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/DerivedTypes.h"
27 #include "llvm/Analysis/Dominators.h"
28 #include "llvm/ADT/BitVector.h"
29 #include "llvm/ADT/DenseMap.h"
30 #include "llvm/ADT/DepthFirstIterator.h"
31 #include "llvm/ADT/PostOrderIterator.h"
32 #include "llvm/ADT/SmallPtrSet.h"
33 #include "llvm/ADT/Statistic.h"
34 #include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
35 #include "llvm/Support/CFG.h"
36 #include "llvm/Support/Compiler.h"
37 #include "llvm/Support/Debug.h"
45 //===----------------------------------------------------------------------===//
47 //===----------------------------------------------------------------------===//
49 /// This class holds the mapping between values and value numbers. It is used
50 /// as an efficient mechanism to determine the expression-wise equivalence of
54 class VISIBILITY_HIDDEN ValueTable {
57 enum ExpressionOpcode { ADD, SUB, MUL, UDIV, SDIV, FDIV, UREM, SREM,
58 FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ,
59 ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
60 ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
61 FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
62 FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
63 FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
64 SHUFFLE, SELECT, TRUNC, ZEXT, SEXT, FPTOUI,
65 FPTOSI, UITOFP, SITOFP, FPTRUNC, FPEXT,
66 PTRTOINT, INTTOPTR, BITCAST, GEP};
68 ExpressionOpcode opcode;
73 std::vector<uint32_t> varargs;
75 bool operator< (const Expression& other) const {
76 if (opcode < other.opcode)
78 else if (opcode > other.opcode)
80 else if (type < other.type)
82 else if (type > other.type)
84 else if (firstVN < other.firstVN)
86 else if (firstVN > other.firstVN)
88 else if (secondVN < other.secondVN)
90 else if (secondVN > other.secondVN)
92 else if (thirdVN < other.thirdVN)
94 else if (thirdVN > other.thirdVN)
97 if (varargs.size() < other.varargs.size())
99 else if (varargs.size() > other.varargs.size())
102 for (size_t i = 0; i < varargs.size(); ++i)
103 if (varargs[i] < other.varargs[i])
105 else if (varargs[i] > other.varargs[i])
114 DenseMap<Value*, uint32_t> valueNumbering;
115 std::map<Expression, uint32_t> expressionNumbering;
117 uint32_t nextValueNumber;
119 Expression::ExpressionOpcode getOpcode(BinaryOperator* BO);
120 Expression::ExpressionOpcode getOpcode(CmpInst* C);
121 Expression::ExpressionOpcode getOpcode(CastInst* C);
122 Expression create_expression(BinaryOperator* BO);
123 Expression create_expression(CmpInst* C);
124 Expression create_expression(ShuffleVectorInst* V);
125 Expression create_expression(ExtractElementInst* C);
126 Expression create_expression(InsertElementInst* V);
127 Expression create_expression(SelectInst* V);
128 Expression create_expression(CastInst* C);
129 Expression create_expression(GetElementPtrInst* G);
131 ValueTable() { nextValueNumber = 1; }
132 uint32_t lookup_or_add(Value* V);
133 uint32_t lookup(Value* V) const;
134 void add(Value* V, uint32_t num);
136 void erase(Value* v);
141 //===----------------------------------------------------------------------===//
142 // ValueTable Internal Functions
143 //===----------------------------------------------------------------------===//
144 ValueTable::Expression::ExpressionOpcode
145 ValueTable::getOpcode(BinaryOperator* BO) {
146 switch(BO->getOpcode()) {
147 case Instruction::Add:
148 return Expression::ADD;
149 case Instruction::Sub:
150 return Expression::SUB;
151 case Instruction::Mul:
152 return Expression::MUL;
153 case Instruction::UDiv:
154 return Expression::UDIV;
155 case Instruction::SDiv:
156 return Expression::SDIV;
157 case Instruction::FDiv:
158 return Expression::FDIV;
159 case Instruction::URem:
160 return Expression::UREM;
161 case Instruction::SRem:
162 return Expression::SREM;
163 case Instruction::FRem:
164 return Expression::FREM;
165 case Instruction::Shl:
166 return Expression::SHL;
167 case Instruction::LShr:
168 return Expression::LSHR;
169 case Instruction::AShr:
170 return Expression::ASHR;
171 case Instruction::And:
172 return Expression::AND;
173 case Instruction::Or:
174 return Expression::OR;
175 case Instruction::Xor:
176 return Expression::XOR;
178 // THIS SHOULD NEVER HAPPEN
180 assert(0 && "Binary operator with unknown opcode?");
181 return Expression::ADD;
185 ValueTable::Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) {
186 if (C->getOpcode() == Instruction::ICmp) {
187 switch (C->getPredicate()) {
188 case ICmpInst::ICMP_EQ:
189 return Expression::ICMPEQ;
190 case ICmpInst::ICMP_NE:
191 return Expression::ICMPNE;
192 case ICmpInst::ICMP_UGT:
193 return Expression::ICMPUGT;
194 case ICmpInst::ICMP_UGE:
195 return Expression::ICMPUGE;
196 case ICmpInst::ICMP_ULT:
197 return Expression::ICMPULT;
198 case ICmpInst::ICMP_ULE:
199 return Expression::ICMPULE;
200 case ICmpInst::ICMP_SGT:
201 return Expression::ICMPSGT;
202 case ICmpInst::ICMP_SGE:
203 return Expression::ICMPSGE;
204 case ICmpInst::ICMP_SLT:
205 return Expression::ICMPSLT;
206 case ICmpInst::ICMP_SLE:
207 return Expression::ICMPSLE;
209 // THIS SHOULD NEVER HAPPEN
211 assert(0 && "Comparison with unknown predicate?");
212 return Expression::ICMPEQ;
215 switch (C->getPredicate()) {
216 case FCmpInst::FCMP_OEQ:
217 return Expression::FCMPOEQ;
218 case FCmpInst::FCMP_OGT:
219 return Expression::FCMPOGT;
220 case FCmpInst::FCMP_OGE:
221 return Expression::FCMPOGE;
222 case FCmpInst::FCMP_OLT:
223 return Expression::FCMPOLT;
224 case FCmpInst::FCMP_OLE:
225 return Expression::FCMPOLE;
226 case FCmpInst::FCMP_ONE:
227 return Expression::FCMPONE;
228 case FCmpInst::FCMP_ORD:
229 return Expression::FCMPORD;
230 case FCmpInst::FCMP_UNO:
231 return Expression::FCMPUNO;
232 case FCmpInst::FCMP_UEQ:
233 return Expression::FCMPUEQ;
234 case FCmpInst::FCMP_UGT:
235 return Expression::FCMPUGT;
236 case FCmpInst::FCMP_UGE:
237 return Expression::FCMPUGE;
238 case FCmpInst::FCMP_ULT:
239 return Expression::FCMPULT;
240 case FCmpInst::FCMP_ULE:
241 return Expression::FCMPULE;
242 case FCmpInst::FCMP_UNE:
243 return Expression::FCMPUNE;
245 // THIS SHOULD NEVER HAPPEN
247 assert(0 && "Comparison with unknown predicate?");
248 return Expression::FCMPOEQ;
253 ValueTable::Expression::ExpressionOpcode
254 ValueTable::getOpcode(CastInst* C) {
255 switch(C->getOpcode()) {
256 case Instruction::Trunc:
257 return Expression::TRUNC;
258 case Instruction::ZExt:
259 return Expression::ZEXT;
260 case Instruction::SExt:
261 return Expression::SEXT;
262 case Instruction::FPToUI:
263 return Expression::FPTOUI;
264 case Instruction::FPToSI:
265 return Expression::FPTOSI;
266 case Instruction::UIToFP:
267 return Expression::UITOFP;
268 case Instruction::SIToFP:
269 return Expression::SITOFP;
270 case Instruction::FPTrunc:
271 return Expression::FPTRUNC;
272 case Instruction::FPExt:
273 return Expression::FPEXT;
274 case Instruction::PtrToInt:
275 return Expression::PTRTOINT;
276 case Instruction::IntToPtr:
277 return Expression::INTTOPTR;
278 case Instruction::BitCast:
279 return Expression::BITCAST;
281 // THIS SHOULD NEVER HAPPEN
283 assert(0 && "Cast operator with unknown opcode?");
284 return Expression::BITCAST;
288 ValueTable::Expression ValueTable::create_expression(BinaryOperator* BO) {
291 e.firstVN = lookup_or_add(BO->getOperand(0));
292 e.secondVN = lookup_or_add(BO->getOperand(1));
294 e.type = BO->getType();
295 e.opcode = getOpcode(BO);
300 ValueTable::Expression ValueTable::create_expression(CmpInst* C) {
303 e.firstVN = lookup_or_add(C->getOperand(0));
304 e.secondVN = lookup_or_add(C->getOperand(1));
306 e.type = C->getType();
307 e.opcode = getOpcode(C);
312 ValueTable::Expression ValueTable::create_expression(CastInst* C) {
315 e.firstVN = lookup_or_add(C->getOperand(0));
318 e.type = C->getType();
319 e.opcode = getOpcode(C);
324 ValueTable::Expression ValueTable::create_expression(ShuffleVectorInst* S) {
327 e.firstVN = lookup_or_add(S->getOperand(0));
328 e.secondVN = lookup_or_add(S->getOperand(1));
329 e.thirdVN = lookup_or_add(S->getOperand(2));
330 e.type = S->getType();
331 e.opcode = Expression::SHUFFLE;
336 ValueTable::Expression ValueTable::create_expression(ExtractElementInst* E) {
339 e.firstVN = lookup_or_add(E->getOperand(0));
340 e.secondVN = lookup_or_add(E->getOperand(1));
342 e.type = E->getType();
343 e.opcode = Expression::EXTRACT;
348 ValueTable::Expression ValueTable::create_expression(InsertElementInst* I) {
351 e.firstVN = lookup_or_add(I->getOperand(0));
352 e.secondVN = lookup_or_add(I->getOperand(1));
353 e.thirdVN = lookup_or_add(I->getOperand(2));
354 e.type = I->getType();
355 e.opcode = Expression::INSERT;
360 ValueTable::Expression ValueTable::create_expression(SelectInst* I) {
363 e.firstVN = lookup_or_add(I->getCondition());
364 e.secondVN = lookup_or_add(I->getTrueValue());
365 e.thirdVN = lookup_or_add(I->getFalseValue());
366 e.type = I->getType();
367 e.opcode = Expression::SELECT;
372 ValueTable::Expression ValueTable::create_expression(GetElementPtrInst* G) {
375 e.firstVN = lookup_or_add(G->getPointerOperand());
378 e.type = G->getType();
379 e.opcode = Expression::SELECT;
381 for (GetElementPtrInst::op_iterator I = G->idx_begin(), E = G->idx_end();
383 e.varargs.push_back(lookup_or_add(*I));
388 //===----------------------------------------------------------------------===//
389 // ValueTable External Functions
390 //===----------------------------------------------------------------------===//
392 /// lookup_or_add - Returns the value number for the specified value, assigning
393 /// it a new number if it did not have one before.
394 uint32_t ValueTable::lookup_or_add(Value* V) {
395 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
396 if (VI != valueNumbering.end())
400 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
401 Expression e = create_expression(BO);
403 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
404 if (EI != expressionNumbering.end()) {
405 valueNumbering.insert(std::make_pair(V, EI->second));
408 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
409 valueNumbering.insert(std::make_pair(V, nextValueNumber));
411 return nextValueNumber++;
413 } else if (CmpInst* C = dyn_cast<CmpInst>(V)) {
414 Expression e = create_expression(C);
416 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
417 if (EI != expressionNumbering.end()) {
418 valueNumbering.insert(std::make_pair(V, EI->second));
421 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
422 valueNumbering.insert(std::make_pair(V, nextValueNumber));
424 return nextValueNumber++;
426 } else if (ShuffleVectorInst* U = dyn_cast<ShuffleVectorInst>(V)) {
427 Expression e = create_expression(U);
429 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
430 if (EI != expressionNumbering.end()) {
431 valueNumbering.insert(std::make_pair(V, EI->second));
434 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
435 valueNumbering.insert(std::make_pair(V, nextValueNumber));
437 return nextValueNumber++;
439 } else if (ExtractElementInst* U = dyn_cast<ExtractElementInst>(V)) {
440 Expression e = create_expression(U);
442 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
443 if (EI != expressionNumbering.end()) {
444 valueNumbering.insert(std::make_pair(V, EI->second));
447 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
448 valueNumbering.insert(std::make_pair(V, nextValueNumber));
450 return nextValueNumber++;
452 } else if (InsertElementInst* U = dyn_cast<InsertElementInst>(V)) {
453 Expression e = create_expression(U);
455 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
456 if (EI != expressionNumbering.end()) {
457 valueNumbering.insert(std::make_pair(V, EI->second));
460 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
461 valueNumbering.insert(std::make_pair(V, nextValueNumber));
463 return nextValueNumber++;
465 } else if (SelectInst* U = dyn_cast<SelectInst>(V)) {
466 Expression e = create_expression(U);
468 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
469 if (EI != expressionNumbering.end()) {
470 valueNumbering.insert(std::make_pair(V, EI->second));
473 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
474 valueNumbering.insert(std::make_pair(V, nextValueNumber));
476 return nextValueNumber++;
478 } else if (CastInst* U = dyn_cast<CastInst>(V)) {
479 Expression e = create_expression(U);
481 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
482 if (EI != expressionNumbering.end()) {
483 valueNumbering.insert(std::make_pair(V, EI->second));
486 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
487 valueNumbering.insert(std::make_pair(V, nextValueNumber));
489 return nextValueNumber++;
491 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
492 Expression e = create_expression(U);
494 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
495 if (EI != expressionNumbering.end()) {
496 valueNumbering.insert(std::make_pair(V, EI->second));
499 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
500 valueNumbering.insert(std::make_pair(V, nextValueNumber));
502 return nextValueNumber++;
505 valueNumbering.insert(std::make_pair(V, nextValueNumber));
506 return nextValueNumber++;
510 /// lookup - Returns the value number of the specified value. Fails if
511 /// the value has not yet been numbered.
512 uint32_t ValueTable::lookup(Value* V) const {
513 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
514 if (VI != valueNumbering.end())
517 assert(0 && "Value not numbered?");
522 /// add - Add the specified value with the given value number, removing
523 /// its old number, if any
524 void ValueTable::add(Value* V, uint32_t num) {
525 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
526 if (VI != valueNumbering.end())
527 valueNumbering.erase(VI);
528 valueNumbering.insert(std::make_pair(V, num));
531 /// clear - Remove all entries from the ValueTable
532 void ValueTable::clear() {
533 valueNumbering.clear();
534 expressionNumbering.clear();
538 /// erase - Remove a value from the value numbering
539 void ValueTable::erase(Value* V) {
540 valueNumbering.erase(V);
543 /// size - Return the number of assigned value numbers
544 unsigned ValueTable::size() {
545 // NOTE: zero is never assigned
546 return nextValueNumber;
549 //===----------------------------------------------------------------------===//
550 // ValueNumberedSet Class
551 //===----------------------------------------------------------------------===//
553 class ValueNumberedSet {
555 SmallPtrSet<Value*, 8> contents;
558 ValueNumberedSet() { numbers.resize(1); }
560 typedef SmallPtrSet<Value*, 8>::iterator iterator;
562 iterator begin() { return contents.begin(); }
563 iterator end() { return contents.end(); }
565 bool insert(Value* v) { return contents.insert(v); }
566 void insert(iterator I, iterator E) { contents.insert(I, E); }
567 void erase(Value* v) { contents.erase(v); }
568 size_t size() { return contents.size(); }
570 void set(unsigned i) {
571 if (i >= numbers.size())
577 void operator=(const ValueNumberedSet& other) {
578 contents = other.contents;
579 numbers = other.numbers;
582 void reset(unsigned i) {
583 if (i < numbers.size())
587 bool test(unsigned i) {
588 if (i >= numbers.size())
591 return numbers.test(i);
600 //===----------------------------------------------------------------------===//
602 //===----------------------------------------------------------------------===//
606 class VISIBILITY_HIDDEN GVNPRE : public FunctionPass {
607 bool runOnFunction(Function &F);
609 static char ID; // Pass identification, replacement for typeid
610 GVNPRE() : FunctionPass((intptr_t)&ID) { }
614 std::vector<Instruction*> createdExpressions;
616 std::map<BasicBlock*, ValueNumberedSet> availableOut;
617 std::map<BasicBlock*, ValueNumberedSet> anticipatedIn;
618 std::map<BasicBlock*, ValueNumberedSet> generatedPhis;
620 // This transformation requires dominator postdominator info
621 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
622 AU.setPreservesCFG();
623 AU.addRequiredID(BreakCriticalEdgesID);
624 AU.addRequired<UnifyFunctionExitNodes>();
625 AU.addRequired<DominatorTree>();
629 // FIXME: eliminate or document these better
630 void dump(ValueNumberedSet& s) const ;
631 void clean(ValueNumberedSet& set) ;
632 Value* find_leader(ValueNumberedSet& vals, uint32_t v) ;
633 Value* phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) ;
634 void phi_translate_set(ValueNumberedSet& anticIn, BasicBlock* pred,
635 BasicBlock* succ, ValueNumberedSet& out) ;
637 void topo_sort(ValueNumberedSet& set,
638 std::vector<Value*>& vec) ;
643 void val_insert(ValueNumberedSet& s, Value* v) ;
644 void val_replace(ValueNumberedSet& s, Value* v) ;
645 bool dependsOnInvoke(Value* V) ;
646 void buildsets_availout(BasicBlock::iterator I,
647 ValueNumberedSet& currAvail,
648 ValueNumberedSet& currPhis,
649 ValueNumberedSet& currExps,
650 SmallPtrSet<Value*, 16>& currTemps) ;
651 bool buildsets_anticout(BasicBlock* BB,
652 ValueNumberedSet& anticOut,
653 std::set<BasicBlock*>& visited) ;
654 unsigned buildsets_anticin(BasicBlock* BB,
655 ValueNumberedSet& anticOut,
656 ValueNumberedSet& currExps,
657 SmallPtrSet<Value*, 16>& currTemps,
658 std::set<BasicBlock*>& visited) ;
659 void buildsets(Function& F) ;
661 void insertion_pre(Value* e, BasicBlock* BB,
662 std::map<BasicBlock*, Value*>& avail,
663 std::map<BasicBlock*,ValueNumberedSet>& new_set) ;
664 unsigned insertion_mergepoint(std::vector<Value*>& workList,
665 df_iterator<DomTreeNode*>& D,
666 std::map<BasicBlock*, ValueNumberedSet>& new_set) ;
667 bool insertion(Function& F) ;
675 // createGVNPREPass - The public interface to this file...
676 FunctionPass *llvm::createGVNPREPass() { return new GVNPRE(); }
678 RegisterPass<GVNPRE> X("gvnpre",
679 "Global Value Numbering/Partial Redundancy Elimination");
682 STATISTIC(NumInsertedVals, "Number of values inserted");
683 STATISTIC(NumInsertedPhis, "Number of PHI nodes inserted");
684 STATISTIC(NumEliminated, "Number of redundant instructions eliminated");
686 /// find_leader - Given a set and a value number, return the first
687 /// element of the set with that value number, or 0 if no such element
689 Value* GVNPRE::find_leader(ValueNumberedSet& vals, uint32_t v) {
693 for (ValueNumberedSet::iterator I = vals.begin(), E = vals.end();
695 if (v == VN.lookup(*I))
701 /// val_insert - Insert a value into a set only if there is not a value
702 /// with the same value number already in the set
703 void GVNPRE::val_insert(ValueNumberedSet& s, Value* v) {
704 uint32_t num = VN.lookup(v);
709 /// val_replace - Insert a value into a set, replacing any values already in
710 /// the set that have the same value number
711 void GVNPRE::val_replace(ValueNumberedSet& s, Value* v) {
712 uint32_t num = VN.lookup(v);
713 Value* leader = find_leader(s, num);
720 /// phi_translate - Given a value, its parent block, and a predecessor of its
721 /// parent, translate the value into legal for the predecessor block. This
722 /// means translating its operands (and recursively, their operands) through
723 /// any phi nodes in the parent into values available in the predecessor
724 Value* GVNPRE::phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) {
729 if (CastInst* U = dyn_cast<CastInst>(V)) {
731 if (isa<Instruction>(U->getOperand(0)))
732 newOp1 = phi_translate(U->getOperand(0), pred, succ);
734 newOp1 = U->getOperand(0);
739 if (newOp1 != U->getOperand(0)) {
740 Instruction* newVal = 0;
741 if (CastInst* C = dyn_cast<CastInst>(U))
742 newVal = CastInst::create(C->getOpcode(),
743 newOp1, C->getType(),
744 C->getName()+".expr");
746 uint32_t v = VN.lookup_or_add(newVal);
748 Value* leader = find_leader(availableOut[pred], v);
750 createdExpressions.push_back(newVal);
760 } if (isa<BinaryOperator>(V) || isa<CmpInst>(V) ||
761 isa<ExtractElementInst>(V)) {
762 User* U = cast<User>(V);
765 if (isa<Instruction>(U->getOperand(0)))
766 newOp1 = phi_translate(U->getOperand(0), pred, succ);
768 newOp1 = U->getOperand(0);
774 if (isa<Instruction>(U->getOperand(1)))
775 newOp2 = phi_translate(U->getOperand(1), pred, succ);
777 newOp2 = U->getOperand(1);
782 if (newOp1 != U->getOperand(0) || newOp2 != U->getOperand(1)) {
783 Instruction* newVal = 0;
784 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
785 newVal = BinaryOperator::create(BO->getOpcode(),
787 BO->getName()+".expr");
788 else if (CmpInst* C = dyn_cast<CmpInst>(U))
789 newVal = CmpInst::create(C->getOpcode(),
792 C->getName()+".expr");
793 else if (ExtractElementInst* E = dyn_cast<ExtractElementInst>(U))
794 newVal = new ExtractElementInst(newOp1, newOp2, E->getName()+".expr");
796 uint32_t v = VN.lookup_or_add(newVal);
798 Value* leader = find_leader(availableOut[pred], v);
800 createdExpressions.push_back(newVal);
809 // Ternary Operations
810 } else if (isa<ShuffleVectorInst>(V) || isa<InsertElementInst>(V) ||
811 isa<SelectInst>(V)) {
812 User* U = cast<User>(V);
815 if (isa<Instruction>(U->getOperand(0)))
816 newOp1 = phi_translate(U->getOperand(0), pred, succ);
818 newOp1 = U->getOperand(0);
824 if (isa<Instruction>(U->getOperand(1)))
825 newOp2 = phi_translate(U->getOperand(1), pred, succ);
827 newOp2 = U->getOperand(1);
833 if (isa<Instruction>(U->getOperand(2)))
834 newOp3 = phi_translate(U->getOperand(2), pred, succ);
836 newOp3 = U->getOperand(2);
841 if (newOp1 != U->getOperand(0) ||
842 newOp2 != U->getOperand(1) ||
843 newOp3 != U->getOperand(2)) {
844 Instruction* newVal = 0;
845 if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
846 newVal = new ShuffleVectorInst(newOp1, newOp2, newOp3,
847 S->getName()+".expr");
848 else if (InsertElementInst* I = dyn_cast<InsertElementInst>(U))
849 newVal = new InsertElementInst(newOp1, newOp2, newOp3,
850 I->getName()+".expr");
851 else if (SelectInst* I = dyn_cast<SelectInst>(U))
852 newVal = new SelectInst(newOp1, newOp2, newOp3, I->getName()+".expr");
854 uint32_t v = VN.lookup_or_add(newVal);
856 Value* leader = find_leader(availableOut[pred], v);
858 createdExpressions.push_back(newVal);
868 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
870 if (isa<Instruction>(U->getPointerOperand()))
871 newOp1 = phi_translate(U->getPointerOperand(), pred, succ);
873 newOp1 = U->getPointerOperand();
878 bool changed_idx = false;
879 std::vector<Value*> newIdx;
880 for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
882 if (isa<Instruction>(*I)) {
883 Value* newVal = phi_translate(*I, pred, succ);
884 newIdx.push_back(newVal);
888 newIdx.push_back(*I);
891 if (newOp1 != U->getPointerOperand() || changed_idx) {
892 Instruction* newVal = new GetElementPtrInst(newOp1,
893 &newIdx[0], newIdx.size(),
894 U->getName()+".expr");
896 uint32_t v = VN.lookup_or_add(newVal);
898 Value* leader = find_leader(availableOut[pred], v);
900 createdExpressions.push_back(newVal);
910 } else if (PHINode* P = dyn_cast<PHINode>(V)) {
911 if (P->getParent() == succ)
912 return P->getIncomingValueForBlock(pred);
918 /// phi_translate_set - Perform phi translation on every element of a set
919 void GVNPRE::phi_translate_set(ValueNumberedSet& anticIn,
920 BasicBlock* pred, BasicBlock* succ,
921 ValueNumberedSet& out) {
922 for (ValueNumberedSet::iterator I = anticIn.begin(),
923 E = anticIn.end(); I != E; ++I) {
924 Value* V = phi_translate(*I, pred, succ);
925 if (V != 0 && !out.test(VN.lookup_or_add(V))) {
927 out.set(VN.lookup(V));
932 /// dependsOnInvoke - Test if a value has an phi node as an operand, any of
933 /// whose inputs is an invoke instruction. If this is true, we cannot safely
934 /// PRE the instruction or anything that depends on it.
935 bool GVNPRE::dependsOnInvoke(Value* V) {
936 if (PHINode* p = dyn_cast<PHINode>(V)) {
937 for (PHINode::op_iterator I = p->op_begin(), E = p->op_end(); I != E; ++I)
938 if (isa<InvokeInst>(*I))
946 /// clean - Remove all non-opaque values from the set whose operands are not
947 /// themselves in the set, as well as all values that depend on invokes (see
949 void GVNPRE::clean(ValueNumberedSet& set) {
950 std::vector<Value*> worklist;
951 worklist.reserve(set.size());
952 topo_sort(set, worklist);
954 for (unsigned i = 0; i < worklist.size(); ++i) {
955 Value* v = worklist[i];
958 if (CastInst* U = dyn_cast<CastInst>(v)) {
959 bool lhsValid = !isa<Instruction>(U->getOperand(0));
960 lhsValid |= set.test(VN.lookup(U->getOperand(0)));
962 lhsValid = !dependsOnInvoke(U->getOperand(0));
966 set.reset(VN.lookup(U));
970 } else if (isa<BinaryOperator>(v) || isa<CmpInst>(v) ||
971 isa<ExtractElementInst>(v)) {
972 User* U = cast<User>(v);
974 bool lhsValid = !isa<Instruction>(U->getOperand(0));
975 lhsValid |= set.test(VN.lookup(U->getOperand(0)));
977 lhsValid = !dependsOnInvoke(U->getOperand(0));
979 bool rhsValid = !isa<Instruction>(U->getOperand(1));
980 rhsValid |= set.test(VN.lookup(U->getOperand(1)));
982 rhsValid = !dependsOnInvoke(U->getOperand(1));
984 if (!lhsValid || !rhsValid) {
986 set.reset(VN.lookup(U));
989 // Handle ternary ops
990 } else if (isa<ShuffleVectorInst>(v) || isa<InsertElementInst>(v) ||
991 isa<SelectInst>(v)) {
992 User* U = cast<User>(v);
994 bool lhsValid = !isa<Instruction>(U->getOperand(0));
995 lhsValid |= set.test(VN.lookup(U->getOperand(0)));
997 lhsValid = !dependsOnInvoke(U->getOperand(0));
999 bool rhsValid = !isa<Instruction>(U->getOperand(1));
1000 rhsValid |= set.test(VN.lookup(U->getOperand(1)));
1002 rhsValid = !dependsOnInvoke(U->getOperand(1));
1004 bool thirdValid = !isa<Instruction>(U->getOperand(2));
1005 thirdValid |= set.test(VN.lookup(U->getOperand(2)));
1007 thirdValid = !dependsOnInvoke(U->getOperand(2));
1009 if (!lhsValid || !rhsValid || !thirdValid) {
1011 set.reset(VN.lookup(U));
1014 // Handle varargs ops
1015 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(v)) {
1016 bool ptrValid = !isa<Instruction>(U->getPointerOperand());
1017 ptrValid |= set.test(VN.lookup(U->getPointerOperand()));
1019 ptrValid = !dependsOnInvoke(U->getPointerOperand());
1021 bool varValid = true;
1022 for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
1025 varValid &= !isa<Instruction>(*I) || set.test(VN.lookup(*I));
1026 varValid &= !dependsOnInvoke(*I);
1029 if (!ptrValid || !varValid) {
1031 set.reset(VN.lookup(U));
1037 /// topo_sort - Given a set of values, sort them by topological
1038 /// order into the provided vector.
1039 void GVNPRE::topo_sort(ValueNumberedSet& set, std::vector<Value*>& vec) {
1040 SmallPtrSet<Value*, 16> visited;
1041 std::vector<Value*> stack;
1042 for (ValueNumberedSet::iterator I = set.begin(), E = set.end();
1044 if (visited.count(*I) == 0)
1045 stack.push_back(*I);
1047 while (!stack.empty()) {
1048 Value* e = stack.back();
1051 if (CastInst* U = dyn_cast<CastInst>(e)) {
1052 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1054 if (l != 0 && isa<Instruction>(l) &&
1055 visited.count(l) == 0)
1063 // Handle binary ops
1064 } else if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
1065 isa<ExtractElementInst>(e)) {
1066 User* U = cast<User>(e);
1067 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1068 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
1070 if (l != 0 && isa<Instruction>(l) &&
1071 visited.count(l) == 0)
1073 else if (r != 0 && isa<Instruction>(r) &&
1074 visited.count(r) == 0)
1082 // Handle ternary ops
1083 } else if (isa<InsertElementInst>(e) || isa<ShuffleVectorInst>(e) ||
1084 isa<SelectInst>(e)) {
1085 User* U = cast<User>(e);
1086 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1087 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
1088 Value* m = find_leader(set, VN.lookup(U->getOperand(2)));
1090 if (l != 0 && isa<Instruction>(l) &&
1091 visited.count(l) == 0)
1093 else if (r != 0 && isa<Instruction>(r) &&
1094 visited.count(r) == 0)
1096 else if (m != 0 && isa<Instruction>(m) &&
1097 visited.count(m) == 0)
1105 // Handle vararg ops
1106 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(e)) {
1107 Value* p = find_leader(set, VN.lookup(U->getPointerOperand()));
1109 if (p != 0 && isa<Instruction>(p) &&
1110 visited.count(p) == 0)
1113 bool push_va = false;
1114 for (GetElementPtrInst::op_iterator I = U->idx_begin(),
1115 E = U->idx_end(); I != E; ++I) {
1116 Value * v = find_leader(set, VN.lookup(*I));
1117 if (v != 0 && isa<Instruction>(v) && visited.count(v) == 0) {
1130 // Handle opaque ops
1142 /// dump - Dump a set of values to standard error
1143 void GVNPRE::dump(ValueNumberedSet& s) const {
1145 for (ValueNumberedSet::iterator I = s.begin(), E = s.end();
1147 DOUT << "" << VN.lookup(*I) << ": ";
1148 DEBUG((*I)->dump());
1153 /// elimination - Phase 3 of the main algorithm. Perform full redundancy
1154 /// elimination by walking the dominator tree and removing any instruction that
1155 /// is dominated by another instruction with the same value number.
1156 bool GVNPRE::elimination() {
1157 bool changed_function = false;
1159 std::vector<std::pair<Instruction*, Value*> > replace;
1160 std::vector<Instruction*> erase;
1162 DominatorTree& DT = getAnalysis<DominatorTree>();
1164 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1165 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1166 BasicBlock* BB = DI->getBlock();
1168 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
1171 if (isa<BinaryOperator>(BI) || isa<CmpInst>(BI) ||
1172 isa<ShuffleVectorInst>(BI) || isa<InsertElementInst>(BI) ||
1173 isa<ExtractElementInst>(BI) || isa<SelectInst>(BI) ||
1174 isa<CastInst>(BI) || isa<GetElementPtrInst>(BI)) {
1175 Value *leader = find_leader(availableOut[BB], VN.lookup(BI));
1178 if (Instruction* Instr = dyn_cast<Instruction>(leader))
1179 if (Instr->getParent() != 0 && Instr != BI) {
1180 replace.push_back(std::make_pair(BI, leader));
1181 erase.push_back(BI);
1188 while (!replace.empty()) {
1189 std::pair<Instruction*, Value*> rep = replace.back();
1191 rep.first->replaceAllUsesWith(rep.second);
1192 changed_function = true;
1195 for (std::vector<Instruction*>::iterator I = erase.begin(), E = erase.end();
1197 (*I)->eraseFromParent();
1199 return changed_function;
1202 /// cleanup - Delete any extraneous values that were created to represent
1203 /// expressions without leaders.
1204 void GVNPRE::cleanup() {
1205 while (!createdExpressions.empty()) {
1206 Instruction* I = createdExpressions.back();
1207 createdExpressions.pop_back();
1213 /// buildsets_availout - When calculating availability, handle an instruction
1214 /// by inserting it into the appropriate sets
1215 void GVNPRE::buildsets_availout(BasicBlock::iterator I,
1216 ValueNumberedSet& currAvail,
1217 ValueNumberedSet& currPhis,
1218 ValueNumberedSet& currExps,
1219 SmallPtrSet<Value*, 16>& currTemps) {
1221 if (PHINode* p = dyn_cast<PHINode>(I)) {
1222 unsigned num = VN.lookup_or_add(p);
1228 } else if (CastInst* U = dyn_cast<CastInst>(I)) {
1229 Value* leftValue = U->getOperand(0);
1231 unsigned num = VN.lookup_or_add(U);
1233 if (isa<Instruction>(leftValue))
1234 if (!currExps.test(VN.lookup(leftValue))) {
1235 currExps.insert(leftValue);
1236 currExps.set(VN.lookup(leftValue));
1239 if (!currExps.test(num)) {
1244 // Handle binary ops
1245 } else if (isa<BinaryOperator>(I) || isa<CmpInst>(I) ||
1246 isa<ExtractElementInst>(I)) {
1247 User* U = cast<User>(I);
1248 Value* leftValue = U->getOperand(0);
1249 Value* rightValue = U->getOperand(1);
1251 unsigned num = VN.lookup_or_add(U);
1253 if (isa<Instruction>(leftValue))
1254 if (!currExps.test(VN.lookup(leftValue))) {
1255 currExps.insert(leftValue);
1256 currExps.set(VN.lookup(leftValue));
1259 if (isa<Instruction>(rightValue))
1260 if (!currExps.test(VN.lookup(rightValue))) {
1261 currExps.insert(rightValue);
1262 currExps.set(VN.lookup(rightValue));
1265 if (!currExps.test(num)) {
1270 // Handle ternary ops
1271 } else if (isa<InsertElementInst>(I) || isa<ShuffleVectorInst>(I) ||
1272 isa<SelectInst>(I)) {
1273 User* U = cast<User>(I);
1274 Value* leftValue = U->getOperand(0);
1275 Value* rightValue = U->getOperand(1);
1276 Value* thirdValue = U->getOperand(2);
1278 VN.lookup_or_add(U);
1280 unsigned num = VN.lookup_or_add(U);
1282 if (isa<Instruction>(leftValue))
1283 if (!currExps.test(VN.lookup(leftValue))) {
1284 currExps.insert(leftValue);
1285 currExps.set(VN.lookup(leftValue));
1287 if (isa<Instruction>(rightValue))
1288 if (!currExps.test(VN.lookup(rightValue))) {
1289 currExps.insert(rightValue);
1290 currExps.set(VN.lookup(rightValue));
1292 if (isa<Instruction>(thirdValue))
1293 if (!currExps.test(VN.lookup(thirdValue))) {
1294 currExps.insert(thirdValue);
1295 currExps.set(VN.lookup(thirdValue));
1298 if (!currExps.test(num)) {
1303 // Handle vararg ops
1304 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(I)) {
1305 Value* ptrValue = U->getPointerOperand();
1307 VN.lookup_or_add(U);
1309 unsigned num = VN.lookup_or_add(U);
1311 if (isa<Instruction>(ptrValue))
1312 if (!currExps.test(VN.lookup(ptrValue))) {
1313 currExps.insert(ptrValue);
1314 currExps.set(VN.lookup(ptrValue));
1317 for (GetElementPtrInst::op_iterator OI = U->idx_begin(), OE = U->idx_end();
1319 if (isa<Instruction>(*OI) && !currExps.test(VN.lookup(*OI))) {
1320 currExps.insert(*OI);
1321 currExps.set(VN.lookup(*OI));
1324 if (!currExps.test(VN.lookup(U))) {
1329 // Handle opaque ops
1330 } else if (!I->isTerminator()){
1331 VN.lookup_or_add(I);
1333 currTemps.insert(I);
1336 if (!I->isTerminator())
1337 if (!currAvail.test(VN.lookup(I))) {
1338 currAvail.insert(I);
1339 currAvail.set(VN.lookup(I));
1343 /// buildsets_anticout - When walking the postdom tree, calculate the ANTIC_OUT
1344 /// set as a function of the ANTIC_IN set of the block's predecessors
1345 bool GVNPRE::buildsets_anticout(BasicBlock* BB,
1346 ValueNumberedSet& anticOut,
1347 std::set<BasicBlock*>& visited) {
1348 if (BB->getTerminator()->getNumSuccessors() == 1) {
1349 if (BB->getTerminator()->getSuccessor(0) != BB &&
1350 visited.count(BB->getTerminator()->getSuccessor(0)) == 0) {
1354 phi_translate_set(anticipatedIn[BB->getTerminator()->getSuccessor(0)],
1355 BB, BB->getTerminator()->getSuccessor(0), anticOut);
1357 } else if (BB->getTerminator()->getNumSuccessors() > 1) {
1358 BasicBlock* first = BB->getTerminator()->getSuccessor(0);
1359 for (ValueNumberedSet::iterator I = anticipatedIn[first].begin(),
1360 E = anticipatedIn[first].end(); I != E; ++I) {
1361 anticOut.insert(*I);
1362 anticOut.set(VN.lookup(*I));
1365 for (unsigned i = 1; i < BB->getTerminator()->getNumSuccessors(); ++i) {
1366 BasicBlock* currSucc = BB->getTerminator()->getSuccessor(i);
1367 ValueNumberedSet& succAnticIn = anticipatedIn[currSucc];
1369 std::vector<Value*> temp;
1371 for (ValueNumberedSet::iterator I = anticOut.begin(),
1372 E = anticOut.end(); I != E; ++I)
1373 if (!succAnticIn.test(VN.lookup(*I)))
1376 for (std::vector<Value*>::iterator I = temp.begin(), E = temp.end();
1379 anticOut.reset(VN.lookup(*I));
1387 /// buildsets_anticin - Walk the postdom tree, calculating ANTIC_OUT for
1388 /// each block. ANTIC_IN is then a function of ANTIC_OUT and the GEN
1389 /// sets populated in buildsets_availout
1390 unsigned GVNPRE::buildsets_anticin(BasicBlock* BB,
1391 ValueNumberedSet& anticOut,
1392 ValueNumberedSet& currExps,
1393 SmallPtrSet<Value*, 16>& currTemps,
1394 std::set<BasicBlock*>& visited) {
1395 ValueNumberedSet& anticIn = anticipatedIn[BB];
1396 unsigned old = anticIn.size();
1398 bool defer = buildsets_anticout(BB, anticOut, visited);
1404 for (ValueNumberedSet::iterator I = anticOut.begin(),
1405 E = anticOut.end(); I != E; ++I) {
1407 anticIn.set(VN.lookup(*I));
1409 for (ValueNumberedSet::iterator I = currExps.begin(),
1410 E = currExps.end(); I != E; ++I) {
1411 if (!anticIn.test(VN.lookup(*I))) {
1413 anticIn.set(VN.lookup(*I));
1417 for (SmallPtrSet<Value*, 16>::iterator I = currTemps.begin(),
1418 E = currTemps.end(); I != E; ++I) {
1420 anticIn.reset(VN.lookup(*I));
1426 if (old != anticIn.size())
1432 /// buildsets - Phase 1 of the main algorithm. Construct the AVAIL_OUT
1433 /// and the ANTIC_IN sets.
1434 void GVNPRE::buildsets(Function& F) {
1435 std::map<BasicBlock*, ValueNumberedSet> generatedExpressions;
1436 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > generatedTemporaries;
1438 DominatorTree &DT = getAnalysis<DominatorTree>();
1440 // Phase 1, Part 1: calculate AVAIL_OUT
1442 // Top-down walk of the dominator tree
1443 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1444 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1446 // Get the sets to update for this block
1447 ValueNumberedSet& currExps = generatedExpressions[DI->getBlock()];
1448 ValueNumberedSet& currPhis = generatedPhis[DI->getBlock()];
1449 SmallPtrSet<Value*, 16>& currTemps = generatedTemporaries[DI->getBlock()];
1450 ValueNumberedSet& currAvail = availableOut[DI->getBlock()];
1452 BasicBlock* BB = DI->getBlock();
1454 // A block inherits AVAIL_OUT from its dominator
1455 if (DI->getIDom() != 0)
1456 currAvail = availableOut[DI->getIDom()->getBlock()];
1458 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
1460 buildsets_availout(BI, currAvail, currPhis, currExps,
1465 // Phase 1, Part 2: calculate ANTIC_IN
1467 std::set<BasicBlock*> visited;
1468 SmallPtrSet<BasicBlock*, 4> block_changed;
1469 for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
1470 block_changed.insert(FI);
1472 bool changed = true;
1473 unsigned iterations = 0;
1477 ValueNumberedSet anticOut;
1479 // Postorder walk of the CFG
1480 for (po_iterator<BasicBlock*> BBI = po_begin(&F.getEntryBlock()),
1481 BBE = po_end(&F.getEntryBlock()); BBI != BBE; ++BBI) {
1482 BasicBlock* BB = *BBI;
1484 if (block_changed.count(BB) != 0) {
1485 unsigned ret = buildsets_anticin(BB, anticOut,generatedExpressions[BB],
1486 generatedTemporaries[BB], visited);
1495 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
1497 block_changed.insert(*PI);
1500 block_changed.erase(BB);
1502 changed |= (ret == 2);
1511 /// insertion_pre - When a partial redundancy has been identified, eliminate it
1512 /// by inserting appropriate values into the predecessors and a phi node in
1514 void GVNPRE::insertion_pre(Value* e, BasicBlock* BB,
1515 std::map<BasicBlock*, Value*>& avail,
1516 std::map<BasicBlock*, ValueNumberedSet>& new_sets) {
1517 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1518 Value* e2 = avail[*PI];
1519 if (!availableOut[*PI].test(VN.lookup(e2))) {
1520 User* U = cast<User>(e2);
1523 if (isa<BinaryOperator>(U->getOperand(0)) ||
1524 isa<CmpInst>(U->getOperand(0)) ||
1525 isa<ShuffleVectorInst>(U->getOperand(0)) ||
1526 isa<ExtractElementInst>(U->getOperand(0)) ||
1527 isa<InsertElementInst>(U->getOperand(0)) ||
1528 isa<SelectInst>(U->getOperand(0)) ||
1529 isa<CastInst>(U->getOperand(0)) ||
1530 isa<GetElementPtrInst>(U->getOperand(0)))
1531 s1 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(0)));
1533 s1 = U->getOperand(0);
1537 if (isa<BinaryOperator>(U) ||
1539 isa<ShuffleVectorInst>(U) ||
1540 isa<ExtractElementInst>(U) ||
1541 isa<InsertElementInst>(U) ||
1543 if (isa<BinaryOperator>(U->getOperand(1)) ||
1544 isa<CmpInst>(U->getOperand(1)) ||
1545 isa<ShuffleVectorInst>(U->getOperand(1)) ||
1546 isa<ExtractElementInst>(U->getOperand(1)) ||
1547 isa<InsertElementInst>(U->getOperand(1)) ||
1548 isa<SelectInst>(U->getOperand(1)) ||
1549 isa<CastInst>(U->getOperand(1)) ||
1550 isa<GetElementPtrInst>(U->getOperand(1))) {
1551 s2 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(1)));
1553 s2 = U->getOperand(1);
1556 // Ternary Operators
1558 if (isa<ShuffleVectorInst>(U) ||
1559 isa<InsertElementInst>(U) ||
1561 if (isa<BinaryOperator>(U->getOperand(2)) ||
1562 isa<CmpInst>(U->getOperand(2)) ||
1563 isa<ShuffleVectorInst>(U->getOperand(2)) ||
1564 isa<ExtractElementInst>(U->getOperand(2)) ||
1565 isa<InsertElementInst>(U->getOperand(2)) ||
1566 isa<SelectInst>(U->getOperand(2)) ||
1567 isa<CastInst>(U->getOperand(2)) ||
1568 isa<GetElementPtrInst>(U->getOperand(2))) {
1569 s3 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(2)));
1571 s3 = U->getOperand(2);
1575 std::vector<Value*> sVarargs;
1576 if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U)) {
1577 for (GetElementPtrInst::op_iterator OI = G->idx_begin(),
1578 OE = G->idx_end(); OI != OE; ++OI) {
1579 if (isa<BinaryOperator>(*OI) ||
1580 isa<CmpInst>(*OI) ||
1581 isa<ShuffleVectorInst>(*OI) ||
1582 isa<ExtractElementInst>(*OI) ||
1583 isa<InsertElementInst>(*OI) ||
1584 isa<SelectInst>(*OI) ||
1585 isa<CastInst>(*OI) ||
1586 isa<GetElementPtrInst>(*OI)) {
1587 sVarargs.push_back(find_leader(availableOut[*PI],
1590 sVarargs.push_back(*OI);
1596 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
1597 newVal = BinaryOperator::create(BO->getOpcode(), s1, s2,
1598 BO->getName()+".gvnpre",
1599 (*PI)->getTerminator());
1600 else if (CmpInst* C = dyn_cast<CmpInst>(U))
1601 newVal = CmpInst::create(C->getOpcode(), C->getPredicate(), s1, s2,
1602 C->getName()+".gvnpre",
1603 (*PI)->getTerminator());
1604 else if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
1605 newVal = new ShuffleVectorInst(s1, s2, s3, S->getName()+".gvnpre",
1606 (*PI)->getTerminator());
1607 else if (InsertElementInst* S = dyn_cast<InsertElementInst>(U))
1608 newVal = new InsertElementInst(s1, s2, s3, S->getName()+".gvnpre",
1609 (*PI)->getTerminator());
1610 else if (ExtractElementInst* S = dyn_cast<ExtractElementInst>(U))
1611 newVal = new ExtractElementInst(s1, s2, S->getName()+".gvnpre",
1612 (*PI)->getTerminator());
1613 else if (SelectInst* S = dyn_cast<SelectInst>(U))
1614 newVal = new SelectInst(s1, s2, s3, S->getName()+".gvnpre",
1615 (*PI)->getTerminator());
1616 else if (CastInst* C = dyn_cast<CastInst>(U))
1617 newVal = CastInst::create(C->getOpcode(), s1, C->getType(),
1618 C->getName()+".gvnpre",
1619 (*PI)->getTerminator());
1620 else if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U))
1621 newVal = new GetElementPtrInst(s1, &sVarargs[0], sVarargs.size(),
1622 G->getName()+".gvnpre",
1623 (*PI)->getTerminator());
1626 VN.add(newVal, VN.lookup(U));
1628 ValueNumberedSet& predAvail = availableOut[*PI];
1629 val_replace(predAvail, newVal);
1630 val_replace(new_sets[*PI], newVal);
1631 predAvail.set(VN.lookup(newVal));
1633 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1634 if (av != avail.end())
1636 avail.insert(std::make_pair(*PI, newVal));
1644 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1646 p = new PHINode(avail[*PI]->getType(), "gvnpre-join", BB->begin());
1648 p->addIncoming(avail[*PI], *PI);
1651 VN.add(p, VN.lookup(e));
1652 val_replace(availableOut[BB], p);
1653 availableOut[BB].set(VN.lookup(e));
1654 generatedPhis[BB].insert(p);
1655 generatedPhis[BB].set(VN.lookup(e));
1656 new_sets[BB].insert(p);
1657 new_sets[BB].set(VN.lookup(e));
1662 /// insertion_mergepoint - When walking the dom tree, check at each merge
1663 /// block for the possibility of a partial redundancy. If present, eliminate it
1664 unsigned GVNPRE::insertion_mergepoint(std::vector<Value*>& workList,
1665 df_iterator<DomTreeNode*>& D,
1666 std::map<BasicBlock*, ValueNumberedSet >& new_sets) {
1667 bool changed_function = false;
1668 bool new_stuff = false;
1670 BasicBlock* BB = D->getBlock();
1671 for (unsigned i = 0; i < workList.size(); ++i) {
1672 Value* e = workList[i];
1674 if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
1675 isa<ExtractElementInst>(e) || isa<InsertElementInst>(e) ||
1676 isa<ShuffleVectorInst>(e) || isa<SelectInst>(e) || isa<CastInst>(e) ||
1677 isa<GetElementPtrInst>(e)) {
1678 if (availableOut[D->getIDom()->getBlock()].test(VN.lookup(e)))
1681 std::map<BasicBlock*, Value*> avail;
1682 bool by_some = false;
1683 bool all_same = true;
1684 Value * first_s = 0;
1686 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;
1688 Value *e2 = phi_translate(e, *PI, BB);
1689 Value *e3 = find_leader(availableOut[*PI], VN.lookup(e2));
1692 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1693 if (av != avail.end())
1695 avail.insert(std::make_pair(*PI, e2));
1698 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1699 if (av != avail.end())
1701 avail.insert(std::make_pair(*PI, e3));
1706 else if (first_s != e3)
1711 if (by_some && !all_same &&
1712 !generatedPhis[BB].test(VN.lookup(e))) {
1713 insertion_pre(e, BB, avail, new_sets);
1715 changed_function = true;
1721 unsigned retval = 0;
1722 if (changed_function)
1730 /// insert - Phase 2 of the main algorithm. Walk the dominator tree looking for
1731 /// merge points. When one is found, check for a partial redundancy. If one is
1732 /// present, eliminate it. Repeat this walk until no changes are made.
1733 bool GVNPRE::insertion(Function& F) {
1734 bool changed_function = false;
1736 DominatorTree &DT = getAnalysis<DominatorTree>();
1738 std::map<BasicBlock*, ValueNumberedSet> new_sets;
1739 bool new_stuff = true;
1742 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1743 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1744 BasicBlock* BB = DI->getBlock();
1749 ValueNumberedSet& availOut = availableOut[BB];
1750 ValueNumberedSet& anticIn = anticipatedIn[BB];
1752 // Replace leaders with leaders inherited from dominator
1753 if (DI->getIDom() != 0) {
1754 ValueNumberedSet& dom_set = new_sets[DI->getIDom()->getBlock()];
1755 for (ValueNumberedSet::iterator I = dom_set.begin(),
1756 E = dom_set.end(); I != E; ++I) {
1757 val_replace(new_sets[BB], *I);
1758 val_replace(availOut, *I);
1762 // If there is more than one predecessor...
1763 if (pred_begin(BB) != pred_end(BB) && ++pred_begin(BB) != pred_end(BB)) {
1764 std::vector<Value*> workList;
1765 workList.reserve(anticIn.size());
1766 topo_sort(anticIn, workList);
1768 unsigned result = insertion_mergepoint(workList, DI, new_sets);
1770 changed_function = true;
1777 return changed_function;
1780 // GVNPRE::runOnFunction - This is the main transformation entry point for a
1783 bool GVNPRE::runOnFunction(Function &F) {
1784 // Clean out global sets from any previous functions
1786 createdExpressions.clear();
1787 availableOut.clear();
1788 anticipatedIn.clear();
1789 generatedPhis.clear();
1791 bool changed_function = false;
1793 // Phase 1: BuildSets
1794 // This phase calculates the AVAIL_OUT and ANTIC_IN sets
1798 // This phase inserts values to make partially redundant values
1800 changed_function |= insertion(F);
1802 // Phase 3: Eliminate
1803 // This phase performs trivial full redundancy elimination
1804 changed_function |= elimination();
1807 // This phase cleans up values that were created solely
1808 // as leaders for expressions
1811 return changed_function;