1 //===- LoopPass.cpp - Loop Pass and Loop Pass Manager ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Devang Patel and is distributed under
6 // the University of Illinois Open Source 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"
20 //===----------------------------------------------------------------------===//
25 // Compare Two loops based on their depth in loop nest.
28 bool operator()( Loop *L1, Loop *L2) const {
29 // Loops with highest depth has the highest priority.
30 return L1->getLoopDepth() < L2->getLoopDepth();
34 // Loop queue used by Loop Pass Manager. This is a wrapper class
35 // that hides implemenation detail (use of priority_queue) inside .cpp file.
38 inline void push(Loop *L) { LPQ.push(L); }
39 inline void pop() { LPQ.pop(); }
40 inline Loop *top() { return LPQ.top(); }
41 inline bool empty() { return LPQ.empty(); }
43 std::priority_queue<Loop *, std::vector<Loop *>, LoopCompare> LPQ;
46 } // End of LLVM namespace
48 //===----------------------------------------------------------------------===//
51 /// LPPassManager manages FPPassManagers and CalLGraphSCCPasses.
53 LPPassManager::LPPassManager(int Depth) : PMDataManager(Depth) {
59 LPPassManager::~LPPassManager() {
63 /// Delete loop from the loop queue. This is used by Loop pass to inform
64 /// Loop Pass Manager that it should skip rest of the passes for this loop.
65 void LPPassManager::deleteLoopFromQueue(Loop *L) {
66 // Do not pop loop from LQ here. It will be done by runOnFunction while loop.
70 // Reoptimize this loop. LPPassManager will re-insert this loop into the
71 // queue. This allows LoopPass to change loop nest for the loop. This
72 // utility may send LPPassManager into infinite loops so use caution.
73 void LPPassManager::redoLoop(Loop *L) {
77 // Recurse through all subloops and all loops into LQ.
78 static void addLoopIntoQueue(Loop *L, LoopQueue *LQ) {
79 for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
80 addLoopIntoQueue(*I, LQ);
84 /// run - Execute all of the passes scheduled for execution. Keep track of
85 /// whether any of the passes modifies the function, and if so, return true.
86 bool LPPassManager::runOnFunction(Function &F) {
87 LoopInfo &LI = getAnalysis<LoopInfo>();
90 // Populate Loop Queue
91 for (LoopInfo::iterator I = LI.begin(), E = LI.end(); I != E; ++I)
92 addLoopIntoQueue(*I, LQ);
94 std::string Msg1 = "Executing Pass '";
95 std::string Msg3 = "' Made Modification '";
98 while (!LQ->empty()) {
101 skipThisLoop = false;
102 redoThisLoop = false;
104 // Run all passes on current SCC
105 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
107 Pass *P = getContainedPass(Index);
108 AnalysisUsage AnUsage;
109 P->getAnalysisUsage(AnUsage);
111 std::string Msg2 = "' on Loop ...\n'";
112 dumpPassInfo(P, Msg1, Msg2);
113 dumpAnalysisSetInfo("Required", P, AnUsage.getRequiredSet());
115 initializeAnalysisImpl(P);
118 LoopPass *LP = dynamic_cast<LoopPass *>(P);
119 assert (LP && "Invalid LPPassManager member");
120 LP->runOnLoop(L, *this);
124 dumpPassInfo(P, Msg3, Msg2);
125 dumpAnalysisSetInfo("Preserved", P, AnUsage.getPreservedSet());
127 removeNotPreservedAnalysis(P);
128 recordAvailableAnalysis(P);
129 removeDeadPasses(P, Msg2);
132 // Do not run other passes on this loop.
136 // Pop the loop from queue after running all passes.
147 //===----------------------------------------------------------------------===//
150 /// Assign pass manager to manage this pass.
151 void LoopPass::assignPassManager(PMStack &PMS,
152 PassManagerType PreferredType) {
153 // Find LPPassManager
154 while (!PMS.empty()) {
155 if (PMS.top()->getPassManagerType() > PMT_LoopPassManager)
161 LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
163 // Create new Loop Pass Manager if it does not exist.
166 assert (!PMS.empty() && "Unable to create Loop Pass Manager");
167 PMDataManager *PMD = PMS.top();
169 // [1] Create new Call Graph Pass Manager
170 LPPM = new LPPassManager(PMD->getDepth() + 1);
172 // [2] Set up new manager's top level manager
173 PMTopLevelManager *TPM = PMD->getTopLevelManager();
174 TPM->addIndirectPassManager(LPPM);
176 // [3] Assign manager to manage this new manager. This may create
177 // and push new managers into PMS
178 Pass *P = dynamic_cast<Pass *>(LPPM);
179 P->assignPassManager(PMS);
181 // [4] Push new manager into PMS