shylie/llvm-project
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
llvm-project/llvm/lib/Transforms/Vectorize/VPlan.cpp
Florian Hahn 668045eb77
[VPlan] Unify Value2VPValue and VPExternalDefs maps (NFCI). 
Before this patch, a VPlan contained 2 mappings for Values -> VPValue:
1) Value2VPValue and 2) VPExternalDefs.

This duplication is unnecessary and there are already cases where
external defs are added to Value2VPValue. This patch replaces all uses
of VPExternalDefs with Value2VPValue.

It clarifies the naming of getOrAddVPValue (to getOrAddExternalVPValue)
and addVPValue (to addExternalVPValue).

At the moment, this is NFC, but will enable additional simplifications
in D147783.

Depends on D147891.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D147892
2023-04-16 15:38:31 +01:00

1141 lines
39 KiB
C++
Raw Blame History

//===- VPlan.cpp - Vectorizer Plan ----------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This is the LLVM vectorization plan. It represents a candidate for
/// vectorization, allowing to plan and optimize how to vectorize a given loop
/// before generating LLVM-IR.
/// The vectorizer uses vectorization plans to estimate the costs of potential
/// candidates and if profitable to execute the desired plan, generating vector
/// LLVM-IR code.
///
//===----------------------------------------------------------------------===//
#include "VPlan.h"
#include "VPlanCFG.h"
#include "VPlanDominatorTree.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GenericDomTreeConstruction.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/LoopVersioning.h"
#include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
#include <cassert>
#include <string>
#include <vector>
using namespace llvm;
namespace llvm {
extern cl::opt<bool> EnableVPlanNativePath;
}
#define DEBUG_TYPE "vplan"
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
raw_ostream &llvm::operator<<(raw_ostream &OS, const VPValue &V) {
const VPInstruction *Instr = dyn_cast<VPInstruction>(&V);
VPSlotTracker SlotTracker(
(Instr && Instr->getParent()) ? Instr->getParent()->getPlan() : nullptr);
V.print(OS, SlotTracker);
return OS;
}
#endif
Value *VPLane::getAsRuntimeExpr(IRBuilderBase &Builder,
const ElementCount &VF) const {
switch (LaneKind) {
case VPLane::Kind::ScalableLast:
// Lane = RuntimeVF - VF.getKnownMinValue() + Lane
return Builder.CreateSub(getRuntimeVF(Builder, Builder.getInt32Ty(), VF),
Builder.getInt32(VF.getKnownMinValue() - Lane));
case VPLane::Kind::First:
return Builder.getInt32(Lane);
}
llvm_unreachable("Unknown lane kind");
}
VPValue::VPValue(const unsigned char SC, Value *UV, VPDef *Def)
: SubclassID(SC), UnderlyingVal(UV), Def(Def) {
if (Def)
Def->addDefinedValue(this);
}
VPValue::~VPValue() {
assert(Users.empty() && "trying to delete a VPValue with remaining users");
if (Def)
Def->removeDefinedValue(this);
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPValue::print(raw_ostream &OS, VPSlotTracker &SlotTracker) const {
if (const VPRecipeBase *R = dyn_cast_or_null<VPRecipeBase>(Def))
R->print(OS, "", SlotTracker);
else
printAsOperand(OS, SlotTracker);
}
void VPValue::dump() const {
const VPRecipeBase *Instr = dyn_cast_or_null<VPRecipeBase>(this->Def);
VPSlotTracker SlotTracker(
(Instr && Instr->getParent()) ? Instr->getParent()->getPlan() : nullptr);
print(dbgs(), SlotTracker);
dbgs() << "\n";
}
void VPDef::dump() const {
const VPRecipeBase *Instr = dyn_cast_or_null<VPRecipeBase>(this);
VPSlotTracker SlotTracker(
(Instr && Instr->getParent()) ? Instr->getParent()->getPlan() : nullptr);
print(dbgs(), "", SlotTracker);
dbgs() << "\n";
}
#endif
VPRecipeBase *VPValue::getDefiningRecipe() {
return cast_or_null<VPRecipeBase>(Def);
}
const VPRecipeBase *VPValue::getDefiningRecipe() const {
return cast_or_null<VPRecipeBase>(Def);
}
// Get the top-most entry block of \p Start. This is the entry block of the
// containing VPlan. This function is templated to support both const and non-const blocks
template <typename T> static T *getPlanEntry(T *Start) {
T *Next = Start;
T *Current = Start;
while ((Next = Next->getParent()))
Current = Next;
SmallSetVector<T *, 8> WorkList;
WorkList.insert(Current);
for (unsigned i = 0; i < WorkList.size(); i++) {
T *Current = WorkList[i];
if (Current->getNumPredecessors() == 0)
return Current;
auto &Predecessors = Current->getPredecessors();
WorkList.insert(Predecessors.begin(), Predecessors.end());
}
llvm_unreachable("VPlan without any entry node without predecessors");
}
VPlan *VPBlockBase::getPlan() { return getPlanEntry(this)->Plan; }
const VPlan *VPBlockBase::getPlan() const { return getPlanEntry(this)->Plan; }
/// \return the VPBasicBlock that is the entry of Block, possibly indirectly.
const VPBasicBlock *VPBlockBase::getEntryBasicBlock() const {
const VPBlockBase *Block = this;
while (const VPRegionBlock *Region = dyn_cast<VPRegionBlock>(Block))
Block = Region->getEntry();
return cast<VPBasicBlock>(Block);
}
VPBasicBlock *VPBlockBase::getEntryBasicBlock() {
VPBlockBase *Block = this;
while (VPRegionBlock *Region = dyn_cast<VPRegionBlock>(Block))
Block = Region->getEntry();
return cast<VPBasicBlock>(Block);
}
void VPBlockBase::setPlan(VPlan *ParentPlan) {
assert(ParentPlan->getEntry() == this &&
"Can only set plan on its entry block.");
Plan = ParentPlan;
}
/// \return the VPBasicBlock that is the exit of Block, possibly indirectly.
const VPBasicBlock *VPBlockBase::getExitingBasicBlock() const {
const VPBlockBase *Block = this;
while (const VPRegionBlock *Region = dyn_cast<VPRegionBlock>(Block))
Block = Region->getExiting();
return cast<VPBasicBlock>(Block);
}
VPBasicBlock *VPBlockBase::getExitingBasicBlock() {
VPBlockBase *Block = this;
while (VPRegionBlock *Region = dyn_cast<VPRegionBlock>(Block))
Block = Region->getExiting();
return cast<VPBasicBlock>(Block);
}
VPBlockBase *VPBlockBase::getEnclosingBlockWithSuccessors() {
if (!Successors.empty() || !Parent)
return this;
assert(Parent->getExiting() == this &&
"Block w/o successors not the exiting block of its parent.");
return Parent->getEnclosingBlockWithSuccessors();
}
VPBlockBase *VPBlockBase::getEnclosingBlockWithPredecessors() {
if (!Predecessors.empty() || !Parent)
return this;
assert(Parent->getEntry() == this &&
"Block w/o predecessors not the entry of its parent.");
return Parent->getEnclosingBlockWithPredecessors();
}
void VPBlockBase::deleteCFG(VPBlockBase *Entry) {
for (VPBlockBase *Block : to_vector(vp_depth_first_shallow(Entry)))
delete Block;
}
VPBasicBlock::iterator VPBasicBlock::getFirstNonPhi() {
iterator It = begin();
while (It != end() && It->isPhi())
It++;
return It;
}
Value *VPTransformState::get(VPValue *Def, const VPIteration &Instance) {
if (!Def->hasDefiningRecipe())
return Def->getLiveInIRValue();
if (hasScalarValue(Def, Instance)) {
return Data
.PerPartScalars[Def][Instance.Part][Instance.Lane.mapToCacheIndex(VF)];
}
assert(hasVectorValue(Def, Instance.Part));
auto *VecPart = Data.PerPartOutput[Def][Instance.Part];
if (!VecPart->getType()->isVectorTy()) {
assert(Instance.Lane.isFirstLane() && "cannot get lane > 0 for scalar");
return VecPart;
}
// TODO: Cache created scalar values.
Value *Lane = Instance.Lane.getAsRuntimeExpr(Builder, VF);
auto *Extract = Builder.CreateExtractElement(VecPart, Lane);
// set(Def, Extract, Instance);
return Extract;
}
BasicBlock *VPTransformState::CFGState::getPreheaderBBFor(VPRecipeBase *R) {
VPRegionBlock *LoopRegion = R->getParent()->getEnclosingLoopRegion();
return VPBB2IRBB[LoopRegion->getPreheaderVPBB()];
}
void VPTransformState::addNewMetadata(Instruction *To,
const Instruction *Orig) {
// If the loop was versioned with memchecks, add the corresponding no-alias
// metadata.
if (LVer && (isa<LoadInst>(Orig) || isa<StoreInst>(Orig)))
LVer->annotateInstWithNoAlias(To, Orig);
}
void VPTransformState::addMetadata(Instruction *To, Instruction *From) {
propagateMetadata(To, From);
addNewMetadata(To, From);
}
void VPTransformState::addMetadata(ArrayRef<Value *> To, Instruction *From) {
for (Value *V : To) {
if (Instruction *I = dyn_cast<Instruction>(V))
addMetadata(I, From);
}
}
void VPTransformState::setDebugLocFromInst(const Value *V) {
const Instruction *Inst = dyn_cast<Instruction>(V);
if (!Inst) {
Builder.SetCurrentDebugLocation(DebugLoc());
return;
}
const DILocation *DIL = Inst->getDebugLoc();
// When a FSDiscriminator is enabled, we don't need to add the multiply
// factors to the discriminators.
if (DIL && Inst->getFunction()->shouldEmitDebugInfoForProfiling() &&
!isa<DbgInfoIntrinsic>(Inst) && !EnableFSDiscriminator) {
// FIXME: For scalable vectors, assume vscale=1.
auto NewDIL =
DIL->cloneByMultiplyingDuplicationFactor(UF * VF.getKnownMinValue());
if (NewDIL)
Builder.SetCurrentDebugLocation(*NewDIL);
else
LLVM_DEBUG(dbgs() << "Failed to create new discriminator: "
<< DIL->getFilename() << " Line: " << DIL->getLine());
} else
Builder.SetCurrentDebugLocation(DIL);
}
BasicBlock *
VPBasicBlock::createEmptyBasicBlock(VPTransformState::CFGState &CFG) {
// BB stands for IR BasicBlocks. VPBB stands for VPlan VPBasicBlocks.
// Pred stands for Predessor. Prev stands for Previous - last visited/created.
BasicBlock *PrevBB = CFG.PrevBB;
BasicBlock *NewBB = BasicBlock::Create(PrevBB->getContext(), getName(),
PrevBB->getParent(), CFG.ExitBB);
LLVM_DEBUG(dbgs() << "LV: created " << NewBB->getName() << '\n');
// Hook up the new basic block to its predecessors.
for (VPBlockBase *PredVPBlock : getHierarchicalPredecessors()) {
VPBasicBlock *PredVPBB = PredVPBlock->getExitingBasicBlock();
auto &PredVPSuccessors = PredVPBB->getHierarchicalSuccessors();
BasicBlock *PredBB = CFG.VPBB2IRBB[PredVPBB];
assert(PredBB && "Predecessor basic-block not found building successor.");
auto *PredBBTerminator = PredBB->getTerminator();
LLVM_DEBUG(dbgs() << "LV: draw edge from" << PredBB->getName() << '\n');
auto *TermBr = dyn_cast<BranchInst>(PredBBTerminator);
if (isa<UnreachableInst>(PredBBTerminator)) {
assert(PredVPSuccessors.size() == 1 &&
"Predecessor ending w/o branch must have single successor.");
DebugLoc DL = PredBBTerminator->getDebugLoc();
PredBBTerminator->eraseFromParent();
auto *Br = BranchInst::Create(NewBB, PredBB);
Br->setDebugLoc(DL);
} else if (TermBr && !TermBr->isConditional()) {
TermBr->setSuccessor(0, NewBB);
} else {
// Set each forward successor here when it is created, excluding
// backedges. A backward successor is set when the branch is created.
unsigned idx = PredVPSuccessors.front() == this ? 0 : 1;
assert(!TermBr->getSuccessor(idx) &&
"Trying to reset an existing successor block.");
TermBr->setSuccessor(idx, NewBB);
}
}
return NewBB;
}
void VPBasicBlock::execute(VPTransformState *State) {
bool Replica = State->Instance && !State->Instance->isFirstIteration();
VPBasicBlock *PrevVPBB = State->CFG.PrevVPBB;
VPBlockBase *SingleHPred = nullptr;
BasicBlock *NewBB = State->CFG.PrevBB; // Reuse it if possible.
auto IsLoopRegion = [](VPBlockBase *BB) {
auto *R = dyn_cast<VPRegionBlock>(BB);
return R && !R->isReplicator();
};
// 1. Create an IR basic block, or reuse the last one or ExitBB if possible.
if (getPlan()->getVectorLoopRegion()->getSingleSuccessor() == this) {
// ExitBB can be re-used for the exit block of the Plan.
NewBB = State->CFG.ExitBB;
State->CFG.PrevBB = NewBB;
// Update the branch instruction in the predecessor to branch to ExitBB.
VPBlockBase *PredVPB = getSingleHierarchicalPredecessor();
VPBasicBlock *ExitingVPBB = PredVPB->getExitingBasicBlock();
assert(PredVPB->getSingleSuccessor() == this &&
"predecessor must have the current block as only successor");
BasicBlock *ExitingBB = State->CFG.VPBB2IRBB[ExitingVPBB];
// The Exit block of a loop is always set to be successor 0 of the Exiting
// block.
cast<BranchInst>(ExitingBB->getTerminator())->setSuccessor(0, NewBB);
} else if (PrevVPBB && /* A */
!((SingleHPred = getSingleHierarchicalPredecessor()) &&
SingleHPred->getExitingBasicBlock() == PrevVPBB &&
PrevVPBB->getSingleHierarchicalSuccessor() &&
(SingleHPred->getParent() == getEnclosingLoopRegion() &&
!IsLoopRegion(SingleHPred))) && /* B */
!(Replica && getPredecessors().empty())) { /* C */
// The last IR basic block is reused, as an optimization, in three cases:
// A. the first VPBB reuses the loop pre-header BB - when PrevVPBB is null;
// B. when the current VPBB has a single (hierarchical) predecessor which
// is PrevVPBB and the latter has a single (hierarchical) successor which
// both are in the same non-replicator region; and
// C. when the current VPBB is an entry of a region replica - where PrevVPBB
// is the exiting VPBB of this region from a previous instance, or the
// predecessor of this region.
NewBB = createEmptyBasicBlock(State->CFG);
State->Builder.SetInsertPoint(NewBB);
// Temporarily terminate with unreachable until CFG is rewired.
UnreachableInst *Terminator = State->Builder.CreateUnreachable();
// Register NewBB in its loop. In innermost loops its the same for all
// BB's.
if (State->CurrentVectorLoop)
State->CurrentVectorLoop->addBasicBlockToLoop(NewBB, *State->LI);
State->Builder.SetInsertPoint(Terminator);
State->CFG.PrevBB = NewBB;
}
// 2. Fill the IR basic block with IR instructions.
LLVM_DEBUG(dbgs() << "LV: vectorizing VPBB:" << getName()
<< " in BB:" << NewBB->getName() << '\n');
State->CFG.VPBB2IRBB[this] = NewBB;
State->CFG.PrevVPBB = this;
for (VPRecipeBase &Recipe : Recipes)
Recipe.execute(*State);
LLVM_DEBUG(dbgs() << "LV: filled BB:" << *NewBB);
}
void VPBasicBlock::dropAllReferences(VPValue *NewValue) {
for (VPRecipeBase &R : Recipes) {
for (auto *Def : R.definedValues())
Def->replaceAllUsesWith(NewValue);
for (unsigned I = 0, E = R.getNumOperands(); I != E; I++)
R.setOperand(I, NewValue);
}
}
VPBasicBlock *VPBasicBlock::splitAt(iterator SplitAt) {
assert((SplitAt == end() || SplitAt->getParent() == this) &&
"can only split at a position in the same block");
SmallVector<VPBlockBase *, 2> Succs(successors());
// First, disconnect the current block from its successors.
for (VPBlockBase *Succ : Succs)
VPBlockUtils::disconnectBlocks(this, Succ);
// Create new empty block after the block to split.
auto *SplitBlock = new VPBasicBlock(getName() + ".split");
VPBlockUtils::insertBlockAfter(SplitBlock, this);
// Add successors for block to split to new block.
for (VPBlockBase *Succ : Succs)
VPBlockUtils::connectBlocks(SplitBlock, Succ);
// Finally, move the recipes starting at SplitAt to new block.
for (VPRecipeBase &ToMove :
make_early_inc_range(make_range(SplitAt, this->end())))
ToMove.moveBefore(*SplitBlock, SplitBlock->end());
return SplitBlock;
}
VPRegionBlock *VPBasicBlock::getEnclosingLoopRegion() {
VPRegionBlock *P = getParent();
if (P && P->isReplicator()) {
P = P->getParent();
assert(!cast<VPRegionBlock>(P)->isReplicator() &&
"unexpected nested replicate regions");
}
return P;
}
static bool hasConditionalTerminator(const VPBasicBlock *VPBB) {
if (VPBB->empty()) {
assert(
VPBB->getNumSuccessors() < 2 &&
"block with multiple successors doesn't have a recipe as terminator");
return false;
}
const VPRecipeBase *R = &VPBB->back();
auto *VPI = dyn_cast<VPInstruction>(R);
bool IsCondBranch =
isa<VPBranchOnMaskRecipe>(R) ||
(VPI && (VPI->getOpcode() == VPInstruction::BranchOnCond ||
VPI->getOpcode() == VPInstruction::BranchOnCount));
(void)IsCondBranch;
if (VPBB->getNumSuccessors() >= 2 || VPBB->isExiting()) {
assert(IsCondBranch && "block with multiple successors not terminated by "
"conditional branch recipe");
return true;
}
assert(
!IsCondBranch &&
"block with 0 or 1 successors terminated by conditional branch recipe");
return false;
}
VPRecipeBase *VPBasicBlock::getTerminator() {
if (hasConditionalTerminator(this))
return &back();
return nullptr;
}
const VPRecipeBase *VPBasicBlock::getTerminator() const {
if (hasConditionalTerminator(this))
return &back();
return nullptr;
}
bool VPBasicBlock::isExiting() const {
return getParent()->getExitingBasicBlock() == this;
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPBlockBase::printSuccessors(raw_ostream &O, const Twine &Indent) const {
if (getSuccessors().empty()) {
O << Indent << "No successors\n";
} else {
O << Indent << "Successor(s): ";
ListSeparator LS;
for (auto *Succ : getSuccessors())
O << LS << Succ->getName();
O << '\n';
}
}
void VPBasicBlock::print(raw_ostream &O, const Twine &Indent,
VPSlotTracker &SlotTracker) const {
O << Indent << getName() << ":\n";
auto RecipeIndent = Indent + " ";
for (const VPRecipeBase &Recipe : *this) {
Recipe.print(O, RecipeIndent, SlotTracker);
O << '\n';
}
printSuccessors(O, Indent);
}
#endif
void VPRegionBlock::dropAllReferences(VPValue *NewValue) {
for (VPBlockBase *Block : vp_depth_first_shallow(Entry))
// Drop all references in VPBasicBlocks and replace all uses with
// DummyValue.
Block->dropAllReferences(NewValue);
}
void VPRegionBlock::execute(VPTransformState *State) {
ReversePostOrderTraversal<VPBlockShallowTraversalWrapper<VPBlockBase *>>
RPOT(Entry);
if (!isReplicator()) {
// Create and register the new vector loop.
Loop *PrevLoop = State->CurrentVectorLoop;
State->CurrentVectorLoop = State->LI->AllocateLoop();
BasicBlock *VectorPH = State->CFG.VPBB2IRBB[getPreheaderVPBB()];
Loop *ParentLoop = State->LI->getLoopFor(VectorPH);
// Insert the new loop into the loop nest and register the new basic blocks
// before calling any utilities such as SCEV that require valid LoopInfo.
if (ParentLoop)
ParentLoop->addChildLoop(State->CurrentVectorLoop);
else
State->LI->addTopLevelLoop(State->CurrentVectorLoop);
// Visit the VPBlocks connected to "this", starting from it.
for (VPBlockBase *Block : RPOT) {
LLVM_DEBUG(dbgs() << "LV: VPBlock in RPO " << Block->getName() << '\n');
Block->execute(State);
}
State->CurrentVectorLoop = PrevLoop;
return;
}
assert(!State->Instance && "Replicating a Region with non-null instance.");
// Enter replicating mode.
State->Instance = VPIteration(0, 0);
for (unsigned Part = 0, UF = State->UF; Part < UF; ++Part) {
State->Instance->Part = Part;
assert(!State->VF.isScalable() && "VF is assumed to be non scalable.");
for (unsigned Lane = 0, VF = State->VF.getKnownMinValue(); Lane < VF;
++Lane) {
State->Instance->Lane = VPLane(Lane, VPLane::Kind::First);
// Visit the VPBlocks connected to \p this, starting from it.
for (VPBlockBase *Block : RPOT) {
LLVM_DEBUG(dbgs() << "LV: VPBlock in RPO " << Block->getName() << '\n');
Block->execute(State);
}
}
}
// Exit replicating mode.
State->Instance.reset();
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPRegionBlock::print(raw_ostream &O, const Twine &Indent,
VPSlotTracker &SlotTracker) const {
O << Indent << (isReplicator() ? "<xVFxUF> " : "<x1> ") << getName() << ": {";
auto NewIndent = Indent + " ";
for (auto *BlockBase : vp_depth_first_shallow(Entry)) {
O << '\n';
BlockBase->print(O, NewIndent, SlotTracker);
}
O << Indent << "}\n";
printSuccessors(O, Indent);
}
#endif
VPlan::~VPlan() {
for (auto &KV : LiveOuts)
delete KV.second;
LiveOuts.clear();
if (Entry) {
VPValue DummyValue;
for (VPBlockBase *Block : vp_depth_first_shallow(Entry))
Block->dropAllReferences(&DummyValue);
VPBlockBase::deleteCFG(Entry);
}
for (VPValue *VPV : VPLiveInsToFree)
delete VPV;
if (TripCount)
delete TripCount;
if (BackedgeTakenCount)
delete BackedgeTakenCount;
}
VPActiveLaneMaskPHIRecipe *VPlan::getActiveLaneMaskPhi() {
VPBasicBlock *Header = getVectorLoopRegion()->getEntryBasicBlock();
for (VPRecipeBase &R : Header->phis()) {
if (isa<VPActiveLaneMaskPHIRecipe>(&R))
return cast<VPActiveLaneMaskPHIRecipe>(&R);
}
return nullptr;
}
void VPlan::prepareToExecute(Value *TripCountV, Value *VectorTripCountV,
Value *CanonicalIVStartValue,
VPTransformState &State,
bool IsEpilogueVectorization) {
// Check if the trip count is needed, and if so build it.
if (TripCount && TripCount->getNumUsers()) {
for (unsigned Part = 0, UF = State.UF; Part < UF; ++Part)
State.set(TripCount, TripCountV, Part);
}
// Check if the backedge taken count is needed, and if so build it.
if (BackedgeTakenCount && BackedgeTakenCount->getNumUsers()) {
IRBuilder<> Builder(State.CFG.PrevBB->getTerminator());
auto *TCMO = Builder.CreateSub(TripCountV,
ConstantInt::get(TripCountV->getType(), 1),
"trip.count.minus.1");
auto VF = State.VF;
Value *VTCMO =
VF.isScalar() ? TCMO : Builder.CreateVectorSplat(VF, TCMO, "broadcast");
for (unsigned Part = 0, UF = State.UF; Part < UF; ++Part)
State.set(BackedgeTakenCount, VTCMO, Part);
}
for (unsigned Part = 0, UF = State.UF; Part < UF; ++Part)
State.set(&VectorTripCount, VectorTripCountV, Part);
// When vectorizing the epilogue loop, the canonical induction start value
// needs to be changed from zero to the value after the main vector loop.
// FIXME: Improve modeling for canonical IV start values in the epilogue loop.
if (CanonicalIVStartValue) {
VPValue *VPV = getVPValueOrAddLiveIn(CanonicalIVStartValue);
auto *IV = getCanonicalIV();
assert(all_of(IV->users(),
[](const VPUser *U) {
if (isa<VPScalarIVStepsRecipe>(U) ||
isa<VPDerivedIVRecipe>(U))
return true;
auto *VPI = cast<VPInstruction>(U);
return VPI->getOpcode() ==
VPInstruction::CanonicalIVIncrement ||
VPI->getOpcode() ==
VPInstruction::CanonicalIVIncrementNUW;
}) &&
"the canonical IV should only be used by its increments or "
"ScalarIVSteps when resetting the start value");
IV->setOperand(0, VPV);
}
}
/// Generate the code inside the preheader and body of the vectorized loop.
/// Assumes a single pre-header basic-block was created for this. Introduce
/// additional basic-blocks as needed, and fill them all.
void VPlan::execute(VPTransformState *State) {
// Set the reverse mapping from VPValues to Values for code generation.
for (auto &Entry : Value2VPValue)
State->VPValue2Value[Entry.second] = Entry.first;
// Initialize CFG state.
State->CFG.PrevVPBB = nullptr;
State->CFG.ExitBB = State->CFG.PrevBB->getSingleSuccessor();
BasicBlock *VectorPreHeader = State->CFG.PrevBB;
State->Builder.SetInsertPoint(VectorPreHeader->getTerminator());
// Generate code in the loop pre-header and body.
for (VPBlockBase *Block : vp_depth_first_shallow(Entry))
Block->execute(State);
VPBasicBlock *LatchVPBB = getVectorLoopRegion()->getExitingBasicBlock();
BasicBlock *VectorLatchBB = State->CFG.VPBB2IRBB[LatchVPBB];
// Fix the latch value of canonical, reduction and first-order recurrences
// phis in the vector loop.
VPBasicBlock *Header = getVectorLoopRegion()->getEntryBasicBlock();
for (VPRecipeBase &R : Header->phis()) {
// Skip phi-like recipes that generate their backedege values themselves.
if (isa<VPWidenPHIRecipe>(&R))
continue;
if (isa<VPWidenPointerInductionRecipe>(&R) ||
isa<VPWidenIntOrFpInductionRecipe>(&R)) {
PHINode *Phi = nullptr;
if (isa<VPWidenIntOrFpInductionRecipe>(&R)) {
Phi = cast<PHINode>(State->get(R.getVPSingleValue(), 0));
} else {
auto *WidenPhi = cast<VPWidenPointerInductionRecipe>(&R);
// TODO: Split off the case that all users of a pointer phi are scalar
// from the VPWidenPointerInductionRecipe.
if (WidenPhi->onlyScalarsGenerated(State->VF))
continue;
auto *GEP = cast<GetElementPtrInst>(State->get(WidenPhi, 0));
Phi = cast<PHINode>(GEP->getPointerOperand());
}
Phi->setIncomingBlock(1, VectorLatchBB);
// Move the last step to the end of the latch block. This ensures
// consistent placement of all induction updates.
Instruction *Inc = cast<Instruction>(Phi->getIncomingValue(1));
Inc->moveBefore(VectorLatchBB->getTerminator()->getPrevNode());
continue;
}
auto *PhiR = cast<VPHeaderPHIRecipe>(&R);
// For canonical IV, first-order recurrences and in-order reduction phis,
// only a single part is generated, which provides the last part from the
// previous iteration. For non-ordered reductions all UF parts are
// generated.
bool SinglePartNeeded = isa<VPCanonicalIVPHIRecipe>(PhiR) ||
isa<VPFirstOrderRecurrencePHIRecipe>(PhiR) ||
(isa<VPReductionPHIRecipe>(PhiR) &&
cast<VPReductionPHIRecipe>(PhiR)->isOrdered());
unsigned LastPartForNewPhi = SinglePartNeeded ? 1 : State->UF;
for (unsigned Part = 0; Part < LastPartForNewPhi; ++Part) {
Value *Phi = State->get(PhiR, Part);
Value *Val = State->get(PhiR->getBackedgeValue(),
SinglePartNeeded ? State->UF - 1 : Part);
cast<PHINode>(Phi)->addIncoming(Val, VectorLatchBB);
}
}
// We do not attempt to preserve DT for outer loop vectorization currently.
if (!EnableVPlanNativePath) {
BasicBlock *VectorHeaderBB = State->CFG.VPBB2IRBB[Header];
State->DT->addNewBlock(VectorHeaderBB, VectorPreHeader);
updateDominatorTree(State->DT, VectorHeaderBB, VectorLatchBB,
State->CFG.ExitBB);
}
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD
void VPlan::print(raw_ostream &O) const {
VPSlotTracker SlotTracker(this);
O << "VPlan '" << getName() << "' {";
bool AnyLiveIn = false;
if (VectorTripCount.getNumUsers() > 0) {
O << "\nLive-in ";
VectorTripCount.printAsOperand(O, SlotTracker);
O << " = vector-trip-count";
AnyLiveIn = true;
}
if (TripCount && TripCount->getNumUsers() > 0) {
O << "\nLive-in ";
TripCount->printAsOperand(O, SlotTracker);
O << " = original trip-count";
AnyLiveIn = true;
}
if (BackedgeTakenCount && BackedgeTakenCount->getNumUsers()) {
O << "\nLive-in ";
BackedgeTakenCount->printAsOperand(O, SlotTracker);
O << " = backedge-taken count";
AnyLiveIn = true;
}
if (AnyLiveIn)
O << "\n";
for (const VPBlockBase *Block : vp_depth_first_shallow(getEntry())) {
O << '\n';
Block->print(O, "", SlotTracker);
}
if (!LiveOuts.empty())
O << "\n";
for (const auto &KV : LiveOuts) {
O << "Live-out ";
KV.second->getPhi()->printAsOperand(O);
O << " = ";
KV.second->getOperand(0)->printAsOperand(O, SlotTracker);
O << "\n";
}
O << "}\n";
}
std::string VPlan::getName() const {
std::string Out;
raw_string_ostream RSO(Out);
RSO << Name << " for ";
if (!VFs.empty()) {
RSO << "VF={" << VFs[0];
for (ElementCount VF : drop_begin(VFs))
RSO << "," << VF;
RSO << "},";
}
if (UFs.empty()) {
RSO << "UF>=1";
} else {
RSO << "UF={" << UFs[0];
for (unsigned UF : drop_begin(UFs))
RSO << "," << UF;
RSO << "}";
}
return Out;
}
LLVM_DUMP_METHOD
void VPlan::printDOT(raw_ostream &O) const {
VPlanPrinter Printer(O, *this);
Printer.dump();
}
LLVM_DUMP_METHOD
void VPlan::dump() const { print(dbgs()); }
#endif
void VPlan::addLiveOut(PHINode *PN, VPValue *V) {
assert(LiveOuts.count(PN) == 0 && "an exit value for PN already exists");
LiveOuts.insert({PN, new VPLiveOut(PN, V)});
}
void VPlan::updateDominatorTree(DominatorTree *DT, BasicBlock *LoopHeaderBB,
BasicBlock *LoopLatchBB,
BasicBlock *LoopExitBB) {
// The vector body may be more than a single basic-block by this point.
// Update the dominator tree information inside the vector body by propagating
// it from header to latch, expecting only triangular control-flow, if any.
BasicBlock *PostDomSucc = nullptr;
for (auto *BB = LoopHeaderBB; BB != LoopLatchBB; BB = PostDomSucc) {
// Get the list of successors of this block.
std::vector<BasicBlock *> Succs(succ_begin(BB), succ_end(BB));
assert(Succs.size() <= 2 &&
"Basic block in vector loop has more than 2 successors.");
PostDomSucc = Succs[0];
if (Succs.size() == 1) {
assert(PostDomSucc->getSinglePredecessor() &&
"PostDom successor has more than one predecessor.");
DT->addNewBlock(PostDomSucc, BB);
continue;
}
BasicBlock *InterimSucc = Succs[1];
if (PostDomSucc->getSingleSuccessor() == InterimSucc) {
PostDomSucc = Succs[1];
InterimSucc = Succs[0];
}
assert(InterimSucc->getSingleSuccessor() == PostDomSucc &&
"One successor of a basic block does not lead to the other.");
assert(InterimSucc->getSinglePredecessor() &&
"Interim successor has more than one predecessor.");
assert(PostDomSucc->hasNPredecessors(2) &&
"PostDom successor has more than two predecessors.");
DT->addNewBlock(InterimSucc, BB);
DT->addNewBlock(PostDomSucc, BB);
}
// Latch block is a new dominator for the loop exit.
DT->changeImmediateDominator(LoopExitBB, LoopLatchBB);
assert(DT->verify(DominatorTree::VerificationLevel::Fast));
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
Twine VPlanPrinter::getUID(const VPBlockBase *Block) {
return (isa<VPRegionBlock>(Block) ? "cluster_N" : "N") +
Twine(getOrCreateBID(Block));
}
Twine VPlanPrinter::getOrCreateName(const VPBlockBase *Block) {
const std::string &Name = Block->getName();
if (!Name.empty())
return Name;
return "VPB" + Twine(getOrCreateBID(Block));
}
void VPlanPrinter::dump() {
Depth = 1;
bumpIndent(0);
OS << "digraph VPlan {\n";
OS << "graph [labelloc=t, fontsize=30; label=\"Vectorization Plan";
if (!Plan.getName().empty())
OS << "\\n" << DOT::EscapeString(Plan.getName());
if (Plan.BackedgeTakenCount) {
OS << ", where:\\n";
Plan.BackedgeTakenCount->print(OS, SlotTracker);
OS << " := BackedgeTakenCount";
}
OS << "\"]\n";
OS << "node [shape=rect, fontname=Courier, fontsize=30]\n";
OS << "edge [fontname=Courier, fontsize=30]\n";
OS << "compound=true\n";
for (const VPBlockBase *Block : vp_depth_first_shallow(Plan.getEntry()))
dumpBlock(Block);
OS << "}\n";
}
void VPlanPrinter::dumpBlock(const VPBlockBase *Block) {
if (const VPBasicBlock *BasicBlock = dyn_cast<VPBasicBlock>(Block))
dumpBasicBlock(BasicBlock);
else if (const VPRegionBlock *Region = dyn_cast<VPRegionBlock>(Block))
dumpRegion(Region);
else
llvm_unreachable("Unsupported kind of VPBlock.");
}
void VPlanPrinter::drawEdge(const VPBlockBase *From, const VPBlockBase *To,
bool Hidden, const Twine &Label) {
// Due to "dot" we print an edge between two regions as an edge between the
// exiting basic block and the entry basic of the respective regions.
const VPBlockBase *Tail = From->getExitingBasicBlock();
const VPBlockBase *Head = To->getEntryBasicBlock();
OS << Indent << getUID(Tail) << " -> " << getUID(Head);
OS << " [ label=\"" << Label << '\"';
if (Tail != From)
OS << " ltail=" << getUID(From);
if (Head != To)
OS << " lhead=" << getUID(To);
if (Hidden)
OS << "; splines=none";
OS << "]\n";
}
void VPlanPrinter::dumpEdges(const VPBlockBase *Block) {
auto &Successors = Block->getSuccessors();
if (Successors.size() == 1)
drawEdge(Block, Successors.front(), false, "");
else if (Successors.size() == 2) {
drawEdge(Block, Successors.front(), false, "T");
drawEdge(Block, Successors.back(), false, "F");
} else {
unsigned SuccessorNumber = 0;
for (auto *Successor : Successors)
drawEdge(Block, Successor, false, Twine(SuccessorNumber++));
}
}
void VPlanPrinter::dumpBasicBlock(const VPBasicBlock *BasicBlock) {
// Implement dot-formatted dump by performing plain-text dump into the
// temporary storage followed by some post-processing.
OS << Indent << getUID(BasicBlock) << " [label =\n";
bumpIndent(1);
std::string Str;
raw_string_ostream SS(Str);
// Use no indentation as we need to wrap the lines into quotes ourselves.
BasicBlock->print(SS, "", SlotTracker);
// We need to process each line of the output separately, so split
// single-string plain-text dump.
SmallVector<StringRef, 0> Lines;
StringRef(Str).rtrim('\n').split(Lines, "\n");
auto EmitLine = [&](StringRef Line, StringRef Suffix) {
OS << Indent << '"' << DOT::EscapeString(Line.str()) << "\\l\"" << Suffix;
};
// Don't need the "+" after the last line.
for (auto Line : make_range(Lines.begin(), Lines.end() - 1))
EmitLine(Line, " +\n");
EmitLine(Lines.back(), "\n");
bumpIndent(-1);
OS << Indent << "]\n";
dumpEdges(BasicBlock);
}
void VPlanPrinter::dumpRegion(const VPRegionBlock *Region) {
OS << Indent << "subgraph " << getUID(Region) << " {\n";
bumpIndent(1);
OS << Indent << "fontname=Courier\n"
<< Indent << "label=\""
<< DOT::EscapeString(Region->isReplicator() ? "<xVFxUF> " : "<x1> ")
<< DOT::EscapeString(Region->getName()) << "\"\n";
// Dump the blocks of the region.
assert(Region->getEntry() && "Region contains no inner blocks.");
for (const VPBlockBase *Block : vp_depth_first_shallow(Region->getEntry()))
dumpBlock(Block);
bumpIndent(-1);
OS << Indent << "}\n";
dumpEdges(Region);
}
void VPlanIngredient::print(raw_ostream &O) const {
if (auto *Inst = dyn_cast<Instruction>(V)) {
if (!Inst->getType()->isVoidTy()) {
Inst->printAsOperand(O, false);
O << " = ";
}
O << Inst->getOpcodeName() << " ";
unsigned E = Inst->getNumOperands();
if (E > 0) {
Inst->getOperand(0)->printAsOperand(O, false);
for (unsigned I = 1; I < E; ++I)
Inst->getOperand(I)->printAsOperand(O << ", ", false);
}
} else // !Inst
V->printAsOperand(O, false);
}
#endif
template void DomTreeBuilder::Calculate<VPDominatorTree>(VPDominatorTree &DT);
void VPValue::replaceAllUsesWith(VPValue *New) {
for (unsigned J = 0; J < getNumUsers();) {
VPUser *User = Users[J];
unsigned NumUsers = getNumUsers();
for (unsigned I = 0, E = User->getNumOperands(); I < E; ++I)
if (User->getOperand(I) == this)
User->setOperand(I, New);
// If a user got removed after updating the current user, the next user to
// update will be moved to the current position, so we only need to
// increment the index if the number of users did not change.
if (NumUsers == getNumUsers())
J++;
}
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void VPValue::printAsOperand(raw_ostream &OS, VPSlotTracker &Tracker) const {
if (const Value *UV = getUnderlyingValue()) {
OS << "ir<";
UV->printAsOperand(OS, false);
OS << ">";
return;
}
unsigned Slot = Tracker.getSlot(this);
if (Slot == unsigned(-1))
OS << "<badref>";
else
OS << "vp<%" << Tracker.getSlot(this) << ">";
}
void VPUser::printOperands(raw_ostream &O, VPSlotTracker &SlotTracker) const {
interleaveComma(operands(), O, [&O, &SlotTracker](VPValue *Op) {
Op->printAsOperand(O, SlotTracker);
});
}
#endif
void VPInterleavedAccessInfo::visitRegion(VPRegionBlock *Region,
Old2NewTy &Old2New,
InterleavedAccessInfo &IAI) {
ReversePostOrderTraversal<VPBlockShallowTraversalWrapper<VPBlockBase *>>
RPOT(Region->getEntry());
for (VPBlockBase *Base : RPOT) {
visitBlock(Base, Old2New, IAI);
}
}
void VPInterleavedAccessInfo::visitBlock(VPBlockBase *Block, Old2NewTy &Old2New,
InterleavedAccessInfo &IAI) {
if (VPBasicBlock *VPBB = dyn_cast<VPBasicBlock>(Block)) {
for (VPRecipeBase &VPI : *VPBB) {
if (isa<VPHeaderPHIRecipe>(&VPI))
continue;
assert(isa<VPInstruction>(&VPI) && "Can only handle VPInstructions");
auto *VPInst = cast<VPInstruction>(&VPI);
auto *Inst = dyn_cast_or_null<Instruction>(VPInst->getUnderlyingValue());
if (!Inst)
continue;
auto *IG = IAI.getInterleaveGroup(Inst);
if (!IG)
continue;
auto NewIGIter = Old2New.find(IG);
if (NewIGIter == Old2New.end())
Old2New[IG] = new InterleaveGroup<VPInstruction>(
IG->getFactor(), IG->isReverse(), IG->getAlign());
if (Inst == IG->getInsertPos())
Old2New[IG]->setInsertPos(VPInst);
InterleaveGroupMap[VPInst] = Old2New[IG];
InterleaveGroupMap[VPInst]->insertMember(
VPInst, IG->getIndex(Inst),
Align(IG->isReverse() ? (-1) * int(IG->getFactor())
: IG->getFactor()));
}
} else if (VPRegionBlock *Region = dyn_cast<VPRegionBlock>(Block))
visitRegion(Region, Old2New, IAI);
else
llvm_unreachable("Unsupported kind of VPBlock.");
}
VPInterleavedAccessInfo::VPInterleavedAccessInfo(VPlan &Plan,
InterleavedAccessInfo &IAI) {
Old2NewTy Old2New;
visitRegion(Plan.getVectorLoopRegion(), Old2New, IAI);
}
void VPSlotTracker::assignSlot(const VPValue *V) {
assert(!Slots.contains(V) && "VPValue already has a slot!");
Slots[V] = NextSlot++;
}
void VPSlotTracker::assignSlots(const VPlan &Plan) {
assignSlot(&Plan.VectorTripCount);
if (Plan.BackedgeTakenCount)
assignSlot(Plan.BackedgeTakenCount);
if (Plan.TripCount)
assignSlot(Plan.TripCount);
ReversePostOrderTraversal<VPBlockDeepTraversalWrapper<const VPBlockBase *>>
RPOT(VPBlockDeepTraversalWrapper<const VPBlockBase *>(Plan.getEntry()));
for (const VPBasicBlock *VPBB :
VPBlockUtils::blocksOnly<const VPBasicBlock>(RPOT))
for (const VPRecipeBase &Recipe : *VPBB)
for (VPValue *Def : Recipe.definedValues())
assignSlot(Def);
}
bool vputils::onlyFirstLaneUsed(VPValue *Def) {
return all_of(Def->users(),
[Def](VPUser *U) { return U->onlyFirstLaneUsed(Def); });
}
VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr,
ScalarEvolution &SE) {
if (auto *E = dyn_cast<SCEVConstant>(Expr))
return Plan.getVPValueOrAddLiveIn(E->getValue());
if (auto *E = dyn_cast<SCEVUnknown>(Expr))
return Plan.getVPValueOrAddLiveIn(E->getValue());
VPBasicBlock *Preheader = Plan.getEntry()->getEntryBasicBlock();
VPExpandSCEVRecipe *Step = new VPExpandSCEVRecipe(Expr, SE);
Preheader->appendRecipe(Step);
return Step;
}
Reference in New Issue View Git Blame Copy Permalink