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-rw-r--r--contrib/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp229
1 files changed, 49 insertions, 180 deletions
diff --git a/contrib/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/contrib/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
index 0e8199f..c4ebfd5 100644
--- a/contrib/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/contrib/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -87,8 +87,8 @@ namespace {
typedef LoopPropsMap::iterator LoopPropsMapIt;
LoopPropsMap LoopsProperties;
- UnswitchedValsMap* CurLoopInstructions;
- LoopProperties* CurrentLoopProperties;
+ UnswitchedValsMap *CurLoopInstructions;
+ LoopProperties *CurrentLoopProperties;
// Max size of code we can produce on remained iterations.
unsigned MaxSize;
@@ -96,30 +96,30 @@ namespace {
public:
LUAnalysisCache() :
- CurLoopInstructions(NULL), CurrentLoopProperties(NULL),
+ CurLoopInstructions(0), CurrentLoopProperties(0),
MaxSize(Threshold)
{}
// Analyze loop. Check its size, calculate is it possible to unswitch
// it. Returns true if we can unswitch this loop.
- bool countLoop(const Loop* L, const TargetTransformInfo &TTI);
+ bool countLoop(const Loop *L, const TargetTransformInfo &TTI);
// Clean all data related to given loop.
- void forgetLoop(const Loop* L);
+ void forgetLoop(const Loop *L);
// Mark case value as unswitched.
// Since SI instruction can be partly unswitched, in order to avoid
// extra unswitching in cloned loops keep track all unswitched values.
- void setUnswitched(const SwitchInst* SI, const Value* V);
+ void setUnswitched(const SwitchInst *SI, const Value *V);
// Check was this case value unswitched before or not.
- bool isUnswitched(const SwitchInst* SI, const Value* V);
+ bool isUnswitched(const SwitchInst *SI, const Value *V);
// Clone all loop-unswitch related loop properties.
// Redistribute unswitching quotas.
// Note, that new loop data is stored inside the VMap.
- void cloneData(const Loop* NewLoop, const Loop* OldLoop,
- const ValueToValueMapTy& VMap);
+ void cloneData(const Loop *NewLoop, const Loop *OldLoop,
+ const ValueToValueMapTy &VMap);
};
class LoopUnswitch : public LoopPass {
@@ -151,8 +151,8 @@ namespace {
static char ID; // Pass ID, replacement for typeid
explicit LoopUnswitch(bool Os = false) :
LoopPass(ID), OptimizeForSize(Os), redoLoop(false),
- currentLoop(NULL), DT(NULL), loopHeader(NULL),
- loopPreheader(NULL) {
+ currentLoop(0), DT(0), loopHeader(0),
+ loopPreheader(0) {
initializeLoopUnswitchPass(*PassRegistry::getPassRegistry());
}
@@ -196,7 +196,7 @@ namespace {
/// Split all of the edges from inside the loop to their exit blocks.
/// Update the appropriate Phi nodes as we do so.
- void SplitExitEdges(Loop *L, const SmallVector<BasicBlock *, 8> &ExitBlocks);
+ void SplitExitEdges(Loop *L, const SmallVectorImpl<BasicBlock *> &ExitBlocks);
bool UnswitchIfProfitable(Value *LoopCond, Constant *Val);
void UnswitchTrivialCondition(Loop *L, Value *Cond, Constant *Val,
@@ -212,8 +212,6 @@ namespace {
Instruction *InsertPt);
void SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L);
- void RemoveBlockIfDead(BasicBlock *BB,
- std::vector<Instruction*> &Worklist, Loop *l);
void RemoveLoopFromHierarchy(Loop *L);
bool IsTrivialUnswitchCondition(Value *Cond, Constant **Val = 0,
BasicBlock **LoopExit = 0);
@@ -225,12 +223,14 @@ namespace {
// it. Returns true if we can unswitch this loop.
bool LUAnalysisCache::countLoop(const Loop *L, const TargetTransformInfo &TTI) {
- std::pair<LoopPropsMapIt, bool> InsertRes =
+ LoopPropsMapIt PropsIt;
+ bool Inserted;
+ llvm::tie(PropsIt, Inserted) =
LoopsProperties.insert(std::make_pair(L, LoopProperties()));
- LoopProperties& Props = InsertRes.first->second;
+ LoopProperties &Props = PropsIt->second;
- if (InsertRes.second) {
+ if (Inserted) {
// New loop.
// Limit the number of instructions to avoid causing significant code
@@ -242,8 +242,7 @@ bool LUAnalysisCache::countLoop(const Loop *L, const TargetTransformInfo &TTI) {
// consideration code simplification opportunities and code that can
// be shared by the resultant unswitched loops.
CodeMetrics Metrics;
- for (Loop::block_iterator I = L->block_begin(),
- E = L->block_end();
+ for (Loop::block_iterator I = L->block_begin(), E = L->block_end();
I != E; ++I)
Metrics.analyzeBasicBlock(*I, TTI);
@@ -253,17 +252,16 @@ bool LUAnalysisCache::countLoop(const Loop *L, const TargetTransformInfo &TTI) {
if (Metrics.notDuplicatable) {
DEBUG(dbgs() << "NOT unswitching loop %"
- << L->getHeader()->getName() << ", contents cannot be "
- << "duplicated!\n");
+ << L->getHeader()->getName() << ", contents cannot be "
+ << "duplicated!\n");
return false;
}
}
if (!Props.CanBeUnswitchedCount) {
DEBUG(dbgs() << "NOT unswitching loop %"
- << L->getHeader()->getName() << ", cost too high: "
- << L->getBlocks().size() << "\n");
-
+ << L->getHeader()->getName() << ", cost too high: "
+ << L->getBlocks().size() << "\n");
return false;
}
@@ -275,41 +273,41 @@ bool LUAnalysisCache::countLoop(const Loop *L, const TargetTransformInfo &TTI) {
}
// Clean all data related to given loop.
-void LUAnalysisCache::forgetLoop(const Loop* L) {
+void LUAnalysisCache::forgetLoop(const Loop *L) {
LoopPropsMapIt LIt = LoopsProperties.find(L);
if (LIt != LoopsProperties.end()) {
- LoopProperties& Props = LIt->second;
+ LoopProperties &Props = LIt->second;
MaxSize += Props.CanBeUnswitchedCount * Props.SizeEstimation;
LoopsProperties.erase(LIt);
}
- CurrentLoopProperties = NULL;
- CurLoopInstructions = NULL;
+ CurrentLoopProperties = 0;
+ CurLoopInstructions = 0;
}
// Mark case value as unswitched.
// Since SI instruction can be partly unswitched, in order to avoid
// extra unswitching in cloned loops keep track all unswitched values.
-void LUAnalysisCache::setUnswitched(const SwitchInst* SI, const Value* V) {
+void LUAnalysisCache::setUnswitched(const SwitchInst *SI, const Value *V) {
(*CurLoopInstructions)[SI].insert(V);
}
// Check was this case value unswitched before or not.
-bool LUAnalysisCache::isUnswitched(const SwitchInst* SI, const Value* V) {
+bool LUAnalysisCache::isUnswitched(const SwitchInst *SI, const Value *V) {
return (*CurLoopInstructions)[SI].count(V);
}
// Clone all loop-unswitch related loop properties.
// Redistribute unswitching quotas.
// Note, that new loop data is stored inside the VMap.
-void LUAnalysisCache::cloneData(const Loop* NewLoop, const Loop* OldLoop,
- const ValueToValueMapTy& VMap) {
+void LUAnalysisCache::cloneData(const Loop *NewLoop, const Loop *OldLoop,
+ const ValueToValueMapTy &VMap) {
- LoopProperties& NewLoopProps = LoopsProperties[NewLoop];
- LoopProperties& OldLoopProps = *CurrentLoopProperties;
- UnswitchedValsMap& Insts = OldLoopProps.UnswitchedVals;
+ LoopProperties &NewLoopProps = LoopsProperties[NewLoop];
+ LoopProperties &OldLoopProps = *CurrentLoopProperties;
+ UnswitchedValsMap &Insts = OldLoopProps.UnswitchedVals;
// Reallocate "can-be-unswitched quota"
@@ -324,9 +322,9 @@ void LUAnalysisCache::cloneData(const Loop* NewLoop, const Loop* OldLoop,
// for new loop switches we clone info about values that was
// already unswitched and has redundant successors.
for (UnswitchedValsIt I = Insts.begin(); I != Insts.end(); ++I) {
- const SwitchInst* OldInst = I->first;
- Value* NewI = VMap.lookup(OldInst);
- const SwitchInst* NewInst = cast_or_null<SwitchInst>(NewI);
+ const SwitchInst *OldInst = I->first;
+ Value *NewI = VMap.lookup(OldInst);
+ const SwitchInst *NewInst = cast_or_null<SwitchInst>(NewI);
assert(NewInst && "All instructions that are in SrcBB must be in VMap.");
NewLoopProps.UnswitchedVals[NewInst] = OldLoopProps.UnswitchedVals[OldInst];
@@ -458,14 +456,14 @@ bool LoopUnswitch::processCurrentLoop() {
// Find a value to unswitch on:
// FIXME: this should chose the most expensive case!
// FIXME: scan for a case with a non-critical edge?
- Constant *UnswitchVal = NULL;
+ Constant *UnswitchVal = 0;
// Do not process same value again and again.
// At this point we have some cases already unswitched and
// some not yet unswitched. Let's find the first not yet unswitched one.
for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
i != e; ++i) {
- Constant* UnswitchValCandidate = i.getCaseValue();
+ Constant *UnswitchValCandidate = i.getCaseValue();
if (!BranchesInfo.isUnswitched(SI, UnswitchValCandidate)) {
UnswitchVal = UnswitchValCandidate;
break;
@@ -511,7 +509,8 @@ static bool isTrivialLoopExitBlockHelper(Loop *L, BasicBlock *BB,
// Already visited. Without more analysis, this could indicate an infinite
// loop.
return false;
- } else if (!L->contains(BB)) {
+ }
+ if (!L->contains(BB)) {
// Otherwise, this is a loop exit, this is fine so long as this is the
// first exit.
if (ExitBB != 0) return false;
@@ -595,11 +594,11 @@ bool LoopUnswitch::IsTrivialUnswitchCondition(Value *Cond, Constant **Val,
// on already unswitched cases.
for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
i != e; ++i) {
- BasicBlock* LoopExitCandidate;
+ BasicBlock *LoopExitCandidate;
if ((LoopExitCandidate = isTrivialLoopExitBlock(currentLoop,
i.getCaseSuccessor()))) {
// Okay, we found a trivial case, remember the value that is trivial.
- ConstantInt* CaseVal = i.getCaseValue();
+ ConstantInt *CaseVal = i.getCaseValue();
// Check that it was not unswitched before, since already unswitched
// trivial vals are looks trivial too.
@@ -752,7 +751,7 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond,
/// SplitExitEdges - Split all of the edges from inside the loop to their exit
/// blocks. Update the appropriate Phi nodes as we do so.
void LoopUnswitch::SplitExitEdges(Loop *L,
- const SmallVector<BasicBlock *, 8> &ExitBlocks){
+ const SmallVectorImpl<BasicBlock *> &ExitBlocks){
for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i) {
BasicBlock *ExitBlock = ExitBlocks[i];
@@ -854,9 +853,8 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
// If the successor of the exit block had PHI nodes, add an entry for
// NewExit.
- PHINode *PN;
- for (BasicBlock::iterator I = ExitSucc->begin(); isa<PHINode>(I); ++I) {
- PN = cast<PHINode>(I);
+ for (BasicBlock::iterator I = ExitSucc->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I) {
Value *V = PN->getIncomingValueForBlock(ExitBlocks[i]);
ValueToValueMapTy::iterator It = VMap.find(V);
if (It != VMap.end()) V = It->second;
@@ -864,8 +862,8 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
}
if (LandingPadInst *LPad = NewExit->getLandingPadInst()) {
- PN = PHINode::Create(LPad->getType(), 0, "",
- ExitSucc->getFirstInsertionPt());
+ PHINode *PN = PHINode::Create(LPad->getType(), 0, "",
+ ExitSucc->getFirstInsertionPt());
for (pred_iterator I = pred_begin(ExitSucc), E = pred_end(ExitSucc);
I != E; ++I) {
@@ -946,117 +944,6 @@ static void ReplaceUsesOfWith(Instruction *I, Value *V,
++NumSimplify;
}
-/// RemoveBlockIfDead - If the specified block is dead, remove it, update loop
-/// information, and remove any dead successors it has.
-///
-void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB,
- std::vector<Instruction*> &Worklist,
- Loop *L) {
- if (pred_begin(BB) != pred_end(BB)) {
- // This block isn't dead, since an edge to BB was just removed, see if there
- // are any easy simplifications we can do now.
- if (BasicBlock *Pred = BB->getSinglePredecessor()) {
- // If it has one pred, fold phi nodes in BB.
- while (isa<PHINode>(BB->begin()))
- ReplaceUsesOfWith(BB->begin(),
- cast<PHINode>(BB->begin())->getIncomingValue(0),
- Worklist, L, LPM);
-
- // If this is the header of a loop and the only pred is the latch, we now
- // have an unreachable loop.
- if (Loop *L = LI->getLoopFor(BB))
- if (loopHeader == BB && L->contains(Pred)) {
- // Remove the branch from the latch to the header block, this makes
- // the header dead, which will make the latch dead (because the header
- // dominates the latch).
- LPM->deleteSimpleAnalysisValue(Pred->getTerminator(), L);
- Pred->getTerminator()->eraseFromParent();
- new UnreachableInst(BB->getContext(), Pred);
-
- // The loop is now broken, remove it from LI.
- RemoveLoopFromHierarchy(L);
-
- // Reprocess the header, which now IS dead.
- RemoveBlockIfDead(BB, Worklist, L);
- return;
- }
-
- // If pred ends in a uncond branch, add uncond branch to worklist so that
- // the two blocks will get merged.
- if (BranchInst *BI = dyn_cast<BranchInst>(Pred->getTerminator()))
- if (BI->isUnconditional())
- Worklist.push_back(BI);
- }
- return;
- }
-
- DEBUG(dbgs() << "Nuking dead block: " << *BB);
-
- // Remove the instructions in the basic block from the worklist.
- for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
- RemoveFromWorklist(I, Worklist);
-
- // Anything that uses the instructions in this basic block should have their
- // uses replaced with undefs.
- // If I is not void type then replaceAllUsesWith undef.
- // This allows ValueHandlers and custom metadata to adjust itself.
- if (!I->getType()->isVoidTy())
- I->replaceAllUsesWith(UndefValue::get(I->getType()));
- }
-
- // If this is the edge to the header block for a loop, remove the loop and
- // promote all subloops.
- if (Loop *BBLoop = LI->getLoopFor(BB)) {
- if (BBLoop->getLoopLatch() == BB) {
- RemoveLoopFromHierarchy(BBLoop);
- if (currentLoop == BBLoop) {
- currentLoop = 0;
- redoLoop = false;
- }
- }
- }
-
- // Remove the block from the loop info, which removes it from any loops it
- // was in.
- LI->removeBlock(BB);
-
-
- // Remove phi node entries in successors for this block.
- TerminatorInst *TI = BB->getTerminator();
- SmallVector<BasicBlock*, 4> Succs;
- for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
- Succs.push_back(TI->getSuccessor(i));
- TI->getSuccessor(i)->removePredecessor(BB);
- }
-
- // Unique the successors, remove anything with multiple uses.
- array_pod_sort(Succs.begin(), Succs.end());
- Succs.erase(std::unique(Succs.begin(), Succs.end()), Succs.end());
-
- // Remove the basic block, including all of the instructions contained in it.
- LPM->deleteSimpleAnalysisValue(BB, L);
- BB->eraseFromParent();
- // Remove successor blocks here that are not dead, so that we know we only
- // have dead blocks in this list. Nondead blocks have a way of becoming dead,
- // then getting removed before we revisit them, which is badness.
- //
- for (unsigned i = 0; i != Succs.size(); ++i)
- if (pred_begin(Succs[i]) != pred_end(Succs[i])) {
- // One exception is loop headers. If this block was the preheader for a
- // loop, then we DO want to visit the loop so the loop gets deleted.
- // We know that if the successor is a loop header, that this loop had to
- // be the preheader: the case where this was the latch block was handled
- // above and headers can only have two predecessors.
- if (!LI->isLoopHeader(Succs[i])) {
- Succs.erase(Succs.begin()+i);
- --i;
- }
- }
-
- for (unsigned i = 0, e = Succs.size(); i != e; ++i)
- RemoveBlockIfDead(Succs[i], Worklist, L);
-}
-
/// RemoveLoopFromHierarchy - We have discovered that the specified loop has
/// become unwrapped, either because the backedge was deleted, or because the
/// edge into the header was removed. If the edge into the header from the
@@ -1088,7 +975,6 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
std::vector<Instruction*> Worklist;
LLVMContext &Context = Val->getContext();
-
// If we know that LIC == Val, or that LIC == NotVal, just replace uses of LIC
// in the loop with the appropriate one directly.
if (IsEqual || (isa<ConstantInt>(Val) &&
@@ -1108,8 +994,8 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
Worklist.push_back(U);
}
- for (std::vector<Instruction*>::iterator UI = Worklist.begin();
- UI != Worklist.end(); ++UI)
+ for (std::vector<Instruction*>::iterator UI = Worklist.begin(),
+ UE = Worklist.end(); UI != UE; ++UI)
(*UI)->replaceUsesOfWith(LIC, Replacement);
SimplifyCode(Worklist, L);
@@ -1266,23 +1152,6 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
continue;
}
- if (ConstantInt *CB = dyn_cast<ConstantInt>(BI->getCondition())){
- // Conditional branch. Turn it into an unconditional branch, then
- // remove dead blocks.
- continue; // FIXME: Enable.
-
- DEBUG(dbgs() << "Folded branch: " << *BI);
- BasicBlock *DeadSucc = BI->getSuccessor(CB->getZExtValue());
- BasicBlock *LiveSucc = BI->getSuccessor(!CB->getZExtValue());
- DeadSucc->removePredecessor(BI->getParent(), true);
- Worklist.push_back(BranchInst::Create(LiveSucc, BI));
- LPM->deleteSimpleAnalysisValue(BI, L);
- BI->eraseFromParent();
- RemoveFromWorklist(BI, Worklist);
- ++NumSimplify;
-
- RemoveBlockIfDead(DeadSucc, Worklist, L);
- }
continue;
}
}
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