if (DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>()) {
// Old dominates New. New node dominates all other nodes dominated by Old.
- DomTreeNode *OldNode = DT->getNode(Old);
- std::vector<DomTreeNode *> Children;
- for (DomTreeNode::iterator I = OldNode->begin(), E = OldNode->end();
- I != E; ++I)
- Children.push_back(*I);
+ if (DomTreeNode *OldNode = DT->getNode(Old)) {
+ std::vector<DomTreeNode *> Children;
+ for (DomTreeNode::iterator I = OldNode->begin(), E = OldNode->end();
+ I != E; ++I)
+ Children.push_back(*I);
DomTreeNode *NewNode = DT->addNewBlock(New,Old);
for (std::vector<DomTreeNode *>::iterator I = Children.begin(),
E = Children.end(); I != E; ++I)
DT->changeImmediateDominator(*I, NewNode);
+ }
}
return New;
/// UpdateAnalysisInformation - Update DominatorTree, LoopInfo, and LCCSA
/// analysis information.
static void UpdateAnalysisInformation(BasicBlock *OldBB, BasicBlock *NewBB,
- BasicBlock *const *Preds,
- unsigned NumPreds, Pass *P,
- bool &HasLoopExit) {
+ ArrayRef<BasicBlock *> Preds,
+ Pass *P, bool &HasLoopExit) {
if (!P) return;
LoopInfo *LI = P->getAnalysisIfAvailable<LoopInfo>();
Loop *L = LI ? LI->getLoopFor(OldBB) : 0;
- bool PreserveLCSSA = P->mustPreserveAnalysisID(LCSSAID);
// If we need to preserve loop analyses, collect some information about how
// this split will affect loops.
bool IsLoopEntry = !!L;
bool SplitMakesNewLoopHeader = false;
if (LI) {
- for (unsigned i = 0; i != NumPreds; ++i) {
+ bool PreserveLCSSA = P->mustPreserveAnalysisID(LCSSAID);
+ for (ArrayRef<BasicBlock*>::iterator
+ i = Preds.begin(), e = Preds.end(); i != e; ++i) {
+ BasicBlock *Pred = *i;
+
// If we need to preserve LCSSA, determine if any of the preds is a loop
// exit.
if (PreserveLCSSA)
- if (Loop *PL = LI->getLoopFor(Preds[i]))
+ if (Loop *PL = LI->getLoopFor(Pred))
if (!PL->contains(OldBB))
HasLoopExit = true;
// If we need to preserve LoopInfo, note whether any of the preds crosses
// an interesting loop boundary.
if (!L) continue;
- if (L->contains(Preds[i]))
+ if (L->contains(Pred))
IsLoopEntry = false;
else
SplitMakesNewLoopHeader = true;
// loops enclose them, and select the most-nested loop which contains the
// loop containing the block being split.
Loop *InnermostPredLoop = 0;
- for (unsigned i = 0; i != NumPreds; ++i)
- if (Loop *PredLoop = LI->getLoopFor(Preds[i])) {
+ for (ArrayRef<BasicBlock*>::iterator
+ i = Preds.begin(), e = Preds.end(); i != e; ++i) {
+ BasicBlock *Pred = *i;
+ if (Loop *PredLoop = LI->getLoopFor(Pred)) {
// Seek a loop which actually contains the block being split (to avoid
// adjacent loops).
while (PredLoop && !PredLoop->contains(OldBB))
InnermostPredLoop->getLoopDepth() < PredLoop->getLoopDepth()))
InnermostPredLoop = PredLoop;
}
+ }
if (InnermostPredLoop)
InnermostPredLoop->addBasicBlockToLoop(NewBB, LI->getBase());
}
}
+/// UpdatePHINodes - Update the PHI nodes in OrigBB to include the values coming
+/// from NewBB. This also updates AliasAnalysis, if available.
+static void UpdatePHINodes(BasicBlock *OrigBB, BasicBlock *NewBB,
+ ArrayRef<BasicBlock*> Preds, BranchInst *BI,
+ Pass *P, bool HasLoopExit) {
+ // Otherwise, create a new PHI node in NewBB for each PHI node in OrigBB.
+ AliasAnalysis *AA = P ? P->getAnalysisIfAvailable<AliasAnalysis>() : 0;
+ for (BasicBlock::iterator I = OrigBB->begin(); isa<PHINode>(I); ) {
+ PHINode *PN = cast<PHINode>(I++);
+
+ // Check to see if all of the values coming in are the same. If so, we
+ // don't need to create a new PHI node, unless it's needed for LCSSA.
+ Value *InVal = 0;
+ if (!HasLoopExit) {
+ InVal = PN->getIncomingValueForBlock(Preds[0]);
+ for (unsigned i = 1, e = Preds.size(); i != e; ++i)
+ if (InVal != PN->getIncomingValueForBlock(Preds[i])) {
+ InVal = 0;
+ break;
+ }
+ }
+
+ if (InVal) {
+ // If all incoming values for the new PHI would be the same, just don't
+ // make a new PHI. Instead, just remove the incoming values from the old
+ // PHI.
+ for (unsigned i = 0, e = Preds.size(); i != e; ++i)
+ PN->removeIncomingValue(Preds[i], false);
+ } else {
+ // If the values coming into the block are not the same, we need a PHI.
+ // Create the new PHI node, insert it into NewBB at the end of the block
+ PHINode *NewPHI =
+ PHINode::Create(PN->getType(), Preds.size(), PN->getName() + ".ph", BI);
+ if (AA) AA->copyValue(PN, NewPHI);
+
+ // Move all of the PHI values for 'Preds' to the new PHI.
+ for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
+ Value *V = PN->removeIncomingValue(Preds[i], false);
+ NewPHI->addIncoming(V, Preds[i]);
+ }
+
+ InVal = NewPHI;
+ }
+
+ // Add an incoming value to the PHI node in the loop for the preheader
+ // edge.
+ PN->addIncoming(InVal, NewBB);
+ }
+}
+
/// SplitBlockPredecessors - This method transforms BB by introducing a new
/// basic block into the function, and moving some of the predecessors of BB to
/// be predecessors of the new block. The new predecessors are indicated by the
/// of the edges being split is an exit of a loop with other exits).
///
BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
- BasicBlock *const *Preds,
- unsigned NumPreds, const char *Suffix,
- Pass *P) {
+ ArrayRef<BasicBlock*> Preds,
+ const char *Suffix, Pass *P) {
// Create new basic block, insert right before the original block.
BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), BB->getName()+Suffix,
BB->getParent(), BB);
BranchInst *BI = BranchInst::Create(BB, NewBB);
// Move the edges from Preds to point to NewBB instead of BB.
- for (unsigned i = 0; i != NumPreds; ++i) {
+ for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
// This is slightly more strict than necessary; the minimum requirement
// is that there be no more than one indirectbr branching to BB. And
// all BlockAddress uses would need to be updated.
// node becomes an incoming value for BB's phi node. However, if the Preds
// list is empty, we need to insert dummy entries into the PHI nodes in BB to
// account for the newly created predecessor.
- if (NumPreds == 0) {
+ if (Preds.size() == 0) {
// Insert dummy values as the incoming value.
for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ++I)
cast<PHINode>(I)->addIncoming(UndefValue::get(I->getType()), NewBB);
// Update DominatorTree, LoopInfo, and LCCSA analysis information.
bool HasLoopExit = false;
- UpdateAnalysisInformation(BB, NewBB, Preds, NumPreds, P, HasLoopExit);
+ UpdateAnalysisInformation(BB, NewBB, Preds, P, HasLoopExit);
- // Otherwise, create a new PHI node in NewBB for each PHI node in BB.
- AliasAnalysis *AA = P ? P->getAnalysisIfAvailable<AliasAnalysis>() : 0;
- for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ) {
- PHINode *PN = cast<PHINode>(I++);
-
- // Check to see if all of the values coming in are the same. If so, we
- // don't need to create a new PHI node, unless it's needed for LCSSA.
- Value *InVal = 0;
- if (!HasLoopExit) {
- InVal = PN->getIncomingValueForBlock(Preds[0]);
- for (unsigned i = 1; i != NumPreds; ++i)
- if (InVal != PN->getIncomingValueForBlock(Preds[i])) {
- InVal = 0;
- break;
- }
- }
+ // Update the PHI nodes in BB with the values coming from NewBB.
+ UpdatePHINodes(BB, NewBB, Preds, BI, P, HasLoopExit);
+ return NewBB;
+}
- if (InVal) {
- // If all incoming values for the new PHI would be the same, just don't
- // make a new PHI. Instead, just remove the incoming values from the old
- // PHI.
- for (unsigned i = 0; i != NumPreds; ++i)
- PN->removeIncomingValue(Preds[i], false);
- } else {
- // If the values coming into the block are not the same, we need a PHI.
- // Create the new PHI node, insert it into NewBB at the end of the block
- PHINode *NewPHI =
- PHINode::Create(PN->getType(), NumPreds, PN->getName()+".ph", BI);
- if (AA) AA->copyValue(PN, NewPHI);
-
- // Move all of the PHI values for 'Preds' to the new PHI.
- for (unsigned i = 0; i != NumPreds; ++i) {
- Value *V = PN->removeIncomingValue(Preds[i], false);
- NewPHI->addIncoming(V, Preds[i]);
- }
- InVal = NewPHI;
- }
-
- // Add an incoming value to the PHI node in the loop for the preheader
- // edge.
- PN->addIncoming(InVal, NewBB);
+/// SplitLandingPadPredecessors - This method transforms the landing pad,
+/// OrigBB, by introducing two new basic blocks into the function. One of those
+/// new basic blocks gets the predecessors listed in Preds. The other basic
+/// block gets the remaining predecessors of OrigBB. The landingpad instruction
+/// OrigBB is clone into both of the new basic blocks. The new blocks are given
+/// the suffixes 'Suffix1' and 'Suffix2', and are returned in the NewBBs vector.
+///
+/// This currently updates the LLVM IR, AliasAnalysis, DominatorTree,
+/// DominanceFrontier, LoopInfo, and LCCSA but no other analyses. In particular,
+/// it does not preserve LoopSimplify (because it's complicated to handle the
+/// case where one of the edges being split is an exit of a loop with other
+/// exits).
+///
+void llvm::SplitLandingPadPredecessors(BasicBlock *OrigBB,
+ ArrayRef<BasicBlock*> Preds,
+ const char *Suffix1, const char *Suffix2,
+ Pass *P,
+ SmallVectorImpl<BasicBlock*> &NewBBs) {
+ assert(OrigBB->isLandingPad() && "Trying to split a non-landing pad!");
+
+ // Create a new basic block for OrigBB's predecessors listed in Preds. Insert
+ // it right before the original block.
+ BasicBlock *NewBB1 = BasicBlock::Create(OrigBB->getContext(),
+ OrigBB->getName() + Suffix1,
+ OrigBB->getParent(), OrigBB);
+ NewBBs.push_back(NewBB1);
+
+ // The new block unconditionally branches to the old block.
+ BranchInst *BI1 = BranchInst::Create(OrigBB, NewBB1);
+
+ // Move the edges from Preds to point to NewBB1 instead of OrigBB.
+ for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
+ // This is slightly more strict than necessary; the minimum requirement
+ // is that there be no more than one indirectbr branching to BB. And
+ // all BlockAddress uses would need to be updated.
+ assert(!isa<IndirectBrInst>(Preds[i]->getTerminator()) &&
+ "Cannot split an edge from an IndirectBrInst");
+ Preds[i]->getTerminator()->replaceUsesOfWith(OrigBB, NewBB1);
}
- return NewBB;
+ // Update DominatorTree, LoopInfo, and LCCSA analysis information.
+ bool HasLoopExit = false;
+ UpdateAnalysisInformation(OrigBB, NewBB1, Preds, P, HasLoopExit);
+
+ // Update the PHI nodes in OrigBB with the values coming from NewBB1.
+ UpdatePHINodes(OrigBB, NewBB1, Preds, BI1, P, HasLoopExit);
+
+ // Move the remaining edges from OrigBB to point to NewBB2.
+ SmallVector<BasicBlock*, 8> NewBB2Preds;
+ for (pred_iterator i = pred_begin(OrigBB), e = pred_end(OrigBB);
+ i != e; ) {
+ BasicBlock *Pred = *i++;
+ if (Pred == NewBB1) continue;
+ assert(!isa<IndirectBrInst>(Pred->getTerminator()) &&
+ "Cannot split an edge from an IndirectBrInst");
+ NewBB2Preds.push_back(Pred);
+ e = pred_end(OrigBB);
+ }
+
+ BasicBlock *NewBB2 = 0;
+ if (!NewBB2Preds.empty()) {
+ // Create another basic block for the rest of OrigBB's predecessors.
+ NewBB2 = BasicBlock::Create(OrigBB->getContext(),
+ OrigBB->getName() + Suffix2,
+ OrigBB->getParent(), OrigBB);
+ NewBBs.push_back(NewBB2);
+
+ // The new block unconditionally branches to the old block.
+ BranchInst *BI2 = BranchInst::Create(OrigBB, NewBB2);
+
+ // Move the remaining edges from OrigBB to point to NewBB2.
+ for (SmallVectorImpl<BasicBlock*>::iterator
+ i = NewBB2Preds.begin(), e = NewBB2Preds.end(); i != e; ++i)
+ (*i)->getTerminator()->replaceUsesOfWith(OrigBB, NewBB2);
+
+ // Update DominatorTree, LoopInfo, and LCCSA analysis information.
+ HasLoopExit = false;
+ UpdateAnalysisInformation(OrigBB, NewBB2, NewBB2Preds, P, HasLoopExit);
+
+ // Update the PHI nodes in OrigBB with the values coming from NewBB2.
+ UpdatePHINodes(OrigBB, NewBB2, NewBB2Preds, BI2, P, HasLoopExit);
+ }
+
+ LandingPadInst *LPad = OrigBB->getLandingPadInst();
+ Instruction *Clone1 = LPad->clone();
+ Clone1->setName(Twine("lpad") + Suffix1);
+ NewBB1->getInstList().insert(NewBB1->getFirstInsertionPt(), Clone1);
+
+ if (NewBB2) {
+ Instruction *Clone2 = LPad->clone();
+ Clone2->setName(Twine("lpad") + Suffix2);
+ NewBB2->getInstList().insert(NewBB2->getFirstInsertionPt(), Clone2);
+
+ // Create a PHI node for the two cloned landingpad instructions.
+ PHINode *PN = PHINode::Create(LPad->getType(), 2, "lpad.phi", LPad);
+ PN->addIncoming(Clone1, NewBB1);
+ PN->addIncoming(Clone2, NewBB2);
+ LPad->replaceAllUsesWith(PN);
+ LPad->eraseFromParent();
+ } else {
+ // There is no second clone. Just replace the landing pad with the first
+ // clone.
+ LPad->replaceAllUsesWith(Clone1);
+ LPad->eraseFromParent();
+ }
}
/// FindFunctionBackedges - Analyze the specified function to find all of the
projects / oota-llvm.git / blobdiff