#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
#include "llvm/Pass.h"
#include <algorithm>
namespace llvm {
-template<typename T>
-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);
-}
+// FIXME: Replace this brittle forward declaration with the include of the new
+// PassManager.h when doing so doesn't break the PassManagerBuilder.
+template <typename IRUnitT> class AnalysisManager;
+class PreservedAnalyses;
class DominatorTree;
class LoopInfo;
SmallPtrSet<const BlockT*, 8> DenseBlockSet;
- LoopBase(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION;
+ /// Indicator that this loop is no longer a valid loop.
+ bool IsInvalid = false;
+
+ LoopBase(const LoopBase<BlockT, LoopT> &) = delete;
const LoopBase<BlockT, LoopT>&
- operator=(const LoopBase<BlockT, LoopT> &) LLVM_DELETED_FUNCTION;
+ operator=(const LoopBase<BlockT, LoopT> &) = delete;
public:
/// Loop ctor - This creates an empty loop.
LoopBase() : ParentLoop(nullptr) {}
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(); }
+ inline iterator_range<block_iterator> blocks() const {
+ return make_range(block_begin(), block_end());
+ }
/// getNumBlocks - Get the number of blocks in this loop in constant time.
unsigned getNumBlocks() const {
return Blocks.size();
}
+ /// Invalidate the loop, indicating that it is no longer a loop.
+ void invalidate() { IsInvalid = true; }
+
+ /// Return true if this loop is no longer valid.
+ bool isInvalid() { return IsInvalid; }
+
/// isLoopExiting - True if terminator in the block can branch to another
/// block that is outside of the current loop.
///
/// current loop, updating the Blocks as appropriate. This does not update
/// the mapping in the LoopInfo class.
void removeBlockFromLoop(BlockT *BB) {
- RemoveFromVector(Blocks, BB);
+ auto I = std::find(Blocks.begin(), Blocks.end(), BB);
+ assert(I != Blocks.end() && "N is not in this list!");
+ Blocks.erase(I);
+
DenseBlockSet.erase(BB);
}
}
// Implementation in LoopInfoImpl.h
-#ifdef __GNUC__
-__extension__ extern template class LoopBase<BasicBlock, Loop>;
-#endif
+extern template class LoopBase<BasicBlock, Loop>;
class Loop : public LoopBase<BasicBlock, Loop> {
public:
/// isLoopInvariant - Return true if the specified value is loop invariant
///
- bool isLoopInvariant(Value *V) const;
+ bool isLoopInvariant(const Value *V) const;
/// hasLoopInvariantOperands - Return true if all the operands of the
/// specified instruction are loop invariant.
- bool hasLoopInvariantOperands(Instruction *I) const;
+ bool hasLoopInvariantOperands(const 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.
/// isLCSSAForm - Return true if the Loop is in LCSSA form
bool isLCSSAForm(DominatorTree &DT) const;
+ /// \brief Return true if this Loop and all inner subloops are in LCSSA form.
+ bool isRecursivelyLCSSAForm(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.
/// cannot find a terminating instruction with location information,
/// it returns an unknown location.
DebugLoc getStartLoc() const {
- DebugLoc StartLoc;
BasicBlock *HeadBB;
// Try the pre-header first.
- if ((HeadBB = getLoopPreheader()) != nullptr) {
- StartLoc = HeadBB->getTerminator()->getDebugLoc();
- if (!StartLoc.isUnknown())
- return StartLoc;
- }
+ if ((HeadBB = getLoopPreheader()) != nullptr)
+ if (DebugLoc DL = HeadBB->getTerminator()->getDebugLoc())
+ return DL;
// If we have no pre-header or there are no instructions with debug
// info in it, try the header.
HeadBB = getHeader();
if (HeadBB)
- StartLoc = HeadBB->getTerminator()->getDebugLoc();
+ return HeadBB->getTerminator()->getDebugLoc();
- return StartLoc;
+ return DebugLoc();
}
private:
template<class BlockT, class LoopT>
class LoopInfoBase {
// BBMap - Mapping of basic blocks to the inner most loop they occur in
- DenseMap<BlockT *, LoopT *> BBMap;
+ DenseMap<const BlockT *, LoopT *> BBMap;
std::vector<LoopT *> TopLevelLoops;
+ std::vector<LoopT *> RemovedLoops;
+
friend class LoopBase<BlockT, LoopT>;
friend class LoopInfo;
- void operator=(const LoopInfoBase &) LLVM_DELETED_FUNCTION;
- LoopInfoBase(const LoopInfoBase &) LLVM_DELETED_FUNCTION;
+ void operator=(const LoopInfoBase &) = delete;
+ LoopInfoBase(const LoopInfoBase &) = delete;
public:
LoopInfoBase() { }
~LoopInfoBase() { releaseMemory(); }
Arg.TopLevelLoops.clear();
}
LoopInfoBase &operator=(LoopInfoBase &&RHS) {
- if (&RHS != this) {
- BBMap = std::move(RHS.BBMap);
+ BBMap = std::move(RHS.BBMap);
- for (auto *L : TopLevelLoops)
- delete L;
- TopLevelLoops = std::move(RHS.TopLevelLoops);
- RHS.TopLevelLoops.clear();
- }
+ for (auto *L : TopLevelLoops)
+ delete L;
+ TopLevelLoops = std::move(RHS.TopLevelLoops);
+ RHS.TopLevelLoops.clear();
return *this;
}
for (auto *L : TopLevelLoops)
delete L;
TopLevelLoops.clear();
+ for (auto *L : RemovedLoops)
+ delete L;
+ RemovedLoops.clear();
}
/// iterator/begin/end - The interface to the top-level loops in the current
/// 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.
///
- LoopT *getLoopFor(const BlockT *BB) const {
- return BBMap.lookup(const_cast<BlockT*>(BB));
- }
+ LoopT *getLoopFor(const BlockT *BB) const { return BBMap.lookup(BB); }
/// operator[] - same as getLoopFor...
///
}
// isLoopHeader - True if the block is a loop header node
- bool isLoopHeader(BlockT *BB) const {
+ bool isLoopHeader(const BlockT *BB) const {
const LoopT *L = getLoopFor(BB);
return L && L->getHeader() == BB;
}
}
/// Create the loop forest using a stable algorithm.
- void Analyze(DominatorTreeBase<BlockT> &DomTree);
+ void analyze(const DominatorTreeBase<BlockT> &DomTree);
// Debugging
void print(raw_ostream &OS) const;
};
// Implementation in LoopInfoImpl.h
-#ifdef __GNUC__
-__extension__ extern template class LoopInfoBase<BasicBlock, Loop>;
-#endif
+extern template class LoopInfoBase<BasicBlock, Loop>;
class LoopInfo : public LoopInfoBase<BasicBlock, Loop> {
typedef LoopInfoBase<BasicBlock, Loop> BaseT;
friend class LoopBase<BasicBlock, Loop>;
- void operator=(const LoopInfo &) LLVM_DELETED_FUNCTION;
- LoopInfo(const LoopInfo &) LLVM_DELETED_FUNCTION;
+ void operator=(const LoopInfo &) = delete;
+ LoopInfo(const LoopInfo &) = delete;
public:
LoopInfo() {}
+ explicit LoopInfo(const DominatorTreeBase<BasicBlock> &DomTree);
LoopInfo(LoopInfo &&Arg) : BaseT(std::move(static_cast<BaseT &>(Arg))) {}
LoopInfo &operator=(LoopInfo &&RHS) {
// Most of the public interface is provided via LoopInfoBase.
- /// 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);
+ /// Update LoopInfo after removing the last backedge from a loop. This updates
+ /// the loop forest and parent loops for each block so that \c L is no longer
+ /// referenced, but does not actually delete \c L immediately. The pointer
+ /// will remain valid until this LoopInfo's memory is released.
+ void markAsRemoved(Loop *L);
/// replacementPreservesLCSSAForm - Returns true if replacing From with To
/// everywhere is guaranteed to preserve LCSSA form.
// it as a replacement will not break LCSSA form.
return ToLoop->contains(getLoopFor(From->getParent()));
}
+
+ /// \brief Checks if moving a specific instruction can break LCSSA in any
+ /// loop.
+ ///
+ /// Return true if moving \p Inst to before \p NewLoc will break LCSSA,
+ /// assuming that the function containing \p Inst and \p NewLoc is currently
+ /// in LCSSA form.
+ bool movementPreservesLCSSAForm(Instruction *Inst, Instruction *NewLoc) {
+ assert(Inst->getFunction() == NewLoc->getFunction() &&
+ "Can't reason about IPO!");
+
+ auto *OldBB = Inst->getParent();
+ auto *NewBB = NewLoc->getParent();
+
+ // Movement within the same loop does not break LCSSA (the equality check is
+ // to avoid doing a hashtable lookup in case of intra-block movement).
+ if (OldBB == NewBB)
+ return true;
+
+ auto *OldLoop = getLoopFor(OldBB);
+ auto *NewLoop = getLoopFor(NewBB);
+
+ if (OldLoop == NewLoop)
+ return true;
+
+ // Check if Outer contains Inner; with the null loop counting as the
+ // "outermost" loop.
+ auto Contains = [](const Loop *Outer, const Loop *Inner) {
+ return !Outer || Outer->contains(Inner);
+ };
+
+ // To check that the movement of Inst to before NewLoc does not break LCSSA,
+ // we need to check two sets of uses for possible LCSSA violations at
+ // NewLoc: the users of NewInst, and the operands of NewInst.
+
+ // If we know we're hoisting Inst out of an inner loop to an outer loop,
+ // then the uses *of* Inst don't need to be checked.
+
+ if (!Contains(NewLoop, OldLoop)) {
+ for (Use &U : Inst->uses()) {
+ auto *UI = cast<Instruction>(U.getUser());
+ auto *UBB = isa<PHINode>(UI) ? cast<PHINode>(UI)->getIncomingBlock(U)
+ : UI->getParent();
+ if (UBB != NewBB && getLoopFor(UBB) != NewLoop)
+ return false;
+ }
+ }
+
+ // If we know we're sinking Inst from an outer loop into an inner loop, then
+ // the *operands* of Inst don't need to be checked.
+
+ if (!Contains(OldLoop, NewLoop)) {
+ // See below on why we can't handle phi nodes here.
+ if (isa<PHINode>(Inst))
+ return false;
+
+ for (Use &U : Inst->operands()) {
+ auto *DefI = dyn_cast<Instruction>(U.get());
+ if (!DefI)
+ return false;
+
+ // This would need adjustment if we allow Inst to be a phi node -- the
+ // new use block won't simply be NewBB.
+
+ auto *DefBlock = DefI->getParent();
+ if (DefBlock != NewBB && getLoopFor(DefBlock) != NewLoop)
+ return false;
+ }
+ }
+
+ return true;
+ }
};
// Allow clients to walk the list of nested loops...
}
};
+/// \brief Analysis pass that exposes the \c LoopInfo for a function.
+class LoopAnalysis {
+ static char PassID;
+
+public:
+ typedef LoopInfo Result;
+
+ /// \brief Opaque, unique identifier for this analysis pass.
+ static void *ID() { return (void *)&PassID; }
+
+ /// \brief Provide a name for the analysis for debugging and logging.
+ static StringRef name() { return "LoopAnalysis"; }
+
+ LoopInfo run(Function &F, AnalysisManager<Function> *AM);
+};
+
+/// \brief Printer pass for the \c LoopAnalysis results.
+class LoopPrinterPass {
+ raw_ostream &OS;
+
+public:
+ explicit LoopPrinterPass(raw_ostream &OS) : OS(OS) {}
+ PreservedAnalyses run(Function &F, AnalysisManager<Function> *AM);
+
+ static StringRef name() { return "LoopPrinterPass"; }
+};
+
/// \brief The legacy pass manager's analysis pass to compute loop information.
class LoopInfoWrapperPass : public FunctionPass {
LoopInfo LI;
void getAnalysisUsage(AnalysisUsage &AU) const override;
};
+/// \brief Pass for printing a loop's contents as LLVM's text IR assembly.
+class PrintLoopPass {
+ raw_ostream &OS;
+ std::string Banner;
+
+public:
+ PrintLoopPass();
+ PrintLoopPass(raw_ostream &OS, const std::string &Banner = "");
+
+ PreservedAnalyses run(Loop &L);
+ static StringRef name() { return "PrintLoopPass"; }
+};
+
} // End llvm namespace
#endif
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