seldom that this needs to be done a second time after adding the
// initial bundle to the region.
for (auto *I = ScheduleStart; I != ScheduleEnd; I = I->getNextNode()) {
doForAllOpcodes(I, [](ScheduleData *SD) {
SD->clearDependencies();
});
}
ReSchedule = true;
}
if (ReSchedule) {
resetSchedule();
initialFillReadyList(ReadyInsts);
}
assert(Bundle && "Failed to find schedule bundle");
LLVM_DEBUG(dbgs() << "SLP: try schedule bundle " << *Bundle << " in block "
<< BB->getName() << "\n");
calculateDependencies(Bundle, true, SLP);
// Now try to schedule the new bundle. As soon as the bundle is "ready" it
// means that there are no cyclic dependencies and we can schedule it.
// Note that's important that we don't "schedule" the bundle yet (see
// cancelScheduling).
while (!Bundle->isReady() && !ReadyInsts.empty()) {
ScheduleData *pickedSD = ReadyInsts.pop_back_val();
if (pickedSD->isSchedulingEntity() && pickedSD->isReady()) {
schedule(pickedSD, ReadyInsts);
}
}
if (!Bundle->isReady()) {
cancelScheduling(VL, S.OpValue);
return None;
}
return Bundle;
}
void BoUpSLP::BlockScheduling::cancelScheduling(ArrayRef<Value *> VL,
Value *OpValue) {
if (isa<PHINode>(OpValue))
return;
ScheduleData *Bundle = getScheduleData(OpValue);
LLVM_DEBUG(dbgs() << "SLP: cancel scheduling of " << *Bundle << "\n");
assert(!Bundle->IsScheduled &&
"Can't cancel bundle which is already scheduled");
assert(Bundle->isSchedulingEntity() && Bundle->isPartOfBundle() &&
"tried to unbundle something which is not a bundle");
// Un-bundle: make single instructions out of the bundle.
ScheduleData *BundleMember = Bundle;
while (BundleMember) {
assert(BundleMember->FirstInBundle == Bundle && "corrupt bundle links");
BundleMember->FirstInBundle = BundleMember;
ScheduleData *Next = BundleMember->NextInBundle;
BundleMember->NextInBundle = nullptr;
BundleMember->UnscheduledDepsInBundle = BundleMember->UnscheduledDeps;
if (BundleMember->UnscheduledDepsInBundle == 0) {
ReadyInsts.insert(BundleMember);
}
BundleMember = Next;
}
}
BoUpSLP::ScheduleData *BoUpSLP::BlockScheduling::allocateScheduleDataChunks() {
// Allocate a new ScheduleData for the instruction.
if (ChunkPos >= ChunkSize) {
ScheduleDataChunks.push_back(std::make_unique<ScheduleData[]>(ChunkSize));
ChunkPos = 0;
}
return &(ScheduleDataChunks.back()[ChunkPos++]);
}
bool BoUpSLP::BlockScheduling::extendSchedulingRegion(Value *V,
const InstructionsState &S) {
if (getScheduleData(V, isOneOf(S, V)))
return true;
Instruction *I = dyn_cast<Instruction>(V);
assert(I && "bundle member must be an instruction");
assert(!isa<PHINode>(I) && "phi nodes don't need to be scheduled");
auto &&CheckSheduleForI = [this, &S](Instruction *I) -> bool {
ScheduleData *ISD = getScheduleData(I);
if (!ISD)
return false;
assert(isInSchedulingRegion(ISD) &&
"ScheduleData not in scheduling region");
ScheduleData *SD = allocateScheduleDataChunks();
SD->Inst = I;
SD->init(SchedulingRegionID, S.OpValue);
ExtraScheduleDataMap[I][S.OpValue] = SD;
return true;
};
if (CheckSheduleForI(I))
return true;
if (!ScheduleStart) {
// It's the first instruction in the new region.
initScheduleData(I, I->getNextNode(), nullptr, nullptr);
ScheduleStart = I;
ScheduleEnd = I->getNextNode();
if (isOneOf(S, I) != I)
CheckSheduleForI(I);
assert(ScheduleEnd && "tried to vectorize a terminator?");
LLVM_DEBUG(dbgs() << "SLP: initialize schedule region to " << *I << "\n");
return true;
}
// Search up and down at the same time, because we don't know if the new
// instruction is above or below the existing scheduling region.
BasicBlock::reverse_iterator UpIter =
++ScheduleStart->getIterator().getReverse();
BasicBlock::reverse_iterator UpperEnd = BB->rend();
BasicBlock::iterator DownIter = ScheduleEnd->getIterator();
BasicBlock::iterator LowerEnd = BB->end();
while (true) {
if (++ScheduleRegionSize > ScheduleRegionSizeLimit) {
LLVM_DEBUG(dbgs() << "SLP: exceeded schedule region size limit\n");
return false;
}
if (UpIter != UpperEnd) {
if (&*UpIter == I) {
initScheduleData(I, ScheduleStart, nullptr, FirstLoadStoreInRegion);
ScheduleStart = I;
if (isOneOf(S, I) != I)
CheckSheduleForI(I);
LLVM_DEBUG(dbgs() << "SLP: extend schedule region start to " << *I
<< "\n");
return true;
}
++UpIter;
}
if (DownIter != LowerEnd) {
if (&*DownIter == I) {
initScheduleData(ScheduleEnd, I->getNextNode(), LastLoadStoreInRegion,
nullptr);
ScheduleEnd = I->getNextNode();
if (isOneOf(S, I) != I)
CheckSheduleForI(I);
assert(ScheduleEnd && "tried to vectorize a terminator?");
LLVM_DEBUG(dbgs() << "SLP: extend schedule region end to " << *I
<< "\n");
return true;
}
++DownIter;
}
assert((UpIter != UpperEnd || DownIter != LowerEnd) &&
"instruction not found in block");
}
return true;
}
void BoUpSLP::BlockScheduling::initScheduleData(Instruction *FromI,
Instruction *ToI,
ScheduleData *PrevLoadStore,
ScheduleData *NextLoadStore) {
ScheduleData *CurrentLoadStore = PrevLoadStore;
for (Instruction *I = FromI; I != ToI; I = I->getNextNode()) {
ScheduleData *SD = ScheduleDataMap[I];
if (!SD) {
SD = allocateScheduleDataChunks();
ScheduleDataMap[I] = SD;
SD->Inst = I;
}
assert(!isInSchedulingRegion(SD) &&
"new ScheduleData already in scheduling region");
SD->init(SchedulingRegionID, I);
if (I->mayReadOrWriteMemory() &&
(!isa<IntrinsicInst>(I) ||
(cast<IntrinsicInst>(I)->getIntrinsicID() != Intrinsic::sideeffect &&
cast<IntrinsicInst>(I)->getIntrinsicID() !=
Intrinsic::pseudoprobe))) {
// Update the linked list of memory accessing instructions.
if (CurrentLoadStore) {
CurrentLoadStore->NextLoadStore = SD;
} else {
FirstLoadStoreInRegion = SD;
}
CurrentLoadStore = SD;
}
}
if (NextLoadStore) {
if (CurrentLoadStore)
CurrentLoadStore->NextLoadStore = NextLoadStore;
} else {
LastLoadStoreInRegion = CurrentLoadStore;
}
}
void BoUpSLP::BlockScheduling::calculateDependencies(ScheduleData *SD,
bool InsertInReadyList,
BoUpSLP *SLP) {
assert(SD->isSchedulingEntity());
SmallVector<ScheduleData *, 10> WorkList;
WorkList.push_back(SD);
while (!WorkList.empty()) {
ScheduleData *SD = WorkList.pop_back_val();
ScheduleData *BundleMember = SD;
while (BundleMember) {
assert(isInSchedulingRegion(BundleMember));
if (!BundleMember->hasValidDependencies()) {
LLVM_DEBUG(dbgs() << "SLP: update deps of " << *BundleMember
<< "\n");
BundleMember->Dependencies = 0;
BundleMember->resetUnscheduledDeps();
// Handle def-use chain dependencies.
if (BundleMember->OpValue != BundleMember->Inst) {
ScheduleData *UseSD = getScheduleData(BundleMember->Inst);
if (UseSD && isInSchedulingRegion(UseSD->FirstInBundle)) {
BundleMember->Dependencies++;
ScheduleData *DestBundle = UseSD->FirstInBundle;
if (!DestBundle->IsScheduled)
BundleMember->incrementUnscheduledDeps(1);
if (!DestBundle->hasValidDependencies())
WorkList.push_back(DestBundle);
}
} else {
for (User *U : BundleMember->Inst->users()) {
if (isa<Instruction>(U)) {
ScheduleData *UseSD = getScheduleData(U);
if (UseSD && isInSchedulingRegion(UseSD->FirstInBundle)) {
BundleMember->Dependencies++;
ScheduleData *DestBundle = UseSD->FirstInBundle;
if (!DestBundle->IsScheduled)
BundleMember->incrementUnscheduledDeps(1);
if (!DestBundle->hasValidDependencies())
WorkList.push_back(DestBundle);
}
} else {
// I'm not sure if this can ever happen. But we need to be safe.
// This lets the instruction/bundle never be scheduled and
// eventually disable vectorization.
BundleMember->Dependencies++;
BundleMember->incrementUnscheduledDeps(1);
}
}
}
// Handle the memory dependencies.
ScheduleData *DepDest = BundleMember->NextLoadStore;
if (DepDest) {
Instruction *SrcInst = BundleMember->Inst;
MemoryLocation SrcLoc = getLocation(SrcInst, SLP->AA);
bool SrcMayWrite = BundleMember->Inst->mayWriteToMemory();
unsigned numAliased = 0;
unsigned DistToSrc = 1;
while (DepDest) {
assert(isInSchedulingRegion(DepDest));
// We have two limits to reduce the complexity:
// 1) AliasedCheckLimit: It's a small limit to reduce calls to
// SLP->isAliased (which is the expensive part in this loop).
// 2) MaxMemDepDistance: It's for very large blocks and it aborts
// the whole loop (even if the loop is fast, it's quadratic).
// It's important for the loop break condition (see below) to
// check this limit even between two read-only instructions.
if (DistToSrc >= MaxMemDepDistance ||
((SrcMayWrite || DepDest->Inst->mayWriteToMemory()) &&
(numAliased >= AliasedCheckLimit ||
SLP->isAliased(SrcLoc, SrcInst, DepDest->Inst)))) {
// We increment the counter only if the locations are aliased
// (instead of counting all alias checks). This gives a better
// balance between reduced runtime and accurate dependencies.
numAliased++;
DepDest->MemoryDependencies.push_back(BundleMember);
BundleMember->Dependencies++;
ScheduleData *DestBundle = DepDest->FirstInBundle;
if (!DestBundle->IsScheduled) {
BundleMember->incrementUnscheduledDeps(1);
}
if (!DestBundle->hasValidDependencies()) {
WorkList.push_back(DestBundle);
}
}
DepDest = DepDest->NextLoadStore;
// Example, explaining the loop break condition: Let's assume our
// starting instruction is i0 and MaxMemDepDistance = 3.
//
// +--------v--v--v
// i0,i1,i2,i3,i4,i5,i6,i7,i8
// +--------^--^--^
//
// MaxMemDepDistance let us stop alias-checking at i3 and we add
// dependencies from i0 to i3,i4,.. (even if they are not aliased).
// Previously we already added dependencies from i3 to i6,i7,i8
// (because of MaxMemDepDistance). As we added a dependency from
// i0 to i3, we have transitive dependencies from i0 to i6,i7,i8
// and we can abort this loop at i6.
if (DistToSrc >= 2 * MaxMemDepDistance)
break;
DistToSrc++;
}
}
}
BundleMember = BundleMember->NextInBundle;
}
if (InsertInReadyList && SD->isReady()) {
ReadyInsts.push_back(SD);
LLVM_DEBUG(dbgs() << "SLP: gets ready on update: " << *SD->Inst
<< "\n");
}
}
}
void BoUpSLP::BlockScheduling::resetSchedule() {
assert(ScheduleStart &&
"tried to reset schedule on block which has not been scheduled");
for (Instruction *I = ScheduleStart; I != ScheduleEnd; I = I->getNextNode()) {
doForAllOpcodes(I, [&](ScheduleData *SD) {
assert(isInSchedulingRegion(SD) &&
"ScheduleData not in scheduling region");
SD->IsScheduled = false;
SD->resetUnscheduledDeps();
});
}
ReadyInsts.clear();
}
void BoUpSLP::scheduleBlock(BlockScheduling *BS) {
if (!BS->ScheduleStart)
return;
LLVM_DEBUG(dbgs() << "SLP: schedule block " << BS->BB->getName() << "\n");
BS->resetSchedule();
// For the real scheduling we use a more sophisticated ready-list: it is
// sorted by the original instruction location. This lets the final schedule
// be as close as possible to the original instruction order.
struct ScheduleDataCompare {
bool operator()(ScheduleData *SD1, ScheduleData *SD2) const {
return SD2->SchedulingPriority < SD1->SchedulingPriority;
}
};
std::set<ScheduleData *, ScheduleDataCompare> ReadyInsts;
// Ensure that all dependency data is updated and fill the ready-list with
// initial instructions.
int Idx = 0;
int NumToSchedule = 0;
for (auto *I = BS->ScheduleStart; I != BS->ScheduleEnd;
I = I->getNextNode()) {
BS->doForAllOpcodes(I, [this, &Idx, &NumToSchedule, BS](ScheduleData *SD) {
assert(SD->isPartOfBundle() ==
(getTreeEntry(SD->Inst) != nullptr) &&
"scheduler and vectorizer bundle mismatch");
SD->FirstInBundle->SchedulingPriority = Idx++;
if (SD->isSchedulingEntity()) {
BS->calculateDependencies(SD, false, this);
NumToSchedule++;
}
});
}
BS->initialFillReadyList(ReadyInsts);
Instruction *LastScheduledInst = BS->ScheduleEnd;
// Do the "real" scheduling.
while (!ReadyInsts.empty()) {
ScheduleData *picked = *ReadyInsts.begin();
ReadyInsts.erase(ReadyInsts.begin());
// Move the scheduled instruction(s) to their dedicated places, if not
// there yet.
ScheduleData *BundleMember = picked;
while (BundleMember) {
Instruction *pickedInst = BundleMember->Inst;
if (LastScheduledInst->getNextNode() != pickedInst) {
BS->BB->getInstList().remove(pickedInst);
BS->BB->getInstList().insert(LastScheduledInst->getIterator(),
pickedInst);
}
LastScheduledInst = pickedInst;
BundleMember = BundleMember->NextInBundle;
}
BS->schedule(picked, ReadyInsts);
NumToSchedule--;
}
assert(NumToSchedule == 0 && "could not schedule all instructions");
// Avoid duplicate scheduling of the block.
BS->ScheduleStart = nullptr;
}
unsigned BoUpSLP::getVectorElementSize(Value *V) {
// If V is a store, just return the width of the stored value (or value
// truncated just before storing) without traversing the expression tree.
// This is the common case.
if (auto *Store = dyn_cast<StoreInst>(V)) {
if (auto *Trunc = dyn_cast<TruncInst>(Store->getValueOperand()))
return DL->getTypeSizeInBits(Trunc->getSrcTy());
else
return DL->getTypeSizeInBits(Store->getValueOperand()->getType());
}
auto E = InstrElementSize.find(V);
if (E != InstrElementSize.end())
return E->second;
// If V is not a store, we can traverse the expression tree to find loads
// that feed it. The type of the loaded value may indicate a more suitable
// width than V's type. We want to base the vector element size on the width
// of memory operations where possible.
SmallVector<Instruction *, 16> Worklist;
SmallPtrSet<Instruction *, 16> Visited;
if (auto *I = dyn_cast<Instruction>(V)) {
Worklist.push_back(I);
Visited.insert(I);
}
// Traverse the expression tree in bottom-up order looking for loads. If we
// encounter an instruction we don't yet handle, we give up.
auto MaxWidth = 0u;
auto FoundUnknownInst = false;
while (!Worklist.empty() && !FoundUnknownInst) {
auto *I = Worklist.pop_back_val();
// We should only be looking at scalar instructions here. If the current
// instruction has a vector type, give up.
auto *Ty = I->getType();
if (isa<VectorType>(Ty))
FoundUnknownInst = true;
// If the current instruction is a load, update MaxWidth to reflect the
// width of the loaded value.
else if (isa<LoadInst>(I))
MaxWidth = std::max<unsigned>(MaxWidth, DL->getTypeSizeInBits(Ty));
// Otherwise, we need to visit the operands of the instruction. We only
// handle the interesting cases from buildTree here. If an operand is an
// instruction we haven't yet visited, we add it to the worklist.
else if (isa<PHINode>(I) || isa<CastInst>(I) || isa<GetElementPtrInst>(I) ||
isa<CmpInst>(I) || isa<SelectInst>(I) || isa<BinaryOperator>(I)) {
for (Use &U : I->operands())
if (auto *J = dyn_cast<Instruction>(U.get()))
if (Visited.insert(J).second)
Worklist.push_back(J);
}
// If we don't yet handle the instruction, give up.
else
FoundUnknownInst = true;
}
int Width = MaxWidth;
// If we didn't encounter a memory access in the expression tree, or if we
// gave up for some reason, just return the width of V. Otherwise, return the
// maximum width we found.
if (!MaxWidth || FoundUnknownInst)
Width = DL->getTypeSizeInBits(V->getType());
for (Instruction *I : Visited)
InstrElementSize[I] = Width;
return Width;
}
// Determine if a value V in a vectorizable expression Expr can be demoted to a
// smaller type with a truncation. We collect the values that will be demoted
// in ToDemote and additional roots that require investigating in Roots.
static bool collectValuesToDemote(Value *V, SmallPtrSetImpl<Value *> &Expr,
SmallVectorImpl<Value *> &ToDemote,
SmallVectorImpl<Value *> &Roots) {
// We can always demote constants.
if (isa<Constant>(V)) {
ToDemote.push_back(V);
return true;
}
// If the value is not an instruction in the expression with only one use, it
// cannot be demoted.
auto *I = dyn_cast<Instruction>(V);
if (!I || !I->hasOneUse() || !Expr.count(I))
return false;
switch (I->getOpcode()) {
// We can always demote truncations and extensions. Since truncations can
// seed additional demotion, we save the truncated value.
case Instruction::Trunc:
Roots.push_back(I->getOperand(0));
break;
case Instruction::ZExt:
case Instruction::SExt:
break;
// We can demote certain binary operations if we can demote both of their
// operands.
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
if (!collectValuesToDemote(I->getOperand(0), Expr, ToDemote, Roots) ||
!collectValuesToDemote(I->getOperand(1), Expr, ToDemote, Roots))
return false;
break;
// We can demote selects if we can demote their true and false values.
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
if (!collectValuesToDemote(SI->getTrueValue(), Expr, ToDemote, Roots) ||
!collectValuesToDemote(SI->getFalseValue(), Expr, ToDemote, Roots))
return false;
break;
}
// We can demote phis if we can demote all their incoming operands. Note that
// we don't need to worry about cycles since we ensure single use above.
case Instruction::PHI: {
PHINode *PN = cast<PHINode>(I);
for (Value *IncValue : PN->incoming_values())
if (!collectValuesToDemote(IncValue, Expr, ToDemote, Roots))
return false;
break;
}
// Otherwise, conservatively give up.
default:
return false;
}
// Record the value that we can demote.
ToDemote.push_back(V);
return true;
}
void BoUpSLP::computeMinimumValueSizes() {
// If there are no external uses, the expression tree must be rooted by a
// store. We can't demote in-memory values, so there is nothing to do here.
if (ExternalUses.empty())
return;
// We only attempt to truncate integer expressions.
auto &TreeRoot = VectorizableTree[0]->Scalars;
auto *TreeRootIT = dyn_cast<IntegerType>(TreeRoot[0]->getType());
if (!TreeRootIT)
return;
// If the expression is not rooted by a store, these roots should have
// external uses. We will rely on InstCombine to rewrite the expression in
// the narrower type. However, InstCombine only rewrites single-use values.
// This means that if a tree entry other than a root is used externally, it
// must have multiple uses and InstCombine will not rewrite it. The code
// below ensures that only the roots are used externally.
SmallPtrSet<Value *, 32> Expr(TreeRoot.begin(), TreeRoot.end());
for (auto &EU : ExternalUses)
if (!Expr.erase(EU.Scalar))
return;
if (!Expr.empty())
return;
// Collect the scalar values of the vectorizable expression. We will use this
// context to determine which values can be demoted. If we see a truncation,
// we mark it as seeding another demotion.
for (auto &EntryPtr : VectorizableTree)
Expr.insert(EntryPtr->Scalars.begin(), EntryPtr->Scalars.end());
// Ensure the roots of the vectorizable tree don't form a cycle. They must
// have a single external user that is not in the vectorizable tree.
for (auto *Root : TreeRoot)
if (!Root->hasOneUse() || Expr.count(*Root->user_begin()))
return;
// Conservatively determine if we can actually truncate the roots of the
// expression. Collect the values that can be demoted in ToDemote and
// additional roots that require investigating in Roots.
SmallVector<Value *, 32> ToDemote;
SmallVector<Value *, 4> Roots;
for (auto *Root : TreeRoot)
if (!collectValuesToDemote(Root, Expr, ToDemote, Roots))
return;
// The maximum bit width required to represent all the values that can be
// demoted without loss of precision. It would be safe to truncate the roots
// of the expression to this width.
auto MaxBitWidth = 8u;
// We first check if all the bits of the roots are demanded. If they're not,
// we can truncate the roots to this narrower type.
for (auto *Root : TreeRoot) {
auto Mask = DB->getDemandedBits(cast<Instruction>(Root));
MaxBitWidth = std::max<unsigned>(
Mask.getBitWidth() - Mask.countLeadingZeros(), MaxBitWidth);
}
// True if the roots can be zero-extended back to their original type, rather
// than sign-extended. We know that if the leading bits are not demanded, we
// can safely zero-extend. So we initialize IsKnownPositive to True.
bool IsKnownPositive = true;
// If all the bits of the roots are demanded, we can try a little harder to
// compute a narrower type. This can happen, for example, if the roots are
// getelementptr indices. InstCombine promotes these indices to the pointer
// width. Thus, all their bits are technically demanded even though the
// address computation might be vectorized in a smaller type.
//
// We start by looking at each entry that can be demoted. We compute the
// maximum bit width required to store the scalar by using ValueTracking to
// compute the number of high-order bits we can truncate.
if (MaxBitWidth == DL->getTypeSizeInBits(TreeRoot[0]->getType()) &&
llvm::all_of(TreeRoot, [](Value *R) {
assert(R->hasOneUse() && "Root should have only one use!");
return isa<GetElementPtrInst>(R->user_back());
})) {
MaxBitWidth = 8u;
// Determine if the sign bit of all the roots is known to be zero. If not,
// IsKnownPositive is set to False.
IsKnownPositive = llvm::all_of(TreeRoot, [&](Value *R) {
KnownBits Known = computeKnownBits(R, *DL);
return Known.isNonNegative();
});
// Determine the maximum number of bits required to store the scalar
// values.
for (auto *Scalar : ToDemote) {
auto NumSignBits = ComputeNumSignBits(Scalar, *DL, 0, AC, nullptr, DT);
auto NumTypeBits = DL->getTypeSizeInBits(Scalar->getType());
MaxBitWidth = std::max<unsigned>(NumTypeBits - NumSignBits, MaxBitWidth);
}
// If we can't prove that the sign bit is zero, we must add one to the
// maximum bit width to account for the unknown sign bit. This preserves
// the existing sign bit so we can safely sign-extend the root back to the
// original type. Otherwise, if we know the sign bit is zero, we will
// zero-extend the root instead.
//
// FIXME: This is somewhat suboptimal, as there will be cases where adding
// one to the maximum bit width will yield a larger-than-necessary
// type. In general, we need to add an extra bit only if we can't
// prove that the upper bit of the original type is equal to the
// upper bit of the proposed smaller type. If these two bits are the
// same (either zero or one) we know that sign-extending from the
// smaller type will result in the same value. Here, since we can't
// yet prove this, we are just making the proposed smaller type
// larger to ensure correctness.
if (!IsKnownPositive)
++MaxBitWidth;
}
// Round MaxBitWidth up to the next power-of-two.
if (!isPowerOf2_64(MaxBitWidth))
MaxBitWidth = NextPowerOf2(MaxBitWidth);
// If the maximum bit width we compute is less than the with of the roots'
// type, we can proceed with the narrowing. Otherwise, do nothing.
if (MaxBitWidth >= TreeRootIT->getBitWidth())
return;
// If we can truncate the root, we must collect additional values that might
// be demoted as a result. That is, those seeded by truncations we will
// modify.
while (!Roots.empty())
collectValuesToDemote(Roots.pop_back_val(), Expr, ToDemote, Roots);
// Finally, map the values we can demote to the maximum bit with we computed.
for (auto *Scalar : ToDemote)
MinBWs[Scalar] = std::make_pair(MaxBitWidth, !IsKnownPositive);
}
namespace {
/// The SLPVectorizer Pass.
struct SLPVectorizer : public FunctionPass {
SLPVectorizerPass Impl;
/// Pass identification, replacement for typeid
static char ID;
explicit SLPVectorizer() : FunctionPass(ID) {
initializeSLPVectorizerPass(*PassRegistry::getPassRegistry());
}
bool doInitialization(Module &M) override {
return false;
}
bool runOnFunction(Function &F) override {
if (skipFunction(F))
return false;
auto *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
auto *TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
auto *TLIP = getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
auto *TLI = TLIP ? &TLIP->getTLI(F) : nullptr;
auto *AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
auto *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
auto *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
auto *AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
auto *DB = &getAnalysis<DemandedBitsWrapperPass>().getDemandedBits();
auto *ORE = &getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE();
return Impl.runImpl(F, SE, TTI, TLI, AA, LI, DT, AC, DB, ORE);
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
FunctionPass::getAnalysisUsage(AU);
AU.addRequired<AssumptionCacheTracker>();
AU.addRequired<ScalarEvolutionWrapperPass>();
AU.addRequired<AAResultsWrapperPass>();
AU.addRequired<TargetTransformInfoWrapperPass>();
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<DemandedBitsWrapperPass>();
AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
AU.addRequired<InjectTLIMappingsLegacy>();
AU.addPreserved<LoopInfoWrapperPass>();
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addPreserved<AAResultsWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
AU.setPreservesCFG();
}
};
} // end anonymous namespace
PreservedAnalyses SLPVectorizerPass::run(Function &F, FunctionAnalysisManager &AM) {
auto *SE = &AM.getResult<ScalarEvolutionAnalysis>(F);
auto *TTI = &AM.getResult<TargetIRAnalysis>(F);
auto *TLI = AM.getCachedResult<TargetLibraryAnalysis>(F);
auto *AA = &AM.getResult<AAManager>(F);
auto *LI = &AM.getResult<LoopAnalysis>(F);
auto *DT = &AM.getResult<DominatorTreeAnalysis>(F);
auto *AC = &AM.getResult<AssumptionAnalysis>(F);
auto *DB = &AM.getResult<DemandedBitsAnalysis>(F);
auto *ORE = &AM.getResult<OptimizationRemarkEmitterAnalysis>(F);
bool Changed = runImpl(F, SE, TTI, TLI, AA, LI, DT, AC, DB, ORE);
if (!Changed)
return PreservedAnalyses::all();
PreservedAnalyses PA;
PA.preserveSet<CFGAnalyses>();
PA.preserve<AAManager>();
PA.preserve<GlobalsAA>();
return PA;
}
bool SLPVectorizerPass::runImpl(Function &F, ScalarEvolution *SE_,
TargetTransformInfo *TTI_,
TargetLibraryInfo *TLI_, AAResults *AA_,
LoopInfo *LI_, DominatorTree *DT_,
AssumptionCache *AC_, DemandedBits *DB_,
OptimizationRemarkEmitter *ORE_) {
if (!RunSLPVectorization)
return false;
SE = SE_;
TTI = TTI_;
TLI = TLI_;
AA = AA_;
LI = LI_;
DT = DT_;
AC = AC_;
DB = DB_;
DL = &F.getParent()->getDataLayout();
Stores.clear();
GEPs.clear();
bool Changed = false;
// If the target claims to have no vector registers don't attempt
// vectorization.
if (!TTI->getNumberOfRegisters(TTI->getRegisterClassForType(true)))
return false;
// Don't vectorize when the attribute NoImplicitFloat is used.
if (F.hasFnAttribute(Attribute::NoImplicitFloat))
return false;
LLVM_DEBUG(dbgs() << "SLP: Analyzing blocks in " << F.getName() << ".\n");
// Use the bottom up slp vectorizer to construct chains that start with
// store instructions.
BoUpSLP R(&F, SE, TTI, TLI, AA, LI, DT, AC, DB, DL, ORE_);
// A general note: the vectorizer must use BoUpSLP::eraseInstruction() to
// delete instructions.
// Scan the blocks in the function in post order.
for (auto BB : post_order(&F.getEntryBlock())) {
collectSeedInstructions(BB);
// Vectorize trees that end at stores.
if (!Stores.empty()) {
LLVM_DEBUG(dbgs() << "SLP: Found stores for " << Stores.size()
<< " underlying objects.\n");
Changed |= vectorizeStoreChains(R);
}
// Vectorize trees that end at reductions.
Changed |= vectorizeChainsInBlock(BB, R);
// Vectorize the index computations of getelementptr instructions. This
// is primarily intended to catch gather-like idioms ending at
// non-consecutive loads.
if (!GEPs.empty()) {
LLVM_DEBUG(dbgs() << "SLP: Found GEPs for " << GEPs.size()
<< " underlying objects.\n");
Changed |= vectorizeGEPIndices(BB, R);
}
}
if (Changed) {
R.optimizeGatherSequence();
LLVM_DEBUG(dbgs() << "SLP: vectorized \"" << F.getName() << "\"\n");
}
return Changed;
}
bool SLPVectorizerPass::vectorizeStoreChain(ArrayRef<Value *> Chain, BoUpSLP &R,
unsigned Idx) {
LLVM_DEBUG(dbgs() << "SLP: Analyzing a store chain of length " << Chain.size()
<< "\n");
const unsigned Sz = R.getVectorElementSize(Chain[0]);
const unsigned MinVF = R.getMinVecRegSize() / Sz;
unsigned VF = Chain.size();
if (!isPowerOf2_32(Sz) || !isPowerOf2_32(VF) || VF < 2 || VF < MinVF)
return false;
LLVM_DEBUG(dbgs() << "SLP: Analyzing " << VF << " stores at offset " << Idx
<< "\n");
R.buildTree(Chain);
Optional<ArrayRef<unsigned>> Order = R.bestOrder();
// TODO: Handle orders of size less than number of elements in the vector.
if (Order && Order->size() == Chain.size()) {
// TODO: reorder tree nodes without tree rebuilding.
SmallVector<Value *, 4> ReorderedOps(Chain.rbegin(), Chain.rend());
llvm::transform(*Order, ReorderedOps.begin(),
[Chain](const unsigned Idx) { return Chain[Idx]; });
R.buildTree(ReorderedOps);
}
if (R.isTreeTinyAndNotFullyVectorizable())
return false;
if (R.isLoadCombineCandidate())
return false;
R.computeMinimumValueSizes();
InstructionCost Cost = R.getTreeCost();
LLVM_DEBUG(dbgs() << "SLP: Found cost = " << Cost << " for VF =" << VF << "\n");
if (Cost < -SLPCostThreshold) {
LLVM_DEBUG(dbgs() << "SLP: Decided to vectorize cost = " << Cost << "\n");
using namespace ore;
R.getORE()->emit(OptimizationRemark(SV_NAME, "StoresVectorized",
cast<StoreInst>(Chain[0]))
<< "Stores SLP vectorized with cost " << NV("Cost", Cost)
<< " and with tree size "
<< NV("TreeSize", R.getTreeSize()));
R.vectorizeTree();
return true;
}
return false;
}
bool SLPVectorizerPass::vectorizeStores(ArrayRef<StoreInst *> Stores,
BoUpSLP &R) {
// We may run into multiple chains that merge into a single chain. We mark the
// stores that we vectorized so that we don't visit the same store twice.
BoUpSLP::ValueSet VectorizedStores;
bool Changed = false;
int E = Stores.size();
SmallBitVector Tails(E, false);
SmallVector<int, 16> ConsecutiveChain(E, E + 1);
int MaxIter = MaxStoreLookup.getValue();
int IterCnt;
auto &&FindConsecutiveAccess = [this, &Stores, &Tails, &IterCnt, MaxIter,
&ConsecutiveChain](int K, int Idx) {
if (IterCnt >= MaxIter)
return true;
++IterCnt;
if (!isConsecutiveAccess(Stores[K], Stores[Idx], *DL, *SE))
return false;
Tails.set(Idx);
ConsecutiveChain[K] = Idx;
return true;
};
// Do a quadratic search on all of the given stores in reverse order and find
// all of the pairs of stores that follow each other.
for (int Idx = E - 1; Idx >= 0; --Idx) {
// If a store has multiple consecutive store candidates, search according
// to the sequence: Idx-1, Idx+1, Idx-2, Idx+2, ...
// This is because usually pairing with immediate succeeding or preceding
// candidate create the best chance to find slp vectorization opportunity.
const int MaxLookDepth = std::max(E - Idx, Idx + 1);
IterCnt = 0;
for (int Offset = 1, F = MaxLookDepth; Offset < F; ++Offset)
if ((Idx >= Offset && FindConsecutiveAccess(Idx - Offset, Idx)) ||
(Idx + Offset < E && FindConsecutiveAccess(Idx + Offset, Idx)))
break;
}
// For stores that start but don't end a link in the chain:
for (int Cnt = E; Cnt > 0; --Cnt) {
int I = Cnt - 1;
if (ConsecutiveChain[I] == E + 1 || Tails.test(I))
continue;
// We found a store instr that starts a chain. Now follow the chain and try
// to vectorize it.
BoUpSLP::ValueList Operands;
// Collect the chain into a list.
while (I != E + 1 && !VectorizedStores.count(Stores[I])) {
Operands.push_back(Stores[I]);
// Move to the next value in the chain.
I = ConsecutiveChain[I];
}
// If a vector register can't hold 1 element, we are done.
unsigned MaxVecRegSize = R.getMaxVecRegSize();
unsigned EltSize = R.getVectorElementSize(Operands[0]);
if (MaxVecRegSize % EltSize != 0)
continue;
unsigned MaxElts = MaxVecRegSize / EltSize;
// FIXME: Is division-by-2 the correct step? Should we assert that the
// register size is a power-of-2?
unsigned StartIdx = 0;
for (unsigned Size = llvm::PowerOf2Ceil(MaxElts); Size >= 2; Size /= 2) {
for (unsigned Cnt = StartIdx, E = Operands.size(); Cnt + Size <= E;) {
ArrayRef<Value *> Slice = makeArrayRef(Operands).slice(Cnt, Size);
if (!VectorizedStores.count(Slice.front()) &&
!VectorizedStores.count(Slice.back()) &&
vectorizeStoreChain(Slice, R, Cnt)) {
// Mark the vectorized stores so that we don't vectorize them again.
VectorizedStores.insert(Slice.begin(), Slice.end());
Changed = true;
// If we vectorized initial block, no need to try to vectorize it
// again.
if (Cnt == StartIdx)
StartIdx += Size;
Cnt += Size;
continue;
}
++Cnt;
}
// Check if the whole array was vectorized already - exit.
if (StartIdx >= Operands.size())
break;
}
}
return Changed;
}
void SLPVectorizerPass::collectSeedInstructions(BasicBlock *BB) {
// Initialize the collections. We will make a single pass over the block.
Stores.clear();
GEPs.clear();
// Visit the store and getelementptr instructions in BB and organize them in
// Stores and GEPs according to the underlying objects of their pointer
// operands.
for (Instruction &I : *BB) {
// Ignore store instructions that are volatile or have a pointer operand
// that doesn't point to a scalar type.
if (auto *SI = dyn_cast<StoreInst>(&I)) {
if (!SI->isSimple())
continue;
if (!isValidElementType(SI->getValueOperand()->getType()))
continue;
Stores[getUnderlyingObject(SI->getPointerOperand())].push_back(SI);
}
// Ignore getelementptr instructions that have more than one index, a
// constant index, or a pointer operand that doesn't point to a scalar
// type.
else if (auto *GEP = dyn_cast<GetElementPtrInst>(&I)) {
auto Idx = GEP->idx_begin()->get();
if (GEP->getNumIndices() > 1 || isa<Constant>(Idx))
continue;
if (!isValidElementType(Idx->getType()))
continue;
if (GEP->getType()->isVectorTy())
continue;
GEPs[GEP->getPointerOperand()].push_back(GEP);
}
}
}
bool SLPVectorizerPass::tryToVectorizePair(Value *A, Value *B, BoUpSLP &R) {
if (!A || !B)
return false;
Value *VL[] = {A, B};
return tryToVectorizeList(VL, R, /*AllowReorder=*/true);
}
bool SLPVectorizerPass::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
bool AllowReorder,
ArrayRef<Value *> InsertUses) {
if (VL.size() < 2)
return false;
LLVM_DEBUG(dbgs() << "SLP: Trying to vectorize a list of length = "
<< VL.size() << ".\n");
// Check that all of the parts are instructions of the same type,
// we permit an alternate opcode via InstructionsState.
InstructionsState S = getSameOpcode(VL);
if (!S.getOpcode())
return false;
Instruction *I0 = cast<Instruction>(S.OpValue);
// Make sure invalid types (including vector type) are rejected before
// determining vectorization factor for scalar instructions.
for (Value *V : VL) {
Type *Ty = V->getType();
if (!isValidElementType(Ty)) {
// NOTE: the following will give user internal llvm type name, which may
// not be useful.
R.getORE()->emit([&]() {
std::string type_str;
llvm::raw_string_ostream rso(type_str);
Ty->print(rso);
return OptimizationRemarkMissed(SV_NAME, "UnsupportedType", I0)
<< "Cannot SLP vectorize list: type "
<< rso.str() + " is unsupported by vectorizer";
});
return false;
}
}
unsigned Sz = R.getVectorElementSize(I0);
unsigned MinVF = std::max(2U, R.getMinVecRegSize() / Sz);
unsigned MaxVF = std::max<unsigned>(PowerOf2Floor(VL.size()), MinVF);
MaxVF = std::min(R.getMaximumVF(Sz, S.getOpcode()), MaxVF);
if (MaxVF < 2) {
R.getORE()->emit([&]() {
return OptimizationRemarkMissed(SV_NAME, "SmallVF", I0)
<< "Cannot SLP vectorize list: vectorization factor "
<< "less than 2 is not supported";
});
return false;
}
bool Changed = false;
bool CandidateFound = false;
InstructionCost MinCost = SLPCostThreshold.getValue();
bool CompensateUseCost =
!InsertUses.empty() && llvm::all_of(InsertUses, [](const Value *V) {
return V && isa<InsertElementInst>(V);
});
assert((!CompensateUseCost || InsertUses.size() == VL.size()) &&
"Each scalar expected to have an associated InsertElement user.");
unsigned NextInst = 0, MaxInst = VL.size();
for (unsigned VF = MaxVF; NextInst + 1 < MaxInst && VF >= MinVF; VF /= 2) {
// No actual vectorization should happen, if number of parts is the same as
// provided vectorization factor (i.e. the scalar type is used for vector
// code during codegen).
auto *VecTy = FixedVectorType::get(VL[0]->getType(), VF);
if (TTI->getNumberOfParts(VecTy) == VF)
continue;
for (unsigned I = NextInst; I < MaxInst; ++I) {
unsigned OpsWidth = 0;
if (I + VF > MaxInst)
OpsWidth = MaxInst - I;
else
OpsWidth = VF;
if (!isPowerOf2_32(OpsWidth) || OpsWidth < 2)
break;
ArrayRef<Value *> Ops = VL.slice(I, OpsWidth);
// Check that a previous iteration of this loop did not delete the Value.
if (llvm::any_of(Ops, [&R](Value *V) {
auto *I = dyn_cast<Instruction>(V);
return I && R.isDeleted(I);
}))
continue;
LLVM_DEBUG(dbgs() << "SLP: Analyzing " << OpsWidth << " operations "
<< "\n");
R.buildTree(Ops);
Optional<ArrayRef<unsigned>> Order = R.bestOrder();
// TODO: check if we can allow reordering for more cases.
if (AllowReorder && Order) {
// TODO: reorder tree nodes without tree rebuilding.
// Conceptually, there is nothing actually preventing us from trying to
// reorder a larger list. In fact, we do exactly this when vectorizing
// reductions. However, at this point, we only expect to get here when
// there are exactly two operations.
assert(Ops.size() == 2);
Value *ReorderedOps[] = {Ops[1], Ops[0]};
R.buildTree(ReorderedOps, None);
}
if (R.isTreeTinyAndNotFullyVectorizable())
continue;
R.computeMinimumValueSizes();
InstructionCost Cost = R.getTreeCost();
CandidateFound = true;
if (CompensateUseCost) {
// TODO: Use TTI's getScalarizationOverhead for sequence of inserts
// rather than sum of single inserts as the latter may overestimate
// cost. This work should imply improving cost estimation for extracts
// that added in for external (for vectorization tree) users,i.e. that
// part should also switch to same interface.
// For example, the following case is projected code after SLP:
// %4 = extractelement <4 x i64> %3, i32 0
// %v0 = insertelement <4 x i64> poison, i64 %4, i32 0
// %5 = extractelement <4 x i64> %3, i32 1
// %v1 = insertelement <4 x i64> %v0, i64 %5, i32 1
// %6 = extractelement <4 x i64> %3, i32 2
// %v2 = insertelement <4 x i64> %v1, i64 %6, i32 2
// %7 = extractelement <4 x i64> %3, i32 3
// %v3 = insertelement <4 x i64> %v2, i64 %7, i32 3
//
// Extracts here added by SLP in order to feed users (the inserts) of
// original scalars and contribute to "ExtractCost" at cost evaluation.
// The inserts in turn form sequence to build an aggregate that
// detected by findBuildAggregate routine.
// SLP makes an assumption that such sequence will be optimized away
// later (instcombine) so it tries to compensate ExctractCost with
// cost of insert sequence.
// Current per element cost calculation approach is not quite accurate
// and tends to create bias toward favoring vectorization.
// Switching to the TTI interface might help a bit.
// Alternative solution could be pattern-match to detect a no-op or
// shuffle.
InstructionCost UserCost = 0;
for (unsigned Lane = 0; Lane < OpsWidth; Lane++) {
auto *IE = cast<InsertElementInst>(InsertUses[I + Lane]);
if (auto *CI = dyn_cast<ConstantInt>(IE->getOperand(2)))
UserCost += TTI->getVectorInstrCost(
Instruction::InsertElement, IE->getType(), CI->getZExtValue());
}
LLVM_DEBUG(dbgs() << "SLP: Compensate cost of users by: " << UserCost
<< ".\n");
Cost -= UserCost;
}
MinCost = std::min(MinCost, Cost);
if (Cost < -SLPCostThreshold) {
LLVM_DEBUG(dbgs() << "SLP: Vectorizing list at cost:" << Cost << ".\n");
R.getORE()->emit(OptimizationRemark(SV_NAME, "VectorizedList",
cast<Instruction>(Ops[0]))
<< "SLP vectorized with cost " << ore::NV("Cost", Cost)
<< " and with tree size "
<< ore::NV("TreeSize", R.getTreeSize()));
R.vectorizeTree();
// Move to the next bundle.
I += VF - 1;
NextInst = I + 1;
Changed = true;
}
}
}
if (!Changed && CandidateFound) {
R.getORE()->emit([&]() {
return OptimizationRemarkMissed(SV_NAME, "NotBeneficial", I0)
<< "List vectorization was possible but not beneficial with cost "
<< ore::NV("Cost", MinCost) << " >= "
<< ore::NV("Treshold", -SLPCostThreshold);
});
} else if (!Changed) {
R.getORE()->emit([&]() {
return OptimizationRemarkMissed(SV_NAME, "NotPossible", I0)
<< "Cannot SLP vectorize list: vectorization was impossible"
<< " with available vectorization factors";
});
}
return Changed;
}
bool SLPVectorizerPass::tryToVectorize(Instruction *I, BoUpSLP &R) {
if (!I)
return false;
if (!isa<BinaryOperator>(I) && !isa<CmpInst>(I))
return false;
Value *P = I->getParent();
// Vectorize in current basic block only.
auto *Op0 = dyn_cast<Instruction>(I->getOperand(0));
auto *Op1 = dyn_cast<Instruction>(I->getOperand(1));
if (!Op0 || !Op1 || Op0->getParent() != P || Op1->getParent() != P)
return false;
// Try to vectorize V.
if (tryToVectorizePair(Op0, Op1, R))
return true;
auto *A = dyn_cast<BinaryOperator>(Op0);
auto *B = dyn_cast<BinaryOperator>(Op1);
// Try to skip B.
if (B && B->hasOneUse()) {
auto *B0 = dyn_cast<BinaryOperator>(B->getOperand(0));
auto *B1 = dyn_cast<BinaryOperator>(B->getOperand(1));
if (B0 && B0->getParent() == P && tryToVectorizePair(A, B0, R))
return true;
if (B1 && B1->getParent() == P && tryToVectorizePair(A, B1, R))
return true;
}
// Try to skip A.
if (A && A->hasOneUse()) {
auto *A0 = dyn_cast<BinaryOperator>(A->getOperand(0));
auto *A1 = dyn_cast<BinaryOperator>(A->getOperand(1));
if (A0 && A0->getParent() == P && tryToVectorizePair(A0, B, R))
return true;
if (A1 && A1->getParent() == P && tryToVectorizePair(A1, B, R))
return true;
}
return false;
}
namespace {
/// Model horizontal reductions.
///
/// A horizontal reduction is a tree of reduction instructions that has values
/// that can be put into a vector as its leaves. For example:
///
/// mul mul mul mul
/// \ / \ /
/// + +
/// \ /
/// +
/// This tree has "mul" as its leaf values and "+" as its reduction
/// instructions. A reduction can feed into a store or a binary operation
/// feeding a phi.
/// ...
/// \ /
/// +
/// |
/// phi +=
///
/// Or:
/// ...
/// \ /
/// +
/// |
/// *p =
///
class HorizontalReduction {
using ReductionOpsType = SmallVector<Value *, 16>;
using ReductionOpsListType = SmallVector<ReductionOpsType, 2>;
ReductionOpsListType ReductionOps;
SmallVector<Value *, 32> ReducedVals;
// Use map vector to make stable output.
MapVector<Instruction *, Value *> ExtraArgs;
WeakTrackingVH ReductionRoot;
/// The type of reduction operation.
RecurKind RdxKind;
/// Checks if instruction is associative and can be vectorized.
static bool isVectorizable(RecurKind Kind, Instruction *I) {
if (Kind == RecurKind::None)
return false;
if (RecurrenceDescriptor::isIntMinMaxRecurrenceKind(Kind))
return true;
if (Kind == RecurKind::FMax || Kind == RecurKind::FMin) {
// FP min/max are associative except for NaN and -0.0. We do not
// have to rule out -0.0 here because the intrinsic semantics do not
// specify a fixed result for it.
return I->getFastMathFlags().noNaNs();
}
return I->isAssociative();
}
/// Checks if the ParentStackElem.first should be marked as a reduction
/// operation with an extra argument or as extra argument itself.
void markExtraArg(std::pair<Instruction *, unsigned> &ParentStackElem,
Value *ExtraArg) {
if (ExtraArgs.count(ParentStackElem.first)) {
ExtraArgs[ParentStackElem.first] = nullptr;
// We ran into something like:
// ParentStackElem.first = ExtraArgs[ParentStackElem.first] + ExtraArg.
// The whole ParentStackElem.first should be considered as an extra value
// in this case.
// Do not perform analysis of remaining operands of ParentStackElem.first
// instruction, this whole instruction is an extra argument.
RecurKind ParentRdxKind = getRdxKind(ParentStackElem.first);
ParentStackElem.second = getNumberOfOperands(ParentRdxKind);
} else {
// We ran into something like:
// ParentStackElem.first += ... + ExtraArg + ...
ExtraArgs[ParentStackElem.first] = ExtraArg;
}
}
/// Creates reduction operation with the current opcode.
static Value *createOp(IRBuilder<> &Builder, RecurKind Kind, Value *LHS,
Value *RHS, const Twine &Name) {
unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(Kind);
switch (Kind) {
case RecurKind::Add:
case RecurKind::Mul:
case RecurKind::Or:
case RecurKind::And:
case RecurKind::Xor:
case RecurKind::FAdd:
case RecurKind::FMul:
return Builder.CreateBinOp((Instruction::BinaryOps)RdxOpcode, LHS, RHS,
Name);
case RecurKind::FMax:
return Builder.CreateBinaryIntrinsic(Intrinsic::maxnum, LHS, RHS);
case RecurKind::FMin:
return Builder.CreateBinaryIntrinsic(Intrinsic::minnum, LHS, RHS);
case RecurKind::SMax: {
Value *Cmp = Builder.CreateICmpSGT(LHS, RHS, Name);
return Builder.CreateSelect(Cmp, LHS, RHS, Name);
}
case RecurKind::SMin: {
Value *Cmp = Builder.CreateICmpSLT(LHS, RHS, Name);
return Builder.CreateSelect(Cmp, LHS, RHS, Name);
}
case RecurKind::UMax: {
Value *Cmp = Builder.CreateICmpUGT(LHS, RHS, Name);
return Builder.CreateSelect(Cmp, LHS, RHS, Name);
}
case RecurKind::UMin: {
Value *Cmp = Builder.CreateICmpULT(LHS, RHS, Name);
return Builder.CreateSelect(Cmp, LHS, RHS, Name);
}
default:
llvm_unreachable("Unknown reduction operation.");
}
}
/// Creates reduction operation with the current opcode with the IR flags
/// from \p ReductionOps.
static Value *createOp(IRBuilder<> &Builder, RecurKind RdxKind, Value *LHS,
Value *RHS, const Twine &Name,
const ReductionOpsListType &ReductionOps) {
Value *Op = createOp(Builder, RdxKind, LHS, RHS, Name);
if (RecurrenceDescriptor::isIntMinMaxRecurrenceKind(RdxKind)) {
if (auto *Sel = dyn_cast<SelectInst>(Op))
propagateIRFlags(Sel->getCondition(), ReductionOps[0]);
propagateIRFlags(Op, ReductionOps[1]);
return Op;
}
propagateIRFlags(Op, ReductionOps[0]);
return Op;
}
/// Creates reduction operation with the current opcode with the IR flags
/// from \p I.
static Value *createOp(IRBuilder<> &Builder, RecurKind RdxKind, Value *LHS,
Value *RHS, const Twine &Name, Instruction *I) {
Value *Op = createOp(Builder, RdxKind, LHS, RHS, Name);
if (RecurrenceDescriptor::isIntMinMaxRecurrenceKind(RdxKind)) {
if (auto *Sel = dyn_cast<SelectInst>(Op)) {
propagateIRFlags(Sel->getCondition(),
cast<SelectInst>(I)->getCondition());
}
}
propagateIRFlags(Op, I);
return Op;
}
static RecurKind getRdxKind(Instruction *I) {
assert(I && "Expected instruction for reduction matching");
TargetTransformInfo::ReductionFlags RdxFlags;
if (match(I, m_Add(m_Value(), m_Value())))
return RecurKind::Add;
if (match(I, m_Mul(m_Value(), m_Value())))
return RecurKind::Mul;
if (match(I, m_And(m_Value(), m_Value())))
return RecurKind::And;
if (match(I, m_Or(m_Value(), m_Value())))
return RecurKind::Or;
if (match(I, m_Xor(m_Value(), m_Value())))
return RecurKind::Xor;
if (match(I, m_FAdd(m_Value(), m_Value())))
return RecurKind::FAdd;
if (match(I, m_FMul(m_Value(), m_Value())))
return RecurKind::FMul;
if (match(I, m_Intrinsic<Intrinsic::maxnum>(m_Value(), m_Value())))
return RecurKind::FMax;
if (match(I, m_Intrinsic<Intrinsic::minnum>(m_Value(), m_Value())))
return RecurKind::FMin;
if (match(I, m_SMax(m_Value(), m_Value())))
return RecurKind::SMax;
if (match(I, m_SMin(m_Value(), m_Value())))
return RecurKind::SMin;
if (match(I, m_UMax(m_Value(), m_Value())))
return RecurKind::UMax;
if (match(I, m_UMin(m_Value(), m_Value())))
return RecurKind::UMin;
if (auto *Select = dyn_cast<SelectInst>(I)) {
// Try harder: look for min/max pattern based on instructions producing
// same values such as: select ((cmp Inst1, Inst2), Inst1, Inst2).
// During the intermediate stages of SLP, it's very common to have
// pattern like this (since optimizeGatherSequence is run only once
// at the end):
// %1 = extractelement <2 x i32> %a, i32 0
// %2 = extractelement <2 x i32> %a, i32 1
// %cond = icmp sgt i32 %1, %2
// %3 = extractelement <2 x i32> %a, i32 0
// %4 = extractelement <2 x i32> %a, i32 1
// %select = select i1 %cond, i32 %3, i32 %4
CmpInst::Predicate Pred;
Instruction *L1;
Instruction *L2;
Value *LHS = Select->getTrueValue();
Value *RHS = Select->getFalseValue();
Value *Cond = Select->getCondition();
// TODO: Support inverse predicates.
if (match(Cond, m_Cmp(Pred, m_Specific(LHS), m_Instruction(L2)))) {
if (!isa<ExtractElementInst>(RHS) ||
!L2->isIdenticalTo(cast<Instruction>(RHS)))
return RecurKind::None;
} else if (match(Cond, m_Cmp(Pred, m_Instruction(L1), m_Specific(RHS)))) {
if (!isa<ExtractElementInst>(LHS) ||
!L1->isIdenticalTo(cast<Instruction>(LHS)))
return RecurKind::None;
} else {
if (!isa<ExtractElementInst>(LHS) || !isa<ExtractElementInst>(RHS))
return RecurKind::None;
if (!match(Cond, m_Cmp(Pred, m_Instruction(L1), m_Instruction(L2))) ||
!L1->isIdenticalTo(cast<Instruction>(LHS)) ||
!L2->isIdenticalTo(cast<Instruction>(RHS)))
return RecurKind::None;
}
TargetTransformInfo::ReductionFlags RdxFlags;
switch (Pred) {
default:
return RecurKind::None;
case CmpInst::ICMP_SGT:
case CmpInst::ICMP_SGE:
return RecurKind::SMax;
case CmpInst::ICMP_SLT:
case CmpInst::ICMP_SLE:
return RecurKind::SMin;
case CmpInst::ICMP_UGT:
case CmpInst::ICMP_UGE:
return RecurKind::UMax;
case CmpInst::ICMP_ULT:
case CmpInst::ICMP_ULE:
return RecurKind::UMin;
}
}
return RecurKind::None;
}
/// Return true if this operation is a cmp+select idiom.
static bool isCmpSel(RecurKind Kind) {
return RecurrenceDescriptor::isIntMinMaxRecurrenceKind(Kind);
}
/// Get the index of the first operand.
static unsigned getFirstOperandIndex(RecurKind Kind) {
// We allow calling this before 'Kind' is set, so handle that specially.
if (Kind == RecurKind::None)
return 0;
return isCmpSel(Kind) ? 1 : 0;
}
/// Total number of operands in the reduction operation.
static unsigned getNumberOfOperands(RecurKind Kind) {
return isCmpSel(Kind) ? 3 : 2;
}
/// Checks if the instruction is in basic block \p BB.
/// For a min/max reduction check that both compare and select are in \p BB.
static bool hasSameParent(RecurKind Kind, Instruction *I, BasicBlock *BB,
bool IsRedOp) {
if (IsRedOp && isCmpSel(Kind)) {
auto *Cmp = cast<Instruction>(cast<SelectInst>(I)->getCondition());
return I->getParent() == BB && Cmp && Cmp->getParent() == BB;
}
return I->getParent() == BB;
}
/// Expected number of uses for reduction operations/reduced values.
static bool hasRequiredNumberOfUses(RecurKind Kind, Instruction *I,
bool IsReductionOp) {
// SelectInst must be used twice while the condition op must have single
// use only.
if (isCmpSel(Kind))
return I->hasNUses(2) &&
(!IsReductionOp ||
cast<SelectInst>(I)->getCondition()->hasOneUse());
// Arithmetic reduction operation must be used once only.
return I->hasOneUse();
}
/// Initializes the list of reduction operations.
void initReductionOps(RecurKind Kind) {
if (isCmpSel(Kind))
ReductionOps.assign(2, ReductionOpsType());
else
ReductionOps.assign(1, ReductionOpsType());
}
/// Add all reduction operations for the reduction instruction \p I.
void addReductionOps(RecurKind Kind, Instruction *I) {
assert(Kind != RecurKind::None && "Expected reduction operation.");
if (isCmpSel(Kind)) {
ReductionOps[0].emplace_back(cast<SelectInst>(I)->getCondition());
ReductionOps[1].emplace_back(I);
} else {
ReductionOps[0].emplace_back(I);
}
}
static Value *getLHS(RecurKind Kind, Instruction *I) {
if (Kind == RecurKind::None)
return nullptr;
return I->getOperand(getFirstOperandIndex(Kind));
}
static Value *getRHS(RecurKind Kind, Instruction *I) {
if (Kind == RecurKind::None)
return nullptr;
return I->getOperand(getFirstOperandIndex(Kind) + 1);
}
public:
HorizontalReduction() = default;
/// Try to find a reduction tree.
bool matchAssociativeReduction(PHINode *Phi, Instruction *B) {
assert((!Phi || is_contained(Phi->operands(), B)) &&
"Phi needs to use the binary operator");
RdxKind = getRdxKind(B);
// We could have a initial reductions that is not an add.
// r *= v1 + v2 + v3 + v4
// In such a case start looking for a tree rooted in the first '+'.
if (Phi) {
if (getLHS(RdxKind, B) == Phi) {
Phi = nullptr;
B = dyn_cast<Instruction>(getRHS(RdxKind, B));
if (!B)
return false;
RdxKind = getRdxKind(B);
} else if (getRHS(RdxKind, B) == Phi) {
Phi = nullptr;
B = dyn_cast<Instruction>(getLHS(RdxKind, B));
if (!B)
return false;
RdxKind = getRdxKind(B);
}
}
if (!isVectorizable(RdxKind, B))
return false;
// Analyze "regular" integer/FP types for reductions - no target-specific
// types or pointers.
Type *Ty = B->getType();
if (!isValidElementType(Ty) || Ty->isPointerTy())
return false;
ReductionRoot = B;
// The opcode for leaf values that we perform a reduction on.
// For example: load(x) + load(y) + load(z) + fptoui(w)
// The leaf opcode for 'w' does not match, so we don't include it as a
// potential candidate for the reduction.
unsigned LeafOpcode = 0;
// Post order traverse the reduction tree starting at B. We only handle true
// trees containing only binary operators.
SmallVector<std::pair<Instruction *, unsigned>, 32> Stack;
Stack.push_back(std::make_pair(B, getFirstOperandIndex(RdxKind)));
initReductionOps(RdxKind);
while (!Stack.empty()) {
Instruction *TreeN = Stack.back().first;
unsigned EdgeToVisit = Stack.back().second++;
const RecurKind TreeRdxKind = getRdxKind(TreeN);
bool IsReducedValue = TreeRdxKind != RdxKind;
// Postorder visit.
if (IsReducedValue || EdgeToVisit == getNumberOfOperands(TreeRdxKind)) {
if (IsReducedValue)
ReducedVals.push_back(TreeN);
else {
auto I = ExtraArgs.find(TreeN);
if (I != ExtraArgs.end() && !I->second) {
// Check if TreeN is an extra argument of its parent operation.
if (Stack.size() <= 1) {
// TreeN can't be an extra argument as it is a root reduction
// operation.
return false;
}
// Yes, TreeN is an extra argument, do not add it to a list of
// reduction operations.
// Stack[Stack.size() - 2] always points to the parent operation.
markExtraArg(Stack[Stack.size() - 2], TreeN);
ExtraArgs.erase(TreeN);
} else
addReductionOps(RdxKind, TreeN);
}
// Retract.
Stack.pop_back();
continue;
}
// Visit left or right.
Value *EdgeVal = TreeN->getOperand(EdgeToVisit);
auto *I = dyn_cast<Instruction>(EdgeVal);
if (!I) {
// Edge value is not a reduction instruction or a leaf instruction.
// (It may be a constant, function argument, or something else.)
markExtraArg(Stack.back(), EdgeVal);
continue;
}
RecurKind EdgeRdxKind = getRdxKind(I);
// Continue analysis if the next operand is a reduction operation or
// (possibly) a leaf value. If the leaf value opcode is not set,
// the first met operation != reduction operation is considered as the
// leaf opcode.
// Only handle trees in the current basic block.
// Each tree node needs to have minimal number of users except for the
// ultimate reduction.
const bool IsRdxInst = EdgeRdxKind == RdxKind;
if (I != Phi && I != B &&
hasSameParent(RdxKind, I, B->getParent(), IsRdxInst) &&
hasRequiredNumberOfUses(RdxKind, I, IsRdxInst) &&
(!LeafOpcode || LeafOpcode == I->getOpcode() || IsRdxInst)) {
if (IsRdxInst) {
// We need to be able to reassociate the reduction operations.
if (!isVectorizable(EdgeRdxKind, I)) {
// I is an extra argument for TreeN (its parent operation).
markExtraArg(Stack.back(), I);
continue;
}
} else if (!LeafOpcode) {
LeafOpcode = I->getOpcode();
}
Stack.push_back(std::make_pair(I, getFirstOperandIndex(EdgeRdxKind)));
continue;
}
// I is an extra argument for TreeN (its parent operation).
markExtraArg(Stack.back(), I);
}
return true;
}
/// Attempt to vectorize the tree found by matchAssociativeReduction.
bool tryToReduce(BoUpSLP &V, TargetTransformInfo *TTI) {
// If there are a sufficient number of reduction values, reduce
// to a nearby power-of-2. We can safely generate oversized
// vectors and rely on the backend to split them to legal sizes.
unsigned NumReducedVals = ReducedVals.size();
if (NumReducedVals < 4)
return false;
// Intersect the fast-math-flags from all reduction operations.
FastMathFlags RdxFMF;
RdxFMF.set();
for (ReductionOpsType &RdxOp : ReductionOps) {
for (Value *RdxVal : RdxOp) {
if (auto *FPMO = dyn_cast<FPMathOperator>(RdxVal))
RdxFMF &= FPMO->getFastMathFlags();
}
}
IRBuilder<> Builder(cast<Instruction>(ReductionRoot));
Builder.setFastMathFlags(RdxFMF);
BoUpSLP::ExtraValueToDebugLocsMap ExternallyUsedValues;
// The same extra argument may be used several times, so log each attempt
// to use it.
for (const std::pair<Instruction *, Value *> &Pair : ExtraArgs) {
assert(Pair.first && "DebugLoc must be set.");
ExternallyUsedValues[Pair.second].push_back(Pair.first);
}
// The compare instruction of a min/max is the insertion point for new
// instructions and may be replaced with a new compare instruction.
auto getCmpForMinMaxReduction = [](Instruction *RdxRootInst) {
assert(isa<SelectInst>(RdxRootInst) &&
"Expected min/max reduction to have select root instruction");
Value *ScalarCond = cast<SelectInst>(RdxRootInst)->getCondition();
assert(isa<Instruction>(ScalarCond) &&
"Expected min/max reduction to have compare condition");
return cast<Instruction>(ScalarCond);
};
// The reduction root is used as the insertion point for new instructions,
// so set it as externally used to prevent it from being deleted.
ExternallyUsedValues[ReductionRoot];
SmallVector<Value *, 16> IgnoreList;
for (ReductionOpsType &RdxOp : ReductionOps)
IgnoreList.append(RdxOp.begin(), RdxOp.end());
unsigned ReduxWidth = PowerOf2Floor(NumReducedVals);
if (NumReducedVals > ReduxWidth) {
// In the loop below, we are building a tree based on a window of
// 'ReduxWidth' values.
// If the operands of those values have common traits (compare predicate,
// constant operand, etc), then we want to group those together to
// minimize the cost of the reduction.
// TODO: This should be extended to count common operands for
// compares and binops.
// Step 1: Count the number of times each compare predicate occurs.
SmallDenseMap<unsigned, unsigned> PredCountMap;
for (Value *RdxVal : ReducedVals) {
CmpInst::Predicate Pred;
if (match(RdxVal, m_Cmp(Pred, m_Value(), m_Value())))
++PredCountMap[Pred];
}
// Step 2: Sort the values so the most common predicates come first.
stable_sort(ReducedVals, [&PredCountMap](Value *A, Value *B) {
CmpInst::Predicate PredA, PredB;
if (match(A, m_Cmp(PredA, m_Value(), m_Value())) &&
match(B, m_Cmp(PredB, m_Value(), m_Value()))) {
return PredCountMap[PredA] > PredCountMap[PredB];
}
return false;
});
}
Value *VectorizedTree = nullptr;
unsigned i = 0;
while (i < NumReducedVals - ReduxWidth + 1 && ReduxWidth > 2) {
ArrayRef<Value *> VL(&ReducedVals[i], ReduxWidth);
V.buildTree(VL, ExternallyUsedValues, IgnoreList);
Optional<ArrayRef<unsigned>> Order = V.bestOrder();
if (Order) {
assert(Order->size() == VL.size() &&
"Order size must be the same as number of vectorized "
"instructions.");
// TODO: reorder tree nodes without tree rebuilding.
SmallVector<Value *, 4> ReorderedOps(VL.size());
llvm::transform(*Order, ReorderedOps.begin(),
[VL](const unsigned Idx) { return VL[Idx]; });
V.buildTree(ReorderedOps, ExternallyUsedValues, IgnoreList);
}
if (V.isTreeTinyAndNotFullyVectorizable())
break;
if (V.isLoadCombineReductionCandidate(RdxKind))
break;
V.computeMinimumValueSizes();
// Estimate cost.
InstructionCost TreeCost = V.getTreeCost();
InstructionCost ReductionCost =
getReductionCost(TTI, ReducedVals[i], ReduxWidth);
InstructionCost Cost = TreeCost + ReductionCost;
if (!Cost.isValid()) {
LLVM_DEBUG(dbgs() << "Encountered invalid baseline cost.\n");
return false;
}
if (Cost >= -SLPCostThreshold) {
V.getORE()->emit([&]() {
return OptimizationRemarkMissed(SV_NAME, "HorSLPNotBeneficial",
cast<Instruction>(VL[0]))
<< "Vectorizing horizontal reduction is possible"
<< "but not beneficial with cost " << ore::NV("Cost", Cost)
<< " and threshold "
<< ore::NV("Threshold", -SLPCostThreshold);
});
break;
}
LLVM_DEBUG(dbgs() << "SLP: Vectorizing horizontal reduction at cost:"
<< Cost << ". (HorRdx)\n");
V.getORE()->emit([&]() {
return OptimizationRemark(SV_NAME, "VectorizedHorizontalReduction",
cast<Instruction>(VL[0]))
<< "Vectorized horizontal reduction with cost "
<< ore::NV("Cost", Cost) << " and with tree size "
<< ore::NV("TreeSize", V.getTreeSize());
});
// Vectorize a tree.
DebugLoc Loc = cast<Instruction>(ReducedVals[i])->getDebugLoc();
Value *VectorizedRoot = V.vectorizeTree(ExternallyUsedValues);
// Emit a reduction. If the root is a select (min/max idiom), the insert
// point is the compare condition of that select.
Instruction *RdxRootInst = cast<Instruction>(ReductionRoot);
if (isCmpSel(RdxKind))
Builder.SetInsertPoint(getCmpForMinMaxReduction(RdxRootInst));
else
Builder.SetInsertPoint(RdxRootInst);
Value *ReducedSubTree =
emitReduction(VectorizedRoot, Builder, ReduxWidth, TTI);
if (!VectorizedTree) {
// Initialize the final value in the reduction.
VectorizedTree = ReducedSubTree;
} else {
// Update the final value in the reduction.
Builder.SetCurrentDebugLocation(Loc);
VectorizedTree = createOp(Builder, RdxKind, VectorizedTree,
ReducedSubTree, "op.rdx", ReductionOps);
}
i += ReduxWidth;
ReduxWidth = PowerOf2Floor(NumReducedVals - i);
}
if (VectorizedTree) {
// Finish the reduction.
for (; i < NumReducedVals; ++i) {
auto *I = cast<Instruction>(ReducedVals[i]);
Builder.SetCurrentDebugLocation(I->getDebugLoc());
VectorizedTree =
createOp(Builder, RdxKind, VectorizedTree, I, "", ReductionOps);
}
for (auto &Pair : ExternallyUsedValues) {
// Add each externally used value to the final reduction.
for (auto *I : Pair.second) {
Builder.SetCurrentDebugLocation(I->getDebugLoc());
VectorizedTree = createOp(Builder, RdxKind, VectorizedTree,
Pair.first, "op.extra", I);
}
}
// Update users. For a min/max reduction that ends with a compare and
// select, we also have to RAUW for the compare instruction feeding the
// reduction root. That's because the original compare may have extra uses
// besides the final select of the reduction.
if (isCmpSel(RdxKind)) {
if (auto *VecSelect = dyn_cast<SelectInst>(VectorizedTree)) {
Instruction *ScalarCmp =
getCmpForMinMaxReduction(cast<Instruction>(ReductionRoot));
ScalarCmp->replaceAllUsesWith(VecSelect->getCondition());
}
}
ReductionRoot->replaceAllUsesWith(VectorizedTree);
// Mark all scalar reduction ops for deletion, they are replaced by the
// vector reductions.
V.eraseInstructions(IgnoreList);
}
return VectorizedTree != nullptr;
}
unsigned numReductionValues() const { return ReducedVals.size(); }
private:
/// Calculate the cost of a reduction.
InstructionCost getReductionCost(TargetTransformInfo *TTI,
Value *FirstReducedVal,
unsigned ReduxWidth) {
Type *ScalarTy = FirstReducedVal->getType();
FixedVectorType *VectorTy = FixedVectorType::get(ScalarTy, ReduxWidth);
InstructionCost VectorCost, ScalarCost;
switch (RdxKind) {
case RecurKind::Add:
case RecurKind::Mul:
case RecurKind::Or:
case RecurKind::And:
case RecurKind::Xor:
case RecurKind::FAdd:
case RecurKind::FMul: {
unsigned RdxOpcode = RecurrenceDescriptor::getOpcode(RdxKind);
VectorCost = TTI->getArithmeticReductionCost(RdxOpcode, VectorTy,
/*IsPairwiseForm=*/false);
ScalarCost = TTI->getArithmeticInstrCost(RdxOpcode, ScalarTy);
break;
}
case RecurKind::FMax:
case RecurKind::FMin: {
auto *VecCondTy = cast<VectorType>(CmpInst::makeCmpResultType(VectorTy));
VectorCost =
TTI->getMinMaxReductionCost(VectorTy, VecCondTy,
/*pairwise=*/false, /*unsigned=*/false);
ScalarCost =
TTI->getCmpSelInstrCost(Instruction::FCmp, ScalarTy) +
TTI->getCmpSelInstrCost(Instruction::Select, ScalarTy,
CmpInst::makeCmpResultType(ScalarTy));
break;
}
case RecurKind::SMax:
case RecurKind::SMin:
case RecurKind::UMax:
case RecurKind::UMin: {
auto *VecCondTy = cast<VectorType>(CmpInst::makeCmpResultType(VectorTy));
bool IsUnsigned =
RdxKind == RecurKind::UMax || RdxKind == RecurKind::UMin;
VectorCost =
TTI->getMinMaxReductionCost(VectorTy, VecCondTy,
/*IsPairwiseForm=*/false, IsUnsigned);
ScalarCost =
TTI->getCmpSelInstrCost(Instruction::ICmp, ScalarTy) +
TTI->getCmpSelInstrCost(Instruction::Select, ScalarTy,
CmpInst::makeCmpResultType(ScalarTy));
break;
}
default:
llvm_unreachable("Expected arithmetic or min/max reduction operation");
}
// Scalar cost is repeated for N-1 elements.
ScalarCost *= (ReduxWidth - 1);
LLVM_DEBUG(dbgs() << "SLP: Adding cost " << VectorCost - ScalarCost
<< " for reduction that starts with " << *FirstReducedVal
<< " (It is a splitting reduction)\n");
return VectorCost - ScalarCost;
}
/// Emit a horizontal reduction of the vectorized value.
Value *emitReduction(Value *VectorizedValue, IRBuilder<> &Builder,
unsigned ReduxWidth, const TargetTransformInfo *TTI) {
assert(VectorizedValue && "Need to have a vectorized tree node");
assert(isPowerOf2_32(ReduxWidth) &&
"We only handle power-of-two reductions for now");
return createSimpleTargetReduction(Builder, TTI, VectorizedValue, RdxKind,
ReductionOps.back());
}
};
} // end anonymous namespace
static Optional<unsigned> getAggregateSize(Instruction *InsertInst) {
if (auto *IE = dyn_cast<InsertElementInst>(InsertInst))
return cast<FixedVectorType>(IE->getType())->getNumElements();
unsigned AggregateSize = 1;
auto *IV = cast<InsertValueInst>(InsertInst);
Type *CurrentType = IV->getType();
do {
if (auto *ST = dyn_cast<StructType>(CurrentType)) {
for (auto *Elt : ST->elements())
if (Elt != ST->getElementType(0)) // check homogeneity
return None;
AggregateSize *= ST->getNumElements();
CurrentType = ST->getElementType(0);
} else if (auto *AT = dyn_cast<ArrayType>(CurrentType)) {
AggregateSize *= AT->getNumElements();
CurrentType = AT->getElementType();
} else if (auto *VT = dyn_cast<FixedVectorType>(CurrentType)) {
AggregateSize *= VT->getNumElements();
return AggregateSize;
} else if (CurrentType->isSingleValueType()) {
return AggregateSize;
} else {
return None;
}
} while (true);
}
static Optional<unsigned> getOperandIndex(Instruction *InsertInst,
unsigned OperandOffset) {
unsigned OperandIndex = OperandOffset;
if (auto *IE = dyn_cast<InsertElementInst>(InsertInst)) {
if (auto *CI = dyn_cast<ConstantInt>(IE->getOperand(2))) {
auto *VT = cast<FixedVectorType>(IE->getType());
OperandIndex *= VT->getNumElements();
OperandIndex += CI->getZExtValue();
return OperandIndex;
}
return None;
}
auto *IV = cast<InsertValueInst>(InsertInst);
Type *CurrentType = IV->getType();
for (unsigned int Index : IV->indices()) {
if (auto *ST = dyn_cast<StructType>(CurrentType)) {
OperandIndex *= ST->getNumElements();
CurrentType = ST->getElementType(Index);
} else if (auto *AT = dyn_cast<ArrayType>(CurrentType)) {
OperandIndex *= AT->getNumElements();
CurrentType = AT->getElementType();
} else {
return None;
}
OperandIndex += Index;
}
return OperandIndex;
}
static bool findBuildAggregate_rec(Instruction *LastInsertInst,
TargetTransformInfo *TTI,
SmallVectorImpl<Value *> &BuildVectorOpds,
SmallVectorImpl<Value *> &InsertElts,
unsigned OperandOffset) {
do {
Value *InsertedOperand = LastInsertInst->getOperand(1);
Optional<unsigned> OperandIndex =
getOperandIndex(LastInsertInst, OperandOffset);
if (!OperandIndex)
return false;
if (isa<InsertElementInst>(InsertedOperand) ||
isa<InsertValueInst>(InsertedOperand)) {
if (!findBuildAggregate_rec(cast<Instruction>(InsertedOperand), TTI,
BuildVectorOpds, InsertElts, *OperandIndex))
return false;
} else {
BuildVectorOpds[*OperandIndex] = InsertedOperand;
InsertElts[*OperandIndex] = LastInsertInst;
}
if (isa<UndefValue>(LastInsertInst->getOperand(0)))
return true;
LastInsertInst = dyn_cast<Instruction>(LastInsertInst->getOperand(0));
} while (LastInsertInst != nullptr &&
(isa<InsertValueInst>(LastInsertInst) ||
isa<InsertElementInst>(LastInsertInst)) &&
LastInsertInst->hasOneUse());
return false;
}
/// Recognize construction of vectors like
/// %ra = insertelement <4 x float> poison, float %s0, i32 0
/// %rb = insertelement <4 x float> %ra, float %s1, i32 1
/// %rc = insertelement <4 x float> %rb, float %s2, i32 2
/// %rd = insertelement <4 x float> %rc, float %s3, i32 3
/// starting from the last insertelement or insertvalue instruction.
///
/// Also recognize homogeneous aggregates like {<2 x float>, <2 x float>},
/// {{float, float}, {float, float}}, [2 x {float, float}] and so on.
/// See llvm/test/Transforms/SLPVectorizer/X86/pr42022.ll for examples.
///
/// Assume LastInsertInst is of InsertElementInst or InsertValueInst type.
///
/// \return true if it matches.
static bool findBuildAggregate(Instruction *LastInsertInst,
TargetTransformInfo *TTI,
SmallVectorImpl<Value *> &BuildVectorOpds,
SmallVectorImpl<Value *> &InsertElts) {
assert((isa<InsertElementInst>(LastInsertInst) ||
isa<InsertValueInst>(LastInsertInst)) &&
"Expected insertelement or insertvalue instruction!");
assert((BuildVectorOpds.empty() && InsertElts.empty()) &&
"Expected empty result vectors!");
Optional<unsigned> AggregateSize = getAggregateSize(LastInsertInst);
if (!AggregateSize)
return false;
BuildVectorOpds.resize(*AggregateSize);
InsertElts.resize(*AggregateSize);
if (findBuildAggregate_rec(LastInsertInst, TTI, BuildVectorOpds, InsertElts,
0)) {
llvm::erase_value(BuildVectorOpds, nullptr);
llvm::erase_value(InsertElts, nullptr);
if (BuildVectorOpds.size() >= 2)
return true;
}
return false;
}
static bool PhiTypeSorterFunc(Value *V, Value *V2) {
return V->getType() < V2->getType();
}
/// Try and get a reduction value from a phi node.
///
/// Given a phi node \p P in a block \p ParentBB, consider possible reductions
/// if they come from either \p ParentBB or a containing loop latch.
///
/// \returns A candidate reduction value if possible, or \code nullptr \endcode
/// if not possible.
static Value *getReductionValue(const DominatorTree *DT, PHINode *P,
BasicBlock *ParentBB, LoopInfo *LI) {
// There are situations where the reduction value is not dominated by the
// reduction phi. Vectorizing such cases has been reported to cause
// miscompiles. See PR25787.
auto DominatedReduxValue = [&](Value *R) {
return isa<Instruction>(R) &&
DT->dominates(P->getParent(), cast<Instruction>(R)->getParent());
};
Value *Rdx = nullptr;
// Return the incoming value if it comes from the same BB as the phi node.
if (P->getIncomingBlock(0) == ParentBB) {
Rdx = P->getIncomingValue(0);
} else if (P->getIncomingBlock(1) == ParentBB) {
Rdx = P->getIncomingValue(1);
}
if (Rdx && DominatedReduxValue(Rdx))
return Rdx;
// Otherwise, check whether we have a loop latch to look at.
Loop *BBL = LI->getLoopFor(ParentBB);
if (!BBL)
return nullptr;
BasicBlock *BBLatch = BBL->getLoopLatch();
if (!BBLatch)
return nullptr;
// There is a loop latch, return the incoming value if it comes from
// that. This reduction pattern occasionally turns up.
if (P->getIncomingBlock(0) == BBLatch) {
Rdx = P->getIncomingValue(0);
} else if (P->getIncomingBlock(1) == BBLatch) {
Rdx = P->getIncomingValue(1);
}
if (Rdx && DominatedReduxValue(Rdx))
return Rdx;
return nullptr;
}
static bool matchRdxBop(Instruction *I, Value *&V0, Value *&V1) {
if (match(I, m_BinOp(m_Value(V0), m_Value(V1))))
return true;
if (match(I, m_Intrinsic<Intrinsic::maxnum>(m_Value(V0), m_Value(V1))))
return true;
if (match(I, m_Intrinsic<Intrinsic::minnum>(m_Value(V0), m_Value(V1))))
return true;
return false;
}
/// Attempt to reduce a horizontal reduction.
/// If it is legal to match a horizontal reduction feeding the phi node \a P
/// with reduction operators \a Root (or one of its operands) in a basic block
/// \a BB, then check if it can be done. If horizontal reduction is not found
/// and root instruction is a binary operation, vectorization of the operands is
/// attempted.
/// \returns true if a horizontal reduction was matched and reduced or operands
/// of one of the binary instruction were vectorized.
/// \returns false if a horizontal reduction was not matched (or not possible)
/// or no vectorization of any binary operation feeding \a Root instruction was
/// performed.
static bool tryToVectorizeHorReductionOrInstOperands(
PHINode *P, Instruction *Root, BasicBlock *BB, BoUpSLP &R,
TargetTransformInfo *TTI,
const function_ref<bool(Instruction *, BoUpSLP &)> Vectorize) {
if (!ShouldVectorizeHor)
return false;
if (!Root)
return false;
if (Root->getParent() != BB || isa<PHINode>(Root))
return false;
// Start analysis starting from Root instruction. If horizontal reduction is
// found, try to vectorize it. If it is not a horizontal reduction or
// vectorization is not possible or not effective, and currently analyzed
// instruction is a binary operation, try to vectorize the operands, using
// pre-order DFS traversal order. If the operands were not vectorized, repeat
// the same procedure considering each operand as a possible root of the
// horizontal reduction.
// Interrupt the process if the Root instruction itself was vectorized or all
// sub-trees not higher that RecursionMaxDepth were analyzed/vectorized.
SmallVector<std::pair<Instruction *, unsigned>, 8> Stack(1, {Root, 0});
SmallPtrSet<Value *, 8> VisitedInstrs;
bool Res = false;
while (!Stack.empty()) {
Instruction *Inst;
unsigned Level;
std::tie(Inst, Level) = Stack.pop_back_val();
Value *B0, *B1;
bool IsBinop = matchRdxBop(Inst, B0, B1);
bool IsSelect = match(Inst, m_Select(m_Value(), m_Value(), m_Value()));
if (IsBinop || IsSelect) {
HorizontalReduction HorRdx;
if (HorRdx.matchAssociativeReduction(P, Inst)) {
if (HorRdx.tryToReduce(R, TTI)) {
Res = true;
// Set P to nullptr to avoid re-analysis of phi node in
// matchAssociativeReduction function unless this is the root node.
P = nullptr;
continue;
}
}
if (P && IsBinop) {
Inst = dyn_cast<Instruction>(B0);
if (Inst == P)
Inst = dyn_cast<Instruction>(B1);
if (!Inst) {
// Set P to nullptr to avoid re-analysis of phi node in
// matchAssociativeReduction function unless this is the root node.
P = nullptr;
continue;
}
}
}
// Set P to nullptr to avoid re-analysis of phi node in
// matchAssociativeReduction function unless this is the root node.
P = nullptr;
if (Vectorize(Inst, R)) {
Res = true;
continue;
}
// Try to vectorize operands.
// Continue analysis for the instruction from the same basic block only to
// save compile time.
if (++Level < RecursionMaxDepth)
for (auto *Op : Inst->operand_values())
if (VisitedInstrs.insert(Op).second)
if (auto *I = dyn_cast<Instruction>(Op))
if (!isa<PHINode>(I) && !R.isDeleted(I) && I->getParent() == BB)
Stack.emplace_back(I, Level);
}
return Res;
}
bool SLPVectorizerPass::vectorizeRootInstruction(PHINode *P, Value *V,
BasicBlock *BB, BoUpSLP &R,
TargetTransformInfo *TTI) {
auto *I = dyn_cast_or_null<Instruction>(V);
if (!I)
return false;
if (!isa<BinaryOperator>(I))
P = nullptr;
// Try to match and vectorize a horizontal reduction.
auto &&ExtraVectorization = [this](Instruction *I, BoUpSLP &R) -> bool {
return tryToVectorize(I, R);
};
return tryToVectorizeHorReductionOrInstOperands(P, I, BB, R, TTI,
ExtraVectorization);
}
bool SLPVectorizerPass::vectorizeInsertValueInst(InsertValueInst *IVI,
BasicBlock *BB, BoUpSLP &R) {
const DataLayout &DL = BB->getModule()->getDataLayout();
if (!R.canMapToVector(IVI->getType(), DL))
return false;
SmallVector<Value *, 16> BuildVectorOpds;
SmallVector<Value *, 16> BuildVectorInsts;
if (!findBuildAggregate(IVI, TTI, BuildVectorOpds, BuildVectorInsts))
return false;
LLVM_DEBUG(dbgs() << "SLP: array mappable to vector: " << *IVI << "\n");
// Aggregate value is unlikely to be processed in vector register, we need to
// extract scalars into scalar registers, so NeedExtraction is set true.
return tryToVectorizeList(BuildVectorOpds, R, /*AllowReorder=*/false,
BuildVectorInsts);
}
bool SLPVectorizerPass::vectorizeInsertElementInst(InsertElementInst *IEI,
BasicBlock *BB, BoUpSLP &R) {
SmallVector<Value *, 16> BuildVectorInsts;
SmallVector<Value *, 16> BuildVectorOpds;
if (!findBuildAggregate(IEI, TTI, BuildVectorOpds, BuildVectorInsts) ||
(llvm::all_of(BuildVectorOpds,
[](Value *V) { return isa<ExtractElementInst>(V); }) &&
isShuffle(BuildVectorOpds)))
return false;
// Vectorize starting with the build vector operands ignoring the BuildVector
// instructions for the purpose of scheduling and user extraction.
return tryToVectorizeList(BuildVectorOpds, R, /*AllowReorder=*/false,
BuildVectorInsts);
}
bool SLPVectorizerPass::vectorizeCmpInst(CmpInst *CI, BasicBlock *BB,
BoUpSLP &R) {
if (tryToVectorizePair(CI->getOperand(0), CI->getOperand(1), R))
return true;
bool OpsChanged = false;
for (int Idx = 0; Idx < 2; ++Idx) {
OpsChanged |=
vectorizeRootInstruction(nullptr, CI->getOperand(Idx), BB, R, TTI);
}
return OpsChanged;
}
bool SLPVectorizerPass::vectorizeSimpleInstructions(
SmallVectorImpl<Instruction *> &Instructions, BasicBlock *BB, BoUpSLP &R) {
bool OpsChanged = false;
for (auto *I : reverse(Instructions)) {
if (R.isDeleted(I))
continue;
if (auto *LastInsertValue = dyn_cast<InsertValueInst>(I))
OpsChanged |= vectorizeInsertValueInst(LastInsertValue, BB, R);
else if (auto *LastInsertElem = dyn_cast<InsertElementInst>(I))
OpsChanged |= vectorizeInsertElementInst(LastInsertElem, BB, R);
else if (auto *CI = dyn_cast<CmpInst>(I))
OpsChanged |= vectorizeCmpInst(CI, BB, R);
}
Instructions.clear();
return OpsChanged;
}
bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
bool Changed = false;
SmallVector<Value *, 4> Incoming;
SmallPtrSet<Value *, 16> VisitedInstrs;
bool HaveVectorizedPhiNodes = true;
while (HaveVectorizedPhiNodes) {
HaveVectorizedPhiNodes = false;
// Collect the incoming values from the PHIs.
Incoming.clear();
for (Instruction &I : *BB) {
PHINode *P = dyn_cast<PHINode>(&I);
if (!P)
break;
if (!VisitedInstrs.count(P) && !R.isDeleted(P))
Incoming.push_back(P);
}
// Sort by type.
llvm::stable_sort(Incoming, PhiTypeSorterFunc);
// Try to vectorize elements base on their type.
for (SmallVector<Value *, 4>::iterator IncIt = Incoming.begin(),
E = Incoming.end();
IncIt != E;) {
// Look for the next elements with the same type.
SmallVector<Value *, 4>::iterator SameTypeIt = IncIt;
while (SameTypeIt != E &&
(*SameTypeIt)->getType() == (*IncIt)->getType()) {
VisitedInstrs.insert(*SameTypeIt);
++SameTypeIt;
}
// Try to vectorize them.
unsigned NumElts = (SameTypeIt - IncIt);
LLVM_DEBUG(dbgs() << "SLP: Trying to vectorize starting at PHIs ("
<< NumElts << ")\n");
// The order in which the phi nodes appear in the program does not matter.
// So allow tryToVectorizeList to reorder them if it is beneficial. This
// is done when there are exactly two elements since tryToVectorizeList
// asserts that there are only two values when AllowReorder is true.
bool AllowReorder = NumElts == 2;
if (NumElts > 1 &&
tryToVectorizeList(makeArrayRef(IncIt, NumElts), R, AllowReorder)) {
// Success start over because instructions might have been changed.
HaveVectorizedPhiNodes = true;
Changed = true;
break;
}
// Start over at the next instruction of a different type (or the end).
IncIt = SameTypeIt;
}
}
VisitedInstrs.clear();
SmallVector<Instruction *, 8> PostProcessInstructions;
SmallDenseSet<Instruction *, 4> KeyNodes;
for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
// Skip instructions with scalable type. The num of elements is unknown at
// compile-time for scalable type.
if (isa<ScalableVectorType>(it->getType()))
continue;
// Skip instructions marked for the deletion.
if (R.isDeleted(&*it))
continue;
// We may go through BB multiple times so skip the one we have checked.
if (!VisitedInstrs.insert(&*it).second) {
if (it->use_empty() && KeyNodes.contains(&*it) &&
vectorizeSimpleInstructions(PostProcessInstructions, BB, R)) {
// We would like to start over since some instructions are deleted
// and the iterator may become invalid value.
Changed = true;
it = BB->begin();
e = BB->end();
}
continue;
}
if (isa<DbgInfoIntrinsic>(it))
continue;
// Try to vectorize reductions that use PHINodes.
if (PHINode *P = dyn_cast<PHINode>(it)) {
// Check that the PHI is a reduction PHI.
if (P->getNumIncomingValues() == 2) {
// Try to match and vectorize a horizontal reduction.
if (vectorizeRootInstruction(P, getReductionValue(DT, P, BB, LI), BB, R,
TTI)) {
Changed = true;
it = BB->begin();
e = BB->end();
continue;
}
}
// Try to vectorize the incoming values of the PHI, to catch reductions
// that feed into PHIs.
for (unsigned I = 0, E = P->getNumIncomingValues(); I != E; I++) {
// Skip if the incoming block is the current BB for now. Also, bypass
// unreachable IR for efficiency and to avoid crashing.
// TODO: Collect the skipped incoming values and try to vectorize them
// after processing BB.
if (BB == P->getIncomingBlock(I) ||
!DT->isReachableFromEntry(P->getIncomingBlock(I)))
continue;
Changed |= vectorizeRootInstruction(nullptr, P->getIncomingValue(I),
P->getIncomingBlock(I), R, TTI);
}
continue;
}
// Ran into an instruction without users, like terminator, or function call
// with ignored return value, store. Ignore unused instructions (basing on
// instruction type, except for CallInst and InvokeInst).
if (it->use_empty() && (it->getType()->isVoidTy() || isa<CallInst>(it) ||
isa<InvokeInst>(it))) {
KeyNodes.insert(&*it);
bool OpsChanged = false;
if (ShouldStartVectorizeHorAtStore || !isa<StoreInst>(it)) {
for (auto *V : it->operand_values()) {
// Try to match and vectorize a horizontal reduction.
OpsChanged |= vectorizeRootInstruction(nullptr, V, BB, R, TTI);
}
}
// Start vectorization of post-process list of instructions from the
// top-tree instructions to try to vectorize as many instructions as
// possible.
OpsChanged |= vectorizeSimpleInstructions(PostProcessInstructions, BB, R);
if (OpsChanged) {
// We would like to start over since some instructions are deleted
// and the iterator may become invalid value.
Changed = true;
it = BB->begin();
e = BB->end();
continue;
}
}
if (isa<InsertElementInst>(it) || isa<CmpInst>(it) ||
isa<InsertValueInst>(it))
PostProcessInstructions.push_back(&*it);
}
return Changed;
}
bool SLPVectorizerPass::vectorizeGEPIndices(BasicBlock *BB, BoUpSLP &R) {
auto Changed = false;
for (auto &Entry : GEPs) {
// If the getelementptr list has fewer than two elements, there's nothing
// to do.
if (Entry.second.size() < 2)
continue;
LLVM_DEBUG(dbgs() << "SLP: Analyzing a getelementptr list of length "
<< Entry.second.size() << ".\n");
// Process the GEP list in chunks suitable for the target's supported
// vector size. If a vector register can't hold 1 element, we are done. We
// are trying to vectorize the index computations, so the maximum number of
// elements is based on the size of the index expression, rather than the
// size of the GEP itself (the target's pointer size).
unsigned MaxVecRegSize = R.getMaxVecRegSize();
unsigned EltSize = R.getVectorElementSize(*Entry.second[0]->idx_begin());
if (MaxVecRegSize < EltSize)
continue;
unsigned MaxElts = MaxVecRegSize / EltSize;
for (unsigned BI = 0, BE = Entry.second.size(); BI < BE; BI += MaxElts) {
auto Len = std::min<unsigned>(BE - BI, MaxElts);
ArrayRef<GetElementPtrInst *> GEPList(&Entry.second[BI], Len);
// Initialize a set a candidate getelementptrs. Note that we use a
// SetVector here to preserve program order. If the index computations
// are vectorizable and begin with loads, we want to minimize the chance
// of having to reorder them later.
SetVector<Value *> Candidates(GEPList.begin(), GEPList.end());
// Some of the candidates may have already been vectorized after we
// initially collected them. If so, they are marked as deleted, so remove
// them from the set of candidates.
Candidates.remove_if(
[&R](Value *I) { return R.isDeleted(cast<Instruction>(I)); });
// Remove from the set of candidates all pairs of getelementptrs with
// constant differences. Such getelementptrs are likely not good
// candidates for vectorization in a bottom-up phase since one can be
// computed from the other. We also ensure all candidate getelementptr
// indices are unique.
for (int I = 0, E = GEPList.size(); I < E && Candidates.size() > 1; ++I) {
auto *GEPI = GEPList[I];
if (!Candidates.count(GEPI))
continue;
auto *SCEVI = SE->getSCEV(GEPList[I]);
for (int J = I + 1; J < E && Candidates.size() > 1; ++J) {
auto *GEPJ = GEPList[J];
auto *SCEVJ = SE->getSCEV(GEPList[J]);
if (isa<SCEVConstant>(SE->getMinusSCEV(SCEVI, SCEVJ))) {
Candidates.remove(GEPI);
Candidates.remove(GEPJ);
} else if (GEPI->idx_begin()->get() == GEPJ->idx_begin()->get()) {
Candidates.remove(GEPJ);
}
}
}
// We break out of the above computation as soon as we know there are
// fewer than two candidates remaining.
if (Candidates.size() < 2)
continue;
// Add the single, non-constant index of each candidate to the bundle. We
// ensured the indices met these constraints when we originally collected
// the getelementptrs.
SmallVector<Value *, 16> Bundle(Candidates.size());
auto BundleIndex = 0u;
for (auto *V : Candidates) {
auto *GEP = cast<GetElementPtrInst>(V);
auto *GEPIdx = GEP->idx_begin()->get();
assert(GEP->getNumIndices() == 1 || !isa<Constant>(GEPIdx));
Bundle[BundleIndex++] = GEPIdx;
}
// Try and vectorize the indices. We are currently only interested in
// gather-like cases of the form:
//
// ... = g[a[0] - b[0]] + g[a[1] - b[1]] + ...
//
// where the loads of "a", the loads of "b", and the subtractions can be
// performed in parallel. It's likely that detecting this pattern in a
// bottom-up phase will be simpler and less costly than building a
// full-blown top-down phase beginning at the consecutive loads.
Changed |= tryToVectorizeList(Bundle, R);
}
}
return Changed;
}
bool SLPVectorizerPass::vectorizeStoreChains(BoUpSLP &R) {
bool Changed = false;
// Attempt to sort and vectorize each of the store-groups.
for (StoreListMap::iterator it = Stores.begin(), e = Stores.end(); it != e;
++it) {
if (it->second.size() < 2)
continue;
LLVM_DEBUG(dbgs() << "SLP: Analyzing a store chain of length "
<< it->second.size() << ".\n");
Changed |= vectorizeStores(it->second, R);
}
return Changed;
}
char SLPVectorizer::ID = 0;
static const char lv_name[] = "SLP Vectorizer";
INITIALIZE_PASS_BEGIN(SLPVectorizer, SV_NAME, lv_name, false, false)
INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
INITIALIZE_PASS_DEPENDENCY(DemandedBitsWrapperPass)
INITIALIZE_PASS_DEPENDENCY(OptimizationRemarkEmitterWrapperPass)
INITIALIZE_PASS_DEPENDENCY(InjectTLIMappingsLegacy)
INITIALIZE_PASS_END(SLPVectorizer, SV_NAME, lv_name, false, false)
Pass *llvm::createSLPVectorizerPass() { return new SLPVectorizer(); }
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