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;
25 LPPassManager::LPPassManager(int Depth)
26 : FunctionPass(&ID), PMDataManager(Depth) {
33 /// Delete loop from the loop queue and loop hierarchy (LoopInfo).
34 void LPPassManager::deleteLoopFromQueue(Loop *L) {
36 if (Loop *ParentLoop = L->getParentLoop()) { // Not a top-level loop.
37 // Reparent all of the blocks in this loop. Since BBLoop had a parent,
38 // they are now all in it.
39 for (Loop::block_iterator I = L->block_begin(), E = L->block_end();
41 if (LI->getLoopFor(*I) == L) // Don't change blocks in subloops.
42 LI->changeLoopFor(*I, ParentLoop);
44 // Remove the loop from its parent loop.
45 for (Loop::iterator I = ParentLoop->begin(), E = ParentLoop->end();;
47 assert(I != E && "Couldn't find loop");
49 ParentLoop->removeChildLoop(I);
54 // Move all subloops into the parent loop.
56 ParentLoop->addChildLoop(L->removeChildLoop(L->end()-1));
58 // Reparent all of the blocks in this loop. Since BBLoop had no parent,
59 // they no longer in a loop at all.
61 for (unsigned i = 0; i != L->getBlocks().size(); ++i) {
62 // Don't change blocks in subloops.
63 if (LI->getLoopFor(L->getBlocks()[i]) == L) {
64 LI->removeBlock(L->getBlocks()[i]);
69 // Remove the loop from the top-level LoopInfo object.
70 for (LoopInfo::iterator I = LI->begin(), E = LI->end();; ++I) {
71 assert(I != E && "Couldn't find loop");
78 // Move all of the subloops to the top-level.
80 LI->addTopLevelLoop(L->removeChildLoop(L->end()-1));
85 // If L is current loop then skip rest of the passes and let
86 // runOnFunction remove L from LQ. Otherwise, remove L from LQ now
87 // and continue applying other passes on CurrentLoop.
88 if (CurrentLoop == L) {
93 for (std::deque<Loop *>::iterator I = LQ.begin(),
94 E = LQ.end(); I != E; ++I) {
102 // Inset loop into loop nest (LoopInfo) and loop queue (LQ).
103 void LPPassManager::insertLoop(Loop *L, Loop *ParentLoop) {
105 assert (CurrentLoop != L && "Cannot insert CurrentLoop");
107 // Insert into loop nest
109 ParentLoop->addChildLoop(L);
111 LI->addTopLevelLoop(L);
113 // Insert L into loop queue
114 if (L == CurrentLoop)
116 else if (!ParentLoop)
117 // This is top level loop.
120 // Insert L after ParentLoop
121 for (std::deque<Loop *>::iterator I = LQ.begin(),
122 E = LQ.end(); I != E; ++I) {
123 if (*I == ParentLoop) {
124 // deque does not support insert after.
133 // Reoptimize this loop. LPPassManager will re-insert this loop into the
134 // queue. This allows LoopPass to change loop nest for the loop. This
135 // utility may send LPPassManager into infinite loops so use caution.
136 void LPPassManager::redoLoop(Loop *L) {
137 assert (CurrentLoop == L && "Can redo only CurrentLoop");
141 /// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
143 void LPPassManager::cloneBasicBlockSimpleAnalysis(BasicBlock *From,
144 BasicBlock *To, Loop *L) {
145 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
146 Pass *P = getContainedPass(Index);
147 LoopPass *LP = dynamic_cast<LoopPass *>(P);
148 LP->cloneBasicBlockAnalysis(From, To, L);
152 /// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes.
153 void LPPassManager::deleteSimpleAnalysisValue(Value *V, Loop *L) {
154 if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
155 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;
157 Instruction &I = *BI;
158 deleteSimpleAnalysisValue(&I, L);
161 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
162 Pass *P = getContainedPass(Index);
163 LoopPass *LP = dynamic_cast<LoopPass *>(P);
164 LP->deleteAnalysisValue(V, L);
169 // Recurse through all subloops and all loops into LQ.
170 static void addLoopIntoQueue(Loop *L, std::deque<Loop *> &LQ) {
172 for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
173 addLoopIntoQueue(*I, LQ);
176 /// Pass Manager itself does not invalidate any analysis info.
177 void LPPassManager::getAnalysisUsage(AnalysisUsage &Info) const {
178 // LPPassManager needs LoopInfo. In the long term LoopInfo class will
179 // become part of LPPassManager.
180 Info.addRequired<LoopInfo>();
181 Info.setPreservesAll();
184 /// run - Execute all of the passes scheduled for execution. Keep track of
185 /// whether any of the passes modifies the function, and if so, return true.
186 bool LPPassManager::runOnFunction(Function &F) {
187 LI = &getAnalysis<LoopInfo>();
188 bool Changed = false;
190 // Collect inherited analysis from Module level pass manager.
191 populateInheritedAnalysis(TPM->activeStack);
193 // Populate Loop Queue
194 for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
195 addLoopIntoQueue(*I, LQ);
197 if (LQ.empty()) // No loops, skip calling finalizers
201 for (std::deque<Loop *>::const_iterator I = LQ.begin(), E = LQ.end();
204 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
205 Pass *P = getContainedPass(Index);
206 LoopPass *LP = dynamic_cast<LoopPass *>(P);
208 Changed |= LP->doInitialization(L, *this);
213 while (!LQ.empty()) {
215 CurrentLoop = LQ.back();
216 skipThisLoop = false;
217 redoThisLoop = false;
219 // Run all passes on current SCC
220 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
221 Pass *P = getContainedPass(Index);
223 dumpPassInfo(P, EXECUTION_MSG, ON_LOOP_MSG, "");
226 initializeAnalysisImpl(P);
228 LoopPass *LP = dynamic_cast<LoopPass *>(P);
230 PassManagerPrettyStackEntry X(LP, *CurrentLoop->getHeader());
232 assert(LP && "Invalid LPPassManager member");
233 Changed |= LP->runOnLoop(CurrentLoop, *this);
238 dumpPassInfo(P, MODIFICATION_MSG, ON_LOOP_MSG, "");
242 verifyPreservedAnalysis(LP);
244 removeNotPreservedAnalysis(P);
245 recordAvailableAnalysis(P);
246 removeDeadPasses(P, "", ON_LOOP_MSG);
248 // If dominator information is available then verify the info if requested.
249 verifyDomInfo(*LP, F);
252 // Do not run other passes on this loop.
256 // Pop the loop from queue after running all passes.
260 LQ.push_back(CurrentLoop);
264 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
265 Pass *P = getContainedPass(Index);
266 LoopPass *LP = dynamic_cast <LoopPass *>(P);
268 Changed |= LP->doFinalization();
274 /// Print passes managed by this manager
275 void LPPassManager::dumpPassStructure(unsigned Offset) {
276 errs().indent(Offset*2) << "Loop Pass Manager\n";
277 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
278 Pass *P = getContainedPass(Index);
279 P->dumpPassStructure(Offset + 1);
280 dumpLastUses(P, Offset+1);
285 //===----------------------------------------------------------------------===//
288 // Check if this pass is suitable for the current LPPassManager, if
289 // available. This pass P is not suitable for a LPPassManager if P
290 // is not preserving higher level analysis info used by other
291 // LPPassManager passes. In such case, pop LPPassManager from the
292 // stack. This will force assignPassManager() to create new
293 // LPPassManger as expected.
294 void LoopPass::preparePassManager(PMStack &PMS) {
296 // Find LPPassManager
297 while (!PMS.empty() &&
298 PMS.top()->getPassManagerType() > PMT_LoopPassManager)
301 LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
303 // If this pass is destroying high level information that is used
304 // by other passes that are managed by LPM then do not insert
305 // this pass in current LPM. Use new LPPassManager.
306 if (LPPM && !LPPM->preserveHigherLevelAnalysis(this))
310 /// Assign pass manager to manage this pass.
311 void LoopPass::assignPassManager(PMStack &PMS,
312 PassManagerType PreferredType) {
313 // Find LPPassManager
314 while (!PMS.empty() &&
315 PMS.top()->getPassManagerType() > PMT_LoopPassManager)
318 LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
320 // Create new Loop Pass Manager if it does not exist.
323 assert (!PMS.empty() && "Unable to create Loop Pass Manager");
324 PMDataManager *PMD = PMS.top();
326 // [1] Create new Call Graph Pass Manager
327 LPPM = new LPPassManager(PMD->getDepth() + 1);
328 LPPM->populateInheritedAnalysis(PMS);
330 // [2] Set up new manager's top level manager
331 PMTopLevelManager *TPM = PMD->getTopLevelManager();
332 TPM->addIndirectPassManager(LPPM);
334 // [3] Assign manager to manage this new manager. This may create
335 // and push new managers into PMS
336 Pass *P = dynamic_cast<Pass *>(LPPM);
337 TPM->schedulePass(P);
339 // [4] Push new manager into PMS