1 //===- LoopPass.cpp - Loop Pass and Loop Pass Manager ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements LoopPass and LPPassManager. All loop optimization
11 // and transformation passes are derived from LoopPass. LPPassManager is
12 // responsible for managing LoopPasses.
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Analysis/LoopPass.h"
19 //===----------------------------------------------------------------------===//
23 char LPPassManager::ID = 0;
24 /// LPPassManager manages FPPassManagers and CalLGraphSCCPasses.
26 LPPassManager::LPPassManager(int Depth)
27 : FunctionPass(&ID), PMDataManager(Depth) {
34 /// Delete loop from the loop queue and loop hierarchy (LoopInfo).
35 void LPPassManager::deleteLoopFromQueue(Loop *L) {
37 if (Loop *ParentLoop = L->getParentLoop()) { // Not a top-level loop.
38 // Reparent all of the blocks in this loop. Since BBLoop had a parent,
39 // they are now all in it.
40 for (Loop::block_iterator I = L->block_begin(), E = L->block_end();
42 if (LI->getLoopFor(*I) == L) // Don't change blocks in subloops.
43 LI->changeLoopFor(*I, ParentLoop);
45 // Remove the loop from its parent loop.
46 for (Loop::iterator I = ParentLoop->begin(), E = ParentLoop->end();;
48 assert(I != E && "Couldn't find loop");
50 ParentLoop->removeChildLoop(I);
55 // Move all subloops into the parent loop.
57 ParentLoop->addChildLoop(L->removeChildLoop(L->end()-1));
59 // Reparent all of the blocks in this loop. Since BBLoop had no parent,
60 // they no longer in a loop at all.
62 for (unsigned i = 0; i != L->getBlocks().size(); ++i) {
63 // Don't change blocks in subloops.
64 if (LI->getLoopFor(L->getBlocks()[i]) == L) {
65 LI->removeBlock(L->getBlocks()[i]);
70 // Remove the loop from the top-level LoopInfo object.
71 for (LoopInfo::iterator I = LI->begin(), E = LI->end();; ++I) {
72 assert(I != E && "Couldn't find loop");
79 // Move all of the subloops to the top-level.
81 LI->addTopLevelLoop(L->removeChildLoop(L->end()-1));
86 // If L is current loop then skip rest of the passes and let
87 // runOnFunction remove L from LQ. Otherwise, remove L from LQ now
88 // and continue applying other passes on CurrentLoop.
89 if (CurrentLoop == L) {
94 for (std::deque<Loop *>::iterator I = LQ.begin(),
95 E = LQ.end(); I != E; ++I) {
103 // Inset loop into loop nest (LoopInfo) and loop queue (LQ).
104 void LPPassManager::insertLoop(Loop *L, Loop *ParentLoop) {
106 assert (CurrentLoop != L && "Cannot insert CurrentLoop");
108 // Insert into loop nest
110 ParentLoop->addChildLoop(L);
112 LI->addTopLevelLoop(L);
114 // Insert L into loop queue
115 if (L == CurrentLoop)
117 else if (!ParentLoop)
118 // This is top level loop.
121 // Insert L after ParentLoop
122 for (std::deque<Loop *>::iterator I = LQ.begin(),
123 E = LQ.end(); I != E; ++I) {
124 if (*I == ParentLoop) {
125 // deque does not support insert after.
134 // Reoptimize this loop. LPPassManager will re-insert this loop into the
135 // queue. This allows LoopPass to change loop nest for the loop. This
136 // utility may send LPPassManager into infinite loops so use caution.
137 void LPPassManager::redoLoop(Loop *L) {
138 assert (CurrentLoop == L && "Can redo only CurrentLoop");
142 /// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
144 void LPPassManager::cloneBasicBlockSimpleAnalysis(BasicBlock *From,
145 BasicBlock *To, Loop *L) {
146 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
147 Pass *P = getContainedPass(Index);
148 LoopPass *LP = dynamic_cast<LoopPass *>(P);
149 LP->cloneBasicBlockAnalysis(From, To, L);
153 /// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes.
154 void LPPassManager::deleteSimpleAnalysisValue(Value *V, Loop *L) {
155 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
156 Pass *P = getContainedPass(Index);
157 LoopPass *LP = dynamic_cast<LoopPass *>(P);
158 LP->deleteAnalysisValue(V, L);
163 // Recurse through all subloops and all loops into LQ.
164 static void addLoopIntoQueue(Loop *L, std::deque<Loop *> &LQ) {
166 for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
167 addLoopIntoQueue(*I, LQ);
170 /// Pass Manager itself does not invalidate any analysis info.
171 void LPPassManager::getAnalysisUsage(AnalysisUsage &Info) const {
172 // LPPassManager needs LoopInfo. In the long term LoopInfo class will
173 // become part of LPPassManager.
174 Info.addRequired<LoopInfo>();
175 Info.setPreservesAll();
178 /// run - Execute all of the passes scheduled for execution. Keep track of
179 /// whether any of the passes modifies the function, and if so, return true.
180 bool LPPassManager::runOnFunction(Function &F) {
181 LI = &getAnalysis<LoopInfo>();
182 bool Changed = false;
184 // Collect inherited analysis from Module level pass manager.
185 populateInheritedAnalysis(TPM->activeStack);
187 // Populate Loop Queue
188 for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
189 addLoopIntoQueue(*I, LQ);
192 for (std::deque<Loop *>::const_iterator I = LQ.begin(), E = LQ.end();
195 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
196 Pass *P = getContainedPass(Index);
197 LoopPass *LP = dynamic_cast<LoopPass *>(P);
199 Changed |= LP->doInitialization(L, *this);
204 while (!LQ.empty()) {
206 CurrentLoop = LQ.back();
207 skipThisLoop = false;
208 redoThisLoop = false;
210 // Run all passes on current SCC
211 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
213 Pass *P = getContainedPass(Index);
215 dumpPassInfo(P, EXECUTION_MSG, ON_LOOP_MSG, "");
218 initializeAnalysisImpl(P);
221 LoopPass *LP = dynamic_cast<LoopPass *>(P);
222 assert (LP && "Invalid LPPassManager member");
223 Changed |= LP->runOnLoop(CurrentLoop, *this);
227 dumpPassInfo(P, MODIFICATION_MSG, ON_LOOP_MSG, "");
230 verifyPreservedAnalysis(LP);
231 removeNotPreservedAnalysis(P);
232 recordAvailableAnalysis(P);
233 removeDeadPasses(P, "", ON_LOOP_MSG);
235 // If dominator information is available then verify the info if requested.
236 verifyDomInfo(*LP, F);
239 // Do not run other passes on this loop.
243 // Pop the loop from queue after running all passes.
247 LQ.push_back(CurrentLoop);
251 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
252 Pass *P = getContainedPass(Index);
253 LoopPass *LP = dynamic_cast <LoopPass *>(P);
255 Changed |= LP->doFinalization();
261 /// Print passes managed by this manager
262 void LPPassManager::dumpPassStructure(unsigned Offset) {
263 llvm::cerr << std::string(Offset*2, ' ') << "Loop Pass Manager\n";
264 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
265 Pass *P = getContainedPass(Index);
266 P->dumpPassStructure(Offset + 1);
267 dumpLastUses(P, Offset+1);
272 //===----------------------------------------------------------------------===//
275 // Check if this pass is suitable for the current LPPassManager, if
276 // available. This pass P is not suitable for a LPPassManager if P
277 // is not preserving higher level analysis info used by other
278 // LPPassManager passes. In such case, pop LPPassManager from the
279 // stack. This will force assignPassManager() to create new
280 // LPPassManger as expected.
281 void LoopPass::preparePassManager(PMStack &PMS) {
283 // Find LPPassManager
284 while (!PMS.empty() &&
285 PMS.top()->getPassManagerType() > PMT_LoopPassManager)
288 LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
290 // If this pass is destroying high level information that is used
291 // by other passes that are managed by LPM then do not insert
292 // this pass in current LPM. Use new LPPassManager.
293 if (LPPM && !LPPM->preserveHigherLevelAnalysis(this))
297 /// Assign pass manager to manage this pass.
298 void LoopPass::assignPassManager(PMStack &PMS,
299 PassManagerType PreferredType) {
300 // Find LPPassManager
301 while (!PMS.empty() &&
302 PMS.top()->getPassManagerType() > PMT_LoopPassManager)
305 LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
307 // Create new Loop Pass Manager if it does not exist.
310 assert (!PMS.empty() && "Unable to create Loop Pass Manager");
311 PMDataManager *PMD = PMS.top();
313 // [1] Create new Call Graph Pass Manager
314 LPPM = new LPPassManager(PMD->getDepth() + 1);
315 LPPM->populateInheritedAnalysis(PMS);
317 // [2] Set up new manager's top level manager
318 PMTopLevelManager *TPM = PMD->getTopLevelManager();
319 TPM->addIndirectPassManager(LPPM);
321 // [3] Assign manager to manage this new manager. This may create
322 // and push new managers into PMS
323 Pass *P = dynamic_cast<Pass *>(LPPM);
324 TPM->schedulePass(P);
326 // [4] Push new manager into PMS