void BlockGenerator::copyBB(ScopStmt &Stmt, BasicBlock *BB, BasicBlock *CopyBB,
ValueMapT &BBMap, ValueMapT &GlobalMap,
LoopToScevMapT <S) {
Builder.SetInsertPoint(CopyBB->begin());
EntryBB = &CopyBB->getParent()->getEntryBlock();
for (Instruction &Inst : *BB)
copyInstruction(Stmt, &Inst, BBMap, GlobalMap, LTS);
// After a basic block was copied store all scalars that escape this block
// in their alloca. First the scalars that have dependences inside the SCoP,
// then the ones that might escape the SCoP.
generateScalarStores(Stmt, BB, BBMap, GlobalMap);
const Region &R = Stmt.getParent()->getRegion();
for (Instruction &Inst : *BB)
handleOutsideUsers(R, &Inst, BBMap[&Inst]);
}
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 BlockGenerator::generateScalarStores(ScopStmt &Stmt, BasicBlock *BB,
ValueMapT &BBMap,
ValueMapT &GlobalMap) {
const Region &R = Stmt.getParent()->getRegion();
assert(Stmt.isBlockStmt() && BB == Stmt.getBasicBlock() &&
"Region statements need to use the generateScalarStores() "
"function in the RegionGenerator");
// Set to remember a store to the phiops alloca of a PHINode. It is needed as
// we might have multiple write accesses to the same PHI and while one is the
// self write of the PHI (to the ScalarMap alloca) the other is the write to
// the operand alloca (PHIOpMap).
SmallPtrSet<PHINode *, 4> SeenPHIs;
// Iterate over all accesses in the given statement.
for (MemoryAccess *MA : Stmt) {
// Skip non-scalar and read accesses.
if (!MA->isScalar() || MA->isRead())
continue;
Instruction *ScalarBase = cast<Instruction>(MA->getBaseAddr());
Instruction *ScalarInst = MA->getAccessInstruction();
PHINode *ScalarBasePHI = dyn_cast<PHINode>(ScalarBase);
// Get the alloca node for the base instruction and the value we want to
// store. In total there are 4 options:
// (1) The base is no PHI, hence it is a simple scalar def-use chain.
// (2) The base is a PHI,
// (a) and the write is caused by an operand in the block.
// (b) and it is the PHI self write (same as case (1)).
// (c) (2a) and (2b) are not distinguishable.
// For case (1) and (2b) we get the alloca from the scalar map and the value
// we want to store is initialized with the instruction attached to the
// memory access. For case (2a) we get the alloca from the PHI operand map
// and the value we want to store is initialized with the incoming value for
// this block. The tricky case (2c) is when both (2a) and (2b) match. This
// happens if the PHI operand is in the same block as the PHI. To handle
// that we choose the alloca of (2a) first and (2b) for the next write
// access to that PHI (there must be 2).
Value *ScalarValue = nullptr;
AllocaInst *ScalarAddr = nullptr;
if (!ScalarBasePHI) {
// Case (1)
ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a");
ScalarValue = ScalarInst;
} else {
int PHIIdx = ScalarBasePHI->getBasicBlockIndex(BB);
if (ScalarBasePHI != ScalarInst) {
// Case (2a)
assert(PHIIdx >= 0 && "Bad scalar write to PHI operand");
SeenPHIs.insert(ScalarBasePHI);
ScalarAddr = getOrCreateAlloca(ScalarBase, PHIOpMap, ".phiops");
ScalarValue = ScalarBasePHI->getIncomingValue(PHIIdx);
} else if (PHIIdx < 0) {
// Case (2b)
ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a");
ScalarValue = ScalarInst;
} else {
// Case (2c)
if (SeenPHIs.insert(ScalarBasePHI).second) {
// First access ==> same as (2a)
ScalarAddr = getOrCreateAlloca(ScalarBase, PHIOpMap, ".phiops");
ScalarValue = ScalarBasePHI->getIncomingValue(PHIIdx);
} else {
// Second access ==> same as (2b)
ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a");
ScalarValue = ScalarInst;
}
}
}
ScalarValue =
getNewScalarValue(ScalarValue, R, ScalarMap, BBMap, GlobalMap);
Builder.CreateStore(ScalarValue, ScalarAddr);
}
}
void BlockGenerator::copyInstruction(ScopStmt &Stmt, const Instruction *Inst,
ValueMapT &BBMap, ValueMapT &GlobalMap,
LoopToScevMapT <S) {
// First check for possible scalar dependences for this instruction.
generateScalarLoads(Stmt, Inst, BBMap);
// Terminator instructions control the control flow. They are explicitly
// expressed in the clast and do not need to be copied.
if (Inst->isTerminator())
return;
Loop *L = getLoopForInst(Inst);
if ((Stmt.isBlockStmt() || !Stmt.getRegion()->contains(L)) &&
canSynthesize(Inst, &LI, &SE, &Stmt.getParent()->getRegion())) {
Value *NewValue = getNewValue(Stmt, Inst, BBMap, GlobalMap, LTS, L);
BBMap[Inst] = NewValue;
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;
}
if (const PHINode *PHI = dyn_cast<PHINode>(Inst)) {
copyPHIInstruction(Stmt, PHI, BBMap, GlobalMap, LTS);
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 RegionGenerator::generateScalarStores(ScopStmt &Stmt, BasicBlock *BB,
ValueMapT &BBMap,
ValueMapT &GlobalMap) {
const Region &R = Stmt.getParent()->getRegion();
Region *StmtR = Stmt.getRegion();
assert(StmtR && "Block statements need to use the generateScalarStores() "
"function in the BlockGenerator");
BasicBlock *ExitBB = StmtR->getExit();
// For region statements three kinds of scalar stores exists:
// (1) A definition used by a non-phi instruction outside the region.
// (2) A phi-instruction in the region entry.
// (3) A write to a phi instruction in the region exit.
// The last case is the tricky one since we do not know anymore which
// predecessor of the exit needs to store the operand value that doesn't
// have a definition in the region. Therefore, we have to check in each
// block in the region if we should store the value or not.
// Iterate over all accesses in the given statement.
for (MemoryAccess *MA : Stmt) {
// Skip non-scalar and read accesses.
if (!MA->isScalar() || MA->isRead())
continue;
Instruction *ScalarBase = cast<Instruction>(MA->getBaseAddr());
Instruction *ScalarInst = MA->getAccessInstruction();
PHINode *ScalarBasePHI = dyn_cast<PHINode>(ScalarBase);
Value *ScalarValue = nullptr;
AllocaInst *ScalarAddr = nullptr;
if (!ScalarBasePHI) {
// Case (1)
ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a");
ScalarValue = ScalarInst;
} else if (ScalarBasePHI->getParent() != ExitBB) {
// Case (2)
assert(ScalarBasePHI->getParent() == StmtR->getEntry() &&
"Bad PHI self write in non-affine region");
assert(ScalarBase == ScalarInst &&
"Bad PHI self write in non-affine region");
ScalarAddr = getOrCreateAlloca(ScalarBase, ScalarMap, ".s2a");
ScalarValue = ScalarInst;
} else {
int PHIIdx = ScalarBasePHI->getBasicBlockIndex(BB);
// Skip accesses we will not handle in this basic block but in another one
// in the statement region.
if (PHIIdx < 0)
continue;
// Case (3)
ScalarAddr = getOrCreateAlloca(ScalarBase, PHIOpMap, ".phiops");
ScalarValue = ScalarBasePHI->getIncomingValue(PHIIdx);
}
ScalarValue =
getNewScalarValue(ScalarValue, R, ScalarMap, BBMap, GlobalMap);
Builder.CreateStore(ScalarValue, ScalarAddr);
}
}
