[llvm-commits] [llvm] r50015 - /llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
Chris Lattner
sabre at nondot.org
Sun Apr 20 17:23:14 PDT 2008
Author: lattner
Date: Sun Apr 20 19:23:14 2008
New Revision: 50015
URL: http://llvm.org/viewvc/llvm-project?rev=50015&view=rev
Log:
simplify code, fit in 80 cols.
Modified:
llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
Modified: llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp?rev=50015&r1=50014&r2=50015&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp Sun Apr 20 19:23:14 2008
@@ -263,14 +263,15 @@
/// SplitBlockPredecessors - Split the specified block into two blocks. We want
/// to move the predecessors specified in the Preds list to point to the new
/// block, leaving the remaining predecessors pointing to BB. This method
-/// updates the SSA PHINode's, but no other analyses.
+/// updates the SSA PHINode's and AliasAnalysis, but no other analyses.
///
BasicBlock *LoopSimplify::SplitBlockPredecessors(BasicBlock *BB,
const char *Suffix,
const std::vector<BasicBlock*> &Preds) {
// Create new basic block, insert right before the original block...
- BasicBlock *NewBB = BasicBlock::Create(BB->getName()+Suffix, BB->getParent(), BB);
+ BasicBlock *NewBB =
+ BasicBlock::Create(BB->getName()+Suffix, BB->getParent(), BB);
// The preheader first gets an unconditional branch to the loop header...
BranchInst *BI = BranchInst::Create(BB, NewBB);
@@ -281,78 +282,79 @@
// into the PHI nodes for the new edge. If the loop is not dead, we move the
// incoming edges in BB into new PHI nodes in NewBB.
//
- if (!Preds.empty()) { // Is the loop not obviously dead?
- // Check to see if the values being merged into the new block need PHI
- // nodes. If so, insert them.
- for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ) {
+ if (Preds.empty()) { // Is the loop obviously dead?
+ for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
- ++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.
- Value *InVal = PN->getIncomingValueForBlock(Preds[0]);
- for (unsigned i = 1, e = Preds.size(); i != e; ++i)
- if (InVal != PN->getIncomingValueForBlock(Preds[i])) {
- InVal = 0;
- break;
- }
+ // Insert dummy values as the incoming value...
+ PN->addIncoming(Constant::getNullValue(PN->getType()), NewBB);
+ }
+ return NewBB;
+ }
+
+ // Check to see if the values being merged into the new block need PHI
+ // nodes. If so, insert them.
+ for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ) {
+ PHINode *PN = cast<PHINode>(I);
+ ++I;
- // If the values coming into the block are not the same, we need a PHI.
- if (InVal == 0) {
- // Create the new PHI node, insert it into NewBB at the end of the block
- PHINode *NewPHI = PHINode::Create(PN->getType(), PN->getName()+".ph", BI);
- if (AA) AA->copyValue(PN, NewPHI);
-
- // Move all of the edges from blocks outside the loop 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;
- } else {
- // Remove all of the edges coming into the PHI nodes from outside of the
- // block.
- for (unsigned i = 0, e = Preds.size(); i != e; ++i)
- PN->removeIncomingValue(Preds[i], false);
+ // 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.
+ Value *InVal = PN->getIncomingValueForBlock(Preds[0]);
+ for (unsigned i = 1, e = Preds.size(); i != e; ++i)
+ if (InVal != PN->getIncomingValueForBlock(Preds[i])) {
+ InVal = 0;
+ break;
}
- // Add an incoming value to the PHI node in the loop for the preheader
- // edge.
- PN->addIncoming(InVal, NewBB);
-
- // Can we eliminate this phi node now?
- if (Value *V = PN->hasConstantValue(true)) {
- Instruction *I = dyn_cast<Instruction>(V);
- // If I is in NewBB, the Dominator call will fail, because NewBB isn't
- // registered in DominatorTree yet. Handle this case explicitly.
- if (!I || (I->getParent() != NewBB &&
- getAnalysis<DominatorTree>().dominates(I, PN))) {
- PN->replaceAllUsesWith(V);
- if (AA) AA->deleteValue(PN);
- BB->getInstList().erase(PN);
- }
+ // If the values coming into the block are not the same, we need a PHI.
+ if (InVal == 0) {
+ // Create the new PHI node, insert it into NewBB at the end of the block
+ PHINode *NewPHI =
+ PHINode::Create(PN->getType(), PN->getName()+".ph", BI);
+ if (AA) AA->copyValue(PN, NewPHI);
+
+ // Move all of the edges from blocks outside the loop 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;
+ } else {
+ // Remove all of the edges coming into the PHI nodes from outside of the
+ // block.
+ for (unsigned i = 0, e = Preds.size(); i != e; ++i)
+ PN->removeIncomingValue(Preds[i], false);
}
- // Now that the PHI nodes are updated, actually move the edges from
- // Preds to point to NewBB instead of BB.
- //
- for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
- TerminatorInst *TI = Preds[i]->getTerminator();
- for (unsigned s = 0, e = TI->getNumSuccessors(); s != e; ++s)
- if (TI->getSuccessor(s) == BB)
- TI->setSuccessor(s, NewBB);
-
- if (Preds[i]->getUnwindDest() == BB)
- Preds[i]->setUnwindDest(NewBB);
+ // Add an incoming value to the PHI node in the loop for the preheader
+ // edge.
+ PN->addIncoming(InVal, NewBB);
+
+ // Can we eliminate this phi node now?
+ if (Value *V = PN->hasConstantValue(true)) {
+ Instruction *I = dyn_cast<Instruction>(V);
+ // If I is in NewBB, the Dominator call will fail, because NewBB isn't
+ // registered in DominatorTree yet. Handle this case explicitly.
+ if (!I || (I->getParent() != NewBB &&
+ getAnalysis<DominatorTree>().dominates(I, PN))) {
+ PN->replaceAllUsesWith(V);
+ if (AA) AA->deleteValue(PN);
+ BB->getInstList().erase(PN);
+ }
}
+ }
- } else { // Otherwise the loop is dead...
- for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ++I) {
- PHINode *PN = cast<PHINode>(I);
- // Insert dummy values as the incoming value...
- PN->addIncoming(Constant::getNullValue(PN->getType()), NewBB);
- }
+ // Now that the PHI nodes are updated, actually move the edges from
+ // Preds to point to NewBB instead of BB.
+ //
+ for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
+ TerminatorInst *TI = Preds[i]->getTerminator();
+ for (unsigned s = 0, e = TI->getNumSuccessors(); s != e; ++s)
+ if (TI->getSuccessor(s) == BB)
+ TI->setSuccessor(s, NewBB);
+
+ if (Preds[i]->getUnwindDest() == BB)
+ Preds[i]->setUnwindDest(NewBB);
}
return NewBB;
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