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Reinstate r133513 (reverted in r133700) with an additional fix for a

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-Wshorten-64-to-32 warning in Instructions.h.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133708 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jay Foad
2011-06-23 09:09:15 +00:00
parent 5b46e8e6b8
commit 95c3e48f95
19 changed files with 222 additions and 167 deletions
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lib/Transforms/Utils/LoopUnroll.cpp
+46 -39
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@@ -47,6 +47,14 @@ static inline void RemapInstruction(Instruction *I,
if (It != VMap.end())
I->setOperand(op, It->second);
}
if (PHINode *PN = dyn_cast<PHINode>(I)) {
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
ValueToValueMapTy::iterator It = VMap.find(PN->getIncomingBlock(i));
if (It != VMap.end())
PN->setIncomingBlock(i, cast<BasicBlock>(It->second));
}
}
}
/// FoldBlockIntoPredecessor - Folds a basic block into its predecessor if it
@@ -75,13 +83,13 @@ static BasicBlock *FoldBlockIntoPredecessor(BasicBlock *BB, LoopInfo* LI) {
// Delete the unconditional branch from the predecessor...
OnlyPred->getInstList().pop_back();
// Move all definitions in the successor to the predecessor...
OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
// Make all PHI nodes that referred to BB now refer to Pred as their
// source...
BB->replaceAllUsesWith(OnlyPred);
// Move all definitions in the successor to the predecessor...
OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
std::string OldName = BB->getName();
// Erase basic block from the function...
@@ -121,14 +129,14 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
BasicBlock *Header = L->getHeader();
BranchInst *BI = dyn_cast<BranchInst>(LatchBlock->getTerminator());
if (!BI || BI->isUnconditional()) {
// The loop-rotate pass can be helpful to avoid this in many cases.
DEBUG(dbgs() <<
" Can't unroll; loop not terminated by a conditional branch.\n");
return false;
}
if (Header->hasAddressTaken()) {
// The loop-rotate pass can be helpful to avoid this in many cases.
DEBUG(dbgs() <<
@@ -202,7 +210,7 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
OrigPHINode.push_back(PN);
if (Instruction *I =
if (Instruction *I =
dyn_cast<Instruction>(PN->getIncomingValueForBlock(LatchBlock)))
if (L->contains(I))
LastValueMap[I] = I;
@@ -215,7 +223,7 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
for (unsigned It = 1; It != Count; ++It) {
std::vector<BasicBlock*> NewBlocks;
for (std::vector<BasicBlock*>::iterator BB = LoopBlocks.begin(),
E = LoopBlocks.end(); BB != E; ++BB) {
ValueToValueMapTy VMap;
@@ -247,16 +255,14 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
// the successor of the latch block. The successor of the exit block will
// be updated specially after unrolling all the way.
if (*BB != LatchBlock)
for (Value::use_iterator UI = (*BB)->use_begin(), UE = (*BB)->use_end();
UI != UE;) {
Instruction *UseInst = cast<Instruction>(*UI);
++UI;
if (isa<PHINode>(UseInst) && !L->contains(UseInst)) {
PHINode *phi = cast<PHINode>(UseInst);
Value *Incoming = phi->getIncomingValueForBlock(*BB);
phi->addIncoming(Incoming, New);
}
}
for (succ_iterator SI = succ_begin(*BB), SE = succ_end(*BB); SI != SE;
++SI)
if (!L->contains(*SI))
for (BasicBlock::iterator BBI = (*SI)->begin();
PHINode *phi = dyn_cast<PHINode>(BBI); ++BBI) {
Value *Incoming = phi->getIncomingValueForBlock(*BB);
phi->addIncoming(Incoming, New);
}
// Keep track of new headers and latches as we create them, so that
// we can insert the proper branches later.
@@ -276,36 +282,32 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
NewBlocks.push_back(New);
}
// Remap all instructions in the most recent iteration
for (unsigned i = 0; i < NewBlocks.size(); ++i)
for (BasicBlock::iterator I = NewBlocks[i]->begin(),
E = NewBlocks[i]->end(); I != E; ++I)
::RemapInstruction(I, LastValueMap);
}
// The latch block exits the loop. If there are any PHI nodes in the
// successor blocks, update them to use the appropriate values computed as the
// last iteration of the loop.
if (Count != 1) {
SmallPtrSet<PHINode*, 8> Users;
for (Value::use_iterator UI = LatchBlock->use_begin(),
UE = LatchBlock->use_end(); UI != UE; ++UI)
if (PHINode *phi = dyn_cast<PHINode>(*UI))
Users.insert(phi);
BasicBlock *LastIterationBB = cast<BasicBlock>(LastValueMap[LatchBlock]);
for (SmallPtrSet<PHINode*,8>::iterator SI = Users.begin(), SE = Users.end();
for (succ_iterator SI = succ_begin(LatchBlock), SE = succ_end(LatchBlock);
SI != SE; ++SI) {
PHINode *PN = *SI;
Value *InVal = PN->removeIncomingValue(LatchBlock, false);
// If this value was defined in the loop, take the value defined by the
// last iteration of the loop.
if (Instruction *InValI = dyn_cast<Instruction>(InVal)) {
if (L->contains(InValI))
InVal = LastValueMap[InVal];
for (BasicBlock::iterator BBI = (*SI)->begin();
PHINode *PN = dyn_cast<PHINode>(BBI); ++BBI) {
Value *InVal = PN->removeIncomingValue(LatchBlock, false);
// If this value was defined in the loop, take the value defined by the
// last iteration of the loop.
if (Instruction *InValI = dyn_cast<Instruction>(InVal)) {
if (L->contains(InValI))
InVal = LastValueMap[InVal];
}
PN->addIncoming(InVal, LastIterationBB);
}
PN->addIncoming(InVal, LastIterationBB);
}
}
@@ -352,14 +354,19 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
// Replace the conditional branch with an unconditional one.
BranchInst::Create(Dest, Term);
Term->eraseFromParent();
// Merge adjacent basic blocks, if possible.
if (BasicBlock *Fold = FoldBlockIntoPredecessor(Dest, LI)) {
std::replace(Latches.begin(), Latches.end(), Dest, Fold);
std::replace(Headers.begin(), Headers.end(), Dest, Fold);
}
}
}
// Merge adjacent basic blocks, if possible.
for (unsigned i = 0, e = Latches.size(); i != e; ++i) {
BranchInst *Term = cast<BranchInst>(Latches[i]->getTerminator());
if (Term->isUnconditional()) {
BasicBlock *Dest = Term->getSuccessor(0);
if (BasicBlock *Fold = FoldBlockIntoPredecessor(Dest, LI))
std::replace(Latches.begin(), Latches.end(), Dest, Fold);
}
}
// At this point, the code is well formed. We now do a quick sweep over the
// inserted code, doing constant propagation and dead code elimination as we
// go.