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llvm-project/polly/lib/CodeGen/BlockGenerators.cpp

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//===--- BlockGenerators.cpp - Generate code for statements -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the BlockGenerator and VectorBlockGenerator classes,
// which generate sequential code and vectorized code for a polyhedral
// statement, respectively.
//
//===----------------------------------------------------------------------===//
#include "polly/ScopInfo.h"
#include "polly/CodeGen/BlockGenerators.h"
#include "polly/CodeGen/CodeGeneration.h"
#include "polly/CodeGen/IslExprBuilder.h"
#include "polly/Options.h"
#include "polly/Support/GICHelper.h"
#include "polly/Support/SCEVValidator.h"
#include "polly/Support/ScopHelper.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/RegionInfo.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "isl/aff.h"
#include "isl/ast.h"
#include "isl/set.h"
#include "isl/ast_build.h"
#include <deque>
using namespace llvm;
using namespace polly;
static cl::opt<bool> Aligned("enable-polly-aligned",
cl::desc("Assumed aligned memory accesses."),
cl::Hidden, cl::init(false), cl::ZeroOrMore,
cl::cat(PollyCategory));
bool polly::canSynthesize(const Instruction *I, const llvm::LoopInfo *LI,
ScalarEvolution *SE, const Region *R) {
if (!I || !SE->isSCEVable(I->getType()))
return false;
if (const SCEV *Scev = SE->getSCEV(const_cast<Instruction *>(I)))
if (!isa<SCEVCouldNotCompute>(Scev))
if (!hasScalarDepsInsideRegion(Scev, R))
return true;
return false;
}
bool polly::isIgnoredIntrinsic(const Value *V) {
if (auto *IT = dyn_cast<IntrinsicInst>(V)) {
switch (IT->getIntrinsicID()) {
// Lifetime markers are supported/ignored.
case llvm::Intrinsic::lifetime_start:
case llvm::Intrinsic::lifetime_end:
// Invariant markers are supported/ignored.
case llvm::Intrinsic::invariant_start:
case llvm::Intrinsic::invariant_end:
// Some misc annotations are supported/ignored.
case llvm::Intrinsic::var_annotation:
case llvm::Intrinsic::ptr_annotation:
case llvm::Intrinsic::annotation:
case llvm::Intrinsic::donothing:
case llvm::Intrinsic::assume:
case llvm::Intrinsic::expect:
return true;
default:
break;
}
}
return false;
}
BlockGenerator::BlockGenerator(PollyIRBuilder &B, LoopInfo &LI,
ScalarEvolution &SE, DominatorTree &DT,
IslExprBuilder *ExprBuilder)
: Builder(B), LI(LI), SE(SE), ExprBuilder(ExprBuilder), DT(DT) {}
Value *BlockGenerator::getNewValue(ScopStmt &Stmt, const Value *Old,
ValueMapT &BBMap, ValueMapT &GlobalMap,
LoopToScevMapT &LTS, Loop *L) const {
// We assume constants never change.
// This avoids map lookups for many calls to this function.
if (isa<Constant>(Old))
return const_cast<Value *>(Old);
if (Value *New = GlobalMap.lookup(Old)) {
if (Old->getType()->getScalarSizeInBits() <
New->getType()->getScalarSizeInBits())
New = Builder.CreateTruncOrBitCast(New, Old->getType());
return New;
}
if (Value *New = BBMap.lookup(Old))
return New;
if (SE.isSCEVable(Old->getType()))
if (const SCEV *Scev = SE.getSCEVAtScope(const_cast<Value *>(Old), L)) {
if (!isa<SCEVCouldNotCompute>(Scev)) {
const SCEV *NewScev = apply(Scev, LTS, SE);
ValueToValueMap VTV;
VTV.insert(BBMap.begin(), BBMap.end());
VTV.insert(GlobalMap.begin(), GlobalMap.end());
NewScev = SCEVParameterRewriter::rewrite(NewScev, SE, VTV);
SCEVExpander Expander(SE, Stmt.getParent()
->getRegion()
.getEntry()
->getParent()
->getParent()
->getDataLayout(),
"polly");
Value *Expanded = Expander.expandCodeFor(NewScev, Old->getType(),
Builder.GetInsertPoint());
BBMap[Old] = Expanded;
return Expanded;
}
}
// A scop-constant value defined by a global or a function parameter.
if (isa<GlobalValue>(Old) || isa<Argument>(Old))
return const_cast<Value *>(Old);
// A scop-constant value defined by an instruction executed outside the scop.
if (const Instruction *Inst = dyn_cast<Instruction>(Old))
if (!Stmt.getParent()->getRegion().contains(Inst->getParent()))
return const_cast<Value *>(Old);
// The scalar dependence is neither available nor SCEVCodegenable.
llvm_unreachable("Unexpected scalar dependence in region!");
return nullptr;
}
void BlockGenerator::copyInstScalar(ScopStmt &Stmt, const Instruction *Inst,
ValueMapT &BBMap, ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
// We do not generate debug intrinsics as we did not investigate how to
// copy them correctly. At the current state, they just crash the code
// generation as the meta-data operands are not correctly copied.
if (isa<DbgInfoIntrinsic>(Inst))
return;
Instruction *NewInst = Inst->clone();
// Replace old operands with the new ones.
for (Value *OldOperand : Inst->operands()) {
Value *NewOperand = getNewValue(Stmt, OldOperand, BBMap, GlobalMap, LTS,
getLoopForInst(Inst));
if (!NewOperand) {
assert(!isa<StoreInst>(NewInst) &&
"Store instructions are always needed!");
delete NewInst;
return;
}
NewInst->replaceUsesOfWith(OldOperand, NewOperand);
}
Builder.Insert(NewInst);
BBMap[Inst] = NewInst;
if (!NewInst->getType()->isVoidTy())
NewInst->setName("p_" + Inst->getName());
}
Value *BlockGenerator::getNewAccessOperand(ScopStmt &Stmt,
const MemoryAccess &MA) {
isl_pw_multi_aff *PWAccRel;
isl_union_map *Schedule;
isl_ast_expr *Expr;
isl_ast_build *Build = Stmt.getAstBuild();
assert(ExprBuilder && Build &&
"Cannot generate new value without IslExprBuilder!");
Schedule = isl_ast_build_get_schedule(Build);
PWAccRel = MA.applyScheduleToAccessRelation(Schedule);
Expr = isl_ast_build_access_from_pw_multi_aff(Build, PWAccRel);
Expr = isl_ast_expr_address_of(Expr);
return ExprBuilder->create(Expr);
}
Value *BlockGenerator::generateLocationAccessed(
ScopStmt &Stmt, const Instruction *Inst, const Value *Pointer,
ValueMapT &BBMap, ValueMapT &GlobalMap, LoopToScevMapT &LTS) {
const MemoryAccess &MA = Stmt.getAccessFor(Inst);
Value *NewPointer;
if (MA.hasNewAccessRelation())
NewPointer = getNewAccessOperand(Stmt, MA);
else
NewPointer =
getNewValue(Stmt, Pointer, BBMap, GlobalMap, LTS, getLoopForInst(Inst));
return NewPointer;
}
Loop *BlockGenerator::getLoopForInst(const llvm::Instruction *Inst) {
return LI.getLoopFor(Inst->getParent());
}
Value *BlockGenerator::generateScalarLoad(ScopStmt &Stmt, const LoadInst *Load,
ValueMapT &BBMap,
ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
const Value *Pointer = Load->getPointerOperand();
Value *NewPointer =
generateLocationAccessed(Stmt, Load, Pointer, BBMap, GlobalMap, LTS);
Value *ScalarLoad = Builder.CreateAlignedLoad(
NewPointer, Load->getAlignment(), Load->getName() + "_p_scalar_");
return ScalarLoad;
}
Value *BlockGenerator::generateScalarStore(ScopStmt &Stmt,
const StoreInst *Store,
ValueMapT &BBMap,
ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
const Value *Pointer = Store->getPointerOperand();
Value *NewPointer =
generateLocationAccessed(Stmt, Store, Pointer, BBMap, GlobalMap, LTS);
Value *ValueOperand = getNewValue(Stmt, Store->getValueOperand(), BBMap,
GlobalMap, LTS, getLoopForInst(Store));
Value *NewStore = Builder.CreateAlignedStore(ValueOperand, NewPointer,
Store->getAlignment());
return NewStore;
}
void BlockGenerator::copyInstruction(ScopStmt &Stmt, const Instruction *Inst,
ValueMapT &BBMap, ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
// Terminator instructions control the control flow. They are explicitly
// expressed in the clast and do not need to be copied.
if (Inst->isTerminator())
return;
if (canSynthesize(Inst, &LI, &SE, &Stmt.getParent()->getRegion()))
return;
if (const LoadInst *Load = dyn_cast<LoadInst>(Inst)) {
Value *NewLoad = generateScalarLoad(Stmt, Load, BBMap, GlobalMap, LTS);
// Compute NewLoad before its insertion in BBMap to make the insertion
// deterministic.
BBMap[Load] = NewLoad;
return;
}
if (const StoreInst *Store = dyn_cast<StoreInst>(Inst)) {
Value *NewStore = generateScalarStore(Stmt, Store, BBMap, GlobalMap, LTS);
// Compute NewStore before its insertion in BBMap to make the insertion
// deterministic.
BBMap[Store] = NewStore;
return;
}
// Skip some special intrinsics for which we do not adjust the semantics to
// the new schedule. All others are handled like every other instruction.
if (auto *IT = dyn_cast<IntrinsicInst>(Inst)) {
switch (IT->getIntrinsicID()) {
// Lifetime markers are ignored.
case llvm::Intrinsic::lifetime_start:
case llvm::Intrinsic::lifetime_end:
// Invariant markers are ignored.
case llvm::Intrinsic::invariant_start:
case llvm::Intrinsic::invariant_end:
// Some misc annotations are ignored.
case llvm::Intrinsic::var_annotation:
case llvm::Intrinsic::ptr_annotation:
case llvm::Intrinsic::annotation:
case llvm::Intrinsic::donothing:
case llvm::Intrinsic::assume:
case llvm::Intrinsic::expect:
return;
default:
// Other intrinsics are copied.
break;
}
}
copyInstScalar(Stmt, Inst, BBMap, GlobalMap, LTS);
}
void BlockGenerator::copyStmt(ScopStmt &Stmt, ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
assert(Stmt.isBlockStmt() &&
"Only block statements can be copied by the block generator");
ValueMapT BBMap;
BasicBlock *BB = Stmt.getBasicBlock();
copyBB(Stmt, BB, BBMap, GlobalMap, LTS);
}
BasicBlock *BlockGenerator::splitBB(BasicBlock *BB) {
BasicBlock *CopyBB =
SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI);
CopyBB->setName("polly.stmt." + BB->getName());
return CopyBB;
}
BasicBlock *BlockGenerator::copyBB(ScopStmt &Stmt, BasicBlock *BB,
ValueMapT &BBMap, ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
BasicBlock *CopyBB = splitBB(BB);
copyBB(Stmt, BB, CopyBB, BBMap, GlobalMap, LTS);
return CopyBB;
}
void BlockGenerator::copyBB(ScopStmt &Stmt, BasicBlock *BB, BasicBlock *CopyBB,
ValueMapT &BBMap, ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
Builder.SetInsertPoint(CopyBB->begin());
for (Instruction &Inst : *BB)
copyInstruction(Stmt, &Inst, BBMap, GlobalMap, LTS);
}
VectorBlockGenerator::VectorBlockGenerator(BlockGenerator &BlockGen,
VectorValueMapT &GlobalMaps,
std::vector<LoopToScevMapT> &VLTS,
isl_map *Schedule)
: BlockGenerator(BlockGen), GlobalMaps(GlobalMaps), VLTS(VLTS),
Schedule(Schedule) {
assert(GlobalMaps.size() > 1 && "Only one vector lane found");
assert(Schedule && "No statement domain provided");
}
Value *VectorBlockGenerator::getVectorValue(ScopStmt &Stmt, const Value *Old,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps,
Loop *L) {
if (Value *NewValue = VectorMap.lookup(Old))
return NewValue;
int Width = getVectorWidth();
Value *Vector = UndefValue::get(VectorType::get(Old->getType(), Width));
for (int Lane = 0; Lane < Width; Lane++)
Vector = Builder.CreateInsertElement(
Vector, getNewValue(Stmt, Old, ScalarMaps[Lane], GlobalMaps[Lane],
VLTS[Lane], L),
Builder.getInt32(Lane));
VectorMap[Old] = Vector;
return Vector;
}
Type *VectorBlockGenerator::getVectorPtrTy(const Value *Val, int Width) {
PointerType *PointerTy = dyn_cast<PointerType>(Val->getType());
assert(PointerTy && "PointerType expected");
Type *ScalarType = PointerTy->getElementType();
VectorType *VectorType = VectorType::get(ScalarType, Width);
return PointerType::getUnqual(VectorType);
}
Value *VectorBlockGenerator::generateStrideOneLoad(
ScopStmt &Stmt, const LoadInst *Load, VectorValueMapT &ScalarMaps,
bool NegativeStride = false) {
unsigned VectorWidth = getVectorWidth();
const Value *Pointer = Load->getPointerOperand();
Type *VectorPtrType = getVectorPtrTy(Pointer, VectorWidth);
unsigned Offset = NegativeStride ? VectorWidth - 1 : 0;
Value *NewPointer = nullptr;
NewPointer = generateLocationAccessed(Stmt, Load, Pointer, ScalarMaps[Offset],
GlobalMaps[Offset], VLTS[Offset]);
Value *VectorPtr =
Builder.CreateBitCast(NewPointer, VectorPtrType, "vector_ptr");
LoadInst *VecLoad =
Builder.CreateLoad(VectorPtr, Load->getName() + "_p_vec_full");
if (!Aligned)
VecLoad->setAlignment(8);
if (NegativeStride) {
SmallVector<Constant *, 16> Indices;
for (int i = VectorWidth - 1; i >= 0; i--)
Indices.push_back(ConstantInt::get(Builder.getInt32Ty(), i));
Constant *SV = llvm::ConstantVector::get(Indices);
Value *RevVecLoad = Builder.CreateShuffleVector(
VecLoad, VecLoad, SV, Load->getName() + "_reverse");
return RevVecLoad;
}
return VecLoad;
}
Value *VectorBlockGenerator::generateStrideZeroLoad(ScopStmt &Stmt,
const LoadInst *Load,
ValueMapT &BBMap) {
const Value *Pointer = Load->getPointerOperand();
Type *VectorPtrType = getVectorPtrTy(Pointer, 1);
Value *NewPointer = generateLocationAccessed(Stmt, Load, Pointer, BBMap,
GlobalMaps[0], VLTS[0]);
Value *VectorPtr = Builder.CreateBitCast(NewPointer, VectorPtrType,
Load->getName() + "_p_vec_p");
LoadInst *ScalarLoad =
Builder.CreateLoad(VectorPtr, Load->getName() + "_p_splat_one");
if (!Aligned)
ScalarLoad->setAlignment(8);
Constant *SplatVector = Constant::getNullValue(
VectorType::get(Builder.getInt32Ty(), getVectorWidth()));
Value *VectorLoad = Builder.CreateShuffleVector(
ScalarLoad, ScalarLoad, SplatVector, Load->getName() + "_p_splat");
return VectorLoad;
}
Value *VectorBlockGenerator::generateUnknownStrideLoad(
ScopStmt &Stmt, const LoadInst *Load, VectorValueMapT &ScalarMaps) {
int VectorWidth = getVectorWidth();
const Value *Pointer = Load->getPointerOperand();
VectorType *VectorType = VectorType::get(
dyn_cast<PointerType>(Pointer->getType())->getElementType(), VectorWidth);
Value *Vector = UndefValue::get(VectorType);
for (int i = 0; i < VectorWidth; i++) {
Value *NewPointer = generateLocationAccessed(
Stmt, Load, Pointer, ScalarMaps[i], GlobalMaps[i], VLTS[i]);
Value *ScalarLoad =
Builder.CreateLoad(NewPointer, Load->getName() + "_p_scalar_");
Vector = Builder.CreateInsertElement(
Vector, ScalarLoad, Builder.getInt32(i), Load->getName() + "_p_vec_");
}
return Vector;
}
void VectorBlockGenerator::generateLoad(ScopStmt &Stmt, const LoadInst *Load,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps) {
if (!VectorType::isValidElementType(Load->getType())) {
for (int i = 0; i < getVectorWidth(); i++)
ScalarMaps[i][Load] =
generateScalarLoad(Stmt, Load, ScalarMaps[i], GlobalMaps[i], VLTS[i]);
return;
}
const MemoryAccess &Access = Stmt.getAccessFor(Load);
// Make sure we have scalar values available to access the pointer to
// the data location.
extractScalarValues(Load, VectorMap, ScalarMaps);
Value *NewLoad;
if (Access.isStrideZero(isl_map_copy(Schedule)))
NewLoad = generateStrideZeroLoad(Stmt, Load, ScalarMaps[0]);
else if (Access.isStrideOne(isl_map_copy(Schedule)))
NewLoad = generateStrideOneLoad(Stmt, Load, ScalarMaps);
else if (Access.isStrideX(isl_map_copy(Schedule), -1))
NewLoad = generateStrideOneLoad(Stmt, Load, ScalarMaps, true);
else
NewLoad = generateUnknownStrideLoad(Stmt, Load, ScalarMaps);
VectorMap[Load] = NewLoad;
}
void VectorBlockGenerator::copyUnaryInst(ScopStmt &Stmt,
const UnaryInstruction *Inst,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps) {
int VectorWidth = getVectorWidth();
Value *NewOperand = getVectorValue(Stmt, Inst->getOperand(0), VectorMap,
ScalarMaps, getLoopForInst(Inst));
assert(isa<CastInst>(Inst) && "Can not generate vector code for instruction");
const CastInst *Cast = dyn_cast<CastInst>(Inst);
VectorType *DestType = VectorType::get(Inst->getType(), VectorWidth);
VectorMap[Inst] = Builder.CreateCast(Cast->getOpcode(), NewOperand, DestType);
}
void VectorBlockGenerator::copyBinaryInst(ScopStmt &Stmt,
const BinaryOperator *Inst,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps) {
Loop *L = getLoopForInst(Inst);
Value *OpZero = Inst->getOperand(0);
Value *OpOne = Inst->getOperand(1);
Value *NewOpZero, *NewOpOne;
NewOpZero = getVectorValue(Stmt, OpZero, VectorMap, ScalarMaps, L);
NewOpOne = getVectorValue(Stmt, OpOne, VectorMap, ScalarMaps, L);
Value *NewInst = Builder.CreateBinOp(Inst->getOpcode(), NewOpZero, NewOpOne,
Inst->getName() + "p_vec");
VectorMap[Inst] = NewInst;
}
void VectorBlockGenerator::copyStore(ScopStmt &Stmt, const StoreInst *Store,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps) {
const MemoryAccess &Access = Stmt.getAccessFor(Store);
const Value *Pointer = Store->getPointerOperand();
Value *Vector = getVectorValue(Stmt, Store->getValueOperand(), VectorMap,
ScalarMaps, getLoopForInst(Store));
// Make sure we have scalar values available to access the pointer to
// the data location.
extractScalarValues(Store, VectorMap, ScalarMaps);
if (Access.isStrideOne(isl_map_copy(Schedule))) {
Type *VectorPtrType = getVectorPtrTy(Pointer, getVectorWidth());
Value *NewPointer = generateLocationAccessed(
Stmt, Store, Pointer, ScalarMaps[0], GlobalMaps[0], VLTS[0]);
Value *VectorPtr =
Builder.CreateBitCast(NewPointer, VectorPtrType, "vector_ptr");
StoreInst *Store = Builder.CreateStore(Vector, VectorPtr);
if (!Aligned)
Store->setAlignment(8);
} else {
for (unsigned i = 0; i < ScalarMaps.size(); i++) {
Value *Scalar = Builder.CreateExtractElement(Vector, Builder.getInt32(i));
Value *NewPointer = generateLocationAccessed(
Stmt, Store, Pointer, ScalarMaps[i], GlobalMaps[i], VLTS[i]);
Builder.CreateStore(Scalar, NewPointer);
}
}
}
bool VectorBlockGenerator::hasVectorOperands(const Instruction *Inst,
ValueMapT &VectorMap) {
for (Value *Operand : Inst->operands())
if (VectorMap.count(Operand))
return true;
return false;
}
bool VectorBlockGenerator::extractScalarValues(const Instruction *Inst,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps) {
bool HasVectorOperand = false;
int VectorWidth = getVectorWidth();
for (Value *Operand : Inst->operands()) {
ValueMapT::iterator VecOp = VectorMap.find(Operand);
if (VecOp == VectorMap.end())
continue;
HasVectorOperand = true;
Value *NewVector = VecOp->second;
for (int i = 0; i < VectorWidth; ++i) {
ValueMapT &SM = ScalarMaps[i];
// If there is one scalar extracted, all scalar elements should have
// already been extracted by the code here. So no need to check for the
// existance of all of them.
if (SM.count(Operand))
break;
SM[Operand] =
Builder.CreateExtractElement(NewVector, Builder.getInt32(i));
}
}
return HasVectorOperand;
}
void VectorBlockGenerator::copyInstScalarized(ScopStmt &Stmt,
const Instruction *Inst,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps) {
bool HasVectorOperand;
int VectorWidth = getVectorWidth();
HasVectorOperand = extractScalarValues(Inst, VectorMap, ScalarMaps);
for (int VectorLane = 0; VectorLane < getVectorWidth(); VectorLane++)
BlockGenerator::copyInstruction(Stmt, Inst, ScalarMaps[VectorLane],
GlobalMaps[VectorLane], VLTS[VectorLane]);
if (!VectorType::isValidElementType(Inst->getType()) || !HasVectorOperand)
return;
// Make the result available as vector value.
VectorType *VectorType = VectorType::get(Inst->getType(), VectorWidth);
Value *Vector = UndefValue::get(VectorType);
for (int i = 0; i < VectorWidth; i++)
Vector = Builder.CreateInsertElement(Vector, ScalarMaps[i][Inst],
Builder.getInt32(i));
VectorMap[Inst] = Vector;
}
int VectorBlockGenerator::getVectorWidth() { return GlobalMaps.size(); }
void VectorBlockGenerator::copyInstruction(ScopStmt &Stmt,
const Instruction *Inst,
ValueMapT &VectorMap,
VectorValueMapT &ScalarMaps) {
// Terminator instructions control the control flow. They are explicitly
// expressed in the clast and do not need to be copied.
if (Inst->isTerminator())
return;
if (canSynthesize(Inst, &LI, &SE, &Stmt.getParent()->getRegion()))
return;
if (const LoadInst *Load = dyn_cast<LoadInst>(Inst)) {
generateLoad(Stmt, Load, VectorMap, ScalarMaps);
return;
}
if (hasVectorOperands(Inst, VectorMap)) {
if (const StoreInst *Store = dyn_cast<StoreInst>(Inst)) {
copyStore(Stmt, Store, VectorMap, ScalarMaps);
return;
}
if (const UnaryInstruction *Unary = dyn_cast<UnaryInstruction>(Inst)) {
copyUnaryInst(Stmt, Unary, VectorMap, ScalarMaps);
return;
}
if (const BinaryOperator *Binary = dyn_cast<BinaryOperator>(Inst)) {
copyBinaryInst(Stmt, Binary, VectorMap, ScalarMaps);
return;
}
// Falltrough: We generate scalar instructions, if we don't know how to
// generate vector code.
}
copyInstScalarized(Stmt, Inst, VectorMap, ScalarMaps);
}
void VectorBlockGenerator::copyStmt(ScopStmt &Stmt) {
assert(Stmt.isBlockStmt() && "TODO: Only block statements can be copied by "
"the vector block generator");
BasicBlock *BB = Stmt.getBasicBlock();
BasicBlock *CopyBB =
SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI);
CopyBB->setName("polly.stmt." + BB->getName());
Builder.SetInsertPoint(CopyBB->begin());
// Create two maps that store the mapping from the original instructions of
// the old basic block to their copies in the new basic block. Those maps
// are basic block local.
//
// As vector code generation is supported there is one map for scalar values
// and one for vector values.
//
// In case we just do scalar code generation, the vectorMap is not used and
// the scalarMap has just one dimension, which contains the mapping.
//
// In case vector code generation is done, an instruction may either appear
// in the vector map once (as it is calculating >vectorwidth< values at a
// time. Or (if the values are calculated using scalar operations), it
// appears once in every dimension of the scalarMap.
VectorValueMapT ScalarBlockMap(getVectorWidth());
ValueMapT VectorBlockMap;
for (Instruction &Inst : *BB)
copyInstruction(Stmt, &Inst, VectorBlockMap, ScalarBlockMap);
}
BasicBlock *RegionGenerator::repairDominance(
BasicBlock *BB, BasicBlock *BBCopy,
DenseMap<BasicBlock *, BasicBlock *> &BlockMap) {
BasicBlock *BBIDom = DT.getNode(BB)->getIDom()->getBlock();
BasicBlock *BBCopyIDom = BlockMap.lookup(BBIDom);
if (BBCopyIDom)
DT.changeImmediateDominator(BBCopy, BBCopyIDom);
return BBCopyIDom;
}
void RegionGenerator::copyStmt(ScopStmt &Stmt, ValueMapT &GlobalMap,
LoopToScevMapT &LTS) {
assert(Stmt.isRegionStmt() &&
"Only region statements can be copied by the block generator");
// The region represented by the statement.
Region *R = Stmt.getRegion();
// The "BBMaps" for the whole region.
DenseMap<BasicBlock *, ValueMapT> RegionMaps;
// A map from old to new blocks in the region
DenseMap<BasicBlock *, BasicBlock *> BlockMap;
// Iterate over all blocks in the region in a breadth-first search.
std::deque<BasicBlock *> Blocks;
SmallPtrSet<BasicBlock *, 8> SeenBlocks;
Blocks.push_back(R->getEntry());
SeenBlocks.insert(R->getEntry());
while (!Blocks.empty()) {
BasicBlock *BB = Blocks.front();
Blocks.pop_front();
// First split the block and update dominance information.
BasicBlock *BBCopy = splitBB(BB);
BasicBlock *BBCopyIDom = repairDominance(BB, BBCopy, BlockMap);
// Get the mapping for this block and initialize it with the mapping
// available at its immediate dominator (in the new region).
ValueMapT &RegionMap = RegionMaps[BBCopy];
RegionMap = RegionMaps[BBCopyIDom];
// Copy the block with the BlockGenerator.
copyBB(Stmt, BB, BBCopy, RegionMap, GlobalMap, LTS);
// And continue with new successors inside the region.
for (auto SI = succ_begin(BB), SE = succ_end(BB); SI != SE; SI++)
if (R->contains(*SI) && SeenBlocks.insert(*SI).second)
Blocks.push_back(*SI);
// In order to remap PHI nodes we store also basic block mappings.
BlockMap[BB] = BBCopy;
}
// Now create a new dedicated region exit block and add it to the region map.
BasicBlock *ExitBBCopy =
SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI);
ExitBBCopy->setName("polly.stmt." + R->getExit()->getName() + ".as.exit");
BlockMap[R->getExit()] = ExitBBCopy;
repairDominance(R->getExit(), ExitBBCopy, BlockMap);
// As the block generator doesn't handle control flow we need to add the
// region control flow by hand after all blocks have been copied.
for (BasicBlock *BB : SeenBlocks) {
BranchInst *BI = cast<BranchInst>(BB->getTerminator());
BasicBlock *BBCopy = BlockMap[BB];
Instruction *BICopy = BBCopy->getTerminator();
ValueMapT &RegionMap = RegionMaps[BBCopy];
RegionMap.insert(BlockMap.begin(), BlockMap.end());
Builder.SetInsertPoint(BBCopy);
copyInstScalar(Stmt, BI, RegionMap, GlobalMap, LTS);
BICopy->eraseFromParent();
}
// Reset the old insert point for the build.
Builder.SetInsertPoint(ExitBBCopy->begin());
}
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