llvm-for-llvmta/include/llvm/Analysis/RegionInfoImpl.h

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//===- RegionInfoImpl.h - SESE region detection analysis --------*- 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
//
//===----------------------------------------------------------------------===//
// Detects single entry single exit regions in the control flow graph.
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_REGIONINFOIMPL_H
#define LLVM_ANALYSIS_REGIONINFOIMPL_H
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Analysis/DominanceFrontier.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Analysis/RegionInfo.h"
#include "llvm/Analysis/RegionIterator.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <iterator>
#include <memory>
#include <set>
#include <string>
#include <type_traits>
#include <vector>
#define DEBUG_TYPE "region"
namespace llvm {
//===----------------------------------------------------------------------===//
/// RegionBase Implementation
template <class Tr>
RegionBase<Tr>::RegionBase(BlockT *Entry, BlockT *Exit,
typename Tr::RegionInfoT *RInfo, DomTreeT *dt,
RegionT *Parent)
: RegionNodeBase<Tr>(Parent, Entry, 1), RI(RInfo), DT(dt), exit(Exit) {}
template <class Tr>
RegionBase<Tr>::~RegionBase() {
// Only clean the cache for this Region. Caches of child Regions will be
// cleaned when the child Regions are deleted.
BBNodeMap.clear();
}
template <class Tr>
void RegionBase<Tr>::replaceEntry(BlockT *BB) {
this->entry.setPointer(BB);
}
template <class Tr>
void RegionBase<Tr>::replaceExit(BlockT *BB) {
assert(exit && "No exit to replace!");
exit = BB;
}
template <class Tr>
void RegionBase<Tr>::replaceEntryRecursive(BlockT *NewEntry) {
std::vector<RegionT *> RegionQueue;
BlockT *OldEntry = getEntry();
RegionQueue.push_back(static_cast<RegionT *>(this));
while (!RegionQueue.empty()) {
RegionT *R = RegionQueue.back();
RegionQueue.pop_back();
R->replaceEntry(NewEntry);
for (std::unique_ptr<RegionT> &Child : *R) {
if (Child->getEntry() == OldEntry)
RegionQueue.push_back(Child.get());
}
}
}
template <class Tr>
void RegionBase<Tr>::replaceExitRecursive(BlockT *NewExit) {
std::vector<RegionT *> RegionQueue;
BlockT *OldExit = getExit();
RegionQueue.push_back(static_cast<RegionT *>(this));
while (!RegionQueue.empty()) {
RegionT *R = RegionQueue.back();
RegionQueue.pop_back();
R->replaceExit(NewExit);
for (std::unique_ptr<RegionT> &Child : *R) {
if (Child->getExit() == OldExit)
RegionQueue.push_back(Child.get());
}
}
}
template <class Tr>
bool RegionBase<Tr>::contains(const BlockT *B) const {
BlockT *BB = const_cast<BlockT *>(B);
if (!DT->getNode(BB))
return false;
BlockT *entry = getEntry(), *exit = getExit();
// Toplevel region.
if (!exit)
return true;
return (DT->dominates(entry, BB) &&
!(DT->dominates(exit, BB) && DT->dominates(entry, exit)));
}
template <class Tr>
bool RegionBase<Tr>::contains(const LoopT *L) const {
// BBs that are not part of any loop are element of the Loop
// described by the NULL pointer. This loop is not part of any region,
// except if the region describes the whole function.
if (!L)
return getExit() == nullptr;
if (!contains(L->getHeader()))
return false;
SmallVector<BlockT *, 8> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);
for (BlockT *BB : ExitingBlocks) {
if (!contains(BB))
return false;
}
return true;
}
template <class Tr>
typename Tr::LoopT *RegionBase<Tr>::outermostLoopInRegion(LoopT *L) const {
if (!contains(L))
return nullptr;
while (L && contains(L->getParentLoop())) {
L = L->getParentLoop();
}
return L;
}
template <class Tr>
typename Tr::LoopT *RegionBase<Tr>::outermostLoopInRegion(LoopInfoT *LI,
BlockT *BB) const {
assert(LI && BB && "LI and BB cannot be null!");
LoopT *L = LI->getLoopFor(BB);
return outermostLoopInRegion(L);
}
template <class Tr>
typename RegionBase<Tr>::BlockT *RegionBase<Tr>::getEnteringBlock() const {
BlockT *entry = getEntry();
BlockT *enteringBlock = nullptr;
for (BlockT *Pred : make_range(InvBlockTraits::child_begin(entry),
InvBlockTraits::child_end(entry))) {
if (DT->getNode(Pred) && !contains(Pred)) {
if (enteringBlock)
return nullptr;
enteringBlock = Pred;
}
}
return enteringBlock;
}
template <class Tr>
bool RegionBase<Tr>::getExitingBlocks(
SmallVectorImpl<BlockT *> &Exitings) const {
bool CoverAll = true;
if (!exit)
return CoverAll;
for (PredIterTy PI = InvBlockTraits::child_begin(exit),
PE = InvBlockTraits::child_end(exit);
PI != PE; ++PI) {
BlockT *Pred = *PI;
if (contains(Pred)) {
Exitings.push_back(Pred);
continue;
}
CoverAll = false;
}
return CoverAll;
}
template <class Tr>
typename RegionBase<Tr>::BlockT *RegionBase<Tr>::getExitingBlock() const {
BlockT *exit = getExit();
BlockT *exitingBlock = nullptr;
if (!exit)
return nullptr;
for (BlockT *Pred : make_range(InvBlockTraits::child_begin(exit),
InvBlockTraits::child_end(exit))) {
if (contains(Pred)) {
if (exitingBlock)
return nullptr;
exitingBlock = Pred;
}
}
return exitingBlock;
}
template <class Tr>
bool RegionBase<Tr>::isSimple() const {
return !isTopLevelRegion() && getEnteringBlock() && getExitingBlock();
}
template <class Tr>
std::string RegionBase<Tr>::getNameStr() const {
std::string exitName;
std::string entryName;
if (getEntry()->getName().empty()) {
raw_string_ostream OS(entryName);
getEntry()->printAsOperand(OS, false);
} else
entryName = std::string(getEntry()->getName());
if (getExit()) {
if (getExit()->getName().empty()) {
raw_string_ostream OS(exitName);
getExit()->printAsOperand(OS, false);
} else
exitName = std::string(getExit()->getName());
} else
exitName = "<Function Return>";
return entryName + " => " + exitName;
}
template <class Tr>
void RegionBase<Tr>::verifyBBInRegion(BlockT *BB) const {
if (!contains(BB))
report_fatal_error("Broken region found: enumerated BB not in region!");
BlockT *entry = getEntry(), *exit = getExit();
for (BlockT *Succ :
make_range(BlockTraits::child_begin(BB), BlockTraits::child_end(BB))) {
if (!contains(Succ) && exit != Succ)
report_fatal_error("Broken region found: edges leaving the region must go "
"to the exit node!");
}
if (entry != BB) {
for (BlockT *Pred : make_range(InvBlockTraits::child_begin(BB),
InvBlockTraits::child_end(BB))) {
if (!contains(Pred))
report_fatal_error("Broken region found: edges entering the region must "
"go to the entry node!");
}
}
}
template <class Tr>
void RegionBase<Tr>::verifyWalk(BlockT *BB, std::set<BlockT *> *visited) const {
BlockT *exit = getExit();
visited->insert(BB);
verifyBBInRegion(BB);
for (BlockT *Succ :
make_range(BlockTraits::child_begin(BB), BlockTraits::child_end(BB))) {
if (Succ != exit && visited->find(Succ) == visited->end())
verifyWalk(Succ, visited);
}
}
template <class Tr>
void RegionBase<Tr>::verifyRegion() const {
// Only do verification when user wants to, otherwise this expensive check
// will be invoked by PMDataManager::verifyPreservedAnalysis when
// a regionpass (marked PreservedAll) finish.
if (!RegionInfoBase<Tr>::VerifyRegionInfo)
return;
std::set<BlockT *> visited;
verifyWalk(getEntry(), &visited);
}
template <class Tr>
void RegionBase<Tr>::verifyRegionNest() const {
for (const std::unique_ptr<RegionT> &R : *this)
R->verifyRegionNest();
verifyRegion();
}
template <class Tr>
typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_begin() {
return GraphTraits<RegionT *>::nodes_begin(static_cast<RegionT *>(this));
}
template <class Tr>
typename RegionBase<Tr>::element_iterator RegionBase<Tr>::element_end() {
return GraphTraits<RegionT *>::nodes_end(static_cast<RegionT *>(this));
}
template <class Tr>
typename RegionBase<Tr>::const_element_iterator
RegionBase<Tr>::element_begin() const {
return GraphTraits<const RegionT *>::nodes_begin(
static_cast<const RegionT *>(this));
}
template <class Tr>
typename RegionBase<Tr>::const_element_iterator
RegionBase<Tr>::element_end() const {
return GraphTraits<const RegionT *>::nodes_end(
static_cast<const RegionT *>(this));
}
template <class Tr>
typename Tr::RegionT *RegionBase<Tr>::getSubRegionNode(BlockT *BB) const {
using RegionT = typename Tr::RegionT;
RegionT *R = RI->getRegionFor(BB);
if (!R || R == this)
return nullptr;
// If we pass the BB out of this region, that means our code is broken.
assert(contains(R) && "BB not in current region!");
while (contains(R->getParent()) && R->getParent() != this)
R = R->getParent();
if (R->getEntry() != BB)
return nullptr;
return R;
}
template <class Tr>
typename Tr::RegionNodeT *RegionBase<Tr>::getBBNode(BlockT *BB) const {
assert(contains(BB) && "Can get BB node out of this region!");
typename BBNodeMapT::const_iterator at = BBNodeMap.find(BB);
if (at == BBNodeMap.end()) {
auto Deconst = const_cast<RegionBase<Tr> *>(this);
typename BBNodeMapT::value_type V = {
BB,
std::make_unique<RegionNodeT>(static_cast<RegionT *>(Deconst), BB)};
at = BBNodeMap.insert(std::move(V)).first;
}
return at->second.get();
}
template <class Tr>
typename Tr::RegionNodeT *RegionBase<Tr>::getNode(BlockT *BB) const {
assert(contains(BB) && "Can get BB node out of this region!");
if (RegionT *Child = getSubRegionNode(BB))
return Child->getNode();
return getBBNode(BB);
}
template <class Tr>
void RegionBase<Tr>::transferChildrenTo(RegionT *To) {
for (std::unique_ptr<RegionT> &R : *this) {
R->parent = To;
To->children.push_back(std::move(R));
}
children.clear();
}
template <class Tr>
void RegionBase<Tr>::addSubRegion(RegionT *SubRegion, bool moveChildren) {
assert(!SubRegion->parent && "SubRegion already has a parent!");
assert(llvm::find_if(*this,
[&](const std::unique_ptr<RegionT> &R) {
return R.get() == SubRegion;
}) == children.end() &&
"Subregion already exists!");
SubRegion->parent = static_cast<RegionT *>(this);
children.push_back(std::unique_ptr<RegionT>(SubRegion));
if (!moveChildren)
return;
assert(SubRegion->children.empty() &&
"SubRegions that contain children are not supported");
for (RegionNodeT *Element : elements()) {
if (!Element->isSubRegion()) {
BlockT *BB = Element->template getNodeAs<BlockT>();
if (SubRegion->contains(BB))
RI->setRegionFor(BB, SubRegion);
}
}
std::vector<std::unique_ptr<RegionT>> Keep;
for (std::unique_ptr<RegionT> &R : *this) {
if (SubRegion->contains(R.get()) && R.get() != SubRegion) {
R->parent = SubRegion;
SubRegion->children.push_back(std::move(R));
} else
Keep.push_back(std::move(R));
}
children.clear();
children.insert(
children.begin(),
std::move_iterator<typename RegionSet::iterator>(Keep.begin()),
std::move_iterator<typename RegionSet::iterator>(Keep.end()));
}
template <class Tr>
typename Tr::RegionT *RegionBase<Tr>::removeSubRegion(RegionT *Child) {
assert(Child->parent == this && "Child is not a child of this region!");
Child->parent = nullptr;
typename RegionSet::iterator I =
llvm::find_if(children, [&](const std::unique_ptr<RegionT> &R) {
return R.get() == Child;
});
assert(I != children.end() && "Region does not exit. Unable to remove.");
children.erase(children.begin() + (I - begin()));
return Child;
}
template <class Tr>
unsigned RegionBase<Tr>::getDepth() const {
unsigned Depth = 0;
for (RegionT *R = getParent(); R != nullptr; R = R->getParent())
++Depth;
return Depth;
}
template <class Tr>
typename Tr::RegionT *RegionBase<Tr>::getExpandedRegion() const {
unsigned NumSuccessors = Tr::getNumSuccessors(exit);
if (NumSuccessors == 0)
return nullptr;
RegionT *R = RI->getRegionFor(exit);
if (R->getEntry() != exit) {
for (BlockT *Pred : make_range(InvBlockTraits::child_begin(getExit()),
InvBlockTraits::child_end(getExit())))
if (!contains(Pred))
return nullptr;
if (Tr::getNumSuccessors(exit) == 1)
return new RegionT(getEntry(), *BlockTraits::child_begin(exit), RI, DT);
return nullptr;
}
while (R->getParent() && R->getParent()->getEntry() == exit)
R = R->getParent();
for (BlockT *Pred : make_range(InvBlockTraits::child_begin(getExit()),
InvBlockTraits::child_end(getExit()))) {
if (!(contains(Pred) || R->contains(Pred)))
return nullptr;
}
return new RegionT(getEntry(), R->getExit(), RI, DT);
}
template <class Tr>
void RegionBase<Tr>::print(raw_ostream &OS, bool print_tree, unsigned level,
PrintStyle Style) const {
if (print_tree)
OS.indent(level * 2) << '[' << level << "] " << getNameStr();
else
OS.indent(level * 2) << getNameStr();
OS << '\n';
if (Style != PrintNone) {
OS.indent(level * 2) << "{\n";
OS.indent(level * 2 + 2);
if (Style == PrintBB) {
for (const auto *BB : blocks())
OS << BB->getName() << ", "; // TODO: remove the last ","
} else if (Style == PrintRN) {
for (const RegionNodeT *Element : elements()) {
OS << *Element << ", "; // TODO: remove the last ",
}
}
OS << '\n';
}
if (print_tree) {
for (const std::unique_ptr<RegionT> &R : *this)
R->print(OS, print_tree, level + 1, Style);
}
if (Style != PrintNone)
OS.indent(level * 2) << "} \n";
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
template <class Tr>
void RegionBase<Tr>::dump() const {
print(dbgs(), true, getDepth(), RegionInfoBase<Tr>::printStyle);
}
#endif
template <class Tr>
void RegionBase<Tr>::clearNodeCache() {
BBNodeMap.clear();
for (std::unique_ptr<RegionT> &R : *this)
R->clearNodeCache();
}
//===----------------------------------------------------------------------===//
// RegionInfoBase implementation
//
template <class Tr>
RegionInfoBase<Tr>::RegionInfoBase() = default;
template <class Tr>
RegionInfoBase<Tr>::~RegionInfoBase() {
releaseMemory();
}
template <class Tr>
void RegionInfoBase<Tr>::verifyBBMap(const RegionT *R) const {
assert(R && "Re must be non-null");
for (const typename Tr::RegionNodeT *Element : R->elements()) {
if (Element->isSubRegion()) {
const RegionT *SR = Element->template getNodeAs<RegionT>();
verifyBBMap(SR);
} else {
BlockT *BB = Element->template getNodeAs<BlockT>();
if (getRegionFor(BB) != R)
report_fatal_error("BB map does not match region nesting");
}
}
}
template <class Tr>
bool RegionInfoBase<Tr>::isCommonDomFrontier(BlockT *BB, BlockT *entry,
BlockT *exit) const {
for (BlockT *P : make_range(InvBlockTraits::child_begin(BB),
InvBlockTraits::child_end(BB))) {
if (DT->dominates(entry, P) && !DT->dominates(exit, P))
return false;
}
return true;
}
template <class Tr>
bool RegionInfoBase<Tr>::isRegion(BlockT *entry, BlockT *exit) const {
assert(entry && exit && "entry and exit must not be null!");
using DST = typename DomFrontierT::DomSetType;
DST *entrySuccs = &DF->find(entry)->second;
// Exit is the header of a loop that contains the entry. In this case,
// the dominance frontier must only contain the exit.
if (!DT->dominates(entry, exit)) {
for (BlockT *successor : *entrySuccs) {
if (successor != exit && successor != entry)
return false;
}
return true;
}
DST *exitSuccs = &DF->find(exit)->second;
// Do not allow edges leaving the region.
for (BlockT *Succ : *entrySuccs) {
if (Succ == exit || Succ == entry)
continue;
if (exitSuccs->find(Succ) == exitSuccs->end())
return false;
if (!isCommonDomFrontier(Succ, entry, exit))
return false;
}
// Do not allow edges pointing into the region.
for (BlockT *Succ : *exitSuccs) {
if (DT->properlyDominates(entry, Succ) && Succ != exit)
return false;
}
return true;
}
template <class Tr>
void RegionInfoBase<Tr>::insertShortCut(BlockT *entry, BlockT *exit,
BBtoBBMap *ShortCut) const {
assert(entry && exit && "entry and exit must not be null!");
typename BBtoBBMap::iterator e = ShortCut->find(exit);
if (e == ShortCut->end())
// No further region at exit available.
(*ShortCut)[entry] = exit;
else {
// We found a region e that starts at exit. Therefore (entry, e->second)
// is also a region, that is larger than (entry, exit). Insert the
// larger one.
BlockT *BB = e->second;
(*ShortCut)[entry] = BB;
}
}
template <class Tr>
typename Tr::DomTreeNodeT *
RegionInfoBase<Tr>::getNextPostDom(DomTreeNodeT *N, BBtoBBMap *ShortCut) const {
typename BBtoBBMap::iterator e = ShortCut->find(N->getBlock());
if (e == ShortCut->end())
return N->getIDom();
return PDT->getNode(e->second)->getIDom();
}
template <class Tr>
bool RegionInfoBase<Tr>::isTrivialRegion(BlockT *entry, BlockT *exit) const {
assert(entry && exit && "entry and exit must not be null!");
unsigned num_successors =
BlockTraits::child_end(entry) - BlockTraits::child_begin(entry);
if (num_successors <= 1 && exit == *(BlockTraits::child_begin(entry)))
return true;
return false;
}
template <class Tr>
typename Tr::RegionT *RegionInfoBase<Tr>::createRegion(BlockT *entry,
BlockT *exit) {
assert(entry && exit && "entry and exit must not be null!");
if (isTrivialRegion(entry, exit))
return nullptr;
RegionT *region =
new RegionT(entry, exit, static_cast<RegionInfoT *>(this), DT);
BBtoRegion.insert({entry, region});
#ifdef EXPENSIVE_CHECKS
region->verifyRegion();
#else
LLVM_DEBUG(region->verifyRegion());
#endif
updateStatistics(region);
return region;
}
template <class Tr>
void RegionInfoBase<Tr>::findRegionsWithEntry(BlockT *entry,
BBtoBBMap *ShortCut) {
assert(entry);
DomTreeNodeT *N = PDT->getNode(entry);
if (!N)
return;
RegionT *lastRegion = nullptr;
BlockT *lastExit = entry;
// As only a BasicBlock that postdominates entry can finish a region, walk the
// post dominance tree upwards.
while ((N = getNextPostDom(N, ShortCut))) {
BlockT *exit = N->getBlock();
if (!exit)
break;
if (isRegion(entry, exit)) {
RegionT *newRegion = createRegion(entry, exit);
if (lastRegion)
newRegion->addSubRegion(lastRegion);
lastRegion = newRegion;
lastExit = exit;
}
// This can never be a region, so stop the search.
if (!DT->dominates(entry, exit))
break;
}
// Tried to create regions from entry to lastExit. Next time take a
// shortcut from entry to lastExit.
if (lastExit != entry)
insertShortCut(entry, lastExit, ShortCut);
}
template <class Tr>
void RegionInfoBase<Tr>::scanForRegions(FuncT &F, BBtoBBMap *ShortCut) {
using FuncPtrT = std::add_pointer_t<FuncT>;
BlockT *entry = GraphTraits<FuncPtrT>::getEntryNode(&F);
DomTreeNodeT *N = DT->getNode(entry);
// Iterate over the dominance tree in post order to start with the small
// regions from the bottom of the dominance tree. If the small regions are
// detected first, detection of bigger regions is faster, as we can jump
// over the small regions.
for (auto DomNode : post_order(N))
findRegionsWithEntry(DomNode->getBlock(), ShortCut);
}
template <class Tr>
typename Tr::RegionT *RegionInfoBase<Tr>::getTopMostParent(RegionT *region) {
while (region->getParent())
region = region->getParent();
return region;
}
template <class Tr>
void RegionInfoBase<Tr>::buildRegionsTree(DomTreeNodeT *N, RegionT *region) {
BlockT *BB = N->getBlock();
// Passed region exit
while (BB == region->getExit())
region = region->getParent();
typename BBtoRegionMap::iterator it = BBtoRegion.find(BB);
// This basic block is a start block of a region. It is already in the
// BBtoRegion relation. Only the child basic blocks have to be updated.
if (it != BBtoRegion.end()) {
RegionT *newRegion = it->second;
region->addSubRegion(getTopMostParent(newRegion));
region = newRegion;
} else {
BBtoRegion[BB] = region;
}
for (DomTreeNodeBase<BlockT> *C : *N) {
buildRegionsTree(C, region);
}
}
#ifdef EXPENSIVE_CHECKS
template <class Tr>
bool RegionInfoBase<Tr>::VerifyRegionInfo = true;
#else
template <class Tr>
bool RegionInfoBase<Tr>::VerifyRegionInfo = false;
#endif
template <class Tr>
typename Tr::RegionT::PrintStyle RegionInfoBase<Tr>::printStyle =
RegionBase<Tr>::PrintNone;
template <class Tr>
void RegionInfoBase<Tr>::print(raw_ostream &OS) const {
OS << "Region tree:\n";
TopLevelRegion->print(OS, true, 0, printStyle);
OS << "End region tree\n";
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
template <class Tr>
void RegionInfoBase<Tr>::dump() const { print(dbgs()); }
#endif
template <class Tr>
void RegionInfoBase<Tr>::releaseMemory() {
BBtoRegion.clear();
if (TopLevelRegion)
delete TopLevelRegion;
TopLevelRegion = nullptr;
}
template <class Tr>
void RegionInfoBase<Tr>::verifyAnalysis() const {
// Do only verify regions if explicitely activated using EXPENSIVE_CHECKS or
// -verify-region-info
if (!RegionInfoBase<Tr>::VerifyRegionInfo)
return;
TopLevelRegion->verifyRegionNest();
verifyBBMap(TopLevelRegion);
}
// Region pass manager support.
template <class Tr>
typename Tr::RegionT *RegionInfoBase<Tr>::getRegionFor(BlockT *BB) const {
return BBtoRegion.lookup(BB);
}
template <class Tr>
void RegionInfoBase<Tr>::setRegionFor(BlockT *BB, RegionT *R) {
BBtoRegion[BB] = R;
}
template <class Tr>
typename Tr::RegionT *RegionInfoBase<Tr>::operator[](BlockT *BB) const {
return getRegionFor(BB);
}
template <class Tr>
typename RegionInfoBase<Tr>::BlockT *
RegionInfoBase<Tr>::getMaxRegionExit(BlockT *BB) const {
BlockT *Exit = nullptr;
while (true) {
// Get largest region that starts at BB.
RegionT *R = getRegionFor(BB);
while (R && R->getParent() && R->getParent()->getEntry() == BB)
R = R->getParent();
// Get the single exit of BB.
if (R && R->getEntry() == BB)
Exit = R->getExit();
else if (++BlockTraits::child_begin(BB) == BlockTraits::child_end(BB))
Exit = *BlockTraits::child_begin(BB);
else // No single exit exists.
return Exit;
// Get largest region that starts at Exit.
RegionT *ExitR = getRegionFor(Exit);
while (ExitR && ExitR->getParent() &&
ExitR->getParent()->getEntry() == Exit)
ExitR = ExitR->getParent();
for (BlockT *Pred : make_range(InvBlockTraits::child_begin(Exit),
InvBlockTraits::child_end(Exit))) {
if (!R->contains(Pred) && !ExitR->contains(Pred))
break;
}
// This stops infinite cycles.
if (DT->dominates(Exit, BB))
break;
BB = Exit;
}
return Exit;
}
template <class Tr>
typename Tr::RegionT *RegionInfoBase<Tr>::getCommonRegion(RegionT *A,
RegionT *B) const {
assert(A && B && "One of the Regions is NULL");
if (A->contains(B))
return A;
while (!B->contains(A))
B = B->getParent();
return B;
}
template <class Tr>
typename Tr::RegionT *
RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<RegionT *> &Regions) const {
RegionT *ret = Regions.pop_back_val();
for (RegionT *R : Regions)
ret = getCommonRegion(ret, R);
return ret;
}
template <class Tr>
typename Tr::RegionT *
RegionInfoBase<Tr>::getCommonRegion(SmallVectorImpl<BlockT *> &BBs) const {
RegionT *ret = getRegionFor(BBs.back());
BBs.pop_back();
for (BlockT *BB : BBs)
ret = getCommonRegion(ret, getRegionFor(BB));
return ret;
}
template <class Tr>
void RegionInfoBase<Tr>::calculate(FuncT &F) {
using FuncPtrT = std::add_pointer_t<FuncT>;
// ShortCut a function where for every BB the exit of the largest region
// starting with BB is stored. These regions can be threated as single BBS.
// This improves performance on linear CFGs.
BBtoBBMap ShortCut;
scanForRegions(F, &ShortCut);
BlockT *BB = GraphTraits<FuncPtrT>::getEntryNode(&F);
buildRegionsTree(DT->getNode(BB), TopLevelRegion);
}
} // end namespace llvm
#undef DEBUG_TYPE
#endif // LLVM_ANALYSIS_REGIONINFOIMPL_H