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"
44 //===----------------------------------------------------------------------===//
46 //===----------------------------------------------------------------------===//
48 /// This class holds the mapping between values and value numbers. It is used
49 /// as an efficient mechanism to determine the expression-wise equivalence of
53 class VISIBILITY_HIDDEN ValueTable {
56 enum ExpressionOpcode { ADD, SUB, MUL, UDIV, SDIV, FDIV, UREM, SREM,
57 FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ,
58 ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
59 ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
60 FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
61 FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
62 FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
63 SHUFFLE, SELECT, TRUNC, ZEXT, SEXT, FPTOUI,
64 FPTOSI, UITOFP, SITOFP, FPTRUNC, FPEXT,
65 PTRTOINT, INTTOPTR, BITCAST, GEP};
67 ExpressionOpcode opcode;
72 std::vector<uint32_t> varargs;
74 bool operator< (const Expression& other) const {
75 if (opcode < other.opcode)
77 else if (opcode > other.opcode)
79 else if (type < other.type)
81 else if (type > other.type)
83 else if (firstVN < other.firstVN)
85 else if (firstVN > other.firstVN)
87 else if (secondVN < other.secondVN)
89 else if (secondVN > other.secondVN)
91 else if (thirdVN < other.thirdVN)
93 else if (thirdVN > other.thirdVN)
96 if (varargs.size() < other.varargs.size())
98 else if (varargs.size() > other.varargs.size())
101 for (size_t i = 0; i < varargs.size(); ++i)
102 if (varargs[i] < other.varargs[i])
104 else if (varargs[i] > other.varargs[i])
113 DenseMap<Value*, uint32_t> valueNumbering;
114 std::map<Expression, uint32_t> expressionNumbering;
116 uint32_t nextValueNumber;
118 Expression::ExpressionOpcode getOpcode(BinaryOperator* BO);
119 Expression::ExpressionOpcode getOpcode(CmpInst* C);
120 Expression::ExpressionOpcode getOpcode(CastInst* C);
121 Expression create_expression(BinaryOperator* BO);
122 Expression create_expression(CmpInst* C);
123 Expression create_expression(ShuffleVectorInst* V);
124 Expression create_expression(ExtractElementInst* C);
125 Expression create_expression(InsertElementInst* V);
126 Expression create_expression(SelectInst* V);
127 Expression create_expression(CastInst* C);
128 Expression create_expression(GetElementPtrInst* G);
130 ValueTable() { nextValueNumber = 1; }
131 uint32_t lookup_or_add(Value* V);
132 uint32_t lookup(Value* V) const;
133 void add(Value* V, uint32_t num);
135 void erase(Value* v);
140 //===----------------------------------------------------------------------===//
141 // ValueTable Internal Functions
142 //===----------------------------------------------------------------------===//
143 ValueTable::Expression::ExpressionOpcode
144 ValueTable::getOpcode(BinaryOperator* BO) {
145 switch(BO->getOpcode()) {
146 case Instruction::Add:
147 return Expression::ADD;
148 case Instruction::Sub:
149 return Expression::SUB;
150 case Instruction::Mul:
151 return Expression::MUL;
152 case Instruction::UDiv:
153 return Expression::UDIV;
154 case Instruction::SDiv:
155 return Expression::SDIV;
156 case Instruction::FDiv:
157 return Expression::FDIV;
158 case Instruction::URem:
159 return Expression::UREM;
160 case Instruction::SRem:
161 return Expression::SREM;
162 case Instruction::FRem:
163 return Expression::FREM;
164 case Instruction::Shl:
165 return Expression::SHL;
166 case Instruction::LShr:
167 return Expression::LSHR;
168 case Instruction::AShr:
169 return Expression::ASHR;
170 case Instruction::And:
171 return Expression::AND;
172 case Instruction::Or:
173 return Expression::OR;
174 case Instruction::Xor:
175 return Expression::XOR;
177 // THIS SHOULD NEVER HAPPEN
179 assert(0 && "Binary operator with unknown opcode?");
180 return Expression::ADD;
184 ValueTable::Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) {
185 if (C->getOpcode() == Instruction::ICmp) {
186 switch (C->getPredicate()) {
187 case ICmpInst::ICMP_EQ:
188 return Expression::ICMPEQ;
189 case ICmpInst::ICMP_NE:
190 return Expression::ICMPNE;
191 case ICmpInst::ICMP_UGT:
192 return Expression::ICMPUGT;
193 case ICmpInst::ICMP_UGE:
194 return Expression::ICMPUGE;
195 case ICmpInst::ICMP_ULT:
196 return Expression::ICMPULT;
197 case ICmpInst::ICMP_ULE:
198 return Expression::ICMPULE;
199 case ICmpInst::ICMP_SGT:
200 return Expression::ICMPSGT;
201 case ICmpInst::ICMP_SGE:
202 return Expression::ICMPSGE;
203 case ICmpInst::ICMP_SLT:
204 return Expression::ICMPSLT;
205 case ICmpInst::ICMP_SLE:
206 return Expression::ICMPSLE;
208 // THIS SHOULD NEVER HAPPEN
210 assert(0 && "Comparison with unknown predicate?");
211 return Expression::ICMPEQ;
214 switch (C->getPredicate()) {
215 case FCmpInst::FCMP_OEQ:
216 return Expression::FCMPOEQ;
217 case FCmpInst::FCMP_OGT:
218 return Expression::FCMPOGT;
219 case FCmpInst::FCMP_OGE:
220 return Expression::FCMPOGE;
221 case FCmpInst::FCMP_OLT:
222 return Expression::FCMPOLT;
223 case FCmpInst::FCMP_OLE:
224 return Expression::FCMPOLE;
225 case FCmpInst::FCMP_ONE:
226 return Expression::FCMPONE;
227 case FCmpInst::FCMP_ORD:
228 return Expression::FCMPORD;
229 case FCmpInst::FCMP_UNO:
230 return Expression::FCMPUNO;
231 case FCmpInst::FCMP_UEQ:
232 return Expression::FCMPUEQ;
233 case FCmpInst::FCMP_UGT:
234 return Expression::FCMPUGT;
235 case FCmpInst::FCMP_UGE:
236 return Expression::FCMPUGE;
237 case FCmpInst::FCMP_ULT:
238 return Expression::FCMPULT;
239 case FCmpInst::FCMP_ULE:
240 return Expression::FCMPULE;
241 case FCmpInst::FCMP_UNE:
242 return Expression::FCMPUNE;
244 // THIS SHOULD NEVER HAPPEN
246 assert(0 && "Comparison with unknown predicate?");
247 return Expression::FCMPOEQ;
252 ValueTable::Expression::ExpressionOpcode
253 ValueTable::getOpcode(CastInst* C) {
254 switch(C->getOpcode()) {
255 case Instruction::Trunc:
256 return Expression::TRUNC;
257 case Instruction::ZExt:
258 return Expression::ZEXT;
259 case Instruction::SExt:
260 return Expression::SEXT;
261 case Instruction::FPToUI:
262 return Expression::FPTOUI;
263 case Instruction::FPToSI:
264 return Expression::FPTOSI;
265 case Instruction::UIToFP:
266 return Expression::UITOFP;
267 case Instruction::SIToFP:
268 return Expression::SITOFP;
269 case Instruction::FPTrunc:
270 return Expression::FPTRUNC;
271 case Instruction::FPExt:
272 return Expression::FPEXT;
273 case Instruction::PtrToInt:
274 return Expression::PTRTOINT;
275 case Instruction::IntToPtr:
276 return Expression::INTTOPTR;
277 case Instruction::BitCast:
278 return Expression::BITCAST;
280 // THIS SHOULD NEVER HAPPEN
282 assert(0 && "Cast operator with unknown opcode?");
283 return Expression::BITCAST;
287 ValueTable::Expression ValueTable::create_expression(BinaryOperator* BO) {
290 e.firstVN = lookup_or_add(BO->getOperand(0));
291 e.secondVN = lookup_or_add(BO->getOperand(1));
293 e.type = BO->getType();
294 e.opcode = getOpcode(BO);
299 ValueTable::Expression ValueTable::create_expression(CmpInst* C) {
302 e.firstVN = lookup_or_add(C->getOperand(0));
303 e.secondVN = lookup_or_add(C->getOperand(1));
305 e.type = C->getType();
306 e.opcode = getOpcode(C);
311 ValueTable::Expression ValueTable::create_expression(CastInst* C) {
314 e.firstVN = lookup_or_add(C->getOperand(0));
317 e.type = C->getType();
318 e.opcode = getOpcode(C);
323 ValueTable::Expression ValueTable::create_expression(ShuffleVectorInst* S) {
326 e.firstVN = lookup_or_add(S->getOperand(0));
327 e.secondVN = lookup_or_add(S->getOperand(1));
328 e.thirdVN = lookup_or_add(S->getOperand(2));
329 e.type = S->getType();
330 e.opcode = Expression::SHUFFLE;
335 ValueTable::Expression ValueTable::create_expression(ExtractElementInst* E) {
338 e.firstVN = lookup_or_add(E->getOperand(0));
339 e.secondVN = lookup_or_add(E->getOperand(1));
341 e.type = E->getType();
342 e.opcode = Expression::EXTRACT;
347 ValueTable::Expression ValueTable::create_expression(InsertElementInst* I) {
350 e.firstVN = lookup_or_add(I->getOperand(0));
351 e.secondVN = lookup_or_add(I->getOperand(1));
352 e.thirdVN = lookup_or_add(I->getOperand(2));
353 e.type = I->getType();
354 e.opcode = Expression::INSERT;
359 ValueTable::Expression ValueTable::create_expression(SelectInst* I) {
362 e.firstVN = lookup_or_add(I->getCondition());
363 e.secondVN = lookup_or_add(I->getTrueValue());
364 e.thirdVN = lookup_or_add(I->getFalseValue());
365 e.type = I->getType();
366 e.opcode = Expression::SELECT;
371 ValueTable::Expression ValueTable::create_expression(GetElementPtrInst* G) {
374 e.firstVN = lookup_or_add(G->getPointerOperand());
377 e.type = G->getType();
378 e.opcode = Expression::SELECT;
380 for (GetElementPtrInst::op_iterator I = G->idx_begin(), E = G->idx_end();
382 e.varargs.push_back(lookup_or_add(*I));
387 //===----------------------------------------------------------------------===//
388 // ValueTable External Functions
389 //===----------------------------------------------------------------------===//
391 /// lookup_or_add - Returns the value number for the specified value, assigning
392 /// it a new number if it did not have one before.
393 uint32_t ValueTable::lookup_or_add(Value* V) {
394 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
395 if (VI != valueNumbering.end())
399 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
400 Expression e = create_expression(BO);
402 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
403 if (EI != expressionNumbering.end()) {
404 valueNumbering.insert(std::make_pair(V, EI->second));
407 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
408 valueNumbering.insert(std::make_pair(V, nextValueNumber));
410 return nextValueNumber++;
412 } else if (CmpInst* C = dyn_cast<CmpInst>(V)) {
413 Expression e = create_expression(C);
415 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
416 if (EI != expressionNumbering.end()) {
417 valueNumbering.insert(std::make_pair(V, EI->second));
420 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
421 valueNumbering.insert(std::make_pair(V, nextValueNumber));
423 return nextValueNumber++;
425 } else if (ShuffleVectorInst* U = dyn_cast<ShuffleVectorInst>(V)) {
426 Expression e = create_expression(U);
428 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
429 if (EI != expressionNumbering.end()) {
430 valueNumbering.insert(std::make_pair(V, EI->second));
433 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
434 valueNumbering.insert(std::make_pair(V, nextValueNumber));
436 return nextValueNumber++;
438 } else if (ExtractElementInst* U = dyn_cast<ExtractElementInst>(V)) {
439 Expression e = create_expression(U);
441 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
442 if (EI != expressionNumbering.end()) {
443 valueNumbering.insert(std::make_pair(V, EI->second));
446 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
447 valueNumbering.insert(std::make_pair(V, nextValueNumber));
449 return nextValueNumber++;
451 } else if (InsertElementInst* U = dyn_cast<InsertElementInst>(V)) {
452 Expression e = create_expression(U);
454 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
455 if (EI != expressionNumbering.end()) {
456 valueNumbering.insert(std::make_pair(V, EI->second));
459 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
460 valueNumbering.insert(std::make_pair(V, nextValueNumber));
462 return nextValueNumber++;
464 } else if (SelectInst* U = dyn_cast<SelectInst>(V)) {
465 Expression e = create_expression(U);
467 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
468 if (EI != expressionNumbering.end()) {
469 valueNumbering.insert(std::make_pair(V, EI->second));
472 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
473 valueNumbering.insert(std::make_pair(V, nextValueNumber));
475 return nextValueNumber++;
477 } else if (CastInst* U = dyn_cast<CastInst>(V)) {
478 Expression e = create_expression(U);
480 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
481 if (EI != expressionNumbering.end()) {
482 valueNumbering.insert(std::make_pair(V, EI->second));
485 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
486 valueNumbering.insert(std::make_pair(V, nextValueNumber));
488 return nextValueNumber++;
490 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
491 Expression e = create_expression(U);
493 std::map<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
494 if (EI != expressionNumbering.end()) {
495 valueNumbering.insert(std::make_pair(V, EI->second));
498 expressionNumbering.insert(std::make_pair(e, nextValueNumber));
499 valueNumbering.insert(std::make_pair(V, nextValueNumber));
501 return nextValueNumber++;
504 valueNumbering.insert(std::make_pair(V, nextValueNumber));
505 return nextValueNumber++;
509 /// lookup - Returns the value number of the specified value. Fails if
510 /// the value has not yet been numbered.
511 uint32_t ValueTable::lookup(Value* V) const {
512 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
513 if (VI != valueNumbering.end())
516 assert(0 && "Value not numbered?");
521 /// add - Add the specified value with the given value number, removing
522 /// its old number, if any
523 void ValueTable::add(Value* V, uint32_t num) {
524 DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
525 if (VI != valueNumbering.end())
526 valueNumbering.erase(VI);
527 valueNumbering.insert(std::make_pair(V, num));
530 /// clear - Remove all entries from the ValueTable
531 void ValueTable::clear() {
532 valueNumbering.clear();
533 expressionNumbering.clear();
537 /// erase - Remove a value from the value numbering
538 void ValueTable::erase(Value* V) {
539 valueNumbering.erase(V);
542 /// size - Return the number of assigned value numbers
543 unsigned ValueTable::size() {
544 // NOTE: zero is never assigned
545 return nextValueNumber;
548 //===----------------------------------------------------------------------===//
549 // ValueNumberedSet Class
550 //===----------------------------------------------------------------------===//
552 class ValueNumberedSet {
554 SmallPtrSet<Value*, 8> contents;
557 ValueNumberedSet() { numbers.resize(1); }
558 ValueNumberedSet(const ValueNumberedSet& other) {
559 numbers = other.numbers;
560 contents = other.contents;
563 typedef SmallPtrSet<Value*, 8>::iterator iterator;
565 iterator begin() { return contents.begin(); }
566 iterator end() { return contents.end(); }
568 bool insert(Value* v) { return contents.insert(v); }
569 void insert(iterator I, iterator E) { contents.insert(I, E); }
570 void erase(Value* v) { contents.erase(v); }
571 unsigned count(Value* v) { return contents.count(v); }
572 size_t size() { return contents.size(); }
574 void set(unsigned i) {
575 if (i >= numbers.size())
581 void operator=(const ValueNumberedSet& other) {
582 contents = other.contents;
583 numbers = other.numbers;
586 void reset(unsigned i) {
587 if (i < numbers.size())
591 bool test(unsigned i) {
592 if (i >= numbers.size())
595 return numbers.test(i);
604 //===----------------------------------------------------------------------===//
606 //===----------------------------------------------------------------------===//
610 class VISIBILITY_HIDDEN GVNPRE : public FunctionPass {
611 bool runOnFunction(Function &F);
613 static char ID; // Pass identification, replacement for typeid
614 GVNPRE() : FunctionPass((intptr_t)&ID) { }
618 std::vector<Instruction*> createdExpressions;
620 DenseMap<BasicBlock*, ValueNumberedSet> availableOut;
621 DenseMap<BasicBlock*, ValueNumberedSet> anticipatedIn;
622 DenseMap<BasicBlock*, ValueNumberedSet> generatedPhis;
624 // This transformation requires dominator postdominator info
625 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
626 AU.setPreservesCFG();
627 AU.addRequiredID(BreakCriticalEdgesID);
628 AU.addRequired<UnifyFunctionExitNodes>();
629 AU.addRequired<DominatorTree>();
633 // FIXME: eliminate or document these better
634 void dump(ValueNumberedSet& s) const ;
635 void clean(ValueNumberedSet& set) ;
636 Value* find_leader(ValueNumberedSet& vals, uint32_t v) ;
637 Value* phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) ;
638 void phi_translate_set(ValueNumberedSet& anticIn, BasicBlock* pred,
639 BasicBlock* succ, ValueNumberedSet& out) ;
641 void topo_sort(ValueNumberedSet& set,
642 std::vector<Value*>& vec) ;
647 void val_insert(ValueNumberedSet& s, Value* v) ;
648 void val_replace(ValueNumberedSet& s, Value* v) ;
649 bool dependsOnInvoke(Value* V) ;
650 void buildsets_availout(BasicBlock::iterator I,
651 ValueNumberedSet& currAvail,
652 ValueNumberedSet& currPhis,
653 ValueNumberedSet& currExps,
654 SmallPtrSet<Value*, 16>& currTemps) ;
655 bool buildsets_anticout(BasicBlock* BB,
656 ValueNumberedSet& anticOut,
657 SmallPtrSet<BasicBlock*, 8>& visited) ;
658 unsigned buildsets_anticin(BasicBlock* BB,
659 ValueNumberedSet& anticOut,
660 ValueNumberedSet& currExps,
661 SmallPtrSet<Value*, 16>& currTemps,
662 SmallPtrSet<BasicBlock*, 8>& visited) ;
663 void buildsets(Function& F) ;
665 void insertion_pre(Value* e, BasicBlock* BB,
666 std::map<BasicBlock*, Value*>& avail,
667 std::map<BasicBlock*,ValueNumberedSet>& new_set) ;
668 unsigned insertion_mergepoint(std::vector<Value*>& workList,
669 df_iterator<DomTreeNode*>& D,
670 std::map<BasicBlock*, ValueNumberedSet>& new_set) ;
671 bool insertion(Function& F) ;
679 // createGVNPREPass - The public interface to this file...
680 FunctionPass *llvm::createGVNPREPass() { return new GVNPRE(); }
682 static RegisterPass<GVNPRE> X("gvnpre",
683 "Global Value Numbering/Partial Redundancy Elimination");
686 STATISTIC(NumInsertedVals, "Number of values inserted");
687 STATISTIC(NumInsertedPhis, "Number of PHI nodes inserted");
688 STATISTIC(NumEliminated, "Number of redundant instructions eliminated");
690 /// find_leader - Given a set and a value number, return the first
691 /// element of the set with that value number, or 0 if no such element
693 Value* GVNPRE::find_leader(ValueNumberedSet& vals, uint32_t v) {
697 for (ValueNumberedSet::iterator I = vals.begin(), E = vals.end();
699 if (v == VN.lookup(*I))
702 assert(0 && "No leader found, but present bit is set?");
706 /// val_insert - Insert a value into a set only if there is not a value
707 /// with the same value number already in the set
708 void GVNPRE::val_insert(ValueNumberedSet& s, Value* v) {
709 uint32_t num = VN.lookup(v);
714 /// val_replace - Insert a value into a set, replacing any values already in
715 /// the set that have the same value number
716 void GVNPRE::val_replace(ValueNumberedSet& s, Value* v) {
717 uint32_t num = VN.lookup(v);
718 Value* leader = find_leader(s, num);
725 /// phi_translate - Given a value, its parent block, and a predecessor of its
726 /// parent, translate the value into legal for the predecessor block. This
727 /// means translating its operands (and recursively, their operands) through
728 /// any phi nodes in the parent into values available in the predecessor
729 Value* GVNPRE::phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) {
734 if (CastInst* U = dyn_cast<CastInst>(V)) {
736 if (isa<Instruction>(U->getOperand(0)))
737 newOp1 = phi_translate(U->getOperand(0), pred, succ);
739 newOp1 = U->getOperand(0);
744 if (newOp1 != U->getOperand(0)) {
745 Instruction* newVal = 0;
746 if (CastInst* C = dyn_cast<CastInst>(U))
747 newVal = CastInst::create(C->getOpcode(),
748 newOp1, C->getType(),
749 C->getName()+".expr");
751 uint32_t v = VN.lookup_or_add(newVal);
753 Value* leader = find_leader(availableOut[pred], v);
755 createdExpressions.push_back(newVal);
765 } if (isa<BinaryOperator>(V) || isa<CmpInst>(V) ||
766 isa<ExtractElementInst>(V)) {
767 User* U = cast<User>(V);
770 if (isa<Instruction>(U->getOperand(0)))
771 newOp1 = phi_translate(U->getOperand(0), pred, succ);
773 newOp1 = U->getOperand(0);
779 if (isa<Instruction>(U->getOperand(1)))
780 newOp2 = phi_translate(U->getOperand(1), pred, succ);
782 newOp2 = U->getOperand(1);
787 if (newOp1 != U->getOperand(0) || newOp2 != U->getOperand(1)) {
788 Instruction* newVal = 0;
789 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
790 newVal = BinaryOperator::create(BO->getOpcode(),
792 BO->getName()+".expr");
793 else if (CmpInst* C = dyn_cast<CmpInst>(U))
794 newVal = CmpInst::create(C->getOpcode(),
797 C->getName()+".expr");
798 else if (ExtractElementInst* E = dyn_cast<ExtractElementInst>(U))
799 newVal = new ExtractElementInst(newOp1, newOp2, E->getName()+".expr");
801 uint32_t v = VN.lookup_or_add(newVal);
803 Value* leader = find_leader(availableOut[pred], v);
805 createdExpressions.push_back(newVal);
814 // Ternary Operations
815 } else if (isa<ShuffleVectorInst>(V) || isa<InsertElementInst>(V) ||
816 isa<SelectInst>(V)) {
817 User* U = cast<User>(V);
820 if (isa<Instruction>(U->getOperand(0)))
821 newOp1 = phi_translate(U->getOperand(0), pred, succ);
823 newOp1 = U->getOperand(0);
829 if (isa<Instruction>(U->getOperand(1)))
830 newOp2 = phi_translate(U->getOperand(1), pred, succ);
832 newOp2 = U->getOperand(1);
838 if (isa<Instruction>(U->getOperand(2)))
839 newOp3 = phi_translate(U->getOperand(2), pred, succ);
841 newOp3 = U->getOperand(2);
846 if (newOp1 != U->getOperand(0) ||
847 newOp2 != U->getOperand(1) ||
848 newOp3 != U->getOperand(2)) {
849 Instruction* newVal = 0;
850 if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
851 newVal = new ShuffleVectorInst(newOp1, newOp2, newOp3,
852 S->getName()+".expr");
853 else if (InsertElementInst* I = dyn_cast<InsertElementInst>(U))
854 newVal = new InsertElementInst(newOp1, newOp2, newOp3,
855 I->getName()+".expr");
856 else if (SelectInst* I = dyn_cast<SelectInst>(U))
857 newVal = new SelectInst(newOp1, newOp2, newOp3, I->getName()+".expr");
859 uint32_t v = VN.lookup_or_add(newVal);
861 Value* leader = find_leader(availableOut[pred], v);
863 createdExpressions.push_back(newVal);
873 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
875 if (isa<Instruction>(U->getPointerOperand()))
876 newOp1 = phi_translate(U->getPointerOperand(), pred, succ);
878 newOp1 = U->getPointerOperand();
883 bool changed_idx = false;
884 std::vector<Value*> newIdx;
885 for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
887 if (isa<Instruction>(*I)) {
888 Value* newVal = phi_translate(*I, pred, succ);
889 newIdx.push_back(newVal);
893 newIdx.push_back(*I);
896 if (newOp1 != U->getPointerOperand() || changed_idx) {
897 Instruction* newVal = new GetElementPtrInst(newOp1,
898 &newIdx[0], newIdx.size(),
899 U->getName()+".expr");
901 uint32_t v = VN.lookup_or_add(newVal);
903 Value* leader = find_leader(availableOut[pred], v);
905 createdExpressions.push_back(newVal);
915 } else if (PHINode* P = dyn_cast<PHINode>(V)) {
916 if (P->getParent() == succ)
917 return P->getIncomingValueForBlock(pred);
923 /// phi_translate_set - Perform phi translation on every element of a set
924 void GVNPRE::phi_translate_set(ValueNumberedSet& anticIn,
925 BasicBlock* pred, BasicBlock* succ,
926 ValueNumberedSet& out) {
927 for (ValueNumberedSet::iterator I = anticIn.begin(),
928 E = anticIn.end(); I != E; ++I) {
929 Value* V = phi_translate(*I, pred, succ);
930 if (V != 0 && !out.test(VN.lookup_or_add(V))) {
932 out.set(VN.lookup(V));
937 /// dependsOnInvoke - Test if a value has an phi node as an operand, any of
938 /// whose inputs is an invoke instruction. If this is true, we cannot safely
939 /// PRE the instruction or anything that depends on it.
940 bool GVNPRE::dependsOnInvoke(Value* V) {
941 if (PHINode* p = dyn_cast<PHINode>(V)) {
942 for (PHINode::op_iterator I = p->op_begin(), E = p->op_end(); I != E; ++I)
943 if (isa<InvokeInst>(*I))
951 /// clean - Remove all non-opaque values from the set whose operands are not
952 /// themselves in the set, as well as all values that depend on invokes (see
954 void GVNPRE::clean(ValueNumberedSet& set) {
955 std::vector<Value*> worklist;
956 worklist.reserve(set.size());
957 topo_sort(set, worklist);
959 for (unsigned i = 0; i < worklist.size(); ++i) {
960 Value* v = worklist[i];
963 if (CastInst* U = dyn_cast<CastInst>(v)) {
964 bool lhsValid = !isa<Instruction>(U->getOperand(0));
965 lhsValid |= set.test(VN.lookup(U->getOperand(0)));
967 lhsValid = !dependsOnInvoke(U->getOperand(0));
971 set.reset(VN.lookup(U));
975 } else if (isa<BinaryOperator>(v) || isa<CmpInst>(v) ||
976 isa<ExtractElementInst>(v)) {
977 User* U = cast<User>(v);
979 bool lhsValid = !isa<Instruction>(U->getOperand(0));
980 lhsValid |= set.test(VN.lookup(U->getOperand(0)));
982 lhsValid = !dependsOnInvoke(U->getOperand(0));
984 bool rhsValid = !isa<Instruction>(U->getOperand(1));
985 rhsValid |= set.test(VN.lookup(U->getOperand(1)));
987 rhsValid = !dependsOnInvoke(U->getOperand(1));
989 if (!lhsValid || !rhsValid) {
991 set.reset(VN.lookup(U));
994 // Handle ternary ops
995 } else if (isa<ShuffleVectorInst>(v) || isa<InsertElementInst>(v) ||
996 isa<SelectInst>(v)) {
997 User* U = cast<User>(v);
999 bool lhsValid = !isa<Instruction>(U->getOperand(0));
1000 lhsValid |= set.test(VN.lookup(U->getOperand(0)));
1002 lhsValid = !dependsOnInvoke(U->getOperand(0));
1004 bool rhsValid = !isa<Instruction>(U->getOperand(1));
1005 rhsValid |= set.test(VN.lookup(U->getOperand(1)));
1007 rhsValid = !dependsOnInvoke(U->getOperand(1));
1009 bool thirdValid = !isa<Instruction>(U->getOperand(2));
1010 thirdValid |= set.test(VN.lookup(U->getOperand(2)));
1012 thirdValid = !dependsOnInvoke(U->getOperand(2));
1014 if (!lhsValid || !rhsValid || !thirdValid) {
1016 set.reset(VN.lookup(U));
1019 // Handle varargs ops
1020 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(v)) {
1021 bool ptrValid = !isa<Instruction>(U->getPointerOperand());
1022 ptrValid |= set.test(VN.lookup(U->getPointerOperand()));
1024 ptrValid = !dependsOnInvoke(U->getPointerOperand());
1026 bool varValid = true;
1027 for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
1030 varValid &= !isa<Instruction>(*I) || set.test(VN.lookup(*I));
1031 varValid &= !dependsOnInvoke(*I);
1034 if (!ptrValid || !varValid) {
1036 set.reset(VN.lookup(U));
1042 /// topo_sort - Given a set of values, sort them by topological
1043 /// order into the provided vector.
1044 void GVNPRE::topo_sort(ValueNumberedSet& set, std::vector<Value*>& vec) {
1045 SmallPtrSet<Value*, 16> visited;
1046 std::vector<Value*> stack;
1047 for (ValueNumberedSet::iterator I = set.begin(), E = set.end();
1049 if (visited.count(*I) == 0)
1050 stack.push_back(*I);
1052 while (!stack.empty()) {
1053 Value* e = stack.back();
1056 if (CastInst* U = dyn_cast<CastInst>(e)) {
1057 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1059 if (l != 0 && isa<Instruction>(l) &&
1060 visited.count(l) == 0)
1068 // Handle binary ops
1069 } else if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
1070 isa<ExtractElementInst>(e)) {
1071 User* U = cast<User>(e);
1072 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1073 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
1075 if (l != 0 && isa<Instruction>(l) &&
1076 visited.count(l) == 0)
1078 else if (r != 0 && isa<Instruction>(r) &&
1079 visited.count(r) == 0)
1087 // Handle ternary ops
1088 } else if (isa<InsertElementInst>(e) || isa<ShuffleVectorInst>(e) ||
1089 isa<SelectInst>(e)) {
1090 User* U = cast<User>(e);
1091 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1092 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
1093 Value* m = find_leader(set, VN.lookup(U->getOperand(2)));
1095 if (l != 0 && isa<Instruction>(l) &&
1096 visited.count(l) == 0)
1098 else if (r != 0 && isa<Instruction>(r) &&
1099 visited.count(r) == 0)
1101 else if (m != 0 && isa<Instruction>(m) &&
1102 visited.count(m) == 0)
1110 // Handle vararg ops
1111 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(e)) {
1112 Value* p = find_leader(set, VN.lookup(U->getPointerOperand()));
1114 if (p != 0 && isa<Instruction>(p) &&
1115 visited.count(p) == 0)
1118 bool push_va = false;
1119 for (GetElementPtrInst::op_iterator I = U->idx_begin(),
1120 E = U->idx_end(); I != E; ++I) {
1121 Value * v = find_leader(set, VN.lookup(*I));
1122 if (v != 0 && isa<Instruction>(v) && visited.count(v) == 0) {
1135 // Handle opaque ops
1147 /// dump - Dump a set of values to standard error
1148 void GVNPRE::dump(ValueNumberedSet& s) const {
1150 for (ValueNumberedSet::iterator I = s.begin(), E = s.end();
1152 DOUT << "" << VN.lookup(*I) << ": ";
1153 DEBUG((*I)->dump());
1158 /// elimination - Phase 3 of the main algorithm. Perform full redundancy
1159 /// elimination by walking the dominator tree and removing any instruction that
1160 /// is dominated by another instruction with the same value number.
1161 bool GVNPRE::elimination() {
1162 bool changed_function = false;
1164 std::vector<std::pair<Instruction*, Value*> > replace;
1165 std::vector<Instruction*> erase;
1167 DominatorTree& DT = getAnalysis<DominatorTree>();
1169 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1170 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1171 BasicBlock* BB = DI->getBlock();
1173 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
1176 if (isa<BinaryOperator>(BI) || isa<CmpInst>(BI) ||
1177 isa<ShuffleVectorInst>(BI) || isa<InsertElementInst>(BI) ||
1178 isa<ExtractElementInst>(BI) || isa<SelectInst>(BI) ||
1179 isa<CastInst>(BI) || isa<GetElementPtrInst>(BI)) {
1181 if (availableOut[BB].test(VN.lookup(BI)) && !availableOut[BB].count(BI)) {
1182 Value *leader = find_leader(availableOut[BB], VN.lookup(BI));
1183 if (Instruction* Instr = dyn_cast<Instruction>(leader))
1184 if (Instr->getParent() != 0 && Instr != BI) {
1185 replace.push_back(std::make_pair(BI, leader));
1186 erase.push_back(BI);
1194 while (!replace.empty()) {
1195 std::pair<Instruction*, Value*> rep = replace.back();
1197 rep.first->replaceAllUsesWith(rep.second);
1198 changed_function = true;
1201 for (std::vector<Instruction*>::iterator I = erase.begin(), E = erase.end();
1203 (*I)->eraseFromParent();
1205 return changed_function;
1208 /// cleanup - Delete any extraneous values that were created to represent
1209 /// expressions without leaders.
1210 void GVNPRE::cleanup() {
1211 while (!createdExpressions.empty()) {
1212 Instruction* I = createdExpressions.back();
1213 createdExpressions.pop_back();
1219 /// buildsets_availout - When calculating availability, handle an instruction
1220 /// by inserting it into the appropriate sets
1221 void GVNPRE::buildsets_availout(BasicBlock::iterator I,
1222 ValueNumberedSet& currAvail,
1223 ValueNumberedSet& currPhis,
1224 ValueNumberedSet& currExps,
1225 SmallPtrSet<Value*, 16>& currTemps) {
1227 if (PHINode* p = dyn_cast<PHINode>(I)) {
1228 unsigned num = VN.lookup_or_add(p);
1234 } else if (CastInst* U = dyn_cast<CastInst>(I)) {
1235 Value* leftValue = U->getOperand(0);
1237 unsigned num = VN.lookup_or_add(U);
1239 if (isa<Instruction>(leftValue))
1240 if (!currExps.test(VN.lookup(leftValue))) {
1241 currExps.insert(leftValue);
1242 currExps.set(VN.lookup(leftValue));
1245 if (!currExps.test(num)) {
1250 // Handle binary ops
1251 } else if (isa<BinaryOperator>(I) || isa<CmpInst>(I) ||
1252 isa<ExtractElementInst>(I)) {
1253 User* U = cast<User>(I);
1254 Value* leftValue = U->getOperand(0);
1255 Value* rightValue = U->getOperand(1);
1257 unsigned num = VN.lookup_or_add(U);
1259 if (isa<Instruction>(leftValue))
1260 if (!currExps.test(VN.lookup(leftValue))) {
1261 currExps.insert(leftValue);
1262 currExps.set(VN.lookup(leftValue));
1265 if (isa<Instruction>(rightValue))
1266 if (!currExps.test(VN.lookup(rightValue))) {
1267 currExps.insert(rightValue);
1268 currExps.set(VN.lookup(rightValue));
1271 if (!currExps.test(num)) {
1276 // Handle ternary ops
1277 } else if (isa<InsertElementInst>(I) || isa<ShuffleVectorInst>(I) ||
1278 isa<SelectInst>(I)) {
1279 User* U = cast<User>(I);
1280 Value* leftValue = U->getOperand(0);
1281 Value* rightValue = U->getOperand(1);
1282 Value* thirdValue = U->getOperand(2);
1284 VN.lookup_or_add(U);
1286 unsigned num = VN.lookup_or_add(U);
1288 if (isa<Instruction>(leftValue))
1289 if (!currExps.test(VN.lookup(leftValue))) {
1290 currExps.insert(leftValue);
1291 currExps.set(VN.lookup(leftValue));
1293 if (isa<Instruction>(rightValue))
1294 if (!currExps.test(VN.lookup(rightValue))) {
1295 currExps.insert(rightValue);
1296 currExps.set(VN.lookup(rightValue));
1298 if (isa<Instruction>(thirdValue))
1299 if (!currExps.test(VN.lookup(thirdValue))) {
1300 currExps.insert(thirdValue);
1301 currExps.set(VN.lookup(thirdValue));
1304 if (!currExps.test(num)) {
1309 // Handle vararg ops
1310 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(I)) {
1311 Value* ptrValue = U->getPointerOperand();
1313 VN.lookup_or_add(U);
1315 unsigned num = VN.lookup_or_add(U);
1317 if (isa<Instruction>(ptrValue))
1318 if (!currExps.test(VN.lookup(ptrValue))) {
1319 currExps.insert(ptrValue);
1320 currExps.set(VN.lookup(ptrValue));
1323 for (GetElementPtrInst::op_iterator OI = U->idx_begin(), OE = U->idx_end();
1325 if (isa<Instruction>(*OI) && !currExps.test(VN.lookup(*OI))) {
1326 currExps.insert(*OI);
1327 currExps.set(VN.lookup(*OI));
1330 if (!currExps.test(VN.lookup(U))) {
1335 // Handle opaque ops
1336 } else if (!I->isTerminator()){
1337 VN.lookup_or_add(I);
1339 currTemps.insert(I);
1342 if (!I->isTerminator())
1343 if (!currAvail.test(VN.lookup(I))) {
1344 currAvail.insert(I);
1345 currAvail.set(VN.lookup(I));
1349 /// buildsets_anticout - When walking the postdom tree, calculate the ANTIC_OUT
1350 /// set as a function of the ANTIC_IN set of the block's predecessors
1351 bool GVNPRE::buildsets_anticout(BasicBlock* BB,
1352 ValueNumberedSet& anticOut,
1353 SmallPtrSet<BasicBlock*, 8>& visited) {
1354 if (BB->getTerminator()->getNumSuccessors() == 1) {
1355 if (BB->getTerminator()->getSuccessor(0) != BB &&
1356 visited.count(BB->getTerminator()->getSuccessor(0)) == 0) {
1360 phi_translate_set(anticipatedIn[BB->getTerminator()->getSuccessor(0)],
1361 BB, BB->getTerminator()->getSuccessor(0), anticOut);
1363 } else if (BB->getTerminator()->getNumSuccessors() > 1) {
1364 BasicBlock* first = BB->getTerminator()->getSuccessor(0);
1365 for (ValueNumberedSet::iterator I = anticipatedIn[first].begin(),
1366 E = anticipatedIn[first].end(); I != E; ++I) {
1367 anticOut.insert(*I);
1368 anticOut.set(VN.lookup(*I));
1371 for (unsigned i = 1; i < BB->getTerminator()->getNumSuccessors(); ++i) {
1372 BasicBlock* currSucc = BB->getTerminator()->getSuccessor(i);
1373 ValueNumberedSet& succAnticIn = anticipatedIn[currSucc];
1375 std::vector<Value*> temp;
1377 for (ValueNumberedSet::iterator I = anticOut.begin(),
1378 E = anticOut.end(); I != E; ++I)
1379 if (!succAnticIn.test(VN.lookup(*I)))
1382 for (std::vector<Value*>::iterator I = temp.begin(), E = temp.end();
1385 anticOut.reset(VN.lookup(*I));
1393 /// buildsets_anticin - Walk the postdom tree, calculating ANTIC_OUT for
1394 /// each block. ANTIC_IN is then a function of ANTIC_OUT and the GEN
1395 /// sets populated in buildsets_availout
1396 unsigned GVNPRE::buildsets_anticin(BasicBlock* BB,
1397 ValueNumberedSet& anticOut,
1398 ValueNumberedSet& currExps,
1399 SmallPtrSet<Value*, 16>& currTemps,
1400 SmallPtrSet<BasicBlock*, 8>& visited) {
1401 ValueNumberedSet& anticIn = anticipatedIn[BB];
1402 unsigned old = anticIn.size();
1404 bool defer = buildsets_anticout(BB, anticOut, visited);
1410 for (ValueNumberedSet::iterator I = anticOut.begin(),
1411 E = anticOut.end(); I != E; ++I) {
1413 anticIn.set(VN.lookup(*I));
1415 for (ValueNumberedSet::iterator I = currExps.begin(),
1416 E = currExps.end(); I != E; ++I) {
1417 if (!anticIn.test(VN.lookup(*I))) {
1419 anticIn.set(VN.lookup(*I));
1423 for (SmallPtrSet<Value*, 16>::iterator I = currTemps.begin(),
1424 E = currTemps.end(); I != E; ++I) {
1426 anticIn.reset(VN.lookup(*I));
1432 if (old != anticIn.size())
1438 /// buildsets - Phase 1 of the main algorithm. Construct the AVAIL_OUT
1439 /// and the ANTIC_IN sets.
1440 void GVNPRE::buildsets(Function& F) {
1441 DenseMap<BasicBlock*, ValueNumberedSet> generatedExpressions;
1442 DenseMap<BasicBlock*, SmallPtrSet<Value*, 16> > generatedTemporaries;
1444 DominatorTree &DT = getAnalysis<DominatorTree>();
1446 // Phase 1, Part 1: calculate AVAIL_OUT
1448 // Top-down walk of the dominator tree
1449 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1450 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1452 // Get the sets to update for this block
1453 ValueNumberedSet& currExps = generatedExpressions[DI->getBlock()];
1454 ValueNumberedSet& currPhis = generatedPhis[DI->getBlock()];
1455 SmallPtrSet<Value*, 16>& currTemps = generatedTemporaries[DI->getBlock()];
1456 ValueNumberedSet& currAvail = availableOut[DI->getBlock()];
1458 BasicBlock* BB = DI->getBlock();
1460 // A block inherits AVAIL_OUT from its dominator
1461 if (DI->getIDom() != 0)
1462 currAvail = availableOut[DI->getIDom()->getBlock()];
1464 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
1466 buildsets_availout(BI, currAvail, currPhis, currExps,
1471 // Phase 1, Part 2: calculate ANTIC_IN
1473 SmallPtrSet<BasicBlock*, 8> visited;
1474 SmallPtrSet<BasicBlock*, 4> block_changed;
1475 for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
1476 block_changed.insert(FI);
1478 bool changed = true;
1479 unsigned iterations = 0;
1483 ValueNumberedSet anticOut;
1485 // Postorder walk of the CFG
1486 for (po_iterator<BasicBlock*> BBI = po_begin(&F.getEntryBlock()),
1487 BBE = po_end(&F.getEntryBlock()); BBI != BBE; ++BBI) {
1488 BasicBlock* BB = *BBI;
1490 if (block_changed.count(BB) != 0) {
1491 unsigned ret = buildsets_anticin(BB, anticOut,generatedExpressions[BB],
1492 generatedTemporaries[BB], visited);
1501 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
1503 block_changed.insert(*PI);
1506 block_changed.erase(BB);
1508 changed |= (ret == 2);
1517 /// insertion_pre - When a partial redundancy has been identified, eliminate it
1518 /// by inserting appropriate values into the predecessors and a phi node in
1520 void GVNPRE::insertion_pre(Value* e, BasicBlock* BB,
1521 std::map<BasicBlock*, Value*>& avail,
1522 std::map<BasicBlock*, ValueNumberedSet>& new_sets) {
1523 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1524 Value* e2 = avail[*PI];
1525 if (!availableOut[*PI].test(VN.lookup(e2))) {
1526 User* U = cast<User>(e2);
1529 if (isa<BinaryOperator>(U->getOperand(0)) ||
1530 isa<CmpInst>(U->getOperand(0)) ||
1531 isa<ShuffleVectorInst>(U->getOperand(0)) ||
1532 isa<ExtractElementInst>(U->getOperand(0)) ||
1533 isa<InsertElementInst>(U->getOperand(0)) ||
1534 isa<SelectInst>(U->getOperand(0)) ||
1535 isa<CastInst>(U->getOperand(0)) ||
1536 isa<GetElementPtrInst>(U->getOperand(0)))
1537 s1 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(0)));
1539 s1 = U->getOperand(0);
1543 if (isa<BinaryOperator>(U) ||
1545 isa<ShuffleVectorInst>(U) ||
1546 isa<ExtractElementInst>(U) ||
1547 isa<InsertElementInst>(U) ||
1549 if (isa<BinaryOperator>(U->getOperand(1)) ||
1550 isa<CmpInst>(U->getOperand(1)) ||
1551 isa<ShuffleVectorInst>(U->getOperand(1)) ||
1552 isa<ExtractElementInst>(U->getOperand(1)) ||
1553 isa<InsertElementInst>(U->getOperand(1)) ||
1554 isa<SelectInst>(U->getOperand(1)) ||
1555 isa<CastInst>(U->getOperand(1)) ||
1556 isa<GetElementPtrInst>(U->getOperand(1))) {
1557 s2 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(1)));
1559 s2 = U->getOperand(1);
1562 // Ternary Operators
1564 if (isa<ShuffleVectorInst>(U) ||
1565 isa<InsertElementInst>(U) ||
1567 if (isa<BinaryOperator>(U->getOperand(2)) ||
1568 isa<CmpInst>(U->getOperand(2)) ||
1569 isa<ShuffleVectorInst>(U->getOperand(2)) ||
1570 isa<ExtractElementInst>(U->getOperand(2)) ||
1571 isa<InsertElementInst>(U->getOperand(2)) ||
1572 isa<SelectInst>(U->getOperand(2)) ||
1573 isa<CastInst>(U->getOperand(2)) ||
1574 isa<GetElementPtrInst>(U->getOperand(2))) {
1575 s3 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(2)));
1577 s3 = U->getOperand(2);
1581 std::vector<Value*> sVarargs;
1582 if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U)) {
1583 for (GetElementPtrInst::op_iterator OI = G->idx_begin(),
1584 OE = G->idx_end(); OI != OE; ++OI) {
1585 if (isa<BinaryOperator>(*OI) ||
1586 isa<CmpInst>(*OI) ||
1587 isa<ShuffleVectorInst>(*OI) ||
1588 isa<ExtractElementInst>(*OI) ||
1589 isa<InsertElementInst>(*OI) ||
1590 isa<SelectInst>(*OI) ||
1591 isa<CastInst>(*OI) ||
1592 isa<GetElementPtrInst>(*OI)) {
1593 sVarargs.push_back(find_leader(availableOut[*PI],
1596 sVarargs.push_back(*OI);
1602 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
1603 newVal = BinaryOperator::create(BO->getOpcode(), s1, s2,
1604 BO->getName()+".gvnpre",
1605 (*PI)->getTerminator());
1606 else if (CmpInst* C = dyn_cast<CmpInst>(U))
1607 newVal = CmpInst::create(C->getOpcode(), C->getPredicate(), s1, s2,
1608 C->getName()+".gvnpre",
1609 (*PI)->getTerminator());
1610 else if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
1611 newVal = new ShuffleVectorInst(s1, s2, s3, S->getName()+".gvnpre",
1612 (*PI)->getTerminator());
1613 else if (InsertElementInst* S = dyn_cast<InsertElementInst>(U))
1614 newVal = new InsertElementInst(s1, s2, s3, S->getName()+".gvnpre",
1615 (*PI)->getTerminator());
1616 else if (ExtractElementInst* S = dyn_cast<ExtractElementInst>(U))
1617 newVal = new ExtractElementInst(s1, s2, S->getName()+".gvnpre",
1618 (*PI)->getTerminator());
1619 else if (SelectInst* S = dyn_cast<SelectInst>(U))
1620 newVal = new SelectInst(s1, s2, s3, S->getName()+".gvnpre",
1621 (*PI)->getTerminator());
1622 else if (CastInst* C = dyn_cast<CastInst>(U))
1623 newVal = CastInst::create(C->getOpcode(), s1, C->getType(),
1624 C->getName()+".gvnpre",
1625 (*PI)->getTerminator());
1626 else if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U))
1627 newVal = new GetElementPtrInst(s1, &sVarargs[0], sVarargs.size(),
1628 G->getName()+".gvnpre",
1629 (*PI)->getTerminator());
1632 VN.add(newVal, VN.lookup(U));
1634 ValueNumberedSet& predAvail = availableOut[*PI];
1635 val_replace(predAvail, newVal);
1636 val_replace(new_sets[*PI], newVal);
1637 predAvail.set(VN.lookup(newVal));
1639 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1640 if (av != avail.end())
1642 avail.insert(std::make_pair(*PI, newVal));
1650 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1652 p = new PHINode(avail[*PI]->getType(), "gvnpre-join", BB->begin());
1654 p->addIncoming(avail[*PI], *PI);
1657 VN.add(p, VN.lookup(e));
1658 val_replace(availableOut[BB], p);
1659 availableOut[BB].set(VN.lookup(e));
1660 generatedPhis[BB].insert(p);
1661 generatedPhis[BB].set(VN.lookup(e));
1662 new_sets[BB].insert(p);
1663 new_sets[BB].set(VN.lookup(e));
1668 /// insertion_mergepoint - When walking the dom tree, check at each merge
1669 /// block for the possibility of a partial redundancy. If present, eliminate it
1670 unsigned GVNPRE::insertion_mergepoint(std::vector<Value*>& workList,
1671 df_iterator<DomTreeNode*>& D,
1672 std::map<BasicBlock*, ValueNumberedSet >& new_sets) {
1673 bool changed_function = false;
1674 bool new_stuff = false;
1676 BasicBlock* BB = D->getBlock();
1677 for (unsigned i = 0; i < workList.size(); ++i) {
1678 Value* e = workList[i];
1680 if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
1681 isa<ExtractElementInst>(e) || isa<InsertElementInst>(e) ||
1682 isa<ShuffleVectorInst>(e) || isa<SelectInst>(e) || isa<CastInst>(e) ||
1683 isa<GetElementPtrInst>(e)) {
1684 if (availableOut[D->getIDom()->getBlock()].test(VN.lookup(e)))
1687 std::map<BasicBlock*, Value*> avail;
1688 bool by_some = false;
1689 bool all_same = true;
1690 Value * first_s = 0;
1692 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;
1694 Value *e2 = phi_translate(e, *PI, BB);
1695 Value *e3 = find_leader(availableOut[*PI], VN.lookup(e2));
1698 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1699 if (av != avail.end())
1701 avail.insert(std::make_pair(*PI, e2));
1704 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1705 if (av != avail.end())
1707 avail.insert(std::make_pair(*PI, e3));
1712 else if (first_s != e3)
1717 if (by_some && !all_same &&
1718 !generatedPhis[BB].test(VN.lookup(e))) {
1719 insertion_pre(e, BB, avail, new_sets);
1721 changed_function = true;
1727 unsigned retval = 0;
1728 if (changed_function)
1736 /// insert - Phase 2 of the main algorithm. Walk the dominator tree looking for
1737 /// merge points. When one is found, check for a partial redundancy. If one is
1738 /// present, eliminate it. Repeat this walk until no changes are made.
1739 bool GVNPRE::insertion(Function& F) {
1740 bool changed_function = false;
1742 DominatorTree &DT = getAnalysis<DominatorTree>();
1744 std::map<BasicBlock*, ValueNumberedSet> new_sets;
1745 bool new_stuff = true;
1748 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1749 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1750 BasicBlock* BB = DI->getBlock();
1755 ValueNumberedSet& availOut = availableOut[BB];
1756 ValueNumberedSet& anticIn = anticipatedIn[BB];
1758 // Replace leaders with leaders inherited from dominator
1759 if (DI->getIDom() != 0) {
1760 ValueNumberedSet& dom_set = new_sets[DI->getIDom()->getBlock()];
1761 for (ValueNumberedSet::iterator I = dom_set.begin(),
1762 E = dom_set.end(); I != E; ++I) {
1763 val_replace(new_sets[BB], *I);
1764 val_replace(availOut, *I);
1768 // If there is more than one predecessor...
1769 if (pred_begin(BB) != pred_end(BB) && ++pred_begin(BB) != pred_end(BB)) {
1770 std::vector<Value*> workList;
1771 workList.reserve(anticIn.size());
1772 topo_sort(anticIn, workList);
1774 unsigned result = insertion_mergepoint(workList, DI, new_sets);
1776 changed_function = true;
1783 return changed_function;
1786 // GVNPRE::runOnFunction - This is the main transformation entry point for a
1789 bool GVNPRE::runOnFunction(Function &F) {
1790 // Clean out global sets from any previous functions
1792 createdExpressions.clear();
1793 availableOut.clear();
1794 anticipatedIn.clear();
1795 generatedPhis.clear();
1797 bool changed_function = false;
1799 // Phase 1: BuildSets
1800 // This phase calculates the AVAIL_OUT and ANTIC_IN sets
1804 // This phase inserts values to make partially redundant values
1806 changed_function |= insertion(F);
1808 // Phase 3: Eliminate
1809 // This phase performs trivial full redundancy elimination
1810 changed_function |= elimination();
1813 // This phase cleans up values that were created solely
1814 // as leaders for expressions
1817 return changed_function;