mirror of
https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41230 91177308-0d34-0410-b5e6-96231b3b80d8
682 lines
25 KiB
C++
682 lines
25 KiB
C++
//===- LoopInfo.cpp - Natural Loop Calculator -----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the LoopInfo class that is used to identify natural loops
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// and determine the loop depth of various nodes of the CFG. Note that the
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// loops identified may actually be several natural loops that share the same
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// header node... not just a single natural loop.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Constants.h"
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#include "llvm/Instructions.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Assembly/Writer.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/Streams.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include <algorithm>
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#include <ostream>
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using namespace llvm;
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char LoopInfo::ID = 0;
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static RegisterPass<LoopInfo>
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X("loops", "Natural Loop Construction", true);
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//===----------------------------------------------------------------------===//
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// Loop implementation
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//
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bool Loop::contains(const BasicBlock *BB) const {
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return std::find(Blocks.begin(), Blocks.end(), BB) != Blocks.end();
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}
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bool Loop::isLoopExit(const BasicBlock *BB) const {
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for (succ_const_iterator SI = succ_begin(BB), SE = succ_end(BB);
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SI != SE; ++SI) {
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if (!contains(*SI))
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return true;
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}
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return false;
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}
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/// getNumBackEdges - Calculate the number of back edges to the loop header.
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///
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unsigned Loop::getNumBackEdges() const {
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unsigned NumBackEdges = 0;
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BasicBlock *H = getHeader();
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for (pred_iterator I = pred_begin(H), E = pred_end(H); I != E; ++I)
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if (contains(*I))
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++NumBackEdges;
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return NumBackEdges;
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}
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/// isLoopInvariant - Return true if the specified value is loop invariant
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///
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bool Loop::isLoopInvariant(Value *V) const {
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if (Instruction *I = dyn_cast<Instruction>(V))
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return !contains(I->getParent());
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return true; // All non-instructions are loop invariant
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}
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void Loop::print(std::ostream &OS, unsigned Depth) const {
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OS << std::string(Depth*2, ' ') << "Loop Containing: ";
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for (unsigned i = 0; i < getBlocks().size(); ++i) {
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if (i) OS << ",";
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WriteAsOperand(OS, getBlocks()[i], false);
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}
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OS << "\n";
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for (iterator I = begin(), E = end(); I != E; ++I)
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(*I)->print(OS, Depth+2);
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}
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/// verifyLoop - Verify loop structure
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void Loop::verifyLoop() const {
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#ifndef NDEBUG
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assert (getHeader() && "Loop header is missing");
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assert (getLoopPreheader() && "Loop preheader is missing");
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assert (getLoopLatch() && "Loop latch is missing");
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for (std::vector<Loop*>::const_iterator I = SubLoops.begin(), E = SubLoops.end();
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I != E; ++I)
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(*I)->verifyLoop();
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#endif
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}
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void Loop::dump() const {
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print(cerr);
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}
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//===----------------------------------------------------------------------===//
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// LoopInfo implementation
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//
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bool LoopInfo::runOnFunction(Function &) {
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releaseMemory();
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Calculate(getAnalysis<DominatorTree>()); // Update
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return false;
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}
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void LoopInfo::releaseMemory() {
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for (std::vector<Loop*>::iterator I = TopLevelLoops.begin(),
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E = TopLevelLoops.end(); I != E; ++I)
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delete *I; // Delete all of the loops...
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BBMap.clear(); // Reset internal state of analysis
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TopLevelLoops.clear();
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}
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void LoopInfo::Calculate(DominatorTree &DT) {
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BasicBlock *RootNode = DT.getRootNode()->getBlock();
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for (df_iterator<BasicBlock*> NI = df_begin(RootNode),
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NE = df_end(RootNode); NI != NE; ++NI)
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if (Loop *L = ConsiderForLoop(*NI, DT))
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TopLevelLoops.push_back(L);
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}
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void LoopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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AU.addRequired<DominatorTree>();
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}
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void LoopInfo::print(std::ostream &OS, const Module* ) const {
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for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
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TopLevelLoops[i]->print(OS);
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#if 0
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for (std::map<BasicBlock*, Loop*>::const_iterator I = BBMap.begin(),
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E = BBMap.end(); I != E; ++I)
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OS << "BB '" << I->first->getName() << "' level = "
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<< I->second->getLoopDepth() << "\n";
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#endif
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}
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static bool isNotAlreadyContainedIn(Loop *SubLoop, Loop *ParentLoop) {
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if (SubLoop == 0) return true;
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if (SubLoop == ParentLoop) return false;
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return isNotAlreadyContainedIn(SubLoop->getParentLoop(), ParentLoop);
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}
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Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, DominatorTree &DT) {
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if (BBMap.find(BB) != BBMap.end()) return 0; // Haven't processed this node?
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std::vector<BasicBlock *> TodoStack;
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// Scan the predecessors of BB, checking to see if BB dominates any of
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// them. This identifies backedges which target this node...
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for (pred_iterator I = pred_begin(BB), E = pred_end(BB); I != E; ++I)
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if (DT.dominates(BB, *I)) // If BB dominates it's predecessor...
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TodoStack.push_back(*I);
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if (TodoStack.empty()) return 0; // No backedges to this block...
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// Create a new loop to represent this basic block...
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Loop *L = new Loop(BB);
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BBMap[BB] = L;
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BasicBlock *EntryBlock = &BB->getParent()->getEntryBlock();
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while (!TodoStack.empty()) { // Process all the nodes in the loop
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BasicBlock *X = TodoStack.back();
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TodoStack.pop_back();
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if (!L->contains(X) && // As of yet unprocessed??
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DT.dominates(EntryBlock, X)) { // X is reachable from entry block?
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// Check to see if this block already belongs to a loop. If this occurs
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// then we have a case where a loop that is supposed to be a child of the
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// current loop was processed before the current loop. When this occurs,
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// this child loop gets added to a part of the current loop, making it a
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// sibling to the current loop. We have to reparent this loop.
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if (Loop *SubLoop = const_cast<Loop*>(getLoopFor(X)))
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if (SubLoop->getHeader() == X && isNotAlreadyContainedIn(SubLoop, L)) {
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// Remove the subloop from it's current parent...
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assert(SubLoop->ParentLoop && SubLoop->ParentLoop != L);
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Loop *SLP = SubLoop->ParentLoop; // SubLoopParent
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std::vector<Loop*>::iterator I =
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std::find(SLP->SubLoops.begin(), SLP->SubLoops.end(), SubLoop);
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assert(I != SLP->SubLoops.end() && "SubLoop not a child of parent?");
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SLP->SubLoops.erase(I); // Remove from parent...
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// Add the subloop to THIS loop...
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SubLoop->ParentLoop = L;
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L->SubLoops.push_back(SubLoop);
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}
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// Normal case, add the block to our loop...
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L->Blocks.push_back(X);
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// Add all of the predecessors of X to the end of the work stack...
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TodoStack.insert(TodoStack.end(), pred_begin(X), pred_end(X));
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}
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}
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// If there are any loops nested within this loop, create them now!
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for (std::vector<BasicBlock*>::iterator I = L->Blocks.begin(),
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E = L->Blocks.end(); I != E; ++I)
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if (Loop *NewLoop = ConsiderForLoop(*I, DT)) {
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L->SubLoops.push_back(NewLoop);
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NewLoop->ParentLoop = L;
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}
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// Add the basic blocks that comprise this loop to the BBMap so that this
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// loop can be found for them.
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//
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for (std::vector<BasicBlock*>::iterator I = L->Blocks.begin(),
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E = L->Blocks.end(); I != E; ++I) {
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std::map<BasicBlock*, Loop*>::iterator BBMI = BBMap.lower_bound(*I);
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if (BBMI == BBMap.end() || BBMI->first != *I) // Not in map yet...
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BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level
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}
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// Now that we have a list of all of the child loops of this loop, check to
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// see if any of them should actually be nested inside of each other. We can
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// accidentally pull loops our of their parents, so we must make sure to
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// organize the loop nests correctly now.
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{
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std::map<BasicBlock*, Loop*> ContainingLoops;
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for (unsigned i = 0; i != L->SubLoops.size(); ++i) {
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Loop *Child = L->SubLoops[i];
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assert(Child->getParentLoop() == L && "Not proper child loop?");
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if (Loop *ContainingLoop = ContainingLoops[Child->getHeader()]) {
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// If there is already a loop which contains this loop, move this loop
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// into the containing loop.
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MoveSiblingLoopInto(Child, ContainingLoop);
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--i; // The loop got removed from the SubLoops list.
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} else {
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// This is currently considered to be a top-level loop. Check to see if
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// any of the contained blocks are loop headers for subloops we have
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// already processed.
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for (unsigned b = 0, e = Child->Blocks.size(); b != e; ++b) {
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Loop *&BlockLoop = ContainingLoops[Child->Blocks[b]];
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if (BlockLoop == 0) { // Child block not processed yet...
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BlockLoop = Child;
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} else if (BlockLoop != Child) {
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Loop *SubLoop = BlockLoop;
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// Reparent all of the blocks which used to belong to BlockLoops
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for (unsigned j = 0, e = SubLoop->Blocks.size(); j != e; ++j)
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ContainingLoops[SubLoop->Blocks[j]] = Child;
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// There is already a loop which contains this block, that means
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// that we should reparent the loop which the block is currently
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// considered to belong to to be a child of this loop.
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MoveSiblingLoopInto(SubLoop, Child);
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--i; // We just shrunk the SubLoops list.
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}
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}
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}
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}
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}
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return L;
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}
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/// MoveSiblingLoopInto - This method moves the NewChild loop to live inside of
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/// the NewParent Loop, instead of being a sibling of it.
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void LoopInfo::MoveSiblingLoopInto(Loop *NewChild, Loop *NewParent) {
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Loop *OldParent = NewChild->getParentLoop();
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assert(OldParent && OldParent == NewParent->getParentLoop() &&
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NewChild != NewParent && "Not sibling loops!");
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// Remove NewChild from being a child of OldParent
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std::vector<Loop*>::iterator I =
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std::find(OldParent->SubLoops.begin(), OldParent->SubLoops.end(), NewChild);
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assert(I != OldParent->SubLoops.end() && "Parent fields incorrect??");
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OldParent->SubLoops.erase(I); // Remove from parent's subloops list
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NewChild->ParentLoop = 0;
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InsertLoopInto(NewChild, NewParent);
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}
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/// InsertLoopInto - This inserts loop L into the specified parent loop. If the
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/// parent loop contains a loop which should contain L, the loop gets inserted
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/// into L instead.
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void LoopInfo::InsertLoopInto(Loop *L, Loop *Parent) {
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BasicBlock *LHeader = L->getHeader();
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assert(Parent->contains(LHeader) && "This loop should not be inserted here!");
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// Check to see if it belongs in a child loop...
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for (unsigned i = 0, e = Parent->SubLoops.size(); i != e; ++i)
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if (Parent->SubLoops[i]->contains(LHeader)) {
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InsertLoopInto(L, Parent->SubLoops[i]);
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return;
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}
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// If not, insert it here!
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Parent->SubLoops.push_back(L);
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L->ParentLoop = Parent;
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}
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/// changeLoopFor - Change the top-level loop that contains BB to the
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/// specified loop. This should be used by transformations that restructure
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/// the loop hierarchy tree.
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void LoopInfo::changeLoopFor(BasicBlock *BB, Loop *L) {
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Loop *&OldLoop = BBMap[BB];
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assert(OldLoop && "Block not in a loop yet!");
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OldLoop = L;
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}
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/// changeTopLevelLoop - Replace the specified loop in the top-level loops
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/// list with the indicated loop.
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void LoopInfo::changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop) {
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std::vector<Loop*>::iterator I = std::find(TopLevelLoops.begin(),
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TopLevelLoops.end(), OldLoop);
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assert(I != TopLevelLoops.end() && "Old loop not at top level!");
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*I = NewLoop;
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assert(NewLoop->ParentLoop == 0 && OldLoop->ParentLoop == 0 &&
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"Loops already embedded into a subloop!");
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}
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/// removeLoop - This removes the specified top-level loop from this loop info
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/// object. The loop is not deleted, as it will presumably be inserted into
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/// another loop.
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Loop *LoopInfo::removeLoop(iterator I) {
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assert(I != end() && "Cannot remove end iterator!");
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Loop *L = *I;
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assert(L->getParentLoop() == 0 && "Not a top-level loop!");
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TopLevelLoops.erase(TopLevelLoops.begin() + (I-begin()));
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return L;
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}
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/// removeBlock - This method completely removes BB from all data structures,
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/// including all of the Loop objects it is nested in and our mapping from
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/// BasicBlocks to loops.
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void LoopInfo::removeBlock(BasicBlock *BB) {
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std::map<BasicBlock *, Loop*>::iterator I = BBMap.find(BB);
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if (I != BBMap.end()) {
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for (Loop *L = I->second; L; L = L->getParentLoop())
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L->removeBlockFromLoop(BB);
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BBMap.erase(I);
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}
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}
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//===----------------------------------------------------------------------===//
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// APIs for simple analysis of the loop.
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//
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/// getExitingBlocks - Return all blocks inside the loop that have successors
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/// outside of the loop. These are the blocks _inside of the current loop_
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/// which branch out. The returned list is always unique.
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///
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void Loop::getExitingBlocks(SmallVectorImpl<BasicBlock*> &ExitingBlocks) const {
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// Sort the blocks vector so that we can use binary search to do quick
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// lookups.
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SmallVector<BasicBlock*, 128> LoopBBs(block_begin(), block_end());
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std::sort(LoopBBs.begin(), LoopBBs.end());
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for (std::vector<BasicBlock*>::const_iterator BI = Blocks.begin(),
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BE = Blocks.end(); BI != BE; ++BI)
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for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I)
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if (!std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I)) {
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// Not in current loop? It must be an exit block.
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ExitingBlocks.push_back(*BI);
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break;
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}
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}
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/// getExitBlocks - Return all of the successor blocks of this loop. These
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/// are the blocks _outside of the current loop_ which are branched to.
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///
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void Loop::getExitBlocks(SmallVectorImpl<BasicBlock*> &ExitBlocks) const {
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// Sort the blocks vector so that we can use binary search to do quick
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// lookups.
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SmallVector<BasicBlock*, 128> LoopBBs(block_begin(), block_end());
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std::sort(LoopBBs.begin(), LoopBBs.end());
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for (std::vector<BasicBlock*>::const_iterator BI = Blocks.begin(),
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BE = Blocks.end(); BI != BE; ++BI)
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for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I)
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if (!std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
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// Not in current loop? It must be an exit block.
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ExitBlocks.push_back(*I);
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}
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/// getUniqueExitBlocks - Return all unique successor blocks of this loop. These
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/// are the blocks _outside of the current loop_ which are branched to. This
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/// assumes that loop is in canonical form.
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//
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void Loop::getUniqueExitBlocks(SmallVectorImpl<BasicBlock*> &ExitBlocks) const {
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// Sort the blocks vector so that we can use binary search to do quick
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// lookups.
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SmallVector<BasicBlock*, 128> LoopBBs(block_begin(), block_end());
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std::sort(LoopBBs.begin(), LoopBBs.end());
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std::vector<BasicBlock*> switchExitBlocks;
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for (std::vector<BasicBlock*>::const_iterator BI = Blocks.begin(),
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BE = Blocks.end(); BI != BE; ++BI) {
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BasicBlock *current = *BI;
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switchExitBlocks.clear();
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for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I) {
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if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
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// If block is inside the loop then it is not a exit block.
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continue;
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pred_iterator PI = pred_begin(*I);
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BasicBlock *firstPred = *PI;
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// If current basic block is this exit block's first predecessor
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// then only insert exit block in to the output ExitBlocks vector.
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// This ensures that same exit block is not inserted twice into
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// ExitBlocks vector.
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if (current != firstPred)
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continue;
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// If a terminator has more then two successors, for example SwitchInst,
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// then it is possible that there are multiple edges from current block
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// to one exit block.
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if (current->getTerminator()->getNumSuccessors() <= 2) {
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ExitBlocks.push_back(*I);
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continue;
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}
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// In case of multiple edges from current block to exit block, collect
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// only one edge in ExitBlocks. Use switchExitBlocks to keep track of
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// duplicate edges.
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if (std::find(switchExitBlocks.begin(), switchExitBlocks.end(), *I)
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== switchExitBlocks.end()) {
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switchExitBlocks.push_back(*I);
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ExitBlocks.push_back(*I);
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}
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}
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}
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}
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/// getLoopPreheader - If there is a preheader for this loop, return it. A
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/// loop has a preheader if there is only one edge to the header of the loop
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/// from outside of the loop. If this is the case, the block branching to the
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/// header of the loop is the preheader node.
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///
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/// This method returns null if there is no preheader for the loop.
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///
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BasicBlock *Loop::getLoopPreheader() const {
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// Keep track of nodes outside the loop branching to the header...
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BasicBlock *Out = 0;
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// Loop over the predecessors of the header node...
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BasicBlock *Header = getHeader();
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for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
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PI != PE; ++PI)
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if (!contains(*PI)) { // If the block is not in the loop...
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if (Out && Out != *PI)
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return 0; // Multiple predecessors outside the loop
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Out = *PI;
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}
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// Make sure there is only one exit out of the preheader.
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assert(Out && "Header of loop has no predecessors from outside loop?");
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succ_iterator SI = succ_begin(Out);
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++SI;
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if (SI != succ_end(Out))
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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;
|
|
}
|
|
|
|
/// 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.
|
|
BasicBlock *Loop::getLoopLatch() const {
|
|
BasicBlock *Header = getHeader();
|
|
pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
|
|
if (PI == PE) return 0; // no preds?
|
|
|
|
BasicBlock *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.
|
|
///
|
|
PHINode *Loop::getCanonicalInductionVariable() const {
|
|
BasicBlock *H = getHeader();
|
|
|
|
BasicBlock *Incoming = 0, *Backedge = 0;
|
|
pred_iterator PI = pred_begin(H);
|
|
assert(PI != pred_end(H) && "Loop must have at least one backedge!");
|
|
Backedge = *PI++;
|
|
if (PI == pred_end(H)) return 0; // dead loop
|
|
Incoming = *PI++;
|
|
if (PI != pred_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 (BasicBlock::iterator I = H->begin(); isa<PHINode>(I); ++I) {
|
|
PHINode *PN = cast<PHINode>(I);
|
|
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.
|
|
///
|
|
Instruction *Loop::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.
|
|
///
|
|
Value *Loop::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));
|
|
|
|
BasicBlock *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;
|
|
}
|
|
|
|
/// isLCSSAForm - Return true if the Loop is in LCSSA form
|
|
bool Loop::isLCSSAForm() const {
|
|
// Sort the blocks vector so that we can use binary search to do quick
|
|
// lookups.
|
|
SmallPtrSet<BasicBlock*, 16> LoopBBs(block_begin(), block_end());
|
|
|
|
for (block_iterator BI = block_begin(), E = block_end(); BI != E; ++BI) {
|
|
BasicBlock *BB = *BI;
|
|
for (BasicBlock::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) {
|
|
BasicBlock *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;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
//===-------------------------------------------------------------------===//
|
|
// APIs for updating loop information after changing the CFG
|
|
//
|
|
|
|
/// addBasicBlockToLoop - This function 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.
|
|
///
|
|
void Loop::addBasicBlockToLoop(BasicBlock *NewBB, LoopInfo &LI) {
|
|
assert((Blocks.empty() || LI[getHeader()] == this) &&
|
|
"Incorrect LI specified for this loop!");
|
|
assert(NewBB && "Cannot add a null basic block to the loop!");
|
|
assert(LI[NewBB] == 0 && "BasicBlock already in the loop!");
|
|
|
|
// Add the loop mapping to the LoopInfo object...
|
|
LI.BBMap[NewBB] = this;
|
|
|
|
// Add the basic block to this loop and all parent loops...
|
|
Loop *L = this;
|
|
while (L) {
|
|
L->Blocks.push_back(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 pointers of the two loops as appropriate.
|
|
void Loop::replaceChildLoopWith(Loop *OldChild, Loop *NewChild) {
|
|
assert(OldChild->ParentLoop == this && "This loop is already broken!");
|
|
assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
|
|
std::vector<Loop*>::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;
|
|
}
|
|
|
|
/// addChildLoop - Add the specified loop to be a child of this loop.
|
|
///
|
|
void Loop::addChildLoop(Loop *NewChild) {
|
|
assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
|
|
NewChild->ParentLoop = this;
|
|
SubLoops.push_back(NewChild);
|
|
}
|
|
|
|
template<typename T>
|
|
static 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);
|
|
}
|
|
|
|
/// 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.
|
|
Loop *Loop::removeChildLoop(iterator I) {
|
|
assert(I != SubLoops.end() && "Cannot remove end iterator!");
|
|
Loop *Child = *I;
|
|
assert(Child->ParentLoop == this && "Child is not a child of this loop!");
|
|
SubLoops.erase(SubLoops.begin()+(I-begin()));
|
|
Child->ParentLoop = 0;
|
|
return Child;
|
|
}
|
|
|
|
|
|
/// removeBlockFromLoop - This removes the specified basic block from the
|
|
/// current loop, updating the Blocks and ExitBlocks lists as appropriate. This
|
|
/// does not update the mapping in the LoopInfo class.
|
|
void Loop::removeBlockFromLoop(BasicBlock *BB) {
|
|
RemoveFromVector(Blocks, BB);
|
|
}
|
|
|
|
// Ensure this file gets linked when LoopInfo.h is used.
|
|
DEFINING_FILE_FOR(LoopInfo)
|