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authorAndrew Trick <atrick@apple.com>2012-06-26 04:11:38 +0000
committerAndrew Trick <atrick@apple.com>2012-06-26 04:11:38 +0000
commitc9b1e25493b393013b28e5d457f2fb2845a4dd9f (patch)
treec1193bd83841e829e703beeb00c1fe6415de5f05 /include/llvm/Analysis
parent5ac3f96c0e4a1f6b8253aabf74fe30b0439e9bdf (diff)
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Enable the new LoopInfo algorithm by default.
The primary advantage is that loop optimizations will be applied in a stable order. This helps debugging and unit test creation. It is also a better overall implementation without pathologically bad performance on deep functions. On large functions (llvm-stress --size=200000 | opt -loops) Before: 0.1263s After: 0.0225s On deep functions (after tweaking llvm-stress, thanks Nadav): Before: 0.2281s After: 0.0227s See r158790 for more comments. The loop tree is now consistently generated in forward order, but loop passes are applied in reverse order over the program. If we have a loop optimization that prefers forward order, that can easily be achieved by adding a different type of LoopPassManager. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159183 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include/llvm/Analysis')
-rw-r--r--include/llvm/Analysis/LoopInfo.h24
-rw-r--r--include/llvm/Analysis/LoopInfoImpl.h179
2 files changed, 11 insertions, 192 deletions
diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index 14d87e0..eeb482d 100644
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -127,8 +127,12 @@ public:
const std::vector<LoopT *> &getSubLoops() const { return SubLoops; }
std::vector<LoopT *> &getSubLoopsVector() { return SubLoops; }
typedef typename std::vector<LoopT *>::const_iterator iterator;
+ typedef typename std::vector<LoopT *>::const_reverse_iterator
+ reverse_iterator;
iterator begin() const { return SubLoops.begin(); }
iterator end() const { return SubLoops.end(); }
+ reverse_iterator rbegin() const { return SubLoops.rbegin(); }
+ reverse_iterator rend() const { return SubLoops.rend(); }
bool empty() const { return SubLoops.empty(); }
/// getBlocks - Get a list of the basic blocks which make up this loop.
@@ -431,8 +435,12 @@ public:
/// function.
///
typedef typename std::vector<LoopT *>::const_iterator iterator;
+ typedef typename std::vector<LoopT *>::const_reverse_iterator
+ reverse_iterator;
iterator begin() const { return TopLevelLoops.begin(); }
iterator end() const { return TopLevelLoops.end(); }
+ reverse_iterator rbegin() const { return TopLevelLoops.rbegin(); }
+ reverse_iterator rend() const { return TopLevelLoops.rend(); }
bool empty() const { return TopLevelLoops.empty(); }
/// getLoopFor - Return the inner most loop that BB lives in. If a basic
@@ -525,19 +533,6 @@ public:
return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop);
}
- void Calculate(DominatorTreeBase<BlockT> &DT);
-
- LoopT *ConsiderForLoop(BlockT *BB, DominatorTreeBase<BlockT> &DT);
-
- /// MoveSiblingLoopInto - This method moves the NewChild loop to live inside
- /// of the NewParent Loop, instead of being a sibling of it.
- void MoveSiblingLoopInto(LoopT *NewChild, LoopT *NewParent);
-
- /// InsertLoopInto - This inserts loop L into the specified parent loop. If
- /// the parent loop contains a loop which should contain L, the loop gets
- /// inserted into L instead.
- void InsertLoopInto(LoopT *L, LoopT *Parent);
-
/// Create the loop forest using a stable algorithm.
void Analyze(DominatorTreeBase<BlockT> &DomTree);
@@ -570,8 +565,11 @@ public:
/// function.
///
typedef LoopInfoBase<BasicBlock, Loop>::iterator iterator;
+ typedef LoopInfoBase<BasicBlock, Loop>::reverse_iterator reverse_iterator;
inline iterator begin() const { return LI.begin(); }
inline iterator end() const { return LI.end(); }
+ inline reverse_iterator rbegin() const { return LI.rbegin(); }
+ inline reverse_iterator rend() const { return LI.rend(); }
bool empty() const { return LI.empty(); }
/// getLoopFor - Return the inner most loop that BB lives in. If a basic
diff --git a/include/llvm/Analysis/LoopInfoImpl.h b/include/llvm/Analysis/LoopInfoImpl.h
index 1be717c..c07fbf7 100644
--- a/include/llvm/Analysis/LoopInfoImpl.h
+++ b/include/llvm/Analysis/LoopInfoImpl.h
@@ -354,185 +354,6 @@ void LoopBase<BlockT, LoopT>::print(raw_ostream &OS, unsigned Depth) const {
}
//===----------------------------------------------------------------------===//
-/// LoopInfo - This class builds and contains all of the top level loop
-/// structures in the specified function.
-///
-
-template<class BlockT, class LoopT>
-void LoopInfoBase<BlockT, LoopT>::Calculate(DominatorTreeBase<BlockT> &DT) {
- BlockT *RootNode = DT.getRootNode()->getBlock();
-
- for (df_iterator<BlockT*> NI = df_begin(RootNode),
- NE = df_end(RootNode); NI != NE; ++NI)
- if (LoopT *L = ConsiderForLoop(*NI, DT))
- TopLevelLoops.push_back(L);
-}
-
-template<class BlockT, class LoopT>
-LoopT *LoopInfoBase<BlockT, LoopT>::
-ConsiderForLoop(BlockT *BB, DominatorTreeBase<BlockT> &DT) {
- if (BBMap.count(BB)) return 0; // Haven't processed this node?
-
- std::vector<BlockT *> TodoStack;
-
- // Scan the predecessors of BB, checking to see if BB dominates any of
- // them. This identifies backedges which target this node...
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
- for (typename InvBlockTraits::ChildIteratorType I =
- InvBlockTraits::child_begin(BB), E = InvBlockTraits::child_end(BB);
- I != E; ++I) {
- typename InvBlockTraits::NodeType *N = *I;
- // If BB dominates its predecessor...
- if (DT.dominates(BB, N) && DT.isReachableFromEntry(N))
- TodoStack.push_back(N);
- }
-
- if (TodoStack.empty()) return 0; // No backedges to this block...
-
- // Create a new loop to represent this basic block...
- LoopT *L = new LoopT(BB);
- BBMap[BB] = L;
-
- while (!TodoStack.empty()) { // Process all the nodes in the loop
- BlockT *X = TodoStack.back();
- TodoStack.pop_back();
-
- if (!L->contains(X) && // As of yet unprocessed??
- DT.isReachableFromEntry(X)) {
- // Check to see if this block already belongs to a loop. If this occurs
- // then we have a case where a loop that is supposed to be a child of
- // the current loop was processed before the current loop. When this
- // occurs, this child loop gets added to a part of the current loop,
- // making it a sibling to the current loop. We have to reparent this
- // loop.
- if (LoopT *SubLoop =
- const_cast<LoopT *>(getLoopFor(X)))
- if (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)){
- // Remove the subloop from its current parent...
- assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L);
- LoopT *SLP = SubLoop->ParentLoop; // SubLoopParent
- typename std::vector<LoopT *>::iterator I =
- std::find(SLP->SubLoops.begin(), SLP->SubLoops.end(), SubLoop);
- assert(I != SLP->SubLoops.end() &&"SubLoop not a child of parent?");
- SLP->SubLoops.erase(I); // Remove from parent...
-
- // Add the subloop to THIS loop...
- SubLoop->ParentLoop = L;
- L->SubLoops.push_back(SubLoop);
- }
-
- // Normal case, add the block to our loop...
- L->Blocks.push_back(X);
-
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
-
- // Add all of the predecessors of X to the end of the work stack...
- TodoStack.insert(TodoStack.end(), InvBlockTraits::child_begin(X),
- InvBlockTraits::child_end(X));
- }
- }
-
- // If there are any loops nested within this loop, create them now!
- for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(),
- E = L->Blocks.end(); I != E; ++I)
- if (LoopT *NewLoop = ConsiderForLoop(*I, DT)) {
- L->SubLoops.push_back(NewLoop);
- NewLoop->ParentLoop = L;
- }
-
- // Add the basic blocks that comprise this loop to the BBMap so that this
- // loop can be found for them.
- //
- for (typename std::vector<BlockT*>::iterator I = L->Blocks.begin(),
- E = L->Blocks.end(); I != E; ++I)
- BBMap.insert(std::make_pair(*I, L));
-
- // Now that we have a list of all of the child loops of this loop, check to
- // see if any of them should actually be nested inside of each other. We
- // can accidentally pull loops our of their parents, so we must make sure to
- // organize the loop nests correctly now.
- {
- std::map<BlockT *, LoopT *> ContainingLoops;
- for (unsigned i = 0; i != L->SubLoops.size(); ++i) {
- LoopT *Child = L->SubLoops[i];
- assert(Child->getParentLoop() == L && "Not proper child loop?");
-
- if (LoopT *ContainingLoop = ContainingLoops[Child->getHeader()]) {
- // If there is already a loop which contains this loop, move this loop
- // into the containing loop.
- MoveSiblingLoopInto(Child, ContainingLoop);
- --i; // The loop got removed from the SubLoops list.
- } else {
- // This is currently considered to be a top-level loop. Check to see
- // if any of the contained blocks are loop headers for subloops we
- // have already processed.
- for (unsigned b = 0, e = Child->Blocks.size(); b != e; ++b) {
- LoopT *&BlockLoop = ContainingLoops[Child->Blocks[b]];
- if (BlockLoop == 0) { // Child block not processed yet...
- BlockLoop = Child;
- } else if (BlockLoop != Child) {
- LoopT *SubLoop = BlockLoop;
- // Reparent all of the blocks which used to belong to BlockLoops
- for (unsigned j = 0, f = SubLoop->Blocks.size(); j != f; ++j)
- ContainingLoops[SubLoop->Blocks[j]] = Child;
-
- // There is already a loop which contains this block, that means
- // that we should reparent the loop which the block is currently
- // considered to belong to to be a child of this loop.
- MoveSiblingLoopInto(SubLoop, Child);
- --i; // We just shrunk the SubLoops list.
- }
- }
- }
- }
- }
-
- return L;
-}
-
-/// MoveSiblingLoopInto - This method moves the NewChild loop to live inside
-/// of the NewParent Loop, instead of being a sibling of it.
-template<class BlockT, class LoopT>
-void LoopInfoBase<BlockT, LoopT>::
-MoveSiblingLoopInto(LoopT *NewChild, LoopT *NewParent) {
- LoopT *OldParent = NewChild->getParentLoop();
- assert(OldParent && OldParent == NewParent->getParentLoop() &&
- NewChild != NewParent && "Not sibling loops!");
-
- // Remove NewChild from being a child of OldParent
- typename std::vector<LoopT *>::iterator I =
- std::find(OldParent->SubLoops.begin(), OldParent->SubLoops.end(),
- NewChild);
- assert(I != OldParent->SubLoops.end() && "Parent fields incorrect??");
- OldParent->SubLoops.erase(I); // Remove from parent's subloops list
- NewChild->ParentLoop = 0;
-
- InsertLoopInto(NewChild, NewParent);
-}
-
-/// InsertLoopInto - This inserts loop L into the specified parent loop. If
-/// the parent loop contains a loop which should contain L, the loop gets
-/// inserted into L instead.
-template<class BlockT, class LoopT>
-void LoopInfoBase<BlockT, LoopT>::InsertLoopInto(LoopT *L, LoopT *Parent) {
- BlockT *LHeader = L->getHeader();
- assert(Parent->contains(LHeader) &&
- "This loop should not be inserted here!");
-
- // Check to see if it belongs in a child loop...
- for (unsigned i = 0, e = static_cast<unsigned>(Parent->SubLoops.size());
- i != e; ++i)
- if (Parent->SubLoops[i]->contains(LHeader)) {
- InsertLoopInto(L, Parent->SubLoops[i]);
- return;
- }
-
- // If not, insert it here!
- Parent->SubLoops.push_back(L);
- L->ParentLoop = Parent;
-}
-
-//===----------------------------------------------------------------------===//
/// Stable LoopInfo Analysis - Build a loop tree using stable iterators so the
/// result does / not depend on use list (block predecessor) order.
///