6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-04-04 10:30:01 +00:00
Code Issues Projects Releases Wiki Activity

Split out the updating of PHI nodes after splitting the BB into a separate

Browse Source 
function.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137979 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2011-08-18 20:51:04 +00:00
parent 9210e840dd
commit 1c44d869cd
1 changed files with 53 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

96
lib/Transforms/Utils/BasicBlockUtils.cpp
View File

@ -389,6 +389,56 @@ static void UpdateAnalysisInformation(BasicBlock *OldBB, BasicBlock *NewBB,
}
}
/// 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
@ -437,49 +487,9 @@ BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
UpdateAnalysisInformation(BB, NewBB, ArrayRef<BasicBlock*>(Preds, NumPreds),
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;
}
}
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);
}
// Update the PHI nodes in BB with the values coming from NewBB.
UpdatePHINodes(BB, NewBB, ArrayRef<BasicBlock*>(Preds, NumPreds), BI,
P, HasLoopExit);
return NewBB;
}