1 //===- GVNPRE.cpp - Eliminate redundant values and expressions ------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the Owen Anderson and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass performs a hybrid of global value numbering and partial redundancy
11 // elimination, known as GVN-PRE. It performs partial redundancy elimination on
12 // values, rather than lexical expressions, allowing a more comprehensive view
13 // the optimization. It replaces redundant values with uses of earlier
14 // occurences of the same value. While this is beneficial in that it eliminates
15 // unneeded computation, it also increases register pressure by creating large
16 // live ranges, and should be used with caution on platforms that are very
17 // sensitive to register pressure.
19 //===----------------------------------------------------------------------===//
21 #define DEBUG_TYPE "gvnpre"
22 #include "llvm/Value.h"
23 #include "llvm/Transforms/Scalar.h"
24 #include "llvm/Instructions.h"
25 #include "llvm/Function.h"
26 #include "llvm/Analysis/Dominators.h"
27 #include "llvm/Analysis/PostDominators.h"
28 #include "llvm/ADT/DepthFirstIterator.h"
29 #include "llvm/ADT/Statistic.h"
30 #include "llvm/Support/CFG.h"
31 #include "llvm/Support/Compiler.h"
32 #include "llvm/Support/Debug.h"
40 //===----------------------------------------------------------------------===//
42 //===----------------------------------------------------------------------===//
44 /// This class holds the mapping between values and value numbers.
47 class VISIBILITY_HIDDEN ValueTable {
50 enum ExpressionOpcode { ADD, SUB, MUL, UDIV, SDIV, FDIV, UREM, SREM,
51 FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ,
52 ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
53 ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
54 FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
55 FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
56 FCMPULT, FCMPULE, FCMPUNE };
58 ExpressionOpcode opcode;
62 bool operator< (const Expression& other) const {
63 if (opcode < other.opcode)
65 else if (opcode > other.opcode)
67 else if (leftVN < other.leftVN)
69 else if (leftVN > other.leftVN)
71 else if (rightVN < other.rightVN)
73 else if (rightVN > other.rightVN)
81 std::map<Value*, uint32_t> valueNumbering;
82 std::map<Expression, uint32_t> expressionNumbering;
84 std::set<Expression> maximalExpressions;
85 std::set<Value*> maximalValues;
87 uint32_t nextValueNumber;
89 Expression::ExpressionOpcode getOpcode(BinaryOperator* BO);
90 Expression::ExpressionOpcode getOpcode(CmpInst* C);
92 ValueTable() { nextValueNumber = 1; }
93 uint32_t lookup_or_add(Value* V);
94 uint32_t lookup(Value* V);
95 void add(Value* V, uint32_t num);
97 std::set<Expression>& getMaximalExpressions() {
98 return maximalExpressions;
101 std::set<Value*>& getMaximalValues() { return maximalValues; }
102 Expression create_expression(BinaryOperator* BO);
103 Expression create_expression(CmpInst* C);
104 void erase(Value* v);
108 ValueTable::Expression::ExpressionOpcode
109 ValueTable::getOpcode(BinaryOperator* BO) {
110 switch(BO->getOpcode()) {
111 case Instruction::Add:
112 return Expression::ADD;
113 case Instruction::Sub:
114 return Expression::SUB;
115 case Instruction::Mul:
116 return Expression::MUL;
117 case Instruction::UDiv:
118 return Expression::UDIV;
119 case Instruction::SDiv:
120 return Expression::SDIV;
121 case Instruction::FDiv:
122 return Expression::FDIV;
123 case Instruction::URem:
124 return Expression::UREM;
125 case Instruction::SRem:
126 return Expression::SREM;
127 case Instruction::FRem:
128 return Expression::FREM;
129 case Instruction::Shl:
130 return Expression::SHL;
131 case Instruction::LShr:
132 return Expression::LSHR;
133 case Instruction::AShr:
134 return Expression::ASHR;
135 case Instruction::And:
136 return Expression::AND;
137 case Instruction::Or:
138 return Expression::OR;
139 case Instruction::Xor:
140 return Expression::XOR;
142 // THIS SHOULD NEVER HAPPEN
144 assert(0 && "Binary operator with unknown opcode?");
145 return Expression::ADD;
149 ValueTable::Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) {
150 if (C->getOpcode() == Instruction::ICmp) {
151 switch (C->getPredicate()) {
152 case ICmpInst::ICMP_EQ:
153 return Expression::ICMPEQ;
154 case ICmpInst::ICMP_NE:
155 return Expression::ICMPNE;
156 case ICmpInst::ICMP_UGT:
157 return Expression::ICMPUGT;
158 case ICmpInst::ICMP_UGE:
159 return Expression::ICMPUGE;
160 case ICmpInst::ICMP_ULT:
161 return Expression::ICMPULT;
162 case ICmpInst::ICMP_ULE:
163 return Expression::ICMPULE;
164 case ICmpInst::ICMP_SGT:
165 return Expression::ICMPSGT;
166 case ICmpInst::ICMP_SGE:
167 return Expression::ICMPSGE;
168 case ICmpInst::ICMP_SLT:
169 return Expression::ICMPSLT;
170 case ICmpInst::ICMP_SLE:
171 return Expression::ICMPSLE;
173 // THIS SHOULD NEVER HAPPEN
175 assert(0 && "Comparison with unknown predicate?");
176 return Expression::ICMPEQ;
179 switch (C->getPredicate()) {
180 case FCmpInst::FCMP_OEQ:
181 return Expression::FCMPOEQ;
182 case FCmpInst::FCMP_OGT:
183 return Expression::FCMPOGT;
184 case FCmpInst::FCMP_OGE:
185 return Expression::FCMPOGE;
186 case FCmpInst::FCMP_OLT:
187 return Expression::FCMPOLT;
188 case FCmpInst::FCMP_OLE:
189 return Expression::FCMPOLE;
190 case FCmpInst::FCMP_ONE:
191 return Expression::FCMPONE;
192 case FCmpInst::FCMP_ORD:
193 return Expression::FCMPORD;
194 case FCmpInst::FCMP_UNO:
195 return Expression::FCMPUNO;
196 case FCmpInst::FCMP_UEQ:
197 return Expression::FCMPUEQ;
198 case FCmpInst::FCMP_UGT:
199 return Expression::FCMPUGT;
200 case FCmpInst::FCMP_UGE:
201 return Expression::FCMPUGE;
202 case FCmpInst::FCMP_ULT:
203 return Expression::FCMPULT;
204 case FCmpInst::FCMP_ULE:
205 return Expression::FCMPULE;
206 case FCmpInst::FCMP_UNE:
207 return Expression::FCMPUNE;
209 // THIS SHOULD NEVER HAPPEN
211 assert(0 && "Comparison with unknown predicate?");
212 return Expression::FCMPOEQ;
217 uint32_t ValueTable::lookup_or_add(Value* V) {
218 maximalValues.insert(V);
220 std::map<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
221 if (VI != valueNumbering.end())
225 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
226 Expression e = create_expression(BO);
228 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
229 if (EI != expressionNumbering.end()) {
230 valueNumbering.insert(std::make_pair(V, EI->second));
233 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
234 valueNumbering.insert(std::make_pair(V, nextValueNumber));
236 return nextValueNumber++;
238 } else if (CmpInst* C = dyn_cast<CmpInst>(V)) {
239 Expression e = create_expression(C);
241 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
242 if (EI != expressionNumbering.end()) {
243 valueNumbering.insert(std::make_pair(V, EI->second));
246 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
247 valueNumbering.insert(std::make_pair(V, nextValueNumber));
249 return nextValueNumber++;
252 valueNumbering.insert(std::make_pair(V, nextValueNumber));
253 return nextValueNumber++;
257 uint32_t ValueTable::lookup(Value* V) {
258 std::map<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
259 if (VI != valueNumbering.end())
262 assert(0 && "Value not numbered?");
267 void ValueTable::add(Value* V, uint32_t num) {
268 std::map<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
269 if (VI != valueNumbering.end())
270 valueNumbering.erase(VI);
271 valueNumbering.insert(std::make_pair(V, num));
274 ValueTable::Expression ValueTable::create_expression(BinaryOperator* BO) {
277 e.leftVN = lookup_or_add(BO->getOperand(0));
278 e.rightVN = lookup_or_add(BO->getOperand(1));
279 e.opcode = getOpcode(BO);
281 maximalExpressions.insert(e);
286 ValueTable::Expression ValueTable::create_expression(CmpInst* C) {
289 e.leftVN = lookup_or_add(C->getOperand(0));
290 e.rightVN = lookup_or_add(C->getOperand(1));
291 e.opcode = getOpcode(C);
293 maximalExpressions.insert(e);
298 void ValueTable::clear() {
299 valueNumbering.clear();
300 expressionNumbering.clear();
301 maximalExpressions.clear();
302 maximalValues.clear();
306 void ValueTable::erase(Value* V) {
307 maximalValues.erase(V);
308 valueNumbering.erase(V);
309 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V))
310 maximalExpressions.erase(create_expression(BO));
311 else if (CmpInst* C = dyn_cast<CmpInst>(V))
312 maximalExpressions.erase(create_expression(C));
317 class VISIBILITY_HIDDEN GVNPRE : public FunctionPass {
318 bool runOnFunction(Function &F);
320 static char ID; // Pass identification, replacement for typeid
321 GVNPRE() : FunctionPass((intptr_t)&ID) { }
325 std::vector<Instruction*> createdExpressions;
327 std::map<BasicBlock*, std::set<Value*> > availableOut;
328 std::map<BasicBlock*, std::set<Value*> > anticipatedIn;
329 std::map<User*, bool> invokeDep;
331 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
332 AU.setPreservesCFG();
333 AU.addRequired<DominatorTree>();
334 AU.addRequired<PostDominatorTree>();
338 // FIXME: eliminate or document these better
339 void dump(const std::set<Value*>& s) const;
340 void dump_unique(const std::set<Value*>& s) const;
341 void clean(std::set<Value*>& set);
342 Value* find_leader(std::set<Value*>& vals,
344 Value* phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ);
345 void phi_translate_set(std::set<Value*>& anticIn, BasicBlock* pred,
346 BasicBlock* succ, std::set<Value*>& out);
348 void topo_sort(std::set<Value*>& set,
349 std::vector<Value*>& vec);
351 // For a given block, calculate the generated expressions, temporaries,
352 // and the AVAIL_OUT set
356 void val_insert(std::set<Value*>& s, Value* v);
357 void val_replace(std::set<Value*>& s, Value* v);
358 bool dependsOnInvoke(Value* V);
366 FunctionPass *llvm::createGVNPREPass() { return new GVNPRE(); }
368 RegisterPass<GVNPRE> X("gvnpre",
369 "Global Value Numbering/Partial Redundancy Elimination");
372 STATISTIC(NumInsertedVals, "Number of values inserted");
373 STATISTIC(NumInsertedPhis, "Number of PHI nodes inserted");
374 STATISTIC(NumEliminated, "Number of redundant instructions eliminated");
376 Value* GVNPRE::find_leader(std::set<Value*>& vals, uint32_t v) {
377 for (std::set<Value*>::iterator I = vals.begin(), E = vals.end();
379 if (v == VN.lookup(*I))
385 void GVNPRE::val_insert(std::set<Value*>& s, Value* v) {
386 uint32_t num = VN.lookup(v);
387 Value* leader = find_leader(s, num);
392 void GVNPRE::val_replace(std::set<Value*>& s, Value* v) {
393 uint32_t num = VN.lookup(v);
394 Value* leader = find_leader(s, num);
395 while (leader != 0) {
397 leader = find_leader(s, num);
402 Value* GVNPRE::phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) {
406 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
408 if (isa<Instruction>(BO->getOperand(0)))
409 newOp1 = phi_translate(find_leader(anticipatedIn[succ],
410 VN.lookup(BO->getOperand(0))),
413 newOp1 = BO->getOperand(0);
419 if (isa<Instruction>(BO->getOperand(1)))
420 newOp2 = phi_translate(find_leader(anticipatedIn[succ],
421 VN.lookup(BO->getOperand(1))),
424 newOp2 = BO->getOperand(1);
429 if (newOp1 != BO->getOperand(0) || newOp2 != BO->getOperand(1)) {
430 Instruction* newVal = BinaryOperator::create(BO->getOpcode(),
432 BO->getName()+".expr");
434 uint32_t v = VN.lookup_or_add(newVal);
436 Value* leader = find_leader(availableOut[pred], v);
438 createdExpressions.push_back(newVal);
446 } else if (PHINode* P = dyn_cast<PHINode>(V)) {
447 if (P->getParent() == succ)
448 return P->getIncomingValueForBlock(pred);
449 } else if (CmpInst* C = dyn_cast<CmpInst>(V)) {
451 if (isa<Instruction>(C->getOperand(0)))
452 newOp1 = phi_translate(find_leader(anticipatedIn[succ],
453 VN.lookup(C->getOperand(0))),
456 newOp1 = C->getOperand(0);
462 if (isa<Instruction>(C->getOperand(1)))
463 newOp2 = phi_translate(find_leader(anticipatedIn[succ],
464 VN.lookup(C->getOperand(1))),
467 newOp2 = C->getOperand(1);
472 if (newOp1 != C->getOperand(0) || newOp2 != C->getOperand(1)) {
473 Instruction* newVal = CmpInst::create(C->getOpcode(),
476 C->getName()+".expr");
478 uint32_t v = VN.lookup_or_add(newVal);
480 Value* leader = find_leader(availableOut[pred], v);
482 createdExpressions.push_back(newVal);
495 void GVNPRE::phi_translate_set(std::set<Value*>& anticIn,
496 BasicBlock* pred, BasicBlock* succ,
497 std::set<Value*>& out) {
498 for (std::set<Value*>::iterator I = anticIn.begin(),
499 E = anticIn.end(); I != E; ++I) {
500 Value* V = phi_translate(*I, pred, succ);
506 bool GVNPRE::dependsOnInvoke(Value* V) {
507 if (PHINode* p = dyn_cast<PHINode>(V)) {
508 for (PHINode::op_iterator I = p->op_begin(), E = p->op_end(); I != E; ++I)
509 if (isa<InvokeInst>(*I))
517 // Remove all expressions whose operands are not themselves in the set
518 void GVNPRE::clean(std::set<Value*>& set) {
519 std::vector<Value*> worklist;
520 topo_sort(set, worklist);
522 for (unsigned i = 0; i < worklist.size(); ++i) {
523 Value* v = worklist[i];
525 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(v)) {
526 bool lhsValid = !isa<Instruction>(BO->getOperand(0));
528 for (std::set<Value*>::iterator I = set.begin(), E = set.end();
530 if (VN.lookup(*I) == VN.lookup(BO->getOperand(0))) {
535 lhsValid = !dependsOnInvoke(BO->getOperand(0));
537 bool rhsValid = !isa<Instruction>(BO->getOperand(1));
539 for (std::set<Value*>::iterator I = set.begin(), E = set.end();
541 if (VN.lookup(*I) == VN.lookup(BO->getOperand(1))) {
546 rhsValid = !dependsOnInvoke(BO->getOperand(1));
548 if (!lhsValid || !rhsValid)
550 } else if (CmpInst* C = dyn_cast<CmpInst>(v)) {
551 bool lhsValid = !isa<Instruction>(C->getOperand(0));
553 for (std::set<Value*>::iterator I = set.begin(), E = set.end();
555 if (VN.lookup(*I) == VN.lookup(C->getOperand(0))) {
560 lhsValid = !dependsOnInvoke(C->getOperand(0));
562 bool rhsValid = !isa<Instruction>(C->getOperand(1));
564 for (std::set<Value*>::iterator I = set.begin(), E = set.end();
566 if (VN.lookup(*I) == VN.lookup(C->getOperand(1))) {
571 rhsValid = !dependsOnInvoke(C->getOperand(1));
573 if (!lhsValid || !rhsValid)
579 void GVNPRE::topo_sort(std::set<Value*>& set,
580 std::vector<Value*>& vec) {
581 std::set<Value*> toErase;
582 for (std::set<Value*>::iterator I = set.begin(), E = set.end();
584 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(*I))
585 for (std::set<Value*>::iterator SI = set.begin(); SI != E; ++SI) {
586 if (VN.lookup(BO->getOperand(0)) == VN.lookup(*SI) ||
587 VN.lookup(BO->getOperand(1)) == VN.lookup(*SI)) {
591 else if (CmpInst* C = dyn_cast<CmpInst>(*I))
592 for (std::set<Value*>::iterator SI = set.begin(); SI != E; ++SI) {
593 if (VN.lookup(C->getOperand(0)) == VN.lookup(*SI) ||
594 VN.lookup(C->getOperand(1)) == VN.lookup(*SI)) {
600 std::vector<Value*> Q;
601 for (std::set<Value*>::iterator I = set.begin(), E = set.end();
603 if (toErase.find(*I) == toErase.end())
607 std::set<Value*> visited;
611 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(e)) {
612 Value* l = find_leader(set, VN.lookup(BO->getOperand(0)));
613 Value* r = find_leader(set, VN.lookup(BO->getOperand(1)));
615 if (l != 0 && isa<Instruction>(l) &&
616 visited.find(l) == visited.end())
618 else if (r != 0 && isa<Instruction>(r) &&
619 visited.find(r) == visited.end())
626 } else if (CmpInst* C = dyn_cast<CmpInst>(e)) {
627 Value* l = find_leader(set, VN.lookup(C->getOperand(0)));
628 Value* r = find_leader(set, VN.lookup(C->getOperand(1)));
630 if (l != 0 && isa<Instruction>(l) &&
631 visited.find(l) == visited.end())
633 else if (r != 0 && isa<Instruction>(r) &&
634 visited.find(r) == visited.end())
650 void GVNPRE::dump(const std::set<Value*>& s) const {
652 for (std::set<Value*>::iterator I = s.begin(), E = s.end();
659 void GVNPRE::dump_unique(const std::set<Value*>& s) const {
661 for (std::set<Value*>::iterator I = s.begin(), E = s.end();
668 void GVNPRE::elimination() {
669 DOUT << "\n\nPhase 3: Elimination\n\n";
671 std::vector<std::pair<Instruction*, Value*> > replace;
672 std::vector<Instruction*> erase;
674 DominatorTree& DT = getAnalysis<DominatorTree>();
676 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
677 E = df_end(DT.getRootNode()); DI != E; ++DI) {
678 BasicBlock* BB = DI->getBlock();
680 DOUT << "Block: " << BB->getName() << "\n";
681 dump_unique(availableOut[BB]);
684 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
687 if (isa<BinaryOperator>(BI) || isa<CmpInst>(BI)) {
688 Value *leader = find_leader(availableOut[BB], VN.lookup(BI));
691 if (Instruction* Instr = dyn_cast<Instruction>(leader))
692 if (Instr->getParent() != 0 && Instr != BI) {
693 replace.push_back(std::make_pair(BI, leader));
701 while (!replace.empty()) {
702 std::pair<Instruction*, Value*> rep = replace.back();
704 rep.first->replaceAllUsesWith(rep.second);
707 for (std::vector<Instruction*>::iterator I = erase.begin(), E = erase.end();
709 (*I)->eraseFromParent();
713 void GVNPRE::cleanup() {
714 while (!createdExpressions.empty()) {
715 Instruction* I = createdExpressions.back();
716 createdExpressions.pop_back();
722 bool GVNPRE::runOnFunction(Function &F) {
724 createdExpressions.clear();
725 availableOut.clear();
726 anticipatedIn.clear();
729 std::map<BasicBlock*, std::set<Value*> > generatedExpressions;
730 std::map<BasicBlock*, std::set<PHINode*> > generatedPhis;
731 std::map<BasicBlock*, std::set<Value*> > generatedTemporaries;
734 DominatorTree &DT = getAnalysis<DominatorTree>();
736 // Phase 1: BuildSets
738 // Phase 1, Part 1: calculate AVAIL_OUT
740 // Top-down walk of the dominator tree
741 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
742 E = df_end(DT.getRootNode()); DI != E; ++DI) {
744 // Get the sets to update for this block
745 std::set<Value*>& currExps = generatedExpressions[DI->getBlock()];
746 std::set<PHINode*>& currPhis = generatedPhis[DI->getBlock()];
747 std::set<Value*>& currTemps = generatedTemporaries[DI->getBlock()];
748 std::set<Value*>& currAvail = availableOut[DI->getBlock()];
750 BasicBlock* BB = DI->getBlock();
752 // A block inherits AVAIL_OUT from its dominator
753 if (DI->getIDom() != 0)
754 currAvail.insert(availableOut[DI->getIDom()->getBlock()].begin(),
755 availableOut[DI->getIDom()->getBlock()].end());
758 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
761 // Handle PHI nodes...
762 if (PHINode* p = dyn_cast<PHINode>(BI)) {
766 // Handle binary ops...
767 } else if (BinaryOperator* BO = dyn_cast<BinaryOperator>(BI)) {
768 Value* leftValue = BO->getOperand(0);
769 Value* rightValue = BO->getOperand(1);
771 VN.lookup_or_add(BO);
773 if (isa<Instruction>(leftValue))
774 val_insert(currExps, leftValue);
775 if (isa<Instruction>(rightValue))
776 val_insert(currExps, rightValue);
777 val_insert(currExps, BO);
780 } else if (CmpInst* C = dyn_cast<CmpInst>(BI)) {
781 Value* leftValue = C->getOperand(0);
782 Value* rightValue = C->getOperand(1);
786 if (isa<Instruction>(leftValue))
787 val_insert(currExps, leftValue);
788 if (isa<Instruction>(rightValue))
789 val_insert(currExps, rightValue);
790 val_insert(currExps, C);
792 // Handle unsupported ops
793 } else if (!BI->isTerminator()){
794 VN.lookup_or_add(BI);
795 currTemps.insert(BI);
798 if (!BI->isTerminator())
799 val_insert(currAvail, BI);
803 DOUT << "Maximal Set: ";
804 dump_unique(VN.getMaximalValues());
807 // If function has no exit blocks, only perform GVN
808 PostDominatorTree &PDT = getAnalysis<PostDominatorTree>();
809 if (PDT[&F.getEntryBlock()] == 0) {
817 // Phase 1, Part 2: calculate ANTIC_IN
819 std::set<BasicBlock*> visited;
822 unsigned iterations = 0;
825 std::set<Value*> anticOut;
827 // Top-down walk of the postdominator tree
828 for (df_iterator<DomTreeNode*> PDI =
829 df_begin(PDT.getRootNode()), E = df_end(PDT.getRootNode());
831 BasicBlock* BB = PDI->getBlock();
835 DOUT << "Block: " << BB->getName() << "\n";
837 dump(generatedTemporaries[BB]);
841 dump_unique(generatedExpressions[BB]);
844 std::set<Value*>& anticIn = anticipatedIn[BB];
845 std::set<Value*> old (anticIn.begin(), anticIn.end());
847 if (BB->getTerminator()->getNumSuccessors() == 1) {
848 if (visited.find(BB->getTerminator()->getSuccessor(0)) ==
850 phi_translate_set(VN.getMaximalValues(), BB,
851 BB->getTerminator()->getSuccessor(0),
854 phi_translate_set(anticipatedIn[BB->getTerminator()->getSuccessor(0)],
855 BB, BB->getTerminator()->getSuccessor(0),
857 } else if (BB->getTerminator()->getNumSuccessors() > 1) {
858 BasicBlock* first = BB->getTerminator()->getSuccessor(0);
859 anticOut.insert(anticipatedIn[first].begin(),
860 anticipatedIn[first].end());
861 for (unsigned i = 1; i < BB->getTerminator()->getNumSuccessors(); ++i) {
862 BasicBlock* currSucc = BB->getTerminator()->getSuccessor(i);
863 std::set<Value*>& succAnticIn = anticipatedIn[currSucc];
865 std::set<Value*> temp;
866 std::insert_iterator<std::set<Value*> > temp_ins(temp,
868 std::set_intersection(anticOut.begin(), anticOut.end(),
869 succAnticIn.begin(), succAnticIn.end(),
873 anticOut.insert(temp.begin(), temp.end());
877 DOUT << "ANTIC_OUT: ";
878 dump_unique(anticOut);
882 std::insert_iterator<std::set<Value*> > s_ins(S, S.begin());
883 std::set_difference(anticOut.begin(), anticOut.end(),
884 generatedTemporaries[BB].begin(),
885 generatedTemporaries[BB].end(),
889 std::insert_iterator<std::set<Value*> > ai_ins(anticIn, anticIn.begin());
890 std::set_difference(generatedExpressions[BB].begin(),
891 generatedExpressions[BB].end(),
892 generatedTemporaries[BB].begin(),
893 generatedTemporaries[BB].end(),
896 for (std::set<Value*>::iterator I = S.begin(), E = S.end();
898 // For non-opaque values, we should already have a value numbering.
899 // However, for opaques, such as constants within PHI nodes, it is
900 // possible that they have not yet received a number. Make sure they do
903 if (isa<BinaryOperator>(*I) || isa<CmpInst>(*I))
904 valNum = VN.lookup(*I);
906 valNum = VN.lookup_or_add(*I);
907 if (find_leader(anticIn, valNum) == 0)
908 val_insert(anticIn, *I);
913 DOUT << "ANTIC_IN: ";
914 dump_unique(anticIn);
917 if (old.size() != anticIn.size())
926 DOUT << "Iterations: " << iterations << "\n";
928 for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
929 DOUT << "Name: " << I->getName().c_str() << "\n";
932 dump(generatedTemporaries[I]);
936 dump_unique(generatedExpressions[I]);
939 DOUT << "ANTIC_IN: ";
940 dump_unique(anticipatedIn[I]);
943 DOUT << "AVAIL_OUT: ";
944 dump_unique(availableOut[I]);
949 DOUT<< "\nPhase 2: Insertion\n";
951 std::map<BasicBlock*, std::set<Value*> > new_sets;
952 unsigned i_iterations = 0;
953 bool new_stuff = true;
956 DOUT << "Iteration: " << i_iterations << "\n\n";
957 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
958 E = df_end(DT.getRootNode()); DI != E; ++DI) {
959 BasicBlock* BB = DI->getBlock();
964 std::set<Value*>& new_set = new_sets[BB];
965 std::set<Value*>& availOut = availableOut[BB];
966 std::set<Value*>& anticIn = anticipatedIn[BB];
970 // Replace leaders with leaders inherited from dominator
971 if (DI->getIDom() != 0) {
972 std::set<Value*>& dom_set = new_sets[DI->getIDom()->getBlock()];
973 for (std::set<Value*>::iterator I = dom_set.begin(),
974 E = dom_set.end(); I != E; ++I) {
976 val_replace(availOut, *I);
980 // If there is more than one predecessor...
981 if (pred_begin(BB) != pred_end(BB) && ++pred_begin(BB) != pred_end(BB)) {
982 std::vector<Value*> workList;
983 topo_sort(anticIn, workList);
985 DOUT << "Merge Block: " << BB->getName() << "\n";
986 DOUT << "ANTIC_IN: ";
987 dump_unique(anticIn);
990 for (unsigned i = 0; i < workList.size(); ++i) {
991 Value* e = workList[i];
993 if (isa<BinaryOperator>(e) || isa<CmpInst>(e)) {
994 if (find_leader(availableOut[DI->getIDom()->getBlock()], VN.lookup(e)) != 0)
997 std::map<BasicBlock*, Value*> avail;
998 bool by_some = false;
1001 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;
1003 Value *e2 = phi_translate(e, *PI, BB);
1004 Value *e3 = find_leader(availableOut[*PI], VN.lookup(e2));
1007 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1008 if (av != avail.end())
1010 avail.insert(std::make_pair(*PI, e2));
1012 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1013 if (av != avail.end())
1015 avail.insert(std::make_pair(*PI, e3));
1023 num_avail < std::distance(pred_begin(BB), pred_end(BB))) {
1024 DOUT << "Processing Value: ";
1028 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
1030 Value* e2 = avail[*PI];
1031 if (!find_leader(availableOut[*PI], VN.lookup(e2))) {
1032 User* U = cast<User>(e2);
1035 if (isa<BinaryOperator>(U->getOperand(0)) ||
1036 isa<CmpInst>(U->getOperand(0)))
1037 s1 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(0)));
1039 s1 = U->getOperand(0);
1042 if (isa<BinaryOperator>(U->getOperand(1)) ||
1043 isa<CmpInst>(U->getOperand(1)))
1044 s2 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(1)));
1046 s2 = U->getOperand(1);
1049 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
1050 newVal = BinaryOperator::create(BO->getOpcode(),
1052 BO->getName()+".gvnpre",
1053 (*PI)->getTerminator());
1054 else if (CmpInst* C = dyn_cast<CmpInst>(U))
1055 newVal = CmpInst::create(C->getOpcode(),
1058 C->getName()+".gvnpre",
1059 (*PI)->getTerminator());
1061 VN.add(newVal, VN.lookup(U));
1063 std::set<Value*>& predAvail = availableOut[*PI];
1064 val_replace(predAvail, newVal);
1066 DOUT << "Creating value: " << std::hex << newVal << std::dec << "\n";
1068 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1069 if (av != avail.end())
1071 avail.insert(std::make_pair(*PI, newVal));
1079 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
1082 p = new PHINode(avail[*PI]->getType(), "gvnpre-join",
1085 p->addIncoming(avail[*PI], *PI);
1088 VN.add(p, VN.lookup(e));
1089 DOUT << "Creating value: " << std::hex << p << std::dec << "\n";
1091 val_replace(availOut, p);
1096 DOUT << "Preds After Processing: ";
1097 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
1099 DEBUG((*PI)->dump());
1102 DOUT << "Merge Block After Processing: ";
1117 // Phase 3: Eliminate