//===----------------------------------------------------------------------===//
//
// This file defines the LoopInfo class that is used to identify natural loops
-// and determine the loop depth of various nodes of the CFG. Note that natural
+// and determine the loop depth of various nodes of the CFG. A natural loop
+// has exactly one entry-point, which is called the header. Note that natural
// loops may actually be several loops that share the same header node.
//
// This analysis calculates the nesting structure of loops in a function. For
// * whether or not a particular block branches out of the loop
// * the successor blocks of the loop
// * the loop depth
-// * the trip count
// * etc...
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_ANALYSIS_LOOP_INFO_H
-#define LLVM_ANALYSIS_LOOP_INFO_H
+#ifndef LLVM_ANALYSIS_LOOPINFO_H
+#define LLVM_ANALYSIS_LOOPINFO_H
-#include "llvm/Pass.h"
-#include "llvm/Constants.h"
-#include "llvm/Instructions.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/GraphTraits.h"
-#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Pass.h"
#include "llvm/Support/CFG.h"
-#include "llvm/Support/Streams.h"
+#include "llvm/Support/raw_ostream.h"
#include <algorithm>
-#include <ostream>
+#include <map>
+
+namespace llvm {
template<typename T>
-static void RemoveFromVector(std::vector<T*> &V, T *N) {
+inline void RemoveFromVector(std::vector<T*> &V, T *N) {
typename std::vector<T*>::iterator I = std::find(V.begin(), V.end(), N);
assert(I != V.end() && "N is not in this list!");
V.erase(I);
}
-namespace llvm {
-
class DominatorTree;
class LoopInfo;
+class Loop;
class PHINode;
-class Instruction;
-template<class N> class LoopInfoBase;
-template<class N> class LoopBase;
-
-typedef LoopBase<BasicBlock> Loop;
+template<class N, class M> class LoopInfoBase;
+template<class N, class M> class LoopBase;
//===----------------------------------------------------------------------===//
/// LoopBase class - Instances of this class are used to represent loops that
/// are detected in the flow graph
///
-template<class BlockT>
+template<class BlockT, class LoopT>
class LoopBase {
- LoopBase<BlockT> *ParentLoop;
+ LoopT *ParentLoop;
// SubLoops - Loops contained entirely within this one.
- std::vector<LoopBase<BlockT>*> SubLoops;
+ std::vector<LoopT *> SubLoops;
// Blocks - The list of blocks in this loop. First entry is the header node.
std::vector<BlockT*> Blocks;
- LoopBase(const LoopBase<BlockT> &); // DO NOT IMPLEMENT
- const LoopBase<BlockT>&operator=(const LoopBase<BlockT> &);// DO NOT IMPLEMENT
+ LoopBase(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION;
+ const LoopBase<BlockT, LoopT>&
+ operator=(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION;
public:
/// Loop ctor - This creates an empty loop.
LoopBase() : ParentLoop(0) {}
/// blocks, where depth 0 is used for blocks not inside any loops.
unsigned getLoopDepth() const {
unsigned D = 1;
- for (const LoopBase<BlockT> *CurLoop = ParentLoop; CurLoop;
+ for (const LoopT *CurLoop = ParentLoop; CurLoop;
CurLoop = CurLoop->ParentLoop)
++D;
return D;
}
BlockT *getHeader() const { return Blocks.front(); }
- LoopBase<BlockT> *getParentLoop() const { return ParentLoop; }
+ LoopT *getParentLoop() const { return ParentLoop; }
+
+ /// setParentLoop is a raw interface for bypassing addChildLoop.
+ void setParentLoop(LoopT *L) { ParentLoop = L; }
+
+ /// contains - Return true if the specified loop is contained within in
+ /// this loop.
+ ///
+ bool contains(const LoopT *L) const {
+ if (L == this) return true;
+ if (L == 0) return false;
+ return contains(L->getParentLoop());
+ }
- /// contains - Return true if the specified basic block is in this loop
+ /// contains - Return true if the specified basic block is in this loop.
///
bool contains(const BlockT *BB) const {
- return std::find(Blocks.begin(), Blocks.end(), BB) != Blocks.end();
+ return std::find(block_begin(), block_end(), BB) != block_end();
+ }
+
+ /// contains - Return true if the specified instruction is in this loop.
+ ///
+ template<class InstT>
+ bool contains(const InstT *Inst) const {
+ return contains(Inst->getParent());
}
/// iterator/begin/end - Return the loops contained entirely within this loop.
///
- const std::vector<LoopBase<BlockT>*> &getSubLoops() const { return SubLoops; }
- typedef typename std::vector<LoopBase<BlockT>*>::const_iterator iterator;
+ 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.
///
const std::vector<BlockT*> &getBlocks() const { return Blocks; }
+ std::vector<BlockT*> &getBlocksVector() { return Blocks; }
typedef typename std::vector<BlockT*>::const_iterator block_iterator;
block_iterator block_begin() const { return Blocks.begin(); }
block_iterator block_end() const { return Blocks.end(); }
- /// isLoopExit - True if terminator in the block can branch to another block
- /// that is outside of the current loop.
+ /// getNumBlocks - Get the number of blocks in this loop in constant time.
+ unsigned getNumBlocks() const {
+ return Blocks.size();
+ }
+
+ /// isLoopExiting - True if terminator in the block can branch to another
+ /// block that is outside of the current loop.
///
- bool isLoopExit(const BlockT *BB) const {
+ bool isLoopExiting(const BlockT *BB) const {
typedef GraphTraits<BlockT*> BlockTraits;
for (typename BlockTraits::ChildIteratorType SI =
BlockTraits::child_begin(const_cast<BlockT*>(BB)),
return NumBackEdges;
}
- /// isLoopInvariant - Return true if the specified value is loop invariant
- ///
- inline bool isLoopInvariant(Value *V) const {
- if (Instruction *I = dyn_cast<Instruction>(V))
- return !contains(I->getParent());
- return true; // All non-instructions are loop invariant
- }
-
//===--------------------------------------------------------------------===//
// APIs for simple analysis of the loop.
//
/// outside of the loop. These are the blocks _inside of the current loop_
/// which branch out. The returned list is always unique.
///
- void getExitingBlocks(SmallVectorImpl<BlockT *> &ExitingBlocks) const {
- // Sort the blocks vector so that we can use binary search to do quick
- // lookups.
- SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end());
- std::sort(LoopBBs.begin(), LoopBBs.end());
+ void getExitingBlocks(SmallVectorImpl<BlockT *> &ExitingBlocks) const;
- typedef GraphTraits<BlockT*> BlockTraits;
- for (typename std::vector<BlockT*>::const_iterator BI = Blocks.begin(),
- BE = Blocks.end(); BI != BE; ++BI)
- for (typename BlockTraits::ChildIteratorType I =
- BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
- I != E; ++I)
- if (!std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I)) {
- // Not in current loop? It must be an exit block.
- ExitingBlocks.push_back(*BI);
- break;
- }
- }
+ /// getExitingBlock - If getExitingBlocks would return exactly one block,
+ /// return that block. Otherwise return null.
+ BlockT *getExitingBlock() const;
/// getExitBlocks - Return all of the successor blocks of this loop. These
/// are the blocks _outside of the current loop_ which are branched to.
///
- void getExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const {
- // Sort the blocks vector so that we can use binary search to do quick
- // lookups.
- SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end());
- std::sort(LoopBBs.begin(), LoopBBs.end());
+ void getExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const;
- typedef GraphTraits<BlockT*> BlockTraits;
- for (typename std::vector<BlockT*>::const_iterator BI = Blocks.begin(),
- BE = Blocks.end(); BI != BE; ++BI)
- for (typename BlockTraits::ChildIteratorType I =
- BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
- I != E; ++I)
- if (!std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
- // Not in current loop? It must be an exit block.
- ExitBlocks.push_back(*I);
- }
+ /// getExitBlock - If getExitBlocks would return exactly one block,
+ /// return that block. Otherwise return null.
+ BlockT *getExitBlock() const;
- /// getUniqueExitBlocks - Return all unique successor blocks of this loop.
- /// These are the blocks _outside of the current loop_ which are branched to.
- /// This assumes that loop is in canonical form.
- ///
- void getUniqueExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const {
- // Sort the blocks vector so that we can use binary search to do quick
- // lookups.
- SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end());
- std::sort(LoopBBs.begin(), LoopBBs.end());
-
- std::vector<BlockT*> switchExitBlocks;
-
- for (typename std::vector<BlockT*>::const_iterator BI = Blocks.begin(),
- BE = Blocks.end(); BI != BE; ++BI) {
-
- BlockT *current = *BI;
- switchExitBlocks.clear();
-
- typedef GraphTraits<BlockT*> BlockTraits;
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
- for (typename BlockTraits::ChildIteratorType I =
- BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
- I != E; ++I) {
- if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
- // If block is inside the loop then it is not a exit block.
- continue;
-
- typename InvBlockTraits::ChildIteratorType PI =
- InvBlockTraits::child_begin(*I);
- BlockT *firstPred = *PI;
-
- // If current basic block is this exit block's first predecessor
- // then only insert exit block in to the output ExitBlocks vector.
- // This ensures that same exit block is not inserted twice into
- // ExitBlocks vector.
- if (current != firstPred)
- continue;
-
- // If a terminator has more then two successors, for example SwitchInst,
- // then it is possible that there are multiple edges from current block
- // to one exit block.
- if (std::distance(BlockTraits::child_begin(current),
- BlockTraits::child_end(current)) <= 2) {
- ExitBlocks.push_back(*I);
- continue;
- }
-
- // In case of multiple edges from current block to exit block, collect
- // only one edge in ExitBlocks. Use switchExitBlocks to keep track of
- // duplicate edges.
- if (std::find(switchExitBlocks.begin(), switchExitBlocks.end(), *I)
- == switchExitBlocks.end()) {
- switchExitBlocks.push_back(*I);
- ExitBlocks.push_back(*I);
- }
- }
- }
- }
+ /// Edge type.
+ typedef std::pair<const BlockT*, const BlockT*> Edge;
+
+ /// getExitEdges - Return all pairs of (_inside_block_,_outside_block_).
+ void getExitEdges(SmallVectorImpl<Edge> &ExitEdges) const;
/// getLoopPreheader - If there is a preheader for this loop, return it. A
/// loop has a preheader if there is only one edge to the header of the loop
///
/// This method returns null if there is no preheader for the loop.
///
- BlockT *getLoopPreheader() const {
- // Keep track of nodes outside the loop branching to the header...
- BlockT *Out = 0;
-
- // Loop over the predecessors of the header node...
- BlockT *Header = getHeader();
- typedef GraphTraits<BlockT*> BlockTraits;
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
- for (typename InvBlockTraits::ChildIteratorType PI =
- InvBlockTraits::child_begin(Header),
- PE = InvBlockTraits::child_end(Header); PI != PE; ++PI)
- if (!contains(*PI)) { // If the block is not in the loop...
- if (Out && Out != *PI)
- return 0; // Multiple predecessors outside the loop
- Out = *PI;
- }
-
- // Make sure there is only one exit out of the preheader.
- assert(Out && "Header of loop has no predecessors from outside loop?");
- typename BlockTraits::ChildIteratorType SI = BlockTraits::child_begin(Out);
- ++SI;
- if (SI != BlockTraits::child_end(Out))
- return 0; // Multiple exits from the block, must not be a preheader.
-
- // If there is exactly one preheader, return it. If there was zero, then
- // Out is still null.
- return Out;
- }
+ BlockT *getLoopPreheader() const;
- /// getLoopLatch - If there is a latch block for this loop, return it. A
- /// latch block is the canonical backedge for a loop. A loop header in normal
- /// form has two edges into it: one from a preheader and one from a latch
- /// block.
- BlockT *getLoopLatch() const {
- BlockT *Header = getHeader();
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
- typename InvBlockTraits::ChildIteratorType PI =
- InvBlockTraits::child_begin(Header);
- typename InvBlockTraits::ChildIteratorType PE =
- InvBlockTraits::child_end(Header);
- if (PI == PE) return 0; // no preds?
-
- BlockT *Latch = 0;
- if (contains(*PI))
- Latch = *PI;
- ++PI;
- if (PI == PE) return 0; // only one pred?
-
- if (contains(*PI)) {
- if (Latch) return 0; // multiple backedges
- Latch = *PI;
- }
- ++PI;
- if (PI != PE) return 0; // more than two preds
-
- return Latch;
- }
-
- /// getCanonicalInductionVariable - Check to see if the loop has a canonical
- /// induction variable: an integer recurrence that starts at 0 and increments
- /// by one each time through the loop. If so, return the phi node that
- /// corresponds to it.
- ///
- inline PHINode *getCanonicalInductionVariable() const {
- BlockT *H = getHeader();
-
- BlockT *Incoming = 0, *Backedge = 0;
- typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
- typename InvBlockTraits::ChildIteratorType PI =
- InvBlockTraits::child_begin(H);
- assert(PI != InvBlockTraits::child_end(H) &&
- "Loop must have at least one backedge!");
- Backedge = *PI++;
- if (PI == InvBlockTraits::child_end(H)) return 0; // dead loop
- Incoming = *PI++;
- if (PI != InvBlockTraits::child_end(H)) return 0; // multiple backedges?
-
- if (contains(Incoming)) {
- if (contains(Backedge))
- return 0;
- std::swap(Incoming, Backedge);
- } else if (!contains(Backedge))
- return 0;
-
- // Loop over all of the PHI nodes, looking for a canonical indvar.
- for (typename BlockT::iterator I = H->begin(); isa<PHINode>(I); ++I) {
- PHINode *PN = cast<PHINode>(I);
- if (ConstantInt *CI =
- dyn_cast<ConstantInt>(PN->getIncomingValueForBlock(Incoming)))
- if (CI->isNullValue())
- if (Instruction *Inc =
- dyn_cast<Instruction>(PN->getIncomingValueForBlock(Backedge)))
- if (Inc->getOpcode() == Instruction::Add &&
- Inc->getOperand(0) == PN)
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Inc->getOperand(1)))
- if (CI->equalsInt(1))
- return PN;
- }
- return 0;
- }
-
- /// getCanonicalInductionVariableIncrement - Return the LLVM value that holds
- /// the canonical induction variable value for the "next" iteration of the
- /// loop. This always succeeds if getCanonicalInductionVariable succeeds.
- ///
- inline Instruction *getCanonicalInductionVariableIncrement() const {
- if (PHINode *PN = getCanonicalInductionVariable()) {
- bool P1InLoop = contains(PN->getIncomingBlock(1));
- return cast<Instruction>(PN->getIncomingValue(P1InLoop));
- }
- return 0;
- }
-
- /// getTripCount - Return a loop-invariant LLVM value indicating the number of
- /// times the loop will be executed. Note that this means that the backedge
- /// of the loop executes N-1 times. If the trip-count cannot be determined,
- /// this returns null.
- ///
- inline Value *getTripCount() const {
- // Canonical loops will end with a 'cmp ne I, V', where I is the incremented
- // canonical induction variable and V is the trip count of the loop.
- Instruction *Inc = getCanonicalInductionVariableIncrement();
- if (Inc == 0) return 0;
- PHINode *IV = cast<PHINode>(Inc->getOperand(0));
-
- BlockT *BackedgeBlock =
- IV->getIncomingBlock(contains(IV->getIncomingBlock(1)));
-
- if (BranchInst *BI = dyn_cast<BranchInst>(BackedgeBlock->getTerminator()))
- if (BI->isConditional()) {
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) {
- if (ICI->getOperand(0) == Inc) {
- if (BI->getSuccessor(0) == getHeader()) {
- if (ICI->getPredicate() == ICmpInst::ICMP_NE)
- return ICI->getOperand(1);
- } else if (ICI->getPredicate() == ICmpInst::ICMP_EQ) {
- return ICI->getOperand(1);
- }
- }
- }
- }
-
- return 0;
- }
-
- /// getSmallConstantTripCount - Returns the trip count of this loop as a
- /// normal unsigned value, if possible. Returns 0 if the trip count is unknown
- /// of not constant. Will also return 0 if the trip count is very large
- /// (>= 2^32)
- inline unsigned getSmallConstantTripCount() const {
- Value* TripCount = this->getTripCount();
- if (TripCount) {
- if (ConstantInt *TripCountC = dyn_cast<ConstantInt>(TripCount)) {
- // Guard against huge trip counts.
- if (TripCountC->getValue().getActiveBits() <= 32) {
- return (unsigned)TripCountC->getZExtValue();
- }
- }
- }
- return 0;
- }
-
- /// getSmallConstantTripMultiple - Returns the largest constant divisor of the
- /// trip count of this loop as a normal unsigned value, if possible. This
- /// means that the actual trip count is always a multiple of the returned
- /// value (don't forget the trip count could very well be zero as well!).
+ /// getLoopPredecessor - If the given loop's header has exactly one unique
+ /// predecessor outside the loop, return it. Otherwise return null.
+ /// This is less strict that the loop "preheader" concept, which requires
+ /// the predecessor to have exactly one successor.
///
- /// Returns 1 if the trip count is unknown or not guaranteed to be the
- /// multiple of a constant (which is also the case if the trip count is simply
- /// constant, use getSmallConstantTripCount for that case), Will also return 1
- /// if the trip count is very large (>= 2^32).
- inline unsigned getSmallConstantTripMultiple() const {
- Value* TripCount = this->getTripCount();
- // This will hold the ConstantInt result, if any
- ConstantInt *Result = NULL;
- if (TripCount) {
- // See if the trip count is constant itself
- Result = dyn_cast<ConstantInt>(TripCount);
- // if not, see if it is a multiplication
- if (!Result)
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TripCount)) {
- switch (BO->getOpcode()) {
- case BinaryOperator::Mul:
- Result = dyn_cast<ConstantInt>(BO->getOperand(1));
- break;
- default:
- break;
- }
- }
- }
- // Guard against huge trip counts.
- if (Result && Result->getValue().getActiveBits() <= 32) {
- return (unsigned)Result->getZExtValue();
- } else {
- return 1;
- }
- }
-
- /// isLCSSAForm - Return true if the Loop is in LCSSA form
- inline bool isLCSSAForm() const {
- // Sort the blocks vector so that we can use binary search to do quick
- // lookups.
- SmallPtrSet<BlockT*, 16> LoopBBs(block_begin(), block_end());
-
- for (block_iterator BI = block_begin(), E = block_end(); BI != E; ++BI) {
- BlockT *BB = *BI;
- for (typename BlockT::iterator I = BB->begin(), E = BB->end(); I != E;++I)
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E;
- ++UI) {
- BlockT *UserBB = cast<Instruction>(*UI)->getParent();
- if (PHINode *P = dyn_cast<PHINode>(*UI)) {
- unsigned OperandNo = UI.getOperandNo();
- UserBB = P->getIncomingBlock(OperandNo/2);
- }
-
- // Check the current block, as a fast-path. Most values are used in
- // the same block they are defined in.
- if (UserBB != BB && !LoopBBs.count(UserBB))
- return false;
- }
- }
+ BlockT *getLoopPredecessor() const;
- return true;
- }
+ /// getLoopLatch - If there is a single latch block for this loop, return it.
+ /// A latch block is a block that contains a branch back to the header.
+ BlockT *getLoopLatch() const;
//===--------------------------------------------------------------------===//
// APIs for updating loop information after changing the CFG
/// to the specified LoopInfo object as being in the current basic block. It
/// is not valid to replace the loop header with this method.
///
- void addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase<BlockT> &LI);
+ void addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase<BlockT, LoopT> &LI);
/// replaceChildLoopWith - This is used when splitting loops up. It replaces
/// the OldChild entry in our children list with NewChild, and updates the
/// parent pointer of OldChild to be null and the NewChild to be this loop.
/// This updates the loop depth of the new child.
- void replaceChildLoopWith(LoopBase<BlockT> *OldChild,
- LoopBase<BlockT> *NewChild) {
- assert(OldChild->ParentLoop == this && "This loop is already broken!");
- assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
- typename std::vector<LoopBase<BlockT>*>::iterator I =
- std::find(SubLoops.begin(), SubLoops.end(), OldChild);
- assert(I != SubLoops.end() && "OldChild not in loop!");
- *I = NewChild;
- OldChild->ParentLoop = 0;
- NewChild->ParentLoop = this;
- }
+ void replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild);
/// addChildLoop - Add the specified loop to be a child of this loop. This
/// updates the loop depth of the new child.
///
- void addChildLoop(LoopBase<BlockT> *NewChild) {
+ void addChildLoop(LoopT *NewChild) {
assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
- NewChild->ParentLoop = this;
+ NewChild->ParentLoop = static_cast<LoopT *>(this);
SubLoops.push_back(NewChild);
}
/// removeChildLoop - This removes the specified child from being a subloop of
/// this loop. The loop is not deleted, as it will presumably be inserted
/// into another loop.
- LoopBase<BlockT> *removeChildLoop(iterator I) {
+ LoopT *removeChildLoop(iterator I) {
assert(I != SubLoops.end() && "Cannot remove end iterator!");
- LoopBase<BlockT> *Child = *I;
+ LoopT *Child = *I;
assert(Child->ParentLoop == this && "Child is not a child of this loop!");
SubLoops.erase(SubLoops.begin()+(I-begin()));
Child->ParentLoop = 0;
}
/// verifyLoop - Verify loop structure
- void verifyLoop() const {
-#ifndef NDEBUG
- assert (getHeader() && "Loop header is missing");
- assert (getLoopPreheader() && "Loop preheader is missing");
- assert (getLoopLatch() && "Loop latch is missing");
- for (typename std::vector<LoopBase<BlockT>*>::const_iterator I =
- SubLoops.begin(), E = SubLoops.end(); I != E; ++I)
- (*I)->verifyLoop();
-#endif
- }
+ void verifyLoop() const;
- void print(std::ostream &OS, unsigned Depth = 0) const {
- OS << std::string(Depth*2, ' ') << "Loop Containing: ";
+ /// verifyLoop - Verify loop structure of this loop and all nested loops.
+ void verifyLoopNest(DenseSet<const LoopT*> *Loops) const;
- for (unsigned i = 0; i < getBlocks().size(); ++i) {
- if (i) OS << ",";
- WriteAsOperand(OS, getBlocks()[i], false);
- }
- OS << "\n";
+ void print(raw_ostream &OS, unsigned Depth = 0) const;
- for (iterator I = begin(), E = end(); I != E; ++I)
- (*I)->print(OS, Depth+2);
- }
-
- void print(std::ostream *O, unsigned Depth = 0) const {
- if (O) print(*O, Depth);
- }
-
- void dump() const {
- print(cerr);
- }
-
-private:
- friend class LoopInfoBase<BlockT>;
- LoopBase(BlockT *BB) : ParentLoop(0) {
+protected:
+ friend class LoopInfoBase<BlockT, LoopT>;
+ explicit LoopBase(BlockT *BB) : ParentLoop(0) {
Blocks.push_back(BB);
}
};
+template<class BlockT, class LoopT>
+raw_ostream& operator<<(raw_ostream &OS, const LoopBase<BlockT, LoopT> &Loop) {
+ Loop.print(OS);
+ return OS;
+}
+
+// Implementation in LoopInfoImpl.h
+#ifdef __GNUC__
+__extension__ extern template class LoopBase<BasicBlock, Loop>;
+#endif
+
+class Loop : public LoopBase<BasicBlock, Loop> {
+public:
+ Loop() {}
+
+ /// isLoopInvariant - Return true if the specified value is loop invariant
+ ///
+ bool isLoopInvariant(Value *V) const;
+
+ /// hasLoopInvariantOperands - Return true if all the operands of the
+ /// specified instruction are loop invariant.
+ bool hasLoopInvariantOperands(Instruction *I) const;
+
+ /// makeLoopInvariant - If the given value is an instruction inside of the
+ /// loop and it can be hoisted, do so to make it trivially loop-invariant.
+ /// Return true if the value after any hoisting is loop invariant. This
+ /// function can be used as a slightly more aggressive replacement for
+ /// isLoopInvariant.
+ ///
+ /// If InsertPt is specified, it is the point to hoist instructions to.
+ /// If null, the terminator of the loop preheader is used.
+ ///
+ bool makeLoopInvariant(Value *V, bool &Changed,
+ Instruction *InsertPt = 0) const;
+
+ /// makeLoopInvariant - If the given instruction is inside of the
+ /// loop and it can be hoisted, do so to make it trivially loop-invariant.
+ /// Return true if the instruction after any hoisting is loop invariant. This
+ /// function can be used as a slightly more aggressive replacement for
+ /// isLoopInvariant.
+ ///
+ /// If InsertPt is specified, it is the point to hoist instructions to.
+ /// If null, the terminator of the loop preheader is used.
+ ///
+ bool makeLoopInvariant(Instruction *I, bool &Changed,
+ Instruction *InsertPt = 0) const;
+
+ /// getCanonicalInductionVariable - Check to see if the loop has a canonical
+ /// induction variable: an integer recurrence that starts at 0 and increments
+ /// by one each time through the loop. If so, return the phi node that
+ /// corresponds to it.
+ ///
+ /// The IndVarSimplify pass transforms loops to have a canonical induction
+ /// variable.
+ ///
+ PHINode *getCanonicalInductionVariable() const;
+
+ /// isLCSSAForm - Return true if the Loop is in LCSSA form
+ bool isLCSSAForm(DominatorTree &DT) const;
+
+ /// isLoopSimplifyForm - Return true if the Loop is in the form that
+ /// the LoopSimplify form transforms loops to, which is sometimes called
+ /// normal form.
+ bool isLoopSimplifyForm() const;
+
+ /// isSafeToClone - Return true if the loop body is safe to clone in practice.
+ bool isSafeToClone() const;
+
+ /// hasDedicatedExits - Return true if no exit block for the loop
+ /// has a predecessor that is outside the loop.
+ bool hasDedicatedExits() const;
+
+ /// getUniqueExitBlocks - Return all unique successor blocks of this loop.
+ /// These are the blocks _outside of the current loop_ which are branched to.
+ /// This assumes that loop exits are in canonical form.
+ ///
+ void getUniqueExitBlocks(SmallVectorImpl<BasicBlock *> &ExitBlocks) const;
+
+ /// getUniqueExitBlock - If getUniqueExitBlocks would return exactly one
+ /// block, return that block. Otherwise return null.
+ BasicBlock *getUniqueExitBlock() const;
+
+ void dump() const;
+
+private:
+ friend class LoopInfoBase<BasicBlock, Loop>;
+ explicit Loop(BasicBlock *BB) : LoopBase<BasicBlock, Loop>(BB) {}
+};
//===----------------------------------------------------------------------===//
/// LoopInfo - This class builds and contains all of the top level loop
/// structures in the specified function.
///
-template<class BlockT>
+template<class BlockT, class LoopT>
class LoopInfoBase {
// BBMap - Mapping of basic blocks to the inner most loop they occur in
- std::map<BlockT*, LoopBase<BlockT>*> BBMap;
- std::vector<LoopBase<BlockT>*> TopLevelLoops;
- friend class LoopBase<BlockT>;
-
+ DenseMap<BlockT *, LoopT *> BBMap;
+ std::vector<LoopT *> TopLevelLoops;
+ friend class LoopBase<BlockT, LoopT>;
+ friend class LoopInfo;
+
+ void operator=(const LoopInfoBase &) LLVM_DELETED_FUNCTION;
+ LoopInfoBase(const LoopInfo &) LLVM_DELETED_FUNCTION;
public:
LoopInfoBase() { }
~LoopInfoBase() { releaseMemory(); }
-
+
void releaseMemory() {
- for (typename std::vector<LoopBase<BlockT>* >::iterator I =
+ for (typename std::vector<LoopT *>::iterator I =
TopLevelLoops.begin(), E = TopLevelLoops.end(); I != E; ++I)
delete *I; // Delete all of the loops...
BBMap.clear(); // Reset internal state of analysis
TopLevelLoops.clear();
}
-
+
/// iterator/begin/end - The interface to the top-level loops in the current
/// function.
///
- typedef typename std::vector<LoopBase<BlockT>*>::const_iterator iterator;
+ 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
/// block is in no loop (for example the entry node), null is returned.
///
- LoopBase<BlockT> *getLoopFor(const BlockT *BB) const {
- typename std::map<BlockT *, LoopBase<BlockT>*>::const_iterator I=
- BBMap.find(const_cast<BlockT*>(BB));
- return I != BBMap.end() ? I->second : 0;
+ LoopT *getLoopFor(const BlockT *BB) const {
+ return BBMap.lookup(const_cast<BlockT*>(BB));
}
-
+
/// operator[] - same as getLoopFor...
///
- const LoopBase<BlockT> *operator[](const BlockT *BB) const {
+ const LoopT *operator[](const BlockT *BB) const {
return getLoopFor(BB);
}
-
+
/// getLoopDepth - Return the loop nesting level of the specified block. A
/// depth of 0 means the block is not inside any loop.
///
unsigned getLoopDepth(const BlockT *BB) const {
- const LoopBase<BlockT> *L = getLoopFor(BB);
+ const LoopT *L = getLoopFor(BB);
return L ? L->getLoopDepth() : 0;
}
// isLoopHeader - True if the block is a loop header node
bool isLoopHeader(BlockT *BB) const {
- const LoopBase<BlockT> *L = getLoopFor(BB);
+ const LoopT *L = getLoopFor(BB);
return L && L->getHeader() == BB;
}
-
+
/// removeLoop - This removes the specified top-level loop from this loop info
/// object. The loop is not deleted, as it will presumably be inserted into
/// another loop.
- LoopBase<BlockT> *removeLoop(iterator I) {
+ LoopT *removeLoop(iterator I) {
assert(I != end() && "Cannot remove end iterator!");
- LoopBase<BlockT> *L = *I;
+ LoopT *L = *I;
assert(L->getParentLoop() == 0 && "Not a top-level loop!");
TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin()));
return L;
}
-
+
/// changeLoopFor - Change the top-level loop that contains BB to the
/// specified loop. This should be used by transformations that restructure
/// the loop hierarchy tree.
- void changeLoopFor(BlockT *BB, LoopBase<BlockT> *L) {
- LoopBase<BlockT> *&OldLoop = BBMap[BB];
- assert(OldLoop && "Block not in a loop yet!");
- OldLoop = L;
+ void changeLoopFor(BlockT *BB, LoopT *L) {
+ if (!L) {
+ BBMap.erase(BB);
+ return;
+ }
+ BBMap[BB] = L;
}
-
+
/// changeTopLevelLoop - Replace the specified loop in the top-level loops
/// list with the indicated loop.
- void changeTopLevelLoop(LoopBase<BlockT> *OldLoop,
- LoopBase<BlockT> *NewLoop) {
- typename std::vector<LoopBase<BlockT>*>::iterator I =
+ void changeTopLevelLoop(LoopT *OldLoop,
+ LoopT *NewLoop) {
+ typename std::vector<LoopT *>::iterator I =
std::find(TopLevelLoops.begin(), TopLevelLoops.end(), OldLoop);
assert(I != TopLevelLoops.end() && "Old loop not at top level!");
*I = NewLoop;
assert(NewLoop->ParentLoop == 0 && OldLoop->ParentLoop == 0 &&
"Loops already embedded into a subloop!");
}
-
+
/// addTopLevelLoop - This adds the specified loop to the collection of
/// top-level loops.
- void addTopLevelLoop(LoopBase<BlockT> *New) {
+ void addTopLevelLoop(LoopT *New) {
assert(New->getParentLoop() == 0 && "Loop already in subloop!");
TopLevelLoops.push_back(New);
}
-
+
/// removeBlock - This method completely removes BB from all data structures,
/// including all of the Loop objects it is nested in and our mapping from
/// BasicBlocks to loops.
void removeBlock(BlockT *BB) {
- typename std::map<BlockT *, LoopBase<BlockT>*>::iterator I = BBMap.find(BB);
+ typename DenseMap<BlockT *, LoopT *>::iterator I = BBMap.find(BB);
if (I != BBMap.end()) {
- for (LoopBase<BlockT> *L = I->second; L; L = L->getParentLoop())
+ for (LoopT *L = I->second; L; L = L->getParentLoop())
L->removeBlockFromLoop(BB);
BBMap.erase(I);
}
}
-
+
// Internals
-
- static bool isNotAlreadyContainedIn(LoopBase<BlockT> *SubLoop,
- LoopBase<BlockT> *ParentLoop) {
+
+ static bool isNotAlreadyContainedIn(const LoopT *SubLoop,
+ const LoopT *ParentLoop) {
if (SubLoop == 0) return true;
if (SubLoop == ParentLoop) return false;
return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop);
}
-
- void 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 (LoopBase<BlockT> *L = ConsiderForLoop(*NI, DT))
- TopLevelLoops.push_back(L);
- }
-
- LoopBase<BlockT> *ConsiderForLoop(BlockT *BB, DominatorTreeBase<BlockT> &DT) {
- if (BBMap.find(BB) != BBMap.end()) 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)
- if (DT.dominates(BB, *I)) // If BB dominates it's predecessor...
- TodoStack.push_back(*I);
-
- if (TodoStack.empty()) return 0; // No backedges to this block...
-
- // Create a new loop to represent this basic block...
- LoopBase<BlockT> *L = new LoopBase<BlockT>(BB);
- BBMap[BB] = L;
-
- BlockT *EntryBlock = BB->getParent()->begin();
-
- 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.dominates(EntryBlock, X)) { // X is reachable from entry block?
- // 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 (LoopBase<BlockT> *SubLoop =
- const_cast<LoopBase<BlockT>*>(getLoopFor(X)))
- if (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)){
- // Remove the subloop from it's current parent...
- assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L);
- LoopBase<BlockT> *SLP = SubLoop->ParentLoop; // SubLoopParent
- typename std::vector<LoopBase<BlockT>*>::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 (LoopBase<BlockT> *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) {
- typename std::map<BlockT*, LoopBase<BlockT>*>::iterator BBMI =
- BBMap.lower_bound(*I);
- if (BBMI == BBMap.end() || BBMI->first != *I) // Not in map yet...
- BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level
- }
- // 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*, LoopBase<BlockT>*> ContainingLoops;
- for (unsigned i = 0; i != L->SubLoops.size(); ++i) {
- LoopBase<BlockT> *Child = L->SubLoops[i];
- assert(Child->getParentLoop() == L && "Not proper child loop?");
-
- if (LoopBase<BlockT> *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) {
- LoopBase<BlockT> *&BlockLoop = ContainingLoops[Child->Blocks[b]];
- if (BlockLoop == 0) { // Child block not processed yet...
- BlockLoop = Child;
- } else if (BlockLoop != Child) {
- LoopBase<BlockT> *SubLoop = BlockLoop;
- // Reparent all of the blocks which used to belong to BlockLoops
- for (unsigned j = 0, e = SubLoop->Blocks.size(); j != e; ++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.
- void MoveSiblingLoopInto(LoopBase<BlockT> *NewChild,
- LoopBase<BlockT> *NewParent) {
- LoopBase<BlockT> *OldParent = NewChild->getParentLoop();
- assert(OldParent && OldParent == NewParent->getParentLoop() &&
- NewChild != NewParent && "Not sibling loops!");
-
- // Remove NewChild from being a child of OldParent
- typename std::vector<LoopBase<BlockT>*>::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.
- void InsertLoopInto(LoopBase<BlockT> *L, LoopBase<BlockT> *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;
- }
+ /// Create the loop forest using a stable algorithm.
+ void Analyze(DominatorTreeBase<BlockT> &DomTree);
- // If not, insert it here!
- Parent->SubLoops.push_back(L);
- L->ParentLoop = Parent;
- }
-
// Debugging
-
- void print(std::ostream &OS, const Module* ) const {
- for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
- TopLevelLoops[i]->print(OS);
- #if 0
- for (std::map<BasicBlock*, Loop*>::const_iterator I = BBMap.begin(),
- E = BBMap.end(); I != E; ++I)
- OS << "BB '" << I->first->getName() << "' level = "
- << I->second->getLoopDepth() << "\n";
- #endif
- }
+
+ void print(raw_ostream &OS) const;
};
+// Implementation in LoopInfoImpl.h
+#ifdef __GNUC__
+__extension__ extern template class LoopInfoBase<BasicBlock, Loop>;
+#endif
+
class LoopInfo : public FunctionPass {
- LoopInfoBase<BasicBlock>* LI;
- friend class LoopBase<BasicBlock>;
-
+ LoopInfoBase<BasicBlock, Loop> LI;
+ friend class LoopBase<BasicBlock, Loop>;
+
+ void operator=(const LoopInfo &) LLVM_DELETED_FUNCTION;
+ LoopInfo(const LoopInfo &) LLVM_DELETED_FUNCTION;
public:
static char ID; // Pass identification, replacement for typeid
- LoopInfo() : FunctionPass(intptr_t(&ID)) {
- LI = new LoopInfoBase<BasicBlock>();
+ LoopInfo() : FunctionPass(ID) {
+ initializeLoopInfoPass(*PassRegistry::getPassRegistry());
}
-
- ~LoopInfo() { delete LI; }
- LoopInfoBase<BasicBlock>& getBase() { return *LI; }
+ LoopInfoBase<BasicBlock, Loop>& getBase() { return LI; }
/// iterator/begin/end - The interface to the top-level loops in the current
/// function.
///
- typedef std::vector<Loop*>::const_iterator iterator;
- inline iterator begin() const { return LI->begin(); }
- inline iterator end() const { return LI->end(); }
+ 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
/// block is in no loop (for example the entry node), null is returned.
///
inline Loop *getLoopFor(const BasicBlock *BB) const {
- return LI->getLoopFor(BB);
+ return LI.getLoopFor(BB);
}
/// operator[] - same as getLoopFor...
///
inline const Loop *operator[](const BasicBlock *BB) const {
- return LI->getLoopFor(BB);
+ return LI.getLoopFor(BB);
}
/// getLoopDepth - Return the loop nesting level of the specified block. A
/// depth of 0 means the block is not inside any loop.
///
inline unsigned getLoopDepth(const BasicBlock *BB) const {
- return LI->getLoopDepth(BB);
+ return LI.getLoopDepth(BB);
}
// isLoopHeader - True if the block is a loop header node
inline bool isLoopHeader(BasicBlock *BB) const {
- return LI->isLoopHeader(BB);
+ return LI.isLoopHeader(BB);
}
/// runOnFunction - Calculate the natural loop information.
///
virtual bool runOnFunction(Function &F);
- virtual void releaseMemory() { LI->releaseMemory(); }
+ virtual void verifyAnalysis() const;
- virtual void print(std::ostream &O, const Module* M = 0) const {
- if (O) LI->print(O, M);
- }
+ virtual void releaseMemory() { LI.releaseMemory(); }
+
+ virtual void print(raw_ostream &O, const Module* M = 0) const;
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
/// removeLoop - This removes the specified top-level loop from this loop info
/// object. The loop is not deleted, as it will presumably be inserted into
/// another loop.
- inline Loop *removeLoop(iterator I) { return LI->removeLoop(I); }
+ inline Loop *removeLoop(iterator I) { return LI.removeLoop(I); }
/// changeLoopFor - Change the top-level loop that contains BB to the
/// specified loop. This should be used by transformations that restructure
/// the loop hierarchy tree.
inline void changeLoopFor(BasicBlock *BB, Loop *L) {
- LI->changeLoopFor(BB, L);
+ LI.changeLoopFor(BB, L);
}
/// changeTopLevelLoop - Replace the specified loop in the top-level loops
/// list with the indicated loop.
inline void changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop) {
- LI->changeTopLevelLoop(OldLoop, NewLoop);
+ LI.changeTopLevelLoop(OldLoop, NewLoop);
}
/// addTopLevelLoop - This adds the specified loop to the collection of
/// top-level loops.
inline void addTopLevelLoop(Loop *New) {
- LI->addTopLevelLoop(New);
+ LI.addTopLevelLoop(New);
}
/// removeBlock - This method completely removes BB from all data structures,
/// including all of the Loop objects it is nested in and our mapping from
/// BasicBlocks to loops.
void removeBlock(BasicBlock *BB) {
- LI->removeBlock(BB);
+ LI.removeBlock(BB);
+ }
+
+ /// updateUnloop - Update LoopInfo after removing the last backedge from a
+ /// loop--now the "unloop". This updates the loop forest and parent loops for
+ /// each block so that Unloop is no longer referenced, but the caller must
+ /// actually delete the Unloop object.
+ void updateUnloop(Loop *Unloop);
+
+ /// replacementPreservesLCSSAForm - Returns true if replacing From with To
+ /// everywhere is guaranteed to preserve LCSSA form.
+ bool replacementPreservesLCSSAForm(Instruction *From, Value *To) {
+ // Preserving LCSSA form is only problematic if the replacing value is an
+ // instruction.
+ Instruction *I = dyn_cast<Instruction>(To);
+ if (!I) return true;
+ // If both instructions are defined in the same basic block then replacement
+ // cannot break LCSSA form.
+ if (I->getParent() == From->getParent())
+ return true;
+ // If the instruction is not defined in a loop then it can safely replace
+ // anything.
+ Loop *ToLoop = getLoopFor(I->getParent());
+ if (!ToLoop) return true;
+ // If the replacing instruction is defined in the same loop as the original
+ // instruction, or in a loop that contains it as an inner loop, then using
+ // it as a replacement will not break LCSSA form.
+ return ToLoop->contains(getLoopFor(From->getParent()));
}
};
// Allow clients to walk the list of nested loops...
template <> struct GraphTraits<const Loop*> {
typedef const Loop NodeType;
- typedef std::vector<Loop*>::const_iterator ChildIteratorType;
+ typedef LoopInfo::iterator ChildIteratorType;
static NodeType *getEntryNode(const Loop *L) { return L; }
static inline ChildIteratorType child_begin(NodeType *N) {
template <> struct GraphTraits<Loop*> {
typedef Loop NodeType;
- typedef std::vector<Loop*>::const_iterator ChildIteratorType;
+ typedef LoopInfo::iterator ChildIteratorType;
static NodeType *getEntryNode(Loop *L) { return L; }
static inline ChildIteratorType child_begin(NodeType *N) {
}
};
-template<class BlockT>
-void LoopBase<BlockT>::addBasicBlockToLoop(BlockT *NewBB,
- LoopInfoBase<BlockT> &LIB) {
- assert((Blocks.empty() || LIB[getHeader()] == this) &&
- "Incorrect LI specified for this loop!");
- assert(NewBB && "Cannot add a null basic block to the loop!");
- assert(LIB[NewBB] == 0 && "BasicBlock already in the loop!");
-
- // Add the loop mapping to the LoopInfo object...
- LIB.BBMap[NewBB] = this;
-
- // Add the basic block to this loop and all parent loops...
- LoopBase<BlockT> *L = this;
- while (L) {
- L->Blocks.push_back(NewBB);
- L = L->getParentLoop();
- }
-}
-
} // End llvm namespace
#endif
projects / oota-llvm.git / blobdiff