// Only allow direct and non-volatile loads and stores...
for (Value::const_use_iterator UI = AI->use_begin(), UE = AI->use_end();
- UI != UE; ++UI) { // Loop over all of the uses of the alloca
+ UI != UE; ++UI) { // Loop over all of the uses of the alloca
const User *U = *UI;
if (const LoadInst *LI = dyn_cast<LoadInst>(U)) {
// Note that atomic loads can be transformed; atomic semantics do
return false;
} else if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (SI->getOperand(0) == AI)
- return false; // Don't allow a store OF the AI, only INTO the AI.
+ return false; // Don't allow a store OF the AI, only INTO the AI.
// Note that atomic stores can be transformed; atomic semantics do
// not have any meaning for a local alloca.
if (SI->isVolatile())
}
namespace {
- struct AllocaInfo;
-
- // Data package used by RenamePass()
- class RenamePassData {
- public:
- typedef std::vector<Value *> ValVector;
-
- RenamePassData() : BB(NULL), Pred(NULL), Values() {}
- RenamePassData(BasicBlock *B, BasicBlock *P,
- const ValVector &V) : BB(B), Pred(P), Values(V) {}
- BasicBlock *BB;
- BasicBlock *Pred;
- ValVector Values;
-
- void swap(RenamePassData &RHS) {
- std::swap(BB, RHS.BB);
- std::swap(Pred, RHS.Pred);
- Values.swap(RHS.Values);
- }
- };
- /// \brief This assigns and keeps a per-bb relative ordering of load/store
- /// instructions in the block that directly load or store an alloca.
+struct AllocaInfo;
+
+// Data package used by RenamePass()
+class RenamePassData {
+public:
+ typedef std::vector<Value *> ValVector;
+
+ RenamePassData() : BB(NULL), Pred(NULL), Values() {}
+ RenamePassData(BasicBlock *B, BasicBlock *P, const ValVector &V)
+ : BB(B), Pred(P), Values(V) {}
+ BasicBlock *BB;
+ BasicBlock *Pred;
+ ValVector Values;
+
+ void swap(RenamePassData &RHS) {
+ std::swap(BB, RHS.BB);
+ std::swap(Pred, RHS.Pred);
+ Values.swap(RHS.Values);
+ }
+};
+
+/// \brief This assigns and keeps a per-bb relative ordering of load/store
+/// instructions in the block that directly load or store an alloca.
+///
+/// This functionality is important because it avoids scanning large basic
+/// blocks multiple times when promoting many allocas in the same block.
+class LargeBlockInfo {
+ /// \brief For each instruction that we track, keep the index of the
+ /// instruction.
///
- /// This functionality is important because it avoids scanning large basic
- /// blocks multiple times when promoting many allocas in the same block.
- class LargeBlockInfo {
- /// \brief For each instruction that we track, keep the index of the
- /// instruction.
- ///
- /// The index starts out as the number of the instruction from the start of
- /// the block.
- DenseMap<const Instruction *, unsigned> InstNumbers;
- public:
-
- /// This code only looks at accesses to allocas.
- static bool isInterestingInstruction(const Instruction *I) {
- return (isa<LoadInst>(I) && isa<AllocaInst>(I->getOperand(0))) ||
- (isa<StoreInst>(I) && isa<AllocaInst>(I->getOperand(1)));
- }
-
- /// Get or calculate the index of the specified instruction.
- unsigned getInstructionIndex(const Instruction *I) {
- assert(isInterestingInstruction(I) &&
- "Not a load/store to/from an alloca?");
-
- // If we already have this instruction number, return it.
- DenseMap<const Instruction *, unsigned>::iterator It = InstNumbers.find(I);
- if (It != InstNumbers.end()) return It->second;
-
- // Scan the whole block to get the instruction. This accumulates
- // information for every interesting instruction in the block, in order to
- // avoid gratuitus rescans.
- const BasicBlock *BB = I->getParent();
- unsigned InstNo = 0;
- for (BasicBlock::const_iterator BBI = BB->begin(), E = BB->end();
- BBI != E; ++BBI)
- if (isInterestingInstruction(BBI))
- InstNumbers[BBI] = InstNo++;
- It = InstNumbers.find(I);
-
- assert(It != InstNumbers.end() && "Didn't insert instruction?");
+ /// The index starts out as the number of the instruction from the start of
+ /// the block.
+ DenseMap<const Instruction *, unsigned> InstNumbers;
+
+public:
+
+ /// This code only looks at accesses to allocas.
+ static bool isInterestingInstruction(const Instruction *I) {
+ return (isa<LoadInst>(I) && isa<AllocaInst>(I->getOperand(0))) ||
+ (isa<StoreInst>(I) && isa<AllocaInst>(I->getOperand(1)));
+ }
+
+ /// Get or calculate the index of the specified instruction.
+ unsigned getInstructionIndex(const Instruction *I) {
+ assert(isInterestingInstruction(I) &&
+ "Not a load/store to/from an alloca?");
+
+ // If we already have this instruction number, return it.
+ DenseMap<const Instruction *, unsigned>::iterator It = InstNumbers.find(I);
+ if (It != InstNumbers.end())
return It->second;
- }
-
- void deleteValue(const Instruction *I) {
- InstNumbers.erase(I);
- }
-
- void clear() {
- InstNumbers.clear();
- }
- };
-
- struct PromoteMem2Reg {
- /// The alloca instructions being promoted.
- std::vector<AllocaInst*> Allocas;
- DominatorTree &DT;
- DIBuilder *DIB;
-
- /// An AliasSetTracker object to update. If null, don't update it.
- AliasSetTracker *AST;
-
- /// Reverse mapping of Allocas.
- DenseMap<AllocaInst*, unsigned> AllocaLookup;
-
- /// \brief The PhiNodes we're adding.
- ///
- /// That map is used to simplify some Phi nodes as we iterate over it, so
- /// it should have deterministic iterators. We could use a MapVector, but
- /// since we already maintain a map from BasicBlock* to a stable numbering
- /// (BBNumbers), the DenseMap is more efficient (also supports removal).
- DenseMap<std::pair<unsigned, unsigned>, PHINode*> NewPhiNodes;
-
- /// For each PHI node, keep track of which entry in Allocas it corresponds
- /// to.
- DenseMap<PHINode*, unsigned> PhiToAllocaMap;
-
- /// If we are updating an AliasSetTracker, then for each alloca that is of
- /// pointer type, we keep track of what to copyValue to the inserted PHI
- /// nodes here.
- std::vector<Value*> PointerAllocaValues;
-
- /// For each alloca, we keep track of the dbg.declare intrinsic that
- /// describes it, if any, so that we can convert it to a dbg.value
- /// intrinsic if the alloca gets promoted.
- SmallVector<DbgDeclareInst*, 8> AllocaDbgDeclares;
-
- /// The set of basic blocks the renamer has already visited.
- ///
- SmallPtrSet<BasicBlock*, 16> Visited;
-
- /// Contains a stable numbering of basic blocks to avoid non-determinstic
- /// behavior.
- DenseMap<BasicBlock*, unsigned> BBNumbers;
-
- /// Maps DomTreeNodes to their level in the dominator tree.
- DenseMap<DomTreeNode*, unsigned> DomLevels;
-
- /// Lazily compute the number of predecessors a block has.
- DenseMap<const BasicBlock*, unsigned> BBNumPreds;
- public:
- PromoteMem2Reg(const std::vector<AllocaInst*> &A, DominatorTree &dt,
- AliasSetTracker *ast)
+
+ // Scan the whole block to get the instruction. This accumulates
+ // information for every interesting instruction in the block, in order to
+ // avoid gratuitus rescans.
+ const BasicBlock *BB = I->getParent();
+ unsigned InstNo = 0;
+ for (BasicBlock::const_iterator BBI = BB->begin(), E = BB->end(); BBI != E;
+ ++BBI)
+ if (isInterestingInstruction(BBI))
+ InstNumbers[BBI] = InstNo++;
+ It = InstNumbers.find(I);
+
+ assert(It != InstNumbers.end() && "Didn't insert instruction?");
+ return It->second;
+ }
+
+ void deleteValue(const Instruction *I) { InstNumbers.erase(I); }
+
+ void clear() { InstNumbers.clear(); }
+};
+
+struct PromoteMem2Reg {
+ /// The alloca instructions being promoted.
+ std::vector<AllocaInst *> Allocas;
+ DominatorTree &DT;
+ DIBuilder *DIB;
+
+ /// An AliasSetTracker object to update. If null, don't update it.
+ AliasSetTracker *AST;
+
+ /// Reverse mapping of Allocas.
+ DenseMap<AllocaInst *, unsigned> AllocaLookup;
+
+ /// \brief The PhiNodes we're adding.
+ ///
+ /// That map is used to simplify some Phi nodes as we iterate over it, so
+ /// it should have deterministic iterators. We could use a MapVector, but
+ /// since we already maintain a map from BasicBlock* to a stable numbering
+ /// (BBNumbers), the DenseMap is more efficient (also supports removal).
+ DenseMap<std::pair<unsigned, unsigned>, PHINode *> NewPhiNodes;
+
+ /// For each PHI node, keep track of which entry in Allocas it corresponds
+ /// to.
+ DenseMap<PHINode *, unsigned> PhiToAllocaMap;
+
+ /// If we are updating an AliasSetTracker, then for each alloca that is of
+ /// pointer type, we keep track of what to copyValue to the inserted PHI
+ /// nodes here.
+ std::vector<Value *> PointerAllocaValues;
+
+ /// For each alloca, we keep track of the dbg.declare intrinsic that
+ /// describes it, if any, so that we can convert it to a dbg.value
+ /// intrinsic if the alloca gets promoted.
+ SmallVector<DbgDeclareInst *, 8> AllocaDbgDeclares;
+
+ /// The set of basic blocks the renamer has already visited.
+ ///
+ SmallPtrSet<BasicBlock *, 16> Visited;
+
+ /// Contains a stable numbering of basic blocks to avoid non-determinstic
+ /// behavior.
+ DenseMap<BasicBlock *, unsigned> BBNumbers;
+
+ /// Maps DomTreeNodes to their level in the dominator tree.
+ DenseMap<DomTreeNode *, unsigned> DomLevels;
+
+ /// Lazily compute the number of predecessors a block has.
+ DenseMap<const BasicBlock *, unsigned> BBNumPreds;
+
+public:
+ PromoteMem2Reg(const std::vector<AllocaInst *> &A, DominatorTree &dt,
+ AliasSetTracker *ast)
: Allocas(A), DT(dt), DIB(0), AST(ast) {}
- ~PromoteMem2Reg() {
- delete DIB;
- }
+ ~PromoteMem2Reg() { delete DIB; }
- void run();
+ void run();
- /// Return true if BB1 dominates BB2 using the DominatorTree.
- bool dominates(BasicBlock *BB1, BasicBlock *BB2) const {
- return DT.dominates(BB1, BB2);
- }
+ /// Return true if BB1 dominates BB2 using the DominatorTree.
+ bool dominates(BasicBlock *BB1, BasicBlock *BB2) const {
+ return DT.dominates(BB1, BB2);
+ }
- private:
- void RemoveFromAllocasList(unsigned &AllocaIdx) {
- Allocas[AllocaIdx] = Allocas.back();
- Allocas.pop_back();
- --AllocaIdx;
- }
+private:
+ void RemoveFromAllocasList(unsigned &AllocaIdx) {
+ Allocas[AllocaIdx] = Allocas.back();
+ Allocas.pop_back();
+ --AllocaIdx;
+ }
- unsigned getNumPreds(const BasicBlock *BB) {
- unsigned &NP = BBNumPreds[BB];
- if (NP == 0)
- NP = std::distance(pred_begin(BB), pred_end(BB))+1;
- return NP-1;
- }
+ unsigned getNumPreds(const BasicBlock *BB) {
+ unsigned &NP = BBNumPreds[BB];
+ if (NP == 0)
+ NP = std::distance(pred_begin(BB), pred_end(BB)) + 1;
+ return NP - 1;
+ }
- void DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
- AllocaInfo &Info);
- void ComputeLiveInBlocks(AllocaInst *AI, AllocaInfo &Info,
- const SmallPtrSet<BasicBlock*, 32> &DefBlocks,
- SmallPtrSet<BasicBlock*, 32> &LiveInBlocks);
-
- void RewriteSingleStoreAlloca(AllocaInst *AI, AllocaInfo &Info,
- LargeBlockInfo &LBI);
- void PromoteSingleBlockAlloca(AllocaInst *AI, AllocaInfo &Info,
- LargeBlockInfo &LBI);
-
- void RenamePass(BasicBlock *BB, BasicBlock *Pred,
- RenamePassData::ValVector &IncVals,
- std::vector<RenamePassData> &Worklist);
- bool QueuePhiNode(BasicBlock *BB, unsigned AllocaIdx, unsigned &Version);
- };
-
- struct AllocaInfo {
- SmallVector<BasicBlock*, 32> DefiningBlocks;
- SmallVector<BasicBlock*, 32> UsingBlocks;
-
- StoreInst *OnlyStore;
- BasicBlock *OnlyBlock;
- bool OnlyUsedInOneBlock;
-
- Value *AllocaPointerVal;
- DbgDeclareInst *DbgDeclare;
-
- void clear() {
- DefiningBlocks.clear();
- UsingBlocks.clear();
- OnlyStore = 0;
- OnlyBlock = 0;
- OnlyUsedInOneBlock = true;
- AllocaPointerVal = 0;
- DbgDeclare = 0;
- }
-
- /// Scan the uses of the specified alloca, filling in the AllocaInfo used
- /// by the rest of the pass to reason about the uses of this alloca.
- void AnalyzeAlloca(AllocaInst *AI) {
- clear();
-
- // As we scan the uses of the alloca instruction, keep track of stores,
- // and decide whether all of the loads and stores to the alloca are within
- // the same basic block.
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
- UI != E;) {
- Instruction *User = cast<Instruction>(*UI++);
-
- if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
- // Remember the basic blocks which define new values for the alloca
- DefiningBlocks.push_back(SI->getParent());
- AllocaPointerVal = SI->getOperand(0);
- OnlyStore = SI;
- } else {
- LoadInst *LI = cast<LoadInst>(User);
- // Otherwise it must be a load instruction, keep track of variable
- // reads.
- UsingBlocks.push_back(LI->getParent());
- AllocaPointerVal = LI;
- }
-
- if (OnlyUsedInOneBlock) {
- if (OnlyBlock == 0)
- OnlyBlock = User->getParent();
- else if (OnlyBlock != User->getParent())
- OnlyUsedInOneBlock = false;
- }
+ void DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
+ AllocaInfo &Info);
+ void ComputeLiveInBlocks(AllocaInst *AI, AllocaInfo &Info,
+ const SmallPtrSet<BasicBlock *, 32> &DefBlocks,
+ SmallPtrSet<BasicBlock *, 32> &LiveInBlocks);
+
+ void RewriteSingleStoreAlloca(AllocaInst *AI, AllocaInfo &Info,
+ LargeBlockInfo &LBI);
+ void PromoteSingleBlockAlloca(AllocaInst *AI, AllocaInfo &Info,
+ LargeBlockInfo &LBI);
+
+ void RenamePass(BasicBlock *BB, BasicBlock *Pred,
+ RenamePassData::ValVector &IncVals,
+ std::vector<RenamePassData> &Worklist);
+ bool QueuePhiNode(BasicBlock *BB, unsigned AllocaIdx, unsigned &Version);
+};
+
+struct AllocaInfo {
+ SmallVector<BasicBlock *, 32> DefiningBlocks;
+ SmallVector<BasicBlock *, 32> UsingBlocks;
+
+ StoreInst *OnlyStore;
+ BasicBlock *OnlyBlock;
+ bool OnlyUsedInOneBlock;
+
+ Value *AllocaPointerVal;
+ DbgDeclareInst *DbgDeclare;
+
+ void clear() {
+ DefiningBlocks.clear();
+ UsingBlocks.clear();
+ OnlyStore = 0;
+ OnlyBlock = 0;
+ OnlyUsedInOneBlock = true;
+ AllocaPointerVal = 0;
+ DbgDeclare = 0;
+ }
+
+ /// Scan the uses of the specified alloca, filling in the AllocaInfo used
+ /// by the rest of the pass to reason about the uses of this alloca.
+ void AnalyzeAlloca(AllocaInst *AI) {
+ clear();
+
+ // As we scan the uses of the alloca instruction, keep track of stores,
+ // and decide whether all of the loads and stores to the alloca are within
+ // the same basic block.
+ for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
+ UI != E;) {
+ Instruction *User = cast<Instruction>(*UI++);
+
+ if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
+ // Remember the basic blocks which define new values for the alloca
+ DefiningBlocks.push_back(SI->getParent());
+ AllocaPointerVal = SI->getOperand(0);
+ OnlyStore = SI;
+ } else {
+ LoadInst *LI = cast<LoadInst>(User);
+ // Otherwise it must be a load instruction, keep track of variable
+ // reads.
+ UsingBlocks.push_back(LI->getParent());
+ AllocaPointerVal = LI;
+ }
+
+ if (OnlyUsedInOneBlock) {
+ if (OnlyBlock == 0)
+ OnlyBlock = User->getParent();
+ else if (OnlyBlock != User->getParent())
+ OnlyUsedInOneBlock = false;
}
-
- DbgDeclare = FindAllocaDbgDeclare(AI);
}
- };
- typedef std::pair<DomTreeNode*, unsigned> DomTreeNodePair;
+ DbgDeclare = FindAllocaDbgDeclare(AI);
+ }
+};
- struct DomTreeNodeCompare {
- bool operator()(const DomTreeNodePair &LHS, const DomTreeNodePair &RHS) {
- return LHS.second < RHS.second;
- }
- };
-} // end of anonymous namespace
+typedef std::pair<DomTreeNode *, unsigned> DomTreeNodePair;
+
+struct DomTreeNodeCompare {
+ bool operator()(const DomTreeNodePair &LHS, const DomTreeNodePair &RHS) {
+ return LHS.second < RHS.second;
+ }
+};
+
+} // end of anonymous namespace
static void removeLifetimeIntrinsicUsers(AllocaInst *AI) {
// Knowing that this alloca is promotable, we know that it's safe to kill all
void PromoteMem2Reg::run() {
Function &F = *DT.getRoot()->getParent();
- if (AST) PointerAllocaValues.resize(Allocas.size());
+ if (AST)
+ PointerAllocaValues.resize(Allocas.size());
AllocaDbgDeclares.resize(Allocas.size());
AllocaInfo Info;
for (unsigned AllocaNum = 0; AllocaNum != Allocas.size(); ++AllocaNum) {
AllocaInst *AI = Allocas[AllocaNum];
- assert(isAllocaPromotable(AI) &&
- "Cannot promote non-promotable alloca!");
+ assert(isAllocaPromotable(AI) && "Cannot promote non-promotable alloca!");
assert(AI->getParent()->getParent() == &F &&
"All allocas should be in the same function, which is same as DF!");
if (AI->use_empty()) {
// If there are no uses of the alloca, just delete it now.
- if (AST) AST->deleteValue(AI);
+ if (AST)
+ AST->deleteValue(AI);
AI->eraseFromParent();
// Remove the alloca from the Allocas list, since it has been processed
++NumDeadAlloca;
continue;
}
-
+
// Calculate the set of read and write-locations for each alloca. This is
// analogous to finding the 'uses' and 'definitions' of each variable.
Info.AnalyzeAlloca(AI);
// Finally, after the scan, check to see if the store is all that is left.
if (Info.UsingBlocks.empty()) {
- // Record debuginfo for the store and remove the declaration's
+ // Record debuginfo for the store and remove the declaration's
// debuginfo.
if (DbgDeclareInst *DDI = Info.DbgDeclare) {
if (!DIB)
Info.OnlyStore->eraseFromParent();
LBI.deleteValue(Info.OnlyStore);
- if (AST) AST->deleteValue(AI);
+ if (AST)
+ AST->deleteValue(AI);
AI->eraseFromParent();
LBI.deleteValue(AI);
-
+
// The alloca has been processed, move on.
RemoveFromAllocasList(AllocaNum);
-
+
++NumSingleStore;
continue;
}
}
-
+
// If the alloca is only read and written in one basic block, just perform a
// linear sweep over the block to eliminate it.
if (Info.OnlyUsedInOneBlock) {
PromoteSingleBlockAlloca(AI, Info, LBI);
-
+
// Finally, after the scan, check to see if the stores are all that is
// left.
if (Info.UsingBlocks.empty()) {
-
+
// Remove the (now dead) stores and alloca.
while (!AI->use_empty()) {
StoreInst *SI = cast<StoreInst>(AI->use_back());
SI->eraseFromParent();
LBI.deleteValue(SI);
}
-
- if (AST) AST->deleteValue(AI);
+
+ if (AST)
+ AST->deleteValue(AI);
AI->eraseFromParent();
LBI.deleteValue(AI);
-
+
// The alloca has been processed, move on.
RemoveFromAllocasList(AllocaNum);
-
+
// The alloca's debuginfo can be removed as well.
if (DbgDeclareInst *DDI = Info.DbgDeclare)
DDI->eraseFromParent();
// If we haven't computed dominator tree levels, do so now.
if (DomLevels.empty()) {
- SmallVector<DomTreeNode*, 32> Worklist;
+ SmallVector<DomTreeNode *, 32> Worklist;
DomTreeNode *Root = DT.getRootNode();
DomLevels[Root] = 0;
// stored into the alloca.
if (AST)
PointerAllocaValues[AllocaNum] = Info.AllocaPointerVal;
-
+
// Remember the dbg.declare intrinsic describing this alloca, if any.
- if (Info.DbgDeclare) AllocaDbgDeclares[AllocaNum] = Info.DbgDeclare;
-
+ if (Info.DbgDeclare)
+ AllocaDbgDeclares[AllocaNum] = Info.DbgDeclare;
+
// Keep the reverse mapping of the 'Allocas' array for the rename pass.
AllocaLookup[Allocas[AllocaNum]] = AllocaNum;
return; // All of the allocas must have been trivial!
LBI.clear();
-
-
+
// Set the incoming values for the basic block to be null values for all of
// the alloca's. We do this in case there is a load of a value that has not
// been stored yet. In this case, it will get this null value.
// RenamePass may add new worklist entries.
RenamePass(RPD.BB, RPD.Pred, RPD.Values, RenamePassWorkList);
} while (!RenamePassWorkList.empty());
-
+
// The renamer uses the Visited set to avoid infinite loops. Clear it now.
Visited.clear();
// tree. Just delete the users now.
if (!A->use_empty())
A->replaceAllUsesWith(UndefValue::get(A->getType()));
- if (AST) AST->deleteValue(A);
+ if (AST)
+ AST->deleteValue(A);
A->eraseFromParent();
}
bool EliminatedAPHI = true;
while (EliminatedAPHI) {
EliminatedAPHI = false;
-
+
// Iterating over NewPhiNodes is deterministic, so it is safe to try to
// simplify and RAUW them as we go. If it was not, we could add uses to
// the values we replace with in a non deterministic order, thus creating
// non deterministic def->use chains.
- for (DenseMap<std::pair<unsigned, unsigned>, PHINode*>::iterator I =
- NewPhiNodes.begin(), E = NewPhiNodes.end(); I != E;) {
+ for (DenseMap<std::pair<unsigned, unsigned>, PHINode *>::iterator
+ I = NewPhiNodes.begin(),
+ E = NewPhiNodes.end();
+ I != E;) {
PHINode *PN = I->second;
// If this PHI node merges one value and/or undefs, get the value.
++I;
}
}
-
+
// At this point, the renamer has added entries to PHI nodes for all reachable
// code. Unfortunately, there may be unreachable blocks which the renamer
// hasn't traversed. If this is the case, the PHI nodes may not
// have incoming values for all predecessors. Loop over all PHI nodes we have
// created, inserting undef values if they are missing any incoming values.
//
- for (DenseMap<std::pair<unsigned, unsigned>, PHINode*>::iterator I =
- NewPhiNodes.begin(), E = NewPhiNodes.end(); I != E; ++I) {
+ for (DenseMap<std::pair<unsigned, unsigned>, PHINode *>::iterator
+ I = NewPhiNodes.begin(),
+ E = NewPhiNodes.end();
+ I != E; ++I) {
// We want to do this once per basic block. As such, only process a block
// when we find the PHI that is the first entry in the block.
PHINode *SomePHI = I->second;
continue;
// Get the preds for BB.
- SmallVector<BasicBlock*, 16> Preds(pred_begin(BB), pred_end(BB));
-
+ SmallVector<BasicBlock *, 16> Preds(pred_begin(BB), pred_end(BB));
+
// Ok, now we know that all of the PHI nodes are missing entries for some
// basic blocks. Start by sorting the incoming predecessors for efficient
// access.
std::sort(Preds.begin(), Preds.end());
-
+
// Now we loop through all BB's which have entries in SomePHI and remove
// them from the Preds list.
for (unsigned i = 0, e = SomePHI->getNumIncomingValues(); i != e; ++i) {
// Do a log(n) search of the Preds list for the entry we want.
- SmallVectorImpl<BasicBlock *>::iterator EntIt =
- std::lower_bound(Preds.begin(), Preds.end(),
- SomePHI->getIncomingBlock(i));
- assert(EntIt != Preds.end() && *EntIt == SomePHI->getIncomingBlock(i)&&
+ SmallVectorImpl<BasicBlock *>::iterator EntIt = std::lower_bound(
+ Preds.begin(), Preds.end(), SomePHI->getIncomingBlock(i));
+ assert(EntIt != Preds.end() && *EntIt == SomePHI->getIncomingBlock(i) &&
"PHI node has entry for a block which is not a predecessor!");
// Remove the entry
SomePHI->addIncoming(UndefVal, Preds[pred]);
}
}
-
+
NewPhiNodes.clear();
}
-
/// \brief Determine which blocks the value is live in.
///
/// These are blocks which lead to uses. Knowing this allows us to avoid
/// inserting PHI nodes into blocks which don't lead to uses (thus, the
/// inserted phi nodes would be dead).
-void PromoteMem2Reg::
-ComputeLiveInBlocks(AllocaInst *AI, AllocaInfo &Info,
- const SmallPtrSet<BasicBlock*, 32> &DefBlocks,
- SmallPtrSet<BasicBlock*, 32> &LiveInBlocks) {
-
+void PromoteMem2Reg::ComputeLiveInBlocks(
+ AllocaInst *AI, AllocaInfo &Info,
+ const SmallPtrSet<BasicBlock *, 32> &DefBlocks,
+ SmallPtrSet<BasicBlock *, 32> &LiveInBlocks) {
+
// To determine liveness, we must iterate through the predecessors of blocks
// where the def is live. Blocks are added to the worklist if we need to
// check their predecessors. Start with all the using blocks.
- SmallVector<BasicBlock*, 64> LiveInBlockWorklist(Info.UsingBlocks.begin(),
- Info.UsingBlocks.end());
-
+ SmallVector<BasicBlock *, 64> LiveInBlockWorklist(Info.UsingBlocks.begin(),
+ Info.UsingBlocks.end());
+
// If any of the using blocks is also a definition block, check to see if the
// definition occurs before or after the use. If it happens before the use,
// the value isn't really live-in.
for (unsigned i = 0, e = LiveInBlockWorklist.size(); i != e; ++i) {
BasicBlock *BB = LiveInBlockWorklist[i];
- if (!DefBlocks.count(BB)) continue;
-
+ if (!DefBlocks.count(BB))
+ continue;
+
// Okay, this is a block that both uses and defines the value. If the first
// reference to the alloca is a def (store), then we know it isn't live-in.
- for (BasicBlock::iterator I = BB->begin(); ; ++I) {
+ for (BasicBlock::iterator I = BB->begin();; ++I) {
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
- if (SI->getOperand(1) != AI) continue;
-
+ if (SI->getOperand(1) != AI)
+ continue;
+
// We found a store to the alloca before a load. The alloca is not
// actually live-in here.
LiveInBlockWorklist[i] = LiveInBlockWorklist.back();
--i, --e;
break;
}
-
+
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
- if (LI->getOperand(0) != AI) continue;
-
+ if (LI->getOperand(0) != AI)
+ continue;
+
// Okay, we found a load before a store to the alloca. It is actually
// live into this block.
break;
}
}
}
-
+
// Now that we have a set of blocks where the phi is live-in, recursively add
// their predecessors until we find the full region the value is live.
while (!LiveInBlockWorklist.empty()) {
BasicBlock *BB = LiveInBlockWorklist.pop_back_val();
-
+
// The block really is live in here, insert it into the set. If already in
// the set, then it has already been processed.
if (!LiveInBlocks.insert(BB))
continue;
-
+
// Since the value is live into BB, it is either defined in a predecessor or
// live into it to. Add the preds to the worklist unless they are a
// defining block.
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
BasicBlock *P = *PI;
-
+
// The value is not live into a predecessor if it defines the value.
if (DefBlocks.count(P))
continue;
-
+
// Otherwise it is, add to the worklist.
LiveInBlockWorklist.push_back(P);
}
void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
AllocaInfo &Info) {
// Unique the set of defining blocks for efficient lookup.
- SmallPtrSet<BasicBlock*, 32> DefBlocks;
+ SmallPtrSet<BasicBlock *, 32> DefBlocks;
DefBlocks.insert(Info.DefiningBlocks.begin(), Info.DefiningBlocks.end());
// Determine which blocks the value is live in. These are blocks which lead
// to uses.
- SmallPtrSet<BasicBlock*, 32> LiveInBlocks;
+ SmallPtrSet<BasicBlock *, 32> LiveInBlocks;
ComputeLiveInBlocks(AI, Info, DefBlocks, LiveInBlocks);
// Use a priority queue keyed on dominator tree level so that inserted nodes
// are handled from the bottom of the dominator tree upwards.
- typedef std::priority_queue<DomTreeNodePair, SmallVector<DomTreeNodePair, 32>,
+ typedef std::priority_queue<DomTreeNodePair,
+ SmallVector<DomTreeNodePair, 32>,
DomTreeNodeCompare> IDFPriorityQueue;
IDFPriorityQueue PQ;
- for (SmallPtrSet<BasicBlock*, 32>::const_iterator I = DefBlocks.begin(),
- E = DefBlocks.end(); I != E; ++I) {
+ for (SmallPtrSet<BasicBlock *, 32>::const_iterator I = DefBlocks.begin(),
+ E = DefBlocks.end();
+ I != E; ++I) {
if (DomTreeNode *Node = DT.getNode(*I))
PQ.push(std::make_pair(Node, DomLevels[Node]));
}
- SmallVector<std::pair<unsigned, BasicBlock*>, 32> DFBlocks;
- SmallPtrSet<DomTreeNode*, 32> Visited;
- SmallVector<DomTreeNode*, 32> Worklist;
+ SmallVector<std::pair<unsigned, BasicBlock *>, 32> DFBlocks;
+ SmallPtrSet<DomTreeNode *, 32> Visited;
+ SmallVector<DomTreeNode *, 32> Worklist;
while (!PQ.empty()) {
DomTreeNodePair RootPair = PQ.top();
PQ.pop();
/// If there is only a single store to this value, replace any loads of it that
/// are directly dominated by the definition with the value stored.
-void PromoteMem2Reg::RewriteSingleStoreAlloca(AllocaInst *AI,
- AllocaInfo &Info,
+void PromoteMem2Reg::RewriteSingleStoreAlloca(AllocaInst *AI, AllocaInfo &Info,
LargeBlockInfo &LBI) {
StoreInst *OnlyStore = Info.OnlyStore;
bool StoringGlobalVal = !isa<Instruction>(OnlyStore->getOperand(0));
// Clear out UsingBlocks. We will reconstruct it here if needed.
Info.UsingBlocks.clear();
-
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end(); UI != E; ) {
+
+ for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end(); UI != E;) {
Instruction *UserInst = cast<Instruction>(*UI++);
if (!isa<LoadInst>(UserInst)) {
assert(UserInst == OnlyStore && "Should only have load/stores");
continue;
}
LoadInst *LI = cast<LoadInst>(UserInst);
-
+
// Okay, if we have a load from the alloca, we want to replace it with the
// only value stored to the alloca. We can do this if the value is
// dominated by the store. If not, we use the rest of the mem2reg machinery
// to insert the phi nodes as needed.
- if (!StoringGlobalVal) { // Non-instructions are always dominated.
+ if (!StoringGlobalVal) { // Non-instructions are always dominated.
if (LI->getParent() == StoreBB) {
// If we have a use that is in the same block as the store, compare the
// indices of the two instructions to see which one came first. If the
Info.UsingBlocks.push_back(StoreBB);
continue;
}
-
+
} else if (LI->getParent() != StoreBB &&
!dominates(StoreBB, LI->getParent())) {
// If the load and store are in different blocks, use BB dominance to
continue;
}
}
-
+
// Otherwise, we *can* safely rewrite this load.
Value *ReplVal = OnlyStore->getOperand(0);
// If the replacement value is the load, this must occur in unreachable
}
namespace {
-
/// This is a helper predicate used to search by the first element of a pair.
struct StoreIndexSearchPredicate {
- bool operator()(const std::pair<unsigned, StoreInst*> &LHS,
- const std::pair<unsigned, StoreInst*> &RHS) {
+ bool operator()(const std::pair<unsigned, StoreInst *> &LHS,
+ const std::pair<unsigned, StoreInst *> &RHS) {
return LHS.first < RHS.first;
}
};
-
}
/// Many allocas are only used within a single basic block. If this is the
// this code is optimized assuming that large blocks happen. This does not
// significantly pessimize the small block case. This uses LargeBlockInfo to
// make it efficient to get the index of various operations in the block.
-
+
// Clear out UsingBlocks. We will reconstruct it here if needed.
Info.UsingBlocks.clear();
-
+
// Walk the use-def list of the alloca, getting the locations of all stores.
- typedef SmallVector<std::pair<unsigned, StoreInst*>, 64> StoresByIndexTy;
+ typedef SmallVector<std::pair<unsigned, StoreInst *>, 64> StoresByIndexTy;
StoresByIndexTy StoresByIndex;
-
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
- UI != E; ++UI)
+
+ for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end(); UI != E;
+ ++UI)
if (StoreInst *SI = dyn_cast<StoreInst>(*UI))
StoresByIndex.push_back(std::make_pair(LBI.getInstructionIndex(SI), SI));
// If there are no stores to the alloca, just replace any loads with undef.
if (StoresByIndex.empty()) {
- for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end(); UI != E;)
+ for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end(); UI != E;)
if (LoadInst *LI = dyn_cast<LoadInst>(*UI++)) {
LI->replaceAllUsesWith(UndefValue::get(LI->getType()));
if (AST && LI->getType()->isPointerTy())
}
return;
}
-
+
// Sort the stores by their index, making it efficient to do a lookup with a
// binary search.
std::sort(StoresByIndex.begin(), StoresByIndex.end());
-
+
// Walk all of the loads from this alloca, replacing them with the nearest
// store above them, if any.
for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end(); UI != E;) {
LoadInst *LI = dyn_cast<LoadInst>(*UI++);
- if (!LI) continue;
-
+ if (!LI)
+ continue;
+
unsigned LoadIdx = LBI.getInstructionIndex(LI);
-
- // Find the nearest store that has a lower than this load.
- StoresByIndexTy::iterator I =
- std::lower_bound(StoresByIndex.begin(), StoresByIndex.end(),
- std::pair<unsigned, StoreInst*>(LoadIdx, static_cast<StoreInst*>(0)),
- StoreIndexSearchPredicate());
-
+
+ // Find the nearest store that has a lower than this load.
+ StoresByIndexTy::iterator I = std::lower_bound(
+ StoresByIndex.begin(), StoresByIndex.end(),
+ std::pair<unsigned, StoreInst *>(LoadIdx, static_cast<StoreInst *>(0)),
+ StoreIndexSearchPredicate());
+
// If there is no store before this load, then we can't promote this load.
if (I == StoresByIndex.begin()) {
// Can't handle this load, bail out.
Info.UsingBlocks.push_back(LI->getParent());
continue;
}
-
+
// Otherwise, there was a store before this load, the load takes its value.
--I;
LI->replaceAllUsesWith(I->second->getOperand(0));
PHINode *&PN = NewPhiNodes[std::make_pair(BBNumbers[BB], AllocaNo)];
// If the BB already has a phi node added for the i'th alloca then we're done!
- if (PN) return false;
+ if (PN)
+ return false;
// Create a PhiNode using the dereferenced type... and add the phi-node to the
// BasicBlock.
PN = PHINode::Create(Allocas[AllocaNo]->getAllocatedType(), getNumPreds(BB),
- Allocas[AllocaNo]->getName() + "." + Twine(Version++),
+ Allocas[AllocaNo]->getName() + "." + Twine(Version++),
BB->begin());
++NumPHIInsert;
PhiToAllocaMap[PN] = AllocaNo;
// inserted by this pass of mem2reg will have the same number of incoming
// operands so far. Remember this count.
unsigned NewPHINumOperands = APN->getNumOperands();
-
+
unsigned NumEdges = 0;
for (succ_iterator I = succ_begin(Pred), E = succ_end(Pred); I != E; ++I)
if (*I == BB)
++NumEdges;
assert(NumEdges && "Must be at least one edge from Pred to BB!");
-
+
// Add entries for all the phis.
BasicBlock::iterator PNI = BB->begin();
do {
unsigned AllocaNo = PhiToAllocaMap[APN];
-
+
// Add N incoming values to the PHI node.
for (unsigned i = 0; i != NumEdges; ++i)
APN->addIncoming(IncomingVals[AllocaNo], Pred);
-
+
// The currently active variable for this block is now the PHI.
IncomingVals[AllocaNo] = APN;
-
+
// Get the next phi node.
++PNI;
APN = dyn_cast<PHINode>(PNI);
- if (APN == 0) break;
-
+ if (APN == 0)
+ break;
+
// Verify that it is missing entries. If not, it is not being inserted
// by this mem2reg invocation so we want to ignore it.
} while (APN->getNumOperands() == NewPHINumOperands);
}
}
-
+
// Don't revisit blocks.
- if (!Visited.insert(BB)) return;
+ if (!Visited.insert(BB))
+ return;
- for (BasicBlock::iterator II = BB->begin(); !isa<TerminatorInst>(II); ) {
+ for (BasicBlock::iterator II = BB->begin(); !isa<TerminatorInst>(II);) {
Instruction *I = II++; // get the instruction, increment iterator
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
AllocaInst *Src = dyn_cast<AllocaInst>(LI->getPointerOperand());
- if (!Src) continue;
-
- DenseMap<AllocaInst*, unsigned>::iterator AI = AllocaLookup.find(Src);
- if (AI == AllocaLookup.end()) continue;
+ if (!Src)
+ continue;
+
+ DenseMap<AllocaInst *, unsigned>::iterator AI = AllocaLookup.find(Src);
+ if (AI == AllocaLookup.end())
+ continue;
Value *V = IncomingVals[AI->second];
// Delete this instruction and mark the name as the current holder of the
// value
AllocaInst *Dest = dyn_cast<AllocaInst>(SI->getPointerOperand());
- if (!Dest) continue;
-
+ if (!Dest)
+ continue;
+
DenseMap<AllocaInst *, unsigned>::iterator ai = AllocaLookup.find(Dest);
if (ai == AllocaLookup.end())
continue;
-
+
// what value were we writing?
IncomingVals[ai->second] = SI->getOperand(0);
// Record debuginfo for the store before removing it.
// 'Recurse' to our successors.
succ_iterator I = succ_begin(BB), E = succ_end(BB);
- if (I == E) return;
+ if (I == E)
+ return;
// Keep track of the successors so we don't visit the same successor twice
- SmallPtrSet<BasicBlock*, 8> VisitedSuccs;
+ SmallPtrSet<BasicBlock *, 8> VisitedSuccs;
// Handle the first successor without using the worklist.
VisitedSuccs.insert(*I);
goto NextIteration;
}
-void llvm::PromoteMemToReg(const std::vector<AllocaInst*> &Allocas,
+void llvm::PromoteMemToReg(const std::vector<AllocaInst *> &Allocas,
DominatorTree &DT, AliasSetTracker *AST) {
// If there is nothing to do, bail out...
- if (Allocas.empty()) return;
+ if (Allocas.empty())
+ return;
PromoteMem2Reg(Allocas, DT, AST).run();
}
projects / oota-llvm.git / commitdiff