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/Support/CFG.h"
35 #include "llvm/Support/Compiler.h"
36 #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 //===----------------------------------------------------------------------===//
550 //===----------------------------------------------------------------------===//
554 class VISIBILITY_HIDDEN GVNPRE : public FunctionPass {
555 bool runOnFunction(Function &F);
557 static char ID; // Pass identification, replacement for typeid
558 GVNPRE() : FunctionPass((intptr_t)&ID) { }
562 std::vector<Instruction*> createdExpressions;
564 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > availableOut;
565 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > anticipatedIn;
567 // This transformation requires dominator postdominator info
568 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
569 AU.setPreservesCFG();
570 AU.addRequired<DominatorTree>();
574 // FIXME: eliminate or document these better
575 void dump(const SmallPtrSet<Value*, 16>& s) const;
576 void clean(SmallPtrSet<Value*, 16>& set, BitVector& presentInSet);
577 Value* find_leader(SmallPtrSet<Value*, 16>& vals,
579 Value* phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ);
580 void phi_translate_set(SmallPtrSet<Value*, 16>& anticIn, BasicBlock* pred,
581 BasicBlock* succ, SmallPtrSet<Value*, 16>& out);
583 void topo_sort(SmallPtrSet<Value*, 16>& set,
584 std::vector<Value*>& vec);
589 void val_insert(SmallPtrSet<Value*, 16>& s, Value* v);
590 void val_replace(SmallPtrSet<Value*, 16>& s, Value* v);
591 bool dependsOnInvoke(Value* V);
592 void buildsets_availout(BasicBlock::iterator I,
593 SmallPtrSet<Value*, 16>& currAvail,
594 SmallPtrSet<PHINode*, 16>& currPhis,
595 SmallPtrSet<Value*, 16>& currExps,
596 SmallPtrSet<Value*, 16>& currTemps,
597 BitVector& availNumbers,
598 BitVector& expNumbers);
599 bool buildsets_anticout(BasicBlock* BB,
600 SmallPtrSet<Value*, 16>& anticOut,
601 std::set<BasicBlock*>& visited);
602 unsigned buildsets_anticin(BasicBlock* BB,
603 SmallPtrSet<Value*, 16>& anticOut,
604 SmallPtrSet<Value*, 16>& currExps,
605 SmallPtrSet<Value*, 16>& currTemps,
606 std::set<BasicBlock*>& visited);
607 void buildsets(Function& F);
609 void insertion_pre(Value* e, BasicBlock* BB,
610 std::map<BasicBlock*, Value*>& avail,
611 SmallPtrSet<Value*, 16>& new_set);
612 unsigned insertion_mergepoint(std::vector<Value*>& workList,
613 df_iterator<DomTreeNode*>& D,
614 SmallPtrSet<Value*, 16>& new_set);
615 bool insertion(Function& F);
623 // createGVNPREPass - The public interface to this file...
624 FunctionPass *llvm::createGVNPREPass() { return new GVNPRE(); }
626 RegisterPass<GVNPRE> X("gvnpre",
627 "Global Value Numbering/Partial Redundancy Elimination");
630 STATISTIC(NumInsertedVals, "Number of values inserted");
631 STATISTIC(NumInsertedPhis, "Number of PHI nodes inserted");
632 STATISTIC(NumEliminated, "Number of redundant instructions eliminated");
634 /// find_leader - Given a set and a value number, return the first
635 /// element of the set with that value number, or 0 if no such element
637 Value* GVNPRE::find_leader(SmallPtrSet<Value*, 16>& vals, uint32_t v) {
638 for (SmallPtrSet<Value*, 16>::iterator I = vals.begin(), E = vals.end();
640 if (v == VN.lookup(*I))
646 /// val_insert - Insert a value into a set only if there is not a value
647 /// with the same value number already in the set
648 void GVNPRE::val_insert(SmallPtrSet<Value*, 16>& s, Value* v) {
649 uint32_t num = VN.lookup(v);
650 Value* leader = find_leader(s, num);
655 /// val_replace - Insert a value into a set, replacing any values already in
656 /// the set that have the same value number
657 void GVNPRE::val_replace(SmallPtrSet<Value*, 16>& s, Value* v) {
658 uint32_t num = VN.lookup(v);
659 Value* leader = find_leader(s, num);
660 while (leader != 0) {
662 leader = find_leader(s, num);
667 /// phi_translate - Given a value, its parent block, and a predecessor of its
668 /// parent, translate the value into legal for the predecessor block. This
669 /// means translating its operands (and recursively, their operands) through
670 /// any phi nodes in the parent into values available in the predecessor
671 Value* GVNPRE::phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) {
676 if (CastInst* U = dyn_cast<CastInst>(V)) {
678 if (isa<Instruction>(U->getOperand(0)))
679 newOp1 = phi_translate(U->getOperand(0), pred, succ);
681 newOp1 = U->getOperand(0);
686 if (newOp1 != U->getOperand(0)) {
687 Instruction* newVal = 0;
688 if (CastInst* C = dyn_cast<CastInst>(U))
689 newVal = CastInst::create(C->getOpcode(),
690 newOp1, C->getType(),
691 C->getName()+".expr");
693 uint32_t v = VN.lookup_or_add(newVal);
695 Value* leader = find_leader(availableOut[pred], v);
697 createdExpressions.push_back(newVal);
707 } if (isa<BinaryOperator>(V) || isa<CmpInst>(V) ||
708 isa<ExtractElementInst>(V)) {
709 User* U = cast<User>(V);
712 if (isa<Instruction>(U->getOperand(0)))
713 newOp1 = phi_translate(U->getOperand(0), pred, succ);
715 newOp1 = U->getOperand(0);
721 if (isa<Instruction>(U->getOperand(1)))
722 newOp2 = phi_translate(U->getOperand(1), pred, succ);
724 newOp2 = U->getOperand(1);
729 if (newOp1 != U->getOperand(0) || newOp2 != U->getOperand(1)) {
730 Instruction* newVal = 0;
731 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
732 newVal = BinaryOperator::create(BO->getOpcode(),
734 BO->getName()+".expr");
735 else if (CmpInst* C = dyn_cast<CmpInst>(U))
736 newVal = CmpInst::create(C->getOpcode(),
739 C->getName()+".expr");
740 else if (ExtractElementInst* E = dyn_cast<ExtractElementInst>(U))
741 newVal = new ExtractElementInst(newOp1, newOp2, E->getName()+".expr");
743 uint32_t v = VN.lookup_or_add(newVal);
745 Value* leader = find_leader(availableOut[pred], v);
747 createdExpressions.push_back(newVal);
756 // Ternary Operations
757 } else if (isa<ShuffleVectorInst>(V) || isa<InsertElementInst>(V) ||
758 isa<SelectInst>(V)) {
759 User* U = cast<User>(V);
762 if (isa<Instruction>(U->getOperand(0)))
763 newOp1 = phi_translate(U->getOperand(0), pred, succ);
765 newOp1 = U->getOperand(0);
771 if (isa<Instruction>(U->getOperand(1)))
772 newOp2 = phi_translate(U->getOperand(1), pred, succ);
774 newOp2 = U->getOperand(1);
780 if (isa<Instruction>(U->getOperand(2)))
781 newOp3 = phi_translate(U->getOperand(2), pred, succ);
783 newOp3 = U->getOperand(2);
788 if (newOp1 != U->getOperand(0) ||
789 newOp2 != U->getOperand(1) ||
790 newOp3 != U->getOperand(2)) {
791 Instruction* newVal = 0;
792 if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
793 newVal = new ShuffleVectorInst(newOp1, newOp2, newOp3,
794 S->getName()+".expr");
795 else if (InsertElementInst* I = dyn_cast<InsertElementInst>(U))
796 newVal = new InsertElementInst(newOp1, newOp2, newOp3,
797 I->getName()+".expr");
798 else if (SelectInst* I = dyn_cast<SelectInst>(U))
799 newVal = new SelectInst(newOp1, newOp2, newOp3, I->getName()+".expr");
801 uint32_t v = VN.lookup_or_add(newVal);
803 Value* leader = find_leader(availableOut[pred], v);
805 createdExpressions.push_back(newVal);
815 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
817 if (isa<Instruction>(U->getPointerOperand()))
818 newOp1 = phi_translate(U->getPointerOperand(), pred, succ);
820 newOp1 = U->getPointerOperand();
825 bool changed_idx = false;
826 std::vector<Value*> newIdx;
827 for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
829 if (isa<Instruction>(*I)) {
830 Value* newVal = phi_translate(*I, pred, succ);
831 newIdx.push_back(newVal);
835 newIdx.push_back(*I);
838 if (newOp1 != U->getPointerOperand() || changed_idx) {
839 Instruction* newVal = new GetElementPtrInst(U->getPointerOperand(),
840 &newIdx[0], newIdx.size(),
841 U->getName()+".expr");
843 uint32_t v = VN.lookup_or_add(newVal);
845 Value* leader = find_leader(availableOut[pred], v);
847 createdExpressions.push_back(newVal);
857 } else if (PHINode* P = dyn_cast<PHINode>(V)) {
858 if (P->getParent() == succ)
859 return P->getIncomingValueForBlock(pred);
865 /// phi_translate_set - Perform phi translation on every element of a set
866 void GVNPRE::phi_translate_set(SmallPtrSet<Value*, 16>& anticIn,
867 BasicBlock* pred, BasicBlock* succ,
868 SmallPtrSet<Value*, 16>& out) {
869 for (SmallPtrSet<Value*, 16>::iterator I = anticIn.begin(),
870 E = anticIn.end(); I != E; ++I) {
871 Value* V = phi_translate(*I, pred, succ);
877 /// dependsOnInvoke - Test if a value has an phi node as an operand, any of
878 /// whose inputs is an invoke instruction. If this is true, we cannot safely
879 /// PRE the instruction or anything that depends on it.
880 bool GVNPRE::dependsOnInvoke(Value* V) {
881 if (PHINode* p = dyn_cast<PHINode>(V)) {
882 for (PHINode::op_iterator I = p->op_begin(), E = p->op_end(); I != E; ++I)
883 if (isa<InvokeInst>(*I))
891 /// clean - Remove all non-opaque values from the set whose operands are not
892 /// themselves in the set, as well as all values that depend on invokes (see
894 void GVNPRE::clean(SmallPtrSet<Value*, 16>& set, BitVector& presentInSet) {
895 std::vector<Value*> worklist;
896 worklist.reserve(set.size());
897 topo_sort(set, worklist);
899 for (unsigned i = 0; i < worklist.size(); ++i) {
900 Value* v = worklist[i];
903 if (CastInst* U = dyn_cast<CastInst>(v)) {
904 bool lhsValid = !isa<Instruction>(U->getOperand(0));
905 lhsValid |= presentInSet.test(VN.lookup(U->getOperand(0)));
907 lhsValid = !dependsOnInvoke(U->getOperand(0));
911 presentInSet.flip(VN.lookup(U));
915 } else if (isa<BinaryOperator>(v) || isa<CmpInst>(v) ||
916 isa<ExtractElementInst>(v)) {
917 User* U = cast<User>(v);
919 bool lhsValid = !isa<Instruction>(U->getOperand(0));
920 lhsValid |= presentInSet.test(VN.lookup(U->getOperand(0)));
922 lhsValid = !dependsOnInvoke(U->getOperand(0));
924 bool rhsValid = !isa<Instruction>(U->getOperand(1));
925 rhsValid |= presentInSet.test(VN.lookup(U->getOperand(1)));
927 rhsValid = !dependsOnInvoke(U->getOperand(1));
929 if (!lhsValid || !rhsValid) {
931 presentInSet.flip(VN.lookup(U));
934 // Handle ternary ops
935 } else if (isa<ShuffleVectorInst>(v) || isa<InsertElementInst>(v) ||
936 isa<SelectInst>(v)) {
937 User* U = cast<User>(v);
939 bool lhsValid = !isa<Instruction>(U->getOperand(0));
940 lhsValid |= presentInSet.test(VN.lookup(U->getOperand(0)));
942 lhsValid = !dependsOnInvoke(U->getOperand(0));
944 bool rhsValid = !isa<Instruction>(U->getOperand(1));
945 rhsValid |= presentInSet.test(VN.lookup(U->getOperand(1)));
947 rhsValid = !dependsOnInvoke(U->getOperand(1));
949 bool thirdValid = !isa<Instruction>(U->getOperand(2));
950 thirdValid |= presentInSet.test(VN.lookup(U->getOperand(2)));
952 thirdValid = !dependsOnInvoke(U->getOperand(2));
954 if (!lhsValid || !rhsValid || !thirdValid) {
956 presentInSet.flip(VN.lookup(U));
959 // Handle varargs ops
960 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(v)) {
961 bool ptrValid = !isa<Instruction>(U->getPointerOperand());
962 ptrValid |= presentInSet.test(VN.lookup(U->getPointerOperand()));
964 ptrValid = !dependsOnInvoke(U->getPointerOperand());
966 bool varValid = true;
967 for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
970 varValid &= !isa<Instruction>(*I) || presentInSet.test(VN.lookup(*I));
971 varValid &= !dependsOnInvoke(*I);
974 if (!ptrValid || !varValid) {
976 presentInSet.flip(VN.lookup(U));
982 /// topo_sort - Given a set of values, sort them by topological
983 /// order into the provided vector.
984 void GVNPRE::topo_sort(SmallPtrSet<Value*, 16>& set, std::vector<Value*>& vec) {
985 SmallPtrSet<Value*, 16> visited;
986 std::vector<Value*> stack;
987 for (SmallPtrSet<Value*, 16>::iterator I = set.begin(), E = set.end();
989 if (visited.count(*I) == 0)
992 while (!stack.empty()) {
993 Value* e = stack.back();
996 if (CastInst* U = dyn_cast<CastInst>(e)) {
997 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
999 if (l != 0 && isa<Instruction>(l) &&
1000 visited.count(l) == 0)
1008 // Handle binary ops
1009 } else if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
1010 isa<ExtractElementInst>(e)) {
1011 User* U = cast<User>(e);
1012 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1013 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
1015 if (l != 0 && isa<Instruction>(l) &&
1016 visited.count(l) == 0)
1018 else if (r != 0 && isa<Instruction>(r) &&
1019 visited.count(r) == 0)
1027 // Handle ternary ops
1028 } else if (isa<InsertElementInst>(e) || isa<ShuffleVectorInst>(e) ||
1029 isa<SelectInst>(e)) {
1030 User* U = cast<User>(e);
1031 Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
1032 Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
1033 Value* m = find_leader(set, VN.lookup(U->getOperand(2)));
1035 if (l != 0 && isa<Instruction>(l) &&
1036 visited.count(l) == 0)
1038 else if (r != 0 && isa<Instruction>(r) &&
1039 visited.count(r) == 0)
1041 else if (m != 0 && isa<Instruction>(m) &&
1042 visited.count(m) == 0)
1050 // Handle vararg ops
1051 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(e)) {
1052 Value* p = find_leader(set, VN.lookup(U->getPointerOperand()));
1054 if (p != 0 && isa<Instruction>(p) &&
1055 visited.count(p) == 0)
1058 bool push_va = false;
1059 for (GetElementPtrInst::op_iterator I = U->idx_begin(),
1060 E = U->idx_end(); I != E; ++I) {
1061 Value * v = find_leader(set, VN.lookup(*I));
1062 if (v != 0 && isa<Instruction>(v) && visited.count(v) == 0) {
1075 // Handle opaque ops
1087 /// dump - Dump a set of values to standard error
1088 void GVNPRE::dump(const SmallPtrSet<Value*, 16>& s) const {
1090 for (SmallPtrSet<Value*, 16>::iterator I = s.begin(), E = s.end();
1092 DOUT << "" << VN.lookup(*I) << ": ";
1093 DEBUG((*I)->dump());
1098 /// elimination - Phase 3 of the main algorithm. Perform full redundancy
1099 /// elimination by walking the dominator tree and removing any instruction that
1100 /// is dominated by another instruction with the same value number.
1101 bool GVNPRE::elimination() {
1102 DOUT << "\n\nPhase 3: Elimination\n\n";
1104 bool changed_function = false;
1106 std::vector<std::pair<Instruction*, Value*> > replace;
1107 std::vector<Instruction*> erase;
1109 DominatorTree& DT = getAnalysis<DominatorTree>();
1111 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1112 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1113 BasicBlock* BB = DI->getBlock();
1115 //DOUT << "Block: " << BB->getName() << "\n";
1116 //dump(availableOut[BB]);
1119 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
1122 if (isa<BinaryOperator>(BI) || isa<CmpInst>(BI) ||
1123 isa<ShuffleVectorInst>(BI) || isa<InsertElementInst>(BI) ||
1124 isa<ExtractElementInst>(BI) || isa<SelectInst>(BI) ||
1125 isa<CastInst>(BI) || isa<GetElementPtrInst>(BI)) {
1126 Value *leader = find_leader(availableOut[BB], VN.lookup(BI));
1129 if (Instruction* Instr = dyn_cast<Instruction>(leader))
1130 if (Instr->getParent() != 0 && Instr != BI) {
1131 replace.push_back(std::make_pair(BI, leader));
1132 erase.push_back(BI);
1139 while (!replace.empty()) {
1140 std::pair<Instruction*, Value*> rep = replace.back();
1142 rep.first->replaceAllUsesWith(rep.second);
1143 changed_function = true;
1146 for (std::vector<Instruction*>::iterator I = erase.begin(), E = erase.end();
1148 (*I)->eraseFromParent();
1150 return changed_function;
1153 /// cleanup - Delete any extraneous values that were created to represent
1154 /// expressions without leaders.
1155 void GVNPRE::cleanup() {
1156 while (!createdExpressions.empty()) {
1157 Instruction* I = createdExpressions.back();
1158 createdExpressions.pop_back();
1164 /// buildsets_availout - When calculating availability, handle an instruction
1165 /// by inserting it into the appropriate sets
1166 void GVNPRE::buildsets_availout(BasicBlock::iterator I,
1167 SmallPtrSet<Value*, 16>& currAvail,
1168 SmallPtrSet<PHINode*, 16>& currPhis,
1169 SmallPtrSet<Value*, 16>& currExps,
1170 SmallPtrSet<Value*, 16>& currTemps,
1171 BitVector& availNumbers,
1172 BitVector& expNumbers) {
1174 if (PHINode* p = dyn_cast<PHINode>(I)) {
1175 VN.lookup_or_add(p);
1176 expNumbers.resize(VN.size());
1177 availNumbers.resize(VN.size());
1182 } else if (CastInst* U = dyn_cast<CastInst>(I)) {
1183 Value* leftValue = U->getOperand(0);
1185 unsigned num = VN.lookup_or_add(U);
1186 expNumbers.resize(VN.size());
1187 availNumbers.resize(VN.size());
1189 if (isa<Instruction>(leftValue))
1190 if (!expNumbers.test(VN.lookup(leftValue))) {
1191 currExps.insert(leftValue);
1192 expNumbers.set(VN.lookup(leftValue));
1195 if (!expNumbers.test(VN.lookup(U))) {
1197 expNumbers.set(num);
1200 // Handle binary ops
1201 } else if (isa<BinaryOperator>(I) || isa<CmpInst>(I) ||
1202 isa<ExtractElementInst>(I)) {
1203 User* U = cast<User>(I);
1204 Value* leftValue = U->getOperand(0);
1205 Value* rightValue = U->getOperand(1);
1207 unsigned num = VN.lookup_or_add(U);
1208 expNumbers.resize(VN.size());
1209 availNumbers.resize(VN.size());
1211 if (isa<Instruction>(leftValue))
1212 if (!expNumbers.test(VN.lookup(leftValue))) {
1213 currExps.insert(leftValue);
1214 expNumbers.set(VN.lookup(leftValue));
1217 if (isa<Instruction>(rightValue))
1218 if (!expNumbers.test(VN.lookup(rightValue))) {
1219 currExps.insert(rightValue);
1220 expNumbers.set(VN.lookup(rightValue));
1223 if (!expNumbers.test(VN.lookup(U))) {
1225 expNumbers.set(num);
1228 // Handle ternary ops
1229 } else if (isa<InsertElementInst>(I) || isa<ShuffleVectorInst>(I) ||
1230 isa<SelectInst>(I)) {
1231 User* U = cast<User>(I);
1232 Value* leftValue = U->getOperand(0);
1233 Value* rightValue = U->getOperand(1);
1234 Value* thirdValue = U->getOperand(2);
1236 VN.lookup_or_add(U);
1238 unsigned num = VN.lookup_or_add(U);
1239 expNumbers.resize(VN.size());
1240 availNumbers.resize(VN.size());
1242 if (isa<Instruction>(leftValue))
1243 if (!expNumbers.test(VN.lookup(leftValue))) {
1244 currExps.insert(leftValue);
1245 expNumbers.set(VN.lookup(leftValue));
1247 if (isa<Instruction>(rightValue))
1248 if (!expNumbers.test(VN.lookup(rightValue))) {
1249 currExps.insert(rightValue);
1250 expNumbers.set(VN.lookup(rightValue));
1252 if (isa<Instruction>(thirdValue))
1253 if (!expNumbers.test(VN.lookup(thirdValue))) {
1254 currExps.insert(thirdValue);
1255 expNumbers.set(VN.lookup(thirdValue));
1258 if (!expNumbers.test(VN.lookup(U))) {
1260 expNumbers.set(num);
1263 // Handle vararg ops
1264 } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(I)) {
1265 Value* ptrValue = U->getPointerOperand();
1267 VN.lookup_or_add(U);
1269 unsigned num = VN.lookup_or_add(U);
1270 expNumbers.resize(VN.size());
1271 availNumbers.resize(VN.size());
1273 if (isa<Instruction>(ptrValue))
1274 if (!expNumbers.test(VN.lookup(ptrValue))) {
1275 currExps.insert(ptrValue);
1276 expNumbers.set(VN.lookup(ptrValue));
1279 for (GetElementPtrInst::op_iterator OI = U->idx_begin(), OE = U->idx_end();
1281 if (isa<Instruction>(*OI) && !expNumbers.test(VN.lookup(*OI))) {
1282 currExps.insert(*OI);
1283 expNumbers.set(VN.lookup(*OI));
1286 if (!expNumbers.test(VN.lookup(U))) {
1288 expNumbers.set(num);
1291 // Handle opaque ops
1292 } else if (!I->isTerminator()){
1293 VN.lookup_or_add(I);
1294 expNumbers.resize(VN.size());
1295 availNumbers.resize(VN.size());
1297 currTemps.insert(I);
1300 if (!I->isTerminator())
1301 if (!availNumbers.test(VN.lookup(I))) {
1302 currAvail.insert(I);
1303 availNumbers.set(VN.lookup(I));
1307 /// buildsets_anticout - When walking the postdom tree, calculate the ANTIC_OUT
1308 /// set as a function of the ANTIC_IN set of the block's predecessors
1309 bool GVNPRE::buildsets_anticout(BasicBlock* BB,
1310 SmallPtrSet<Value*, 16>& anticOut,
1311 std::set<BasicBlock*>& visited) {
1312 if (BB->getTerminator()->getNumSuccessors() == 1) {
1313 if (BB->getTerminator()->getSuccessor(0) != BB &&
1314 visited.count(BB->getTerminator()->getSuccessor(0)) == 0) {
1315 DOUT << "DEFER: " << BB->getName() << "\n";
1319 phi_translate_set(anticipatedIn[BB->getTerminator()->getSuccessor(0)],
1320 BB, BB->getTerminator()->getSuccessor(0), anticOut);
1322 } else if (BB->getTerminator()->getNumSuccessors() > 1) {
1323 BasicBlock* first = BB->getTerminator()->getSuccessor(0);
1324 anticOut.insert(anticipatedIn[first].begin(), anticipatedIn[first].end());
1326 for (unsigned i = 1; i < BB->getTerminator()->getNumSuccessors(); ++i) {
1327 BasicBlock* currSucc = BB->getTerminator()->getSuccessor(i);
1328 SmallPtrSet<Value*, 16>& succAnticIn = anticipatedIn[currSucc];
1330 std::vector<Value*> temp;
1332 for (SmallPtrSet<Value*, 16>::iterator I = anticOut.begin(),
1333 E = anticOut.end(); I != E; ++I)
1334 if (succAnticIn.count(*I) == 0)
1337 for (std::vector<Value*>::iterator I = temp.begin(), E = temp.end();
1346 /// buildsets_anticin - Walk the postdom tree, calculating ANTIC_OUT for
1347 /// each block. ANTIC_IN is then a function of ANTIC_OUT and the GEN
1348 /// sets populated in buildsets_availout
1349 unsigned GVNPRE::buildsets_anticin(BasicBlock* BB,
1350 SmallPtrSet<Value*, 16>& anticOut,
1351 SmallPtrSet<Value*, 16>& currExps,
1352 SmallPtrSet<Value*, 16>& currTemps,
1353 std::set<BasicBlock*>& visited) {
1354 SmallPtrSet<Value*, 16>& anticIn = anticipatedIn[BB];
1355 unsigned old = anticIn.size();
1357 bool defer = buildsets_anticout(BB, anticOut, visited);
1363 BitVector numbers(VN.size());
1364 for (SmallPtrSet<Value*, 16>::iterator I = anticOut.begin(),
1365 E = anticOut.end(); I != E; ++I) {
1366 unsigned num = VN.lookup_or_add(*I);
1367 numbers.resize(VN.size());
1369 if (isa<Instruction>(*I)) {
1374 for (SmallPtrSet<Value*, 16>::iterator I = currExps.begin(),
1375 E = currExps.end(); I != E; ++I) {
1376 if (!numbers.test(VN.lookup_or_add(*I))) {
1378 numbers.set(VN.lookup(*I));
1382 for (SmallPtrSet<Value*, 16>::iterator I = currTemps.begin(),
1383 E = currTemps.end(); I != E; ++I) {
1385 numbers.flip(VN.lookup(*I));
1388 clean(anticIn, numbers);
1391 if (old != anticIn.size())
1397 /// buildsets - Phase 1 of the main algorithm. Construct the AVAIL_OUT
1398 /// and the ANTIC_IN sets.
1399 void GVNPRE::buildsets(Function& F) {
1400 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > generatedExpressions;
1401 std::map<BasicBlock*, SmallPtrSet<PHINode*, 16> > generatedPhis;
1402 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > generatedTemporaries;
1404 DominatorTree &DT = getAnalysis<DominatorTree>();
1406 // Phase 1, Part 1: calculate AVAIL_OUT
1408 // Top-down walk of the dominator tree
1409 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1410 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1412 // Get the sets to update for this block
1413 SmallPtrSet<Value*, 16>& currExps = generatedExpressions[DI->getBlock()];
1414 SmallPtrSet<PHINode*, 16>& currPhis = generatedPhis[DI->getBlock()];
1415 SmallPtrSet<Value*, 16>& currTemps = generatedTemporaries[DI->getBlock()];
1416 SmallPtrSet<Value*, 16>& currAvail = availableOut[DI->getBlock()];
1418 BasicBlock* BB = DI->getBlock();
1420 // A block inherits AVAIL_OUT from its dominator
1421 if (DI->getIDom() != 0)
1422 currAvail.insert(availableOut[DI->getIDom()->getBlock()].begin(),
1423 availableOut[DI->getIDom()->getBlock()].end());
1425 BitVector availNumbers(VN.size());
1426 for (SmallPtrSet<Value*, 16>::iterator I = currAvail.begin(),
1427 E = currAvail.end(); I != E; ++I)
1428 availNumbers.set(VN.lookup(*I));
1430 BitVector expNumbers(VN.size());
1431 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
1433 buildsets_availout(BI, currAvail, currPhis, currExps,
1434 currTemps, availNumbers, expNumbers);
1438 // Phase 1, Part 2: calculate ANTIC_IN
1440 std::set<BasicBlock*> visited;
1441 SmallPtrSet<BasicBlock*, 4> block_changed;
1442 for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
1443 block_changed.insert(FI);
1445 bool changed = true;
1446 unsigned iterations = 0;
1450 SmallPtrSet<Value*, 16> anticOut;
1452 // Postorder walk of the CFG
1453 for (po_iterator<BasicBlock*> BBI = po_begin(&F.getEntryBlock()),
1454 BBE = po_end(&F.getEntryBlock()); BBI != BBE; ++BBI) {
1455 BasicBlock* BB = *BBI;
1457 if (block_changed.count(BB) != 0) {
1458 unsigned ret = buildsets_anticin(BB, anticOut,generatedExpressions[BB],
1459 generatedTemporaries[BB], visited);
1468 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
1470 block_changed.insert(*PI);
1473 block_changed.erase(BB);
1475 changed |= (ret == 2);
1483 DOUT << "ITERATIONS: " << iterations << "\n";
1486 /// insertion_pre - When a partial redundancy has been identified, eliminate it
1487 /// by inserting appropriate values into the predecessors and a phi node in
1489 void GVNPRE::insertion_pre(Value* e, BasicBlock* BB,
1490 std::map<BasicBlock*, Value*>& avail,
1491 SmallPtrSet<Value*, 16>& new_set) {
1492 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1493 Value* e2 = avail[*PI];
1494 if (!find_leader(availableOut[*PI], VN.lookup(e2))) {
1495 User* U = cast<User>(e2);
1498 if (isa<BinaryOperator>(U->getOperand(0)) ||
1499 isa<CmpInst>(U->getOperand(0)) ||
1500 isa<ShuffleVectorInst>(U->getOperand(0)) ||
1501 isa<ExtractElementInst>(U->getOperand(0)) ||
1502 isa<InsertElementInst>(U->getOperand(0)) ||
1503 isa<SelectInst>(U->getOperand(0)) ||
1504 isa<CastInst>(U->getOperand(0)) ||
1505 isa<GetElementPtrInst>(U->getOperand(0)))
1506 s1 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(0)));
1508 s1 = U->getOperand(0);
1512 if (isa<BinaryOperator>(U) ||
1514 isa<ShuffleVectorInst>(U) ||
1515 isa<ExtractElementInst>(U) ||
1516 isa<InsertElementInst>(U) ||
1518 if (isa<BinaryOperator>(U->getOperand(1)) ||
1519 isa<CmpInst>(U->getOperand(1)) ||
1520 isa<ShuffleVectorInst>(U->getOperand(1)) ||
1521 isa<ExtractElementInst>(U->getOperand(1)) ||
1522 isa<InsertElementInst>(U->getOperand(1)) ||
1523 isa<SelectInst>(U->getOperand(1)) ||
1524 isa<CastInst>(U->getOperand(1)) ||
1525 isa<GetElementPtrInst>(U->getOperand(1))) {
1526 s2 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(1)));
1528 s2 = U->getOperand(1);
1531 // Ternary Operators
1533 if (isa<ShuffleVectorInst>(U) ||
1534 isa<InsertElementInst>(U) ||
1536 if (isa<BinaryOperator>(U->getOperand(2)) ||
1537 isa<CmpInst>(U->getOperand(2)) ||
1538 isa<ShuffleVectorInst>(U->getOperand(2)) ||
1539 isa<ExtractElementInst>(U->getOperand(2)) ||
1540 isa<InsertElementInst>(U->getOperand(2)) ||
1541 isa<SelectInst>(U->getOperand(2)) ||
1542 isa<CastInst>(U->getOperand(2)) ||
1543 isa<GetElementPtrInst>(U->getOperand(2))) {
1544 s3 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(2)));
1546 s3 = U->getOperand(2);
1550 std::vector<Value*> sVarargs;
1551 if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U)) {
1552 for (GetElementPtrInst::op_iterator OI = G->idx_begin(),
1553 OE = G->idx_end(); OI != OE; ++OI) {
1554 if (isa<BinaryOperator>(*OI) ||
1555 isa<CmpInst>(*OI) ||
1556 isa<ShuffleVectorInst>(*OI) ||
1557 isa<ExtractElementInst>(*OI) ||
1558 isa<InsertElementInst>(*OI) ||
1559 isa<SelectInst>(*OI) ||
1560 isa<CastInst>(*OI) ||
1561 isa<GetElementPtrInst>(*OI)) {
1562 sVarargs.push_back(find_leader(availableOut[*PI],
1565 sVarargs.push_back(*OI);
1571 if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
1572 newVal = BinaryOperator::create(BO->getOpcode(), s1, s2,
1573 BO->getName()+".gvnpre",
1574 (*PI)->getTerminator());
1575 else if (CmpInst* C = dyn_cast<CmpInst>(U))
1576 newVal = CmpInst::create(C->getOpcode(), C->getPredicate(), s1, s2,
1577 C->getName()+".gvnpre",
1578 (*PI)->getTerminator());
1579 else if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
1580 newVal = new ShuffleVectorInst(s1, s2, s3, S->getName()+".gvnpre",
1581 (*PI)->getTerminator());
1582 else if (InsertElementInst* S = dyn_cast<InsertElementInst>(U))
1583 newVal = new InsertElementInst(s1, s2, s3, S->getName()+".gvnpre",
1584 (*PI)->getTerminator());
1585 else if (ExtractElementInst* S = dyn_cast<ExtractElementInst>(U))
1586 newVal = new ExtractElementInst(s1, s2, S->getName()+".gvnpre",
1587 (*PI)->getTerminator());
1588 else if (SelectInst* S = dyn_cast<SelectInst>(U))
1589 newVal = new SelectInst(S->getCondition(), S->getTrueValue(),
1590 S->getFalseValue(), S->getName()+".gvnpre",
1591 (*PI)->getTerminator());
1592 else if (CastInst* C = dyn_cast<CastInst>(U))
1593 newVal = CastInst::create(C->getOpcode(), s1, C->getType(),
1594 C->getName()+".gvnpre",
1595 (*PI)->getTerminator());
1596 else if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U))
1597 newVal = new GetElementPtrInst(s1, &sVarargs[0], sVarargs.size(),
1598 G->getName()+".gvnpre",
1599 (*PI)->getTerminator());
1602 VN.add(newVal, VN.lookup(U));
1604 SmallPtrSet<Value*, 16>& predAvail = availableOut[*PI];
1605 val_replace(predAvail, newVal);
1607 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1608 if (av != avail.end())
1610 avail.insert(std::make_pair(*PI, newVal));
1618 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
1620 p = new PHINode(avail[*PI]->getType(), "gvnpre-join", BB->begin());
1622 p->addIncoming(avail[*PI], *PI);
1625 VN.add(p, VN.lookup(e));
1626 val_replace(availableOut[BB], p);
1632 /// insertion_mergepoint - When walking the dom tree, check at each merge
1633 /// block for the possibility of a partial redundancy. If present, eliminate it
1634 unsigned GVNPRE::insertion_mergepoint(std::vector<Value*>& workList,
1635 df_iterator<DomTreeNode*>& D,
1636 SmallPtrSet<Value*, 16>& new_set) {
1637 bool changed_function = false;
1638 bool new_stuff = false;
1640 BasicBlock* BB = D->getBlock();
1641 for (unsigned i = 0; i < workList.size(); ++i) {
1642 Value* e = workList[i];
1644 if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
1645 isa<ExtractElementInst>(e) || isa<InsertElementInst>(e) ||
1646 isa<ShuffleVectorInst>(e) || isa<SelectInst>(e) || isa<CastInst>(e) ||
1647 isa<GetElementPtrInst>(e)) {
1648 if (find_leader(availableOut[D->getIDom()->getBlock()],
1652 std::map<BasicBlock*, Value*> avail;
1653 bool by_some = false;
1656 for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;
1658 Value *e2 = phi_translate(e, *PI, BB);
1659 Value *e3 = find_leader(availableOut[*PI], VN.lookup(e2));
1662 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1663 if (av != avail.end())
1665 avail.insert(std::make_pair(*PI, e2));
1667 std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
1668 if (av != avail.end())
1670 avail.insert(std::make_pair(*PI, e3));
1677 if (by_some && num_avail < std::distance(pred_begin(BB), pred_end(BB))) {
1678 insertion_pre(e, BB, avail, new_set);
1680 changed_function = true;
1686 unsigned retval = 0;
1687 if (changed_function)
1695 /// insert - Phase 2 of the main algorithm. Walk the dominator tree looking for
1696 /// merge points. When one is found, check for a partial redundancy. If one is
1697 /// present, eliminate it. Repeat this walk until no changes are made.
1698 bool GVNPRE::insertion(Function& F) {
1699 bool changed_function = false;
1701 DominatorTree &DT = getAnalysis<DominatorTree>();
1703 std::map<BasicBlock*, SmallPtrSet<Value*, 16> > new_sets;
1704 bool new_stuff = true;
1707 for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
1708 E = df_end(DT.getRootNode()); DI != E; ++DI) {
1709 BasicBlock* BB = DI->getBlock();
1714 SmallPtrSet<Value*, 16>& new_set = new_sets[BB];
1715 SmallPtrSet<Value*, 16>& availOut = availableOut[BB];
1716 SmallPtrSet<Value*, 16>& anticIn = anticipatedIn[BB];
1720 // Replace leaders with leaders inherited from dominator
1721 if (DI->getIDom() != 0) {
1722 SmallPtrSet<Value*, 16>& dom_set = new_sets[DI->getIDom()->getBlock()];
1723 for (SmallPtrSet<Value*, 16>::iterator I = dom_set.begin(),
1724 E = dom_set.end(); I != E; ++I) {
1726 val_replace(availOut, *I);
1730 // If there is more than one predecessor...
1731 if (pred_begin(BB) != pred_end(BB) && ++pred_begin(BB) != pred_end(BB)) {
1732 std::vector<Value*> workList;
1733 workList.reserve(anticIn.size());
1734 topo_sort(anticIn, workList);
1736 unsigned result = insertion_mergepoint(workList, DI, new_set);
1738 changed_function = true;
1745 return changed_function;
1748 // GVNPRE::runOnFunction - This is the main transformation entry point for a
1751 bool GVNPRE::runOnFunction(Function &F) {
1752 // Clean out global sets from any previous functions
1754 createdExpressions.clear();
1755 availableOut.clear();
1756 anticipatedIn.clear();
1758 bool changed_function = false;
1760 // Phase 1: BuildSets
1761 // This phase calculates the AVAIL_OUT and ANTIC_IN sets
1764 for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) {
1765 DOUT << "AVAIL_OUT: " << FI->getName() << "\n";
1766 dump(availableOut[FI]);
1768 DOUT << "ANTIC_IN: " << FI->getName() << "\n";
1769 dump(anticipatedIn[FI]);
1774 // This phase inserts values to make partially redundant values
1776 changed_function |= insertion(F);
1778 // Phase 3: Eliminate
1779 // This phase performs trivial full redundancy elimination
1780 changed_function |= elimination();
1783 // This phase cleans up values that were created solely
1784 // as leaders for expressions
1787 return changed_function;