//===- llvm/Analysis/LoopInfoImpl.h - Natural Loop Calculator ---*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This is the generic implementation of LoopInfo used for both Loops and
// MachineLoops.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LOOPINFOIMPL_H
#define LLVM_ANALYSIS_LOOPINFOIMPL_H
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetOperations.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/IR/Dominators.h"
namespace llvm {
//===----------------------------------------------------------------------===//
// APIs for simple analysis of the loop. See header notes.
/// getExitingBlocks - Return all blocks inside the loop that have successors
/// outside of the loop. These are the blocks _inside of the current loop_
/// which branch out. The returned list is always unique.
///
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::getExitingBlocks(
SmallVectorImpl<BlockT *> &ExitingBlocks) const {
assert(!isInvalid() && "Loop not in a valid state!");
for (const auto BB : blocks())
for (auto *Succ : children<BlockT *>(BB))
if (!contains(Succ)) {
// Not in current loop? It must be an exit block.
ExitingBlocks.push_back(BB);
break;
}
}
/// getExitingBlock - If getExitingBlocks would return exactly one block,
/// return that block. Otherwise return null.
template <class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getExitingBlock() const {
assert(!isInvalid() && "Loop not in a valid state!");
auto notInLoop = [&](BlockT *BB) { return !contains(BB); };
auto isExitBlock = [&](BlockT *BB, bool AllowRepeats) -> BlockT * {
assert(!AllowRepeats && "Unexpected parameter value.");
// Child not in current loop? It must be an exit block.
return any_of(children<BlockT *>(BB), notInLoop) ? BB : nullptr;
};
return find_singleton<BlockT>(blocks(), isExitBlock);
}
/// getExitBlocks - Return all of the successor blocks of this loop. These
/// are the blocks _outside of the current loop_ which are branched to.
///
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::getExitBlocks(
SmallVectorImpl<BlockT *> &ExitBlocks) const {
assert(!isInvalid() && "Loop not in a valid state!");
for (const auto BB : blocks())
for (auto *Succ : children<BlockT *>(BB))
if (!contains(Succ))
// Not in current loop? It must be an exit block.
ExitBlocks.push_back(Succ);
}
/// getExitBlock - If getExitBlocks would return exactly one block,
/// return that block. Otherwise return null.
template <class BlockT, class LoopT>
std::pair<BlockT *, bool> getExitBlockHelper(const LoopBase<BlockT, LoopT> *L,
bool Unique) {
assert(!L->isInvalid() && "Loop not in a valid state!");
auto notInLoop = [&](BlockT *BB,
bool AllowRepeats) -> std::pair<BlockT *, bool> {
assert(AllowRepeats == Unique && "Unexpected parameter value.");
return {!L->contains(BB) ? BB : nullptr, false};
};
auto singleExitBlock = [&](BlockT *BB,
bool AllowRepeats) -> std::pair<BlockT *, bool> {
assert(AllowRepeats == Unique && "Unexpected parameter value.");
return find_singleton_nested<BlockT>(children<BlockT *>(BB), notInLoop,
AllowRepeats);
};
return find_singleton_nested<BlockT>(L->blocks(), singleExitBlock, Unique);
}
template <class BlockT, class LoopT>
bool LoopBase<BlockT, LoopT>::hasNoExitBlocks() const {
auto RC = getExitBlockHelper(this, false);
if (RC.second)
// found multiple exit blocks
return false;
// return true if there is no exit block
return !RC.first;
}
/// getExitBlock - If getExitBlocks would return exactly one block,
/// return that block. Otherwise return null.
template <class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getExitBlock() const {
return getExitBlockHelper(this, false).first;
}
template <class BlockT, class LoopT>
bool LoopBase<BlockT, LoopT>::hasDedicatedExits() const {
// Each predecessor of each exit block of a normal loop is contained
// within the loop.
SmallVector<BlockT *, 4> UniqueExitBlocks;
getUniqueExitBlocks(UniqueExitBlocks);
for (BlockT *EB : UniqueExitBlocks)
for (BlockT *Predecessor : children<Inverse<BlockT *>>(EB))
if (!contains(Predecessor))
return false;
// All the requirements are met.
return true;
}
// Helper function to get unique loop exits. Pred is a predicate pointing to
// BasicBlocks in a loop which should be considered to find loop exits.
template <class BlockT, class LoopT, typename PredicateT>
void getUniqueExitBlocksHelper(const LoopT *L,
SmallVectorImpl<BlockT *> &ExitBlocks,
PredicateT Pred) {
assert(!L->isInvalid() && "Loop not in a valid state!");
SmallPtrSet<BlockT *, 32> Visited;
auto Filtered = make_filter_range(L->blocks(), Pred);
for (BlockT *BB : Filtered)
for (BlockT *Successor : children<BlockT *>(BB))
if (!L->contains(Successor))
if (Visited.insert(Successor).second)
ExitBlocks.push_back(Successor);
}
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::getUniqueExitBlocks(
SmallVectorImpl<BlockT *> &ExitBlocks) const {
getUniqueExitBlocksHelper(this, ExitBlocks,
[](const BlockT *BB) { return true; });
}
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::getUniqueNonLatchExitBlocks(
SmallVectorImpl<BlockT *> &ExitBlocks) const {
const BlockT *Latch = getLoopLatch();
assert(Latch && "Latch block must exists");
getUniqueExitBlocksHelper(this, ExitBlocks,
[Latch](const BlockT *BB) { return BB != Latch; });
}
template <class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getUniqueExitBlock() const {
return getExitBlockHelper(this, true).first;
}
/// getExitEdges - Return all pairs of (_inside_block_,_outside_block_).
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::getExitEdges(
SmallVectorImpl<Edge> &ExitEdges) const {
assert(!isInvalid() && "Loop not in a valid state!");
for (const auto BB : blocks())
for (auto *Succ : children<BlockT *>(BB))
if (!contains(Succ))
// Not in current loop? It must be an exit block.
ExitEdges.emplace_back(BB, Succ);
}
/// 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
/// from outside of the loop and it is legal to hoist instructions into the
/// predecessor. If this is the case, the block branching to the header of the
/// loop is the preheader node.
///
/// This method returns null if there is no preheader for the loop.
///
template <class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getLoopPreheader() const {
assert(!isInvalid() && "Loop not in a valid state!");
// Keep track of nodes outside the loop branching to the header...
BlockT *Out = getLoopPredecessor();
if (!Out)
return nullptr;
// Make sure we are allowed to hoist instructions into the predecessor.
if (!Out->isLegalToHoistInto())
return nullptr;
// Make sure there is only one exit out of the preheader.
typedef GraphTraits<BlockT *> BlockTraits;
typename BlockTraits::ChildIteratorType SI = BlockTraits::child_begin(Out);
++SI;
if (SI != BlockTraits::child_end(Out))
return nullptr; // Multiple exits from the block, must not be a preheader.
// The predecessor has exactly one successor, so it is a preheader.
return Out;
}
/// 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.
///
template <class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getLoopPredecessor() const {
assert(!isInvalid() && "Loop not in a valid state!");
// Keep track of nodes outside the loop branching to the header...
BlockT *Out = nullptr;
// Loop over the predecessors of the header node...
BlockT *Header = getHeader();
for (const auto Pred : children<Inverse<BlockT *>>(Header)) {
if (!contains(Pred)) { // If the block is not in the loop...
if (Out && Out != Pred)
return nullptr; // Multiple predecessors outside the loop
Out = Pred;
}
}
return Out;
}
/// 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.
template <class BlockT, class LoopT>
BlockT *LoopBase<BlockT, LoopT>::getLoopLatch() const {
assert(!isInvalid() && "Loop not in a valid state!");
BlockT *Header = getHeader();
BlockT *Latch = nullptr;
for (const auto Pred : children<Inverse<BlockT *>>(Header)) {
if (contains(Pred)) {
if (Latch)
return nullptr;
Latch = Pred;
}
}
return Latch;
}
//===----------------------------------------------------------------------===//
// APIs for updating loop information after changing the CFG
//
/// addBasicBlockToLoop - This method is used by other analyses to update loop
/// information. NewBB is set to be a new member of the current loop.
/// Because of this, it is added as a member of all parent loops, and is added
/// to the specified LoopInfo object as being in the current basic block. It
/// is not valid to replace the loop header with this method.
///
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::addBasicBlockToLoop(
BlockT *NewBB, LoopInfoBase<BlockT, LoopT> &LIB) {
assert(!isInvalid() && "Loop not in a valid state!");
#ifndef NDEBUG
if (!Blocks.empty()) {
auto SameHeader = LIB[getHeader()];
assert(contains(SameHeader) && getHeader() == SameHeader->getHeader() &&
"Incorrect LI specified for this loop!");
}
#endif
assert(NewBB && "Cannot add a null basic block to the loop!");
assert(!LIB[NewBB] && "BasicBlock already in the loop!");
LoopT *L = static_cast<LoopT *>(this);
// Add the loop mapping to the LoopInfo object...
LIB.BBMap[NewBB] = L;
// Add the basic block to this loop and all parent loops...
while (L) {
L->addBlockEntry(NewBB);
L = L->getParentLoop();
}
}
/// 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.
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::replaceChildLoopWith(LoopT *OldChild,
LoopT *NewChild) {
assert(!isInvalid() && "Loop not in a valid state!");
assert(OldChild->ParentLoop == this && "This loop is already broken!");
assert(!NewChild->ParentLoop && "NewChild already has a parent!");
typename std::vector<LoopT *>::iterator I = find(SubLoops, OldChild);
assert(I != SubLoops.end() && "OldChild not in loop!");
*I = NewChild;
OldChild->ParentLoop = nullptr;
NewChild->ParentLoop = static_cast<LoopT *>(this);
}
/// verifyLoop - Verify loop structure
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::verifyLoop() const {
assert(!isInvalid() && "Loop not in a valid state!");
#ifndef NDEBUG
assert(!Blocks.empty() && "Loop header is missing");
// Setup for using a depth-first iterator to visit every block in the loop.
SmallVector<BlockT *, 8> ExitBBs;
getExitBlocks(ExitBBs);
df_iterator_default_set<BlockT *> VisitSet;
VisitSet.insert(ExitBBs.begin(), ExitBBs.end());
// Keep track of the BBs visited.
SmallPtrSet<BlockT *, 8> VisitedBBs;
// Check the individual blocks.
for (BlockT *BB : depth_first_ext(getHeader(), VisitSet)) {
assert(std::any_of(GraphTraits<BlockT *>::child_begin(BB),
GraphTraits<BlockT *>::child_end(BB),
[&](BlockT *B) { return contains(B); }) &&
"Loop block has no in-loop successors!");
assert(std::any_of(GraphTraits<Inverse<BlockT *>>::child_begin(BB),
GraphTraits<Inverse<BlockT *>>::child_end(BB),
[&](BlockT *B) { return contains(B); }) &&
"Loop block has no in-loop predecessors!");
SmallVector<BlockT *, 2> OutsideLoopPreds;
for (BlockT *B :
llvm::make_range(GraphTraits<Inverse<BlockT *>>::child_begin(BB),
GraphTraits<Inverse<BlockT *>>::child_end(BB)))
if (!contains(B))
OutsideLoopPreds.push_back(B);
if (BB == getHeader()) {
assert(!OutsideLoopPreds.empty() && "Loop is unreachable!");
} else if (!OutsideLoopPreds.empty()) {
// A non-header loop shouldn't be reachable from outside the loop,
// though it is permitted if the predecessor is not itself actually
// reachable.
BlockT *EntryBB = &BB->getParent()->front();
for (BlockT *CB : depth_first(EntryBB))
for (unsigned i = 0, e = OutsideLoopPreds.size(); i != e; ++i)
assert(CB != OutsideLoopPreds[i] &&
"Loop has multiple entry points!");
}
assert(BB != &getHeader()->getParent()->front() &&
"Loop contains function entry block!");
VisitedBBs.insert(BB);
}
if (VisitedBBs.size() != getNumBlocks()) {
dbgs() << "The following blocks are unreachable in the loop: ";
for (auto *BB : Blocks) {
if (!VisitedBBs.count(BB)) {
dbgs() << *BB << "\n";
}
}
assert(false && "Unreachable block in loop");
}
// Check the subloops.
for (iterator I = begin(), E = end(); I != E; ++I)
// Each block in each subloop should be contained within this loop.
for (block_iterator BI = (*I)->block_begin(), BE = (*I)->block_end();
BI != BE; ++BI) {
assert(contains(*BI) &&
"Loop does not contain all the blocks of a subloop!");
}
// Check the parent loop pointer.
if (ParentLoop) {
assert(is_contained(*ParentLoop, this) &&
"Loop is not a subloop of its parent!");
}
#endif
}
/// verifyLoop - Verify loop structure of this loop and all nested loops.
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::verifyLoopNest(
DenseSet<const LoopT *> *Loops) const {
assert(!isInvalid() && "Loop not in a valid state!");
Loops->insert(static_cast<const LoopT *>(this));
// Verify this loop.
verifyLoop();
// Verify the subloops.
for (iterator I = begin(), E = end(); I != E; ++I)
(*I)->verifyLoopNest(Loops);
}
template <class BlockT, class LoopT>
void LoopBase<BlockT, LoopT>::print(raw_ostream &OS, bool Verbose,
bool PrintNested, unsigned Depth) const {
OS.indent(Depth * 2);
if (static_cast<const LoopT *>(this)->isAnnotatedParallel())
OS << "Parallel ";
OS << "Loop at depth " << getLoopDepth() << " containing: ";
BlockT *H = getHeader();
for (unsigned i = 0; i < getBlocks().size(); ++i) {
BlockT *BB = getBlocks()[i];
if (!Verbose) {
if (i)
OS << ",";
BB->printAsOperand(OS, false);
} else
OS << "\n";
if (BB == H)
OS << "<header>";
if (isLoopLatch(BB))
OS << "<latch>";
if (isLoopExiting(BB))
OS << "<exiting>";
if (Verbose)
BB->print(OS);
}
if (PrintNested) {
OS << "\n";
for (iterator I = begin(), E = end(); I != E; ++I)
(*I)->print(OS, /*Verbose*/ false, PrintNested, Depth + 2);
}
}
//===----------------------------------------------------------------------===//
/// Stable LoopInfo Analysis - Build a loop tree using stable iterators so the
/// result does / not depend on use list (block predecessor) order.
///
/// Discover a subloop with the specified backedges such that: All blocks within
/// this loop are mapped to this loop or a subloop. And all subloops within this
/// loop have their parent loop set to this loop or a subloop.
template <class BlockT, class LoopT>
static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT *> Backedges,
LoopInfoBase<BlockT, LoopT> *LI,
const DomTreeBase<BlockT> &DomTree) {
typedef GraphTraits<Inverse<BlockT *>> InvBlockTraits;
unsigned NumBlocks = 0;
unsigned NumSubloops = 0;
// Perform a backward CFG traversal using a worklist.
std::vector<BlockT *> ReverseCFGWorklist(Backedges.begin(), Backedges.end());
while (!ReverseCFGWorklist.empty()) {
BlockT *PredBB = ReverseCFGWorklist.back();
ReverseCFGWorklist.pop_back();
LoopT *Subloop = LI->getLoopFor(PredBB);
if (!Subloop) {
if (!DomTree.isReachableFromEntry(PredBB))
continue;
// This is an undiscovered block. Map it to the current loop.
LI->changeLoopFor(PredBB, L);
++NumBlocks;
if (PredBB == L->getHeader())
continue;
// Push all block predecessors on the worklist.
ReverseCFGWorklist.insert(ReverseCFGWorklist.end(),
InvBlockTraits::child_begin(PredBB),
InvBlockTraits::child_end(PredBB));
} else {
// This is a discovered block. Find its outermost discovered loop.
Subloop = Subloop->getOutermostLoop();
// If it is already discovered to be a subloop of this loop, continue.
if (Subloop == L)
continue;
// Discover a subloop of this loop.
Subloop->setParentLoop(L);
++NumSubloops;
NumBlocks += Subloop->getBlocksVector().capacity();
PredBB = Subloop->getHeader();
// Continue traversal along predecessors that are not loop-back edges from
// within this subloop tree itself. Note that a predecessor may directly
// reach another subloop that is not yet discovered to be a subloop of
// this loop, which we must traverse.
for (const auto Pred : children<Inverse<BlockT *>>(PredBB)) {
if (LI->getLoopFor(Pred) != Subloop)
ReverseCFGWorklist.push_back(Pred);
}
}
}
L->getSubLoopsVector().reserve(NumSubloops);
L->reserveBlocks(NumBlocks);
}
/// Populate all loop data in a stable order during a single forward DFS.
template <class BlockT, class LoopT> class PopulateLoopsDFS {
typedef GraphTraits<BlockT *> BlockTraits;
typedef typename BlockTraits::ChildIteratorType SuccIterTy;
LoopInfoBase<BlockT, LoopT> *LI;
public:
PopulateLoopsDFS(LoopInfoBase<BlockT, LoopT> *li) : LI(li) {}
void traverse(BlockT *EntryBlock);
protected:
void insertIntoLoop(BlockT *Block);
};
/// Top-level driver for the forward DFS within the loop.
template <class BlockT, class LoopT>
void PopulateLoopsDFS<BlockT, LoopT>::traverse(BlockT *EntryBlock) {
for (BlockT *BB : post_order(EntryBlock))
insertIntoLoop(BB);
}
/// Add a single Block to its ancestor loops in PostOrder. If the block is a
/// subloop header, add the subloop to its parent in PostOrder, then reverse the
/// Block and Subloop vectors of the now complete subloop to achieve RPO.
template <class BlockT, class LoopT>
void PopulateLoopsDFS<BlockT, LoopT>::insertIntoLoop(BlockT *Block) {
LoopT *Subloop = LI->getLoopFor(Block);
if (Subloop && Block == Subloop->getHeader()) {
// We reach this point once per subloop after processing all the blocks in
// the subloop.
if (!Subloop->isOutermost())
Subloop->getParentLoop()->getSubLoopsVector().push_back(Subloop);
else
LI->addTopLevelLoop(Subloop);
// For convenience, Blocks and Subloops are inserted in postorder. Reverse
// the lists, except for the loop header, which is always at the beginning.
Subloop->reverseBlock(1);
std::reverse(Subloop->getSubLoopsVector().begin(),
Subloop->getSubLoopsVector().end());
Subloop = Subloop->getParentLoop();
}
for (; Subloop; Subloop = Subloop->getParentLoop())
Subloop->addBlockEntry(Block);
}
/// Analyze LoopInfo discovers loops during a postorder DominatorTree traversal
/// interleaved with backward CFG traversals within each subloop
/// (discoverAndMapSubloop). The backward traversal skips inner subloops, so
/// this part of the algorithm is linear in the number of CFG edges. Subloop and
/// Block vectors are then populated during a single forward CFG traversal
/// (PopulateLoopDFS).
///
/// During the two CFG traversals each block is seen three times:
/// 1) Discovered and mapped by a reverse CFG traversal.
/// 2) Visited during a forward DFS CFG traversal.
/// 3) Reverse-inserted in the loop in postorder following forward DFS.
///
/// The Block vectors are inclusive, so step 3 requires loop-depth number of
/// insertions per block.
template <class BlockT, class LoopT>
void LoopInfoBase<BlockT, LoopT>::analyze(const DomTreeBase<BlockT> &DomTree) {
// Postorder traversal of the dominator tree.
const DomTreeNodeBase<BlockT> *DomRoot = DomTree.getRootNode();
for (auto DomNode : post_order(DomRoot)) {
BlockT *Header = DomNode->getBlock();
SmallVector<BlockT *, 4> Backedges;
// Check each predecessor of the potential loop header.
for (const auto Backedge : children<Inverse<BlockT *>>(Header)) {
// If Header dominates predBB, this is a new loop. Collect the backedges.
if (DomTree.dominates(Header, Backedge) &&
DomTree.isReachableFromEntry(Backedge)) {
Backedges.push_back(Backedge);
}
}
// Perform a backward CFG traversal to discover and map blocks in this loop.
if (!Backedges.empty()) {
LoopT *L = AllocateLoop(Header);
discoverAndMapSubloop(L, ArrayRef<BlockT *>(Backedges), this, DomTree);
}
}
// Perform a single forward CFG traversal to populate block and subloop
// vectors for all loops.
PopulateLoopsDFS<BlockT, LoopT> DFS(this);
DFS.traverse(DomRoot->getBlock());
}
template <class BlockT, class LoopT>
SmallVector<LoopT *, 4>
LoopInfoBase<BlockT, LoopT>::getLoopsInPreorder() const {
SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist;
// The outer-most loop actually goes into the result in the same relative
// order as we walk it. But LoopInfo stores the top level loops in reverse
// program order so for here we reverse it to get forward program order.
// FIXME: If we change the order of LoopInfo we will want to remove the
// reverse here.
for (LoopT *RootL : reverse(*this)) {
auto PreOrderLoopsInRootL = RootL->getLoopsInPreorder();
PreOrderLoops.append(PreOrderLoopsInRootL.begin(),
PreOrderLoopsInRootL.end());
}
return PreOrderLoops;
}
template <class BlockT, class LoopT>
SmallVector<LoopT *, 4>
LoopInfoBase<BlockT, LoopT>::getLoopsInReverseSiblingPreorder() const {
SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist;
// The outer-most loop actually goes into the result in the same relative
// order as we walk it. LoopInfo stores the top level loops in reverse
// program order so we walk in order here.
// FIXME: If we change the order of LoopInfo we will want to add a reverse
// here.
for (LoopT *RootL : *this) {
assert(PreOrderWorklist.empty() &&
"Must start with an empty preorder walk worklist.");
PreOrderWorklist.push_back(RootL);
do {
LoopT *L = PreOrderWorklist.pop_back_val();
// Sub-loops are stored in forward program order, but will process the
// worklist backwards so we can just append them in order.
PreOrderWorklist.append(L->begin(), L->end());
PreOrderLoops.push_back(L);
} while (!PreOrderWorklist.empty());
}
return PreOrderLoops;
}
// Debugging
template <class BlockT, class LoopT>
void LoopInfoBase<BlockT, LoopT>::print(raw_ostream &OS) const {
for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
TopLevelLoops[i]->print(OS);
#if 0
for (DenseMap<BasicBlock*, LoopT*>::const_iterator I = BBMap.begin(),
E = BBMap.end(); I != E; ++I)
OS << "BB '" << I->first->getName() << "' level = "
<< I->second->getLoopDepth() << "\n";
#endif
}
template <typename T>
bool compareVectors(std::vector<T> &BB1, std::vector<T> &BB2) {
llvm::sort(BB1);
llvm::sort(BB2);
return BB1 == BB2;
}
template <class BlockT, class LoopT>
void addInnerLoopsToHeadersMap(DenseMap<BlockT *, const LoopT *> &LoopHeaders,
const LoopInfoBase<BlockT, LoopT> &LI,
const LoopT &L) {
LoopHeaders[L.getHeader()] = &L;
for (LoopT *SL : L)
addInnerLoopsToHeadersMap(LoopHeaders, LI, *SL);
}
#ifndef NDEBUG
template <class BlockT, class LoopT>
static void compareLoops(const LoopT *L, const LoopT *OtherL,
DenseMap<BlockT *, const LoopT *> &OtherLoopHeaders) {
BlockT *H = L->getHeader();
BlockT *OtherH = OtherL->getHeader();
assert(H == OtherH &&
"Mismatched headers even though found in the same map entry!");
assert(L->getLoopDepth() == OtherL->getLoopDepth() &&
"Mismatched loop depth!");
const LoopT *ParentL = L, *OtherParentL = OtherL;
do {
assert(ParentL->getHeader() == OtherParentL->getHeader() &&
"Mismatched parent loop headers!");
ParentL = ParentL->getParentLoop();
OtherParentL = OtherParentL->getParentLoop();
} while (ParentL);
for (const LoopT *SubL : *L) {
BlockT *SubH = SubL->getHeader();
const LoopT *OtherSubL = OtherLoopHeaders.lookup(SubH);
assert(OtherSubL && "Inner loop is missing in computed loop info!");
OtherLoopHeaders.erase(SubH);
compareLoops(SubL, OtherSubL, OtherLoopHeaders);
}
std::vector<BlockT *> BBs = L->getBlocks();
std::vector<BlockT *> OtherBBs = OtherL->getBlocks();
assert(compareVectors(BBs, OtherBBs) &&
"Mismatched basic blocks in the loops!");
const SmallPtrSetImpl<const BlockT *> &BlocksSet = L->getBlocksSet();
const SmallPtrSetImpl<const BlockT *> &OtherBlocksSet =
OtherL->getBlocksSet();
assert(BlocksSet.size() == OtherBlocksSet.size() &&
llvm::set_is_subset(BlocksSet, OtherBlocksSet) &&
"Mismatched basic blocks in BlocksSets!");
}
#endif
template <class BlockT, class LoopT>
void LoopInfoBase<BlockT, LoopT>::verify(
const DomTreeBase<BlockT> &DomTree) const {
DenseSet<const LoopT *> Loops;
for (iterator I = begin(), E = end(); I != E; ++I) {
assert((*I)->isOutermost() && "Top-level loop has a parent!");
(*I)->verifyLoopNest(&Loops);
}
// Verify that blocks are mapped to valid loops.
#ifndef NDEBUG
for (auto &Entry : BBMap) {
const BlockT *BB = Entry.first;
LoopT *L = Entry.second;
assert(Loops.count(L) && "orphaned loop");
assert(L->contains(BB) && "orphaned block");
for (LoopT *ChildLoop : *L)
assert(!ChildLoop->contains(BB) &&
"BBMap should point to the innermost loop containing BB");
}
// Recompute LoopInfo to verify loops structure.
LoopInfoBase<BlockT, LoopT> OtherLI;
OtherLI.analyze(DomTree);
// Build a map we can use to move from our LI to the computed one. This
// allows us to ignore the particular order in any layer of the loop forest
// while still comparing the structure.
DenseMap<BlockT *, const LoopT *> OtherLoopHeaders;
for (LoopT *L : OtherLI)
addInnerLoopsToHeadersMap(OtherLoopHeaders, OtherLI, *L);
// Walk the top level loops and ensure there is a corresponding top-level
// loop in the computed version and then recursively compare those loop
// nests.
for (LoopT *L : *this) {
BlockT *Header = L->getHeader();
const LoopT *OtherL = OtherLoopHeaders.lookup(Header);
assert(OtherL && "Top level loop is missing in computed loop info!");
// Now that we've matched this loop, erase its header from the map.
OtherLoopHeaders.erase(Header);
// And recursively compare these loops.
compareLoops(L, OtherL, OtherLoopHeaders);
}
// Any remaining entries in the map are loops which were found when computing
// a fresh LoopInfo but not present in the current one.
if (!OtherLoopHeaders.empty()) {
for (const auto &HeaderAndLoop : OtherLoopHeaders)
dbgs() << "Found new loop: " << *HeaderAndLoop.second << "\n";
llvm_unreachable("Found new loops when recomputing LoopInfo!");
}
#endif
}
} // End llvm namespace
#endif