+++ /dev/null
-//===- GVNPRE.cpp - Eliminate redundant values and expressions ------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass performs a hybrid of global value numbering and partial redundancy
-// elimination, known as GVN-PRE. It performs partial redundancy elimination on
-// values, rather than lexical expressions, allowing a more comprehensive view
-// the optimization. It replaces redundant values with uses of earlier
-// occurences of the same value. While this is beneficial in that it eliminates
-// unneeded computation, it also increases register pressure by creating large
-// live ranges, and should be used with caution on platforms that are very
-// sensitive to register pressure.
-//
-// Note that this pass does the value numbering itself, it does not use the
-// ValueNumbering analysis passes.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "gvnpre"
-#include "llvm/Value.h"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Instructions.h"
-#include "llvm/Function.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Analysis/Dominators.h"
-#include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/ADT/PostOrderIterator.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
-#include "llvm/Support/CFG.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorHandling.h"
-#include <algorithm>
-#include <deque>
-#include <map>
-using namespace llvm;
-
-//===----------------------------------------------------------------------===//
-// ValueTable Class
-//===----------------------------------------------------------------------===//
-
-namespace {
-
-/// This class holds the mapping between values and value numbers. It is used
-/// as an efficient mechanism to determine the expression-wise equivalence of
-/// two values.
-
-struct Expression {
- enum ExpressionOpcode { ADD, FADD, SUB, FSUB, MUL, FMUL,
- UDIV, SDIV, FDIV, UREM, SREM,
- FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ,
- ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
- ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
- FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
- FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
- FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
- SHUFFLE, SELECT, TRUNC, ZEXT, SEXT, FPTOUI,
- FPTOSI, UITOFP, SITOFP, FPTRUNC, FPEXT,
- PTRTOINT, INTTOPTR, BITCAST, GEP, EMPTY,
- TOMBSTONE };
-
- ExpressionOpcode opcode;
- const Type* type;
- uint32_t firstVN;
- uint32_t secondVN;
- uint32_t thirdVN;
- SmallVector<uint32_t, 4> varargs;
-
- Expression() { }
- explicit Expression(ExpressionOpcode o) : opcode(o) { }
-
- bool operator==(const Expression &other) const {
- if (opcode != other.opcode)
- return false;
- else if (opcode == EMPTY || opcode == TOMBSTONE)
- return true;
- else if (type != other.type)
- return false;
- else if (firstVN != other.firstVN)
- return false;
- else if (secondVN != other.secondVN)
- return false;
- else if (thirdVN != other.thirdVN)
- return false;
- else {
- if (varargs.size() != other.varargs.size())
- return false;
-
- for (size_t i = 0; i < varargs.size(); ++i)
- if (varargs[i] != other.varargs[i])
- return false;
-
- return true;
- }
- }
-
- bool operator!=(const Expression &other) const {
- if (opcode != other.opcode)
- return true;
- else if (opcode == EMPTY || opcode == TOMBSTONE)
- return false;
- else if (type != other.type)
- return true;
- else if (firstVN != other.firstVN)
- return true;
- else if (secondVN != other.secondVN)
- return true;
- else if (thirdVN != other.thirdVN)
- return true;
- else {
- if (varargs.size() != other.varargs.size())
- return true;
-
- for (size_t i = 0; i < varargs.size(); ++i)
- if (varargs[i] != other.varargs[i])
- return true;
-
- return false;
- }
- }
-};
-
-}
-
-namespace {
- class ValueTable {
- private:
- DenseMap<Value*, uint32_t> valueNumbering;
- DenseMap<Expression, uint32_t> expressionNumbering;
-
- uint32_t nextValueNumber;
-
- Expression::ExpressionOpcode getOpcode(BinaryOperator* BO);
- Expression::ExpressionOpcode getOpcode(CmpInst* C);
- Expression::ExpressionOpcode getOpcode(CastInst* C);
- Expression create_expression(BinaryOperator* BO);
- Expression create_expression(CmpInst* C);
- Expression create_expression(ShuffleVectorInst* V);
- Expression create_expression(ExtractElementInst* C);
- Expression create_expression(InsertElementInst* V);
- Expression create_expression(SelectInst* V);
- Expression create_expression(CastInst* C);
- Expression create_expression(GetElementPtrInst* G);
- public:
- ValueTable() { nextValueNumber = 1; }
- uint32_t lookup_or_add(Value* V);
- uint32_t lookup(Value* V) const;
- void add(Value* V, uint32_t num);
- void clear();
- void erase(Value* v);
- unsigned size();
- };
-}
-
-namespace llvm {
-template <> struct DenseMapInfo<Expression> {
- static inline Expression getEmptyKey() {
- return Expression(Expression::EMPTY);
- }
-
- static inline Expression getTombstoneKey() {
- return Expression(Expression::TOMBSTONE);
- }
-
- static unsigned getHashValue(const Expression e) {
- unsigned hash = e.opcode;
-
- hash = e.firstVN + hash * 37;
- hash = e.secondVN + hash * 37;
- hash = e.thirdVN + hash * 37;
-
- hash = ((unsigned)((uintptr_t)e.type >> 4) ^
- (unsigned)((uintptr_t)e.type >> 9)) +
- hash * 37;
-
- for (SmallVector<uint32_t, 4>::const_iterator I = e.varargs.begin(),
- E = e.varargs.end(); I != E; ++I)
- hash = *I + hash * 37;
-
- return hash;
- }
- static bool isEqual(const Expression &LHS, const Expression &RHS) {
- return LHS == RHS;
- }
- static bool isPod() { return true; }
-};
-}
-
-//===----------------------------------------------------------------------===//
-// ValueTable Internal Functions
-//===----------------------------------------------------------------------===//
-Expression::ExpressionOpcode
- ValueTable::getOpcode(BinaryOperator* BO) {
- switch(BO->getOpcode()) {
- case Instruction::Add:
- return Expression::ADD;
- case Instruction::FAdd:
- return Expression::FADD;
- case Instruction::Sub:
- return Expression::SUB;
- case Instruction::FSub:
- return Expression::FSUB;
- case Instruction::Mul:
- return Expression::MUL;
- case Instruction::FMul:
- return Expression::FMUL;
- case Instruction::UDiv:
- return Expression::UDIV;
- case Instruction::SDiv:
- return Expression::SDIV;
- case Instruction::FDiv:
- return Expression::FDIV;
- case Instruction::URem:
- return Expression::UREM;
- case Instruction::SRem:
- return Expression::SREM;
- case Instruction::FRem:
- return Expression::FREM;
- case Instruction::Shl:
- return Expression::SHL;
- case Instruction::LShr:
- return Expression::LSHR;
- case Instruction::AShr:
- return Expression::ASHR;
- case Instruction::And:
- return Expression::AND;
- case Instruction::Or:
- return Expression::OR;
- case Instruction::Xor:
- return Expression::XOR;
-
- // THIS SHOULD NEVER HAPPEN
- default:
- llvm_unreachable("Binary operator with unknown opcode?");
- return Expression::ADD;
- }
-}
-
-Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) {
- if (C->getOpcode() == Instruction::ICmp) {
- switch (C->getPredicate()) {
- case ICmpInst::ICMP_EQ:
- return Expression::ICMPEQ;
- case ICmpInst::ICMP_NE:
- return Expression::ICMPNE;
- case ICmpInst::ICMP_UGT:
- return Expression::ICMPUGT;
- case ICmpInst::ICMP_UGE:
- return Expression::ICMPUGE;
- case ICmpInst::ICMP_ULT:
- return Expression::ICMPULT;
- case ICmpInst::ICMP_ULE:
- return Expression::ICMPULE;
- case ICmpInst::ICMP_SGT:
- return Expression::ICMPSGT;
- case ICmpInst::ICMP_SGE:
- return Expression::ICMPSGE;
- case ICmpInst::ICMP_SLT:
- return Expression::ICMPSLT;
- case ICmpInst::ICMP_SLE:
- return Expression::ICMPSLE;
-
- // THIS SHOULD NEVER HAPPEN
- default:
- llvm_unreachable("Comparison with unknown predicate?");
- return Expression::ICMPEQ;
- }
- } else {
- switch (C->getPredicate()) {
- case FCmpInst::FCMP_OEQ:
- return Expression::FCMPOEQ;
- case FCmpInst::FCMP_OGT:
- return Expression::FCMPOGT;
- case FCmpInst::FCMP_OGE:
- return Expression::FCMPOGE;
- case FCmpInst::FCMP_OLT:
- return Expression::FCMPOLT;
- case FCmpInst::FCMP_OLE:
- return Expression::FCMPOLE;
- case FCmpInst::FCMP_ONE:
- return Expression::FCMPONE;
- case FCmpInst::FCMP_ORD:
- return Expression::FCMPORD;
- case FCmpInst::FCMP_UNO:
- return Expression::FCMPUNO;
- case FCmpInst::FCMP_UEQ:
- return Expression::FCMPUEQ;
- case FCmpInst::FCMP_UGT:
- return Expression::FCMPUGT;
- case FCmpInst::FCMP_UGE:
- return Expression::FCMPUGE;
- case FCmpInst::FCMP_ULT:
- return Expression::FCMPULT;
- case FCmpInst::FCMP_ULE:
- return Expression::FCMPULE;
- case FCmpInst::FCMP_UNE:
- return Expression::FCMPUNE;
-
- // THIS SHOULD NEVER HAPPEN
- default:
- llvm_unreachable("Comparison with unknown predicate?");
- return Expression::FCMPOEQ;
- }
- }
-}
-
-Expression::ExpressionOpcode
- ValueTable::getOpcode(CastInst* C) {
- switch(C->getOpcode()) {
- case Instruction::Trunc:
- return Expression::TRUNC;
- case Instruction::ZExt:
- return Expression::ZEXT;
- case Instruction::SExt:
- return Expression::SEXT;
- case Instruction::FPToUI:
- return Expression::FPTOUI;
- case Instruction::FPToSI:
- return Expression::FPTOSI;
- case Instruction::UIToFP:
- return Expression::UITOFP;
- case Instruction::SIToFP:
- return Expression::SITOFP;
- case Instruction::FPTrunc:
- return Expression::FPTRUNC;
- case Instruction::FPExt:
- return Expression::FPEXT;
- case Instruction::PtrToInt:
- return Expression::PTRTOINT;
- case Instruction::IntToPtr:
- return Expression::INTTOPTR;
- case Instruction::BitCast:
- return Expression::BITCAST;
-
- // THIS SHOULD NEVER HAPPEN
- default:
- llvm_unreachable("Cast operator with unknown opcode?");
- return Expression::BITCAST;
- }
-}
-
-Expression ValueTable::create_expression(BinaryOperator* BO) {
- Expression e;
-
- e.firstVN = lookup_or_add(BO->getOperand(0));
- e.secondVN = lookup_or_add(BO->getOperand(1));
- e.thirdVN = 0;
- e.type = BO->getType();
- e.opcode = getOpcode(BO);
-
- return e;
-}
-
-Expression ValueTable::create_expression(CmpInst* C) {
- Expression e;
-
- e.firstVN = lookup_or_add(C->getOperand(0));
- e.secondVN = lookup_or_add(C->getOperand(1));
- e.thirdVN = 0;
- e.type = C->getType();
- e.opcode = getOpcode(C);
-
- return e;
-}
-
-Expression ValueTable::create_expression(CastInst* C) {
- Expression e;
-
- e.firstVN = lookup_or_add(C->getOperand(0));
- e.secondVN = 0;
- e.thirdVN = 0;
- e.type = C->getType();
- e.opcode = getOpcode(C);
-
- return e;
-}
-
-Expression ValueTable::create_expression(ShuffleVectorInst* S) {
- Expression e;
-
- e.firstVN = lookup_or_add(S->getOperand(0));
- e.secondVN = lookup_or_add(S->getOperand(1));
- e.thirdVN = lookup_or_add(S->getOperand(2));
- e.type = S->getType();
- e.opcode = Expression::SHUFFLE;
-
- return e;
-}
-
-Expression ValueTable::create_expression(ExtractElementInst* E) {
- Expression e;
-
- e.firstVN = lookup_or_add(E->getOperand(0));
- e.secondVN = lookup_or_add(E->getOperand(1));
- e.thirdVN = 0;
- e.type = E->getType();
- e.opcode = Expression::EXTRACT;
-
- return e;
-}
-
-Expression ValueTable::create_expression(InsertElementInst* I) {
- Expression e;
-
- e.firstVN = lookup_or_add(I->getOperand(0));
- e.secondVN = lookup_or_add(I->getOperand(1));
- e.thirdVN = lookup_or_add(I->getOperand(2));
- e.type = I->getType();
- e.opcode = Expression::INSERT;
-
- return e;
-}
-
-Expression ValueTable::create_expression(SelectInst* I) {
- Expression e;
-
- e.firstVN = lookup_or_add(I->getCondition());
- e.secondVN = lookup_or_add(I->getTrueValue());
- e.thirdVN = lookup_or_add(I->getFalseValue());
- e.type = I->getType();
- e.opcode = Expression::SELECT;
-
- return e;
-}
-
-Expression ValueTable::create_expression(GetElementPtrInst* G) {
- Expression e;
-
- e.firstVN = lookup_or_add(G->getPointerOperand());
- e.secondVN = 0;
- e.thirdVN = 0;
- e.type = G->getType();
- e.opcode = Expression::GEP;
-
- for (GetElementPtrInst::op_iterator I = G->idx_begin(), E = G->idx_end();
- I != E; ++I)
- e.varargs.push_back(lookup_or_add(*I));
-
- return e;
-}
-
-//===----------------------------------------------------------------------===//
-// ValueTable External Functions
-//===----------------------------------------------------------------------===//
-
-/// lookup_or_add - Returns the value number for the specified value, assigning
-/// it a new number if it did not have one before.
-uint32_t ValueTable::lookup_or_add(Value* V) {
- DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
- if (VI != valueNumbering.end())
- return VI->second;
-
-
- if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
- Expression e = create_expression(BO);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else if (CmpInst* C = dyn_cast<CmpInst>(V)) {
- Expression e = create_expression(C);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else if (ShuffleVectorInst* U = dyn_cast<ShuffleVectorInst>(V)) {
- Expression e = create_expression(U);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else if (ExtractElementInst* U = dyn_cast<ExtractElementInst>(V)) {
- Expression e = create_expression(U);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else if (InsertElementInst* U = dyn_cast<InsertElementInst>(V)) {
- Expression e = create_expression(U);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else if (SelectInst* U = dyn_cast<SelectInst>(V)) {
- Expression e = create_expression(U);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else if (CastInst* U = dyn_cast<CastInst>(V)) {
- Expression e = create_expression(U);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
- Expression e = create_expression(U);
-
- DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
- if (EI != expressionNumbering.end()) {
- valueNumbering.insert(std::make_pair(V, EI->second));
- return EI->second;
- } else {
- expressionNumbering.insert(std::make_pair(e, nextValueNumber));
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
-
- return nextValueNumber++;
- }
- } else {
- valueNumbering.insert(std::make_pair(V, nextValueNumber));
- return nextValueNumber++;
- }
-}
-
-/// lookup - Returns the value number of the specified value. Fails if
-/// the value has not yet been numbered.
-uint32_t ValueTable::lookup(Value* V) const {
- DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
- if (VI != valueNumbering.end())
- return VI->second;
- else
- llvm_unreachable("Value not numbered?");
-
- return 0;
-}
-
-/// add - Add the specified value with the given value number, removing
-/// its old number, if any
-void ValueTable::add(Value* V, uint32_t num) {
- DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
- if (VI != valueNumbering.end())
- valueNumbering.erase(VI);
- valueNumbering.insert(std::make_pair(V, num));
-}
-
-/// clear - Remove all entries from the ValueTable
-void ValueTable::clear() {
- valueNumbering.clear();
- expressionNumbering.clear();
- nextValueNumber = 1;
-}
-
-/// erase - Remove a value from the value numbering
-void ValueTable::erase(Value* V) {
- valueNumbering.erase(V);
-}
-
-/// size - Return the number of assigned value numbers
-unsigned ValueTable::size() {
- // NOTE: zero is never assigned
- return nextValueNumber;
-}
-
-namespace {
-
-//===----------------------------------------------------------------------===//
-// ValueNumberedSet Class
-//===----------------------------------------------------------------------===//
-
-class ValueNumberedSet {
- private:
- SmallPtrSet<Value*, 8> contents;
- BitVector numbers;
- public:
- ValueNumberedSet() { numbers.resize(1); }
- ValueNumberedSet(const ValueNumberedSet& other) {
- numbers = other.numbers;
- contents = other.contents;
- }
-
- typedef SmallPtrSet<Value*, 8>::iterator iterator;
-
- iterator begin() { return contents.begin(); }
- iterator end() { return contents.end(); }
-
- bool insert(Value* v) { return contents.insert(v); }
- void insert(iterator I, iterator E) { contents.insert(I, E); }
- void erase(Value* v) { contents.erase(v); }
- unsigned count(Value* v) { return contents.count(v); }
- size_t size() { return contents.size(); }
-
- void set(unsigned i) {
- if (i >= numbers.size())
- numbers.resize(i+1);
-
- numbers.set(i);
- }
-
- void operator=(const ValueNumberedSet& other) {
- contents = other.contents;
- numbers = other.numbers;
- }
-
- void reset(unsigned i) {
- if (i < numbers.size())
- numbers.reset(i);
- }
-
- bool test(unsigned i) {
- if (i >= numbers.size())
- return false;
-
- return numbers.test(i);
- }
-
- void clear() {
- contents.clear();
- numbers.clear();
- }
-};
-
-}
-
-//===----------------------------------------------------------------------===//
-// GVNPRE Pass
-//===----------------------------------------------------------------------===//
-
-namespace {
- class GVNPRE : public FunctionPass {
- bool runOnFunction(Function &F);
- public:
- static char ID; // Pass identification, replacement for typeid
- GVNPRE() : FunctionPass(&ID) {}
-
- private:
- ValueTable VN;
- SmallVector<Instruction*, 8> createdExpressions;
-
- DenseMap<BasicBlock*, ValueNumberedSet> availableOut;
- DenseMap<BasicBlock*, ValueNumberedSet> anticipatedIn;
- DenseMap<BasicBlock*, ValueNumberedSet> generatedPhis;
-
- // This transformation requires dominator postdominator info
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesCFG();
- AU.addRequiredID(BreakCriticalEdgesID);
- AU.addRequired<UnifyFunctionExitNodes>();
- AU.addRequired<DominatorTree>();
- }
-
- // Helper fuctions
- // FIXME: eliminate or document these better
- void dump(ValueNumberedSet& s) const ;
- void clean(ValueNumberedSet& set) ;
- Value* find_leader(ValueNumberedSet& vals, uint32_t v) ;
- Value* phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) ;
- void phi_translate_set(ValueNumberedSet& anticIn, BasicBlock* pred,
- BasicBlock* succ, ValueNumberedSet& out) ;
-
- void topo_sort(ValueNumberedSet& set,
- SmallVector<Value*, 8>& vec) ;
-
- void cleanup() ;
- bool elimination() ;
-
- void val_insert(ValueNumberedSet& s, Value* v) ;
- void val_replace(ValueNumberedSet& s, Value* v) ;
- bool dependsOnInvoke(Value* V) ;
- void buildsets_availout(BasicBlock::iterator I,
- ValueNumberedSet& currAvail,
- ValueNumberedSet& currPhis,
- ValueNumberedSet& currExps,
- SmallPtrSet<Value*, 16>& currTemps);
- bool buildsets_anticout(BasicBlock* BB,
- ValueNumberedSet& anticOut,
- SmallPtrSet<BasicBlock*, 8>& visited);
- unsigned buildsets_anticin(BasicBlock* BB,
- ValueNumberedSet& anticOut,
- ValueNumberedSet& currExps,
- SmallPtrSet<Value*, 16>& currTemps,
- SmallPtrSet<BasicBlock*, 8>& visited);
- void buildsets(Function& F) ;
-
- void insertion_pre(Value* e, BasicBlock* BB,
- DenseMap<BasicBlock*, Value*>& avail,
- std::map<BasicBlock*,ValueNumberedSet>& new_set);
- unsigned insertion_mergepoint(SmallVector<Value*, 8>& workList,
- df_iterator<DomTreeNode*>& D,
- std::map<BasicBlock*, ValueNumberedSet>& new_set);
- bool insertion(Function& F) ;
-
- };
-
- char GVNPRE::ID = 0;
-
-}
-
-// createGVNPREPass - The public interface to this file...
-FunctionPass *llvm::createGVNPREPass() { return new GVNPRE(); }
-
-static RegisterPass<GVNPRE> X("gvnpre",
- "Global Value Numbering/Partial Redundancy Elimination");
-
-
-STATISTIC(NumInsertedVals, "Number of values inserted");
-STATISTIC(NumInsertedPhis, "Number of PHI nodes inserted");
-STATISTIC(NumEliminated, "Number of redundant instructions eliminated");
-
-/// find_leader - Given a set and a value number, return the first
-/// element of the set with that value number, or 0 if no such element
-/// is present
-Value* GVNPRE::find_leader(ValueNumberedSet& vals, uint32_t v) {
- if (!vals.test(v))
- return 0;
-
- for (ValueNumberedSet::iterator I = vals.begin(), E = vals.end();
- I != E; ++I)
- if (v == VN.lookup(*I))
- return *I;
-
- llvm_unreachable("No leader found, but present bit is set?");
- return 0;
-}
-
-/// val_insert - Insert a value into a set only if there is not a value
-/// with the same value number already in the set
-void GVNPRE::val_insert(ValueNumberedSet& s, Value* v) {
- uint32_t num = VN.lookup(v);
- if (!s.test(num))
- s.insert(v);
-}
-
-/// val_replace - Insert a value into a set, replacing any values already in
-/// the set that have the same value number
-void GVNPRE::val_replace(ValueNumberedSet& s, Value* v) {
- if (s.count(v)) return;
-
- uint32_t num = VN.lookup(v);
- Value* leader = find_leader(s, num);
- if (leader != 0)
- s.erase(leader);
- s.insert(v);
- s.set(num);
-}
-
-/// phi_translate - Given a value, its parent block, and a predecessor of its
-/// parent, translate the value into legal for the predecessor block. This
-/// means translating its operands (and recursively, their operands) through
-/// any phi nodes in the parent into values available in the predecessor
-Value* GVNPRE::phi_translate(Value* V, BasicBlock* pred, BasicBlock* succ) {
- if (V == 0)
- return 0;
-
- // Unary Operations
- if (CastInst* U = dyn_cast<CastInst>(V)) {
- Value* newOp1 = 0;
- if (isa<Instruction>(U->getOperand(0)))
- newOp1 = phi_translate(U->getOperand(0), pred, succ);
- else
- newOp1 = U->getOperand(0);
-
- if (newOp1 == 0)
- return 0;
-
- if (newOp1 != U->getOperand(0)) {
- Instruction* newVal = 0;
- if (CastInst* C = dyn_cast<CastInst>(U))
- newVal = CastInst::Create(C->getOpcode(),
- newOp1, C->getType(),
- C->getName()+".expr");
-
- uint32_t v = VN.lookup_or_add(newVal);
-
- Value* leader = find_leader(availableOut[pred], v);
- if (leader == 0) {
- createdExpressions.push_back(newVal);
- return newVal;
- } else {
- VN.erase(newVal);
- delete newVal;
- return leader;
- }
- }
-
- // Binary Operations
- } if (isa<BinaryOperator>(V) || isa<CmpInst>(V) ||
- isa<ExtractElementInst>(V)) {
- User* U = cast<User>(V);
-
- Value* newOp1 = 0;
- if (isa<Instruction>(U->getOperand(0)))
- newOp1 = phi_translate(U->getOperand(0), pred, succ);
- else
- newOp1 = U->getOperand(0);
-
- if (newOp1 == 0)
- return 0;
-
- Value* newOp2 = 0;
- if (isa<Instruction>(U->getOperand(1)))
- newOp2 = phi_translate(U->getOperand(1), pred, succ);
- else
- newOp2 = U->getOperand(1);
-
- if (newOp2 == 0)
- return 0;
-
- if (newOp1 != U->getOperand(0) || newOp2 != U->getOperand(1)) {
- Instruction* newVal = 0;
- if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
- newVal = BinaryOperator::Create(BO->getOpcode(),
- newOp1, newOp2,
- BO->getName()+".expr");
- else if (CmpInst* C = dyn_cast<CmpInst>(U))
- newVal = CmpInst::Create(C->getOpcode(),
- C->getPredicate(),
- newOp1, newOp2,
- C->getName()+".expr");
- else if (ExtractElementInst* E = dyn_cast<ExtractElementInst>(U))
- newVal = ExtractElementInst::Create(newOp1, newOp2,
- E->getName()+".expr");
-
- uint32_t v = VN.lookup_or_add(newVal);
-
- Value* leader = find_leader(availableOut[pred], v);
- if (leader == 0) {
- createdExpressions.push_back(newVal);
- return newVal;
- } else {
- VN.erase(newVal);
- delete newVal;
- return leader;
- }
- }
-
- // Ternary Operations
- } else if (isa<ShuffleVectorInst>(V) || isa<InsertElementInst>(V) ||
- isa<SelectInst>(V)) {
- User* U = cast<User>(V);
-
- Value* newOp1 = 0;
- if (isa<Instruction>(U->getOperand(0)))
- newOp1 = phi_translate(U->getOperand(0), pred, succ);
- else
- newOp1 = U->getOperand(0);
-
- if (newOp1 == 0)
- return 0;
-
- Value* newOp2 = 0;
- if (isa<Instruction>(U->getOperand(1)))
- newOp2 = phi_translate(U->getOperand(1), pred, succ);
- else
- newOp2 = U->getOperand(1);
-
- if (newOp2 == 0)
- return 0;
-
- Value* newOp3 = 0;
- if (isa<Instruction>(U->getOperand(2)))
- newOp3 = phi_translate(U->getOperand(2), pred, succ);
- else
- newOp3 = U->getOperand(2);
-
- if (newOp3 == 0)
- return 0;
-
- if (newOp1 != U->getOperand(0) ||
- newOp2 != U->getOperand(1) ||
- newOp3 != U->getOperand(2)) {
- Instruction* newVal = 0;
- if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
- newVal = new ShuffleVectorInst(newOp1, newOp2, newOp3,
- S->getName() + ".expr");
- else if (InsertElementInst* I = dyn_cast<InsertElementInst>(U))
- newVal = InsertElementInst::Create(newOp1, newOp2, newOp3,
- I->getName() + ".expr");
- else if (SelectInst* I = dyn_cast<SelectInst>(U))
- newVal = SelectInst::Create(newOp1, newOp2, newOp3,
- I->getName() + ".expr");
-
- uint32_t v = VN.lookup_or_add(newVal);
-
- Value* leader = find_leader(availableOut[pred], v);
- if (leader == 0) {
- createdExpressions.push_back(newVal);
- return newVal;
- } else {
- VN.erase(newVal);
- delete newVal;
- return leader;
- }
- }
-
- // Varargs operators
- } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
- Value* newOp1 = 0;
- if (isa<Instruction>(U->getPointerOperand()))
- newOp1 = phi_translate(U->getPointerOperand(), pred, succ);
- else
- newOp1 = U->getPointerOperand();
-
- if (newOp1 == 0)
- return 0;
-
- bool changed_idx = false;
- SmallVector<Value*, 4> newIdx;
- for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
- I != E; ++I)
- if (isa<Instruction>(*I)) {
- Value* newVal = phi_translate(*I, pred, succ);
- newIdx.push_back(newVal);
- if (newVal != *I)
- changed_idx = true;
- } else {
- newIdx.push_back(*I);
- }
-
- if (newOp1 != U->getPointerOperand() || changed_idx) {
- Instruction* newVal =
- GetElementPtrInst::Create(newOp1,
- newIdx.begin(), newIdx.end(),
- U->getName()+".expr");
-
- uint32_t v = VN.lookup_or_add(newVal);
-
- Value* leader = find_leader(availableOut[pred], v);
- if (leader == 0) {
- createdExpressions.push_back(newVal);
- return newVal;
- } else {
- VN.erase(newVal);
- delete newVal;
- return leader;
- }
- }
-
- // PHI Nodes
- } else if (PHINode* P = dyn_cast<PHINode>(V)) {
- if (P->getParent() == succ)
- return P->getIncomingValueForBlock(pred);
- }
-
- return V;
-}
-
-/// phi_translate_set - Perform phi translation on every element of a set
-void GVNPRE::phi_translate_set(ValueNumberedSet& anticIn,
- BasicBlock* pred, BasicBlock* succ,
- ValueNumberedSet& out) {
- for (ValueNumberedSet::iterator I = anticIn.begin(),
- E = anticIn.end(); I != E; ++I) {
- Value* V = phi_translate(*I, pred, succ);
- if (V != 0 && !out.test(VN.lookup_or_add(V))) {
- out.insert(V);
- out.set(VN.lookup(V));
- }
- }
-}
-
-/// dependsOnInvoke - Test if a value has an phi node as an operand, any of
-/// whose inputs is an invoke instruction. If this is true, we cannot safely
-/// PRE the instruction or anything that depends on it.
-bool GVNPRE::dependsOnInvoke(Value* V) {
- if (PHINode* p = dyn_cast<PHINode>(V)) {
- for (PHINode::op_iterator I = p->op_begin(), E = p->op_end(); I != E; ++I)
- if (isa<InvokeInst>(*I))
- return true;
- return false;
- } else {
- return false;
- }
-}
-
-/// clean - Remove all non-opaque values from the set whose operands are not
-/// themselves in the set, as well as all values that depend on invokes (see
-/// above)
-void GVNPRE::clean(ValueNumberedSet& set) {
- SmallVector<Value*, 8> worklist;
- worklist.reserve(set.size());
- topo_sort(set, worklist);
-
- for (unsigned i = 0; i < worklist.size(); ++i) {
- Value* v = worklist[i];
-
- // Handle unary ops
- if (CastInst* U = dyn_cast<CastInst>(v)) {
- bool lhsValid = !isa<Instruction>(U->getOperand(0));
- lhsValid |= set.test(VN.lookup(U->getOperand(0)));
- if (lhsValid)
- lhsValid = !dependsOnInvoke(U->getOperand(0));
-
- if (!lhsValid) {
- set.erase(U);
- set.reset(VN.lookup(U));
- }
-
- // Handle binary ops
- } else if (isa<BinaryOperator>(v) || isa<CmpInst>(v) ||
- isa<ExtractElementInst>(v)) {
- User* U = cast<User>(v);
-
- bool lhsValid = !isa<Instruction>(U->getOperand(0));
- lhsValid |= set.test(VN.lookup(U->getOperand(0)));
- if (lhsValid)
- lhsValid = !dependsOnInvoke(U->getOperand(0));
-
- bool rhsValid = !isa<Instruction>(U->getOperand(1));
- rhsValid |= set.test(VN.lookup(U->getOperand(1)));
- if (rhsValid)
- rhsValid = !dependsOnInvoke(U->getOperand(1));
-
- if (!lhsValid || !rhsValid) {
- set.erase(U);
- set.reset(VN.lookup(U));
- }
-
- // Handle ternary ops
- } else if (isa<ShuffleVectorInst>(v) || isa<InsertElementInst>(v) ||
- isa<SelectInst>(v)) {
- User* U = cast<User>(v);
-
- bool lhsValid = !isa<Instruction>(U->getOperand(0));
- lhsValid |= set.test(VN.lookup(U->getOperand(0)));
- if (lhsValid)
- lhsValid = !dependsOnInvoke(U->getOperand(0));
-
- bool rhsValid = !isa<Instruction>(U->getOperand(1));
- rhsValid |= set.test(VN.lookup(U->getOperand(1)));
- if (rhsValid)
- rhsValid = !dependsOnInvoke(U->getOperand(1));
-
- bool thirdValid = !isa<Instruction>(U->getOperand(2));
- thirdValid |= set.test(VN.lookup(U->getOperand(2)));
- if (thirdValid)
- thirdValid = !dependsOnInvoke(U->getOperand(2));
-
- if (!lhsValid || !rhsValid || !thirdValid) {
- set.erase(U);
- set.reset(VN.lookup(U));
- }
-
- // Handle varargs ops
- } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(v)) {
- bool ptrValid = !isa<Instruction>(U->getPointerOperand());
- ptrValid |= set.test(VN.lookup(U->getPointerOperand()));
- if (ptrValid)
- ptrValid = !dependsOnInvoke(U->getPointerOperand());
-
- bool varValid = true;
- for (GetElementPtrInst::op_iterator I = U->idx_begin(), E = U->idx_end();
- I != E; ++I)
- if (varValid) {
- varValid &= !isa<Instruction>(*I) || set.test(VN.lookup(*I));
- varValid &= !dependsOnInvoke(*I);
- }
-
- if (!ptrValid || !varValid) {
- set.erase(U);
- set.reset(VN.lookup(U));
- }
- }
- }
-}
-
-/// topo_sort - Given a set of values, sort them by topological
-/// order into the provided vector.
-void GVNPRE::topo_sort(ValueNumberedSet& set, SmallVector<Value*, 8>& vec) {
- SmallPtrSet<Value*, 16> visited;
- SmallVector<Value*, 8> stack;
- for (ValueNumberedSet::iterator I = set.begin(), E = set.end();
- I != E; ++I) {
- if (visited.count(*I) == 0)
- stack.push_back(*I);
-
- while (!stack.empty()) {
- Value* e = stack.back();
-
- // Handle unary ops
- if (CastInst* U = dyn_cast<CastInst>(e)) {
- Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
-
- if (l != 0 && isa<Instruction>(l) &&
- visited.count(l) == 0)
- stack.push_back(l);
- else {
- vec.push_back(e);
- visited.insert(e);
- stack.pop_back();
- }
-
- // Handle binary ops
- } else if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
- isa<ExtractElementInst>(e)) {
- User* U = cast<User>(e);
- Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
- Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
-
- if (l != 0 && isa<Instruction>(l) &&
- visited.count(l) == 0)
- stack.push_back(l);
- else if (r != 0 && isa<Instruction>(r) &&
- visited.count(r) == 0)
- stack.push_back(r);
- else {
- vec.push_back(e);
- visited.insert(e);
- stack.pop_back();
- }
-
- // Handle ternary ops
- } else if (isa<InsertElementInst>(e) || isa<ShuffleVectorInst>(e) ||
- isa<SelectInst>(e)) {
- User* U = cast<User>(e);
- Value* l = find_leader(set, VN.lookup(U->getOperand(0)));
- Value* r = find_leader(set, VN.lookup(U->getOperand(1)));
- Value* m = find_leader(set, VN.lookup(U->getOperand(2)));
-
- if (l != 0 && isa<Instruction>(l) &&
- visited.count(l) == 0)
- stack.push_back(l);
- else if (r != 0 && isa<Instruction>(r) &&
- visited.count(r) == 0)
- stack.push_back(r);
- else if (m != 0 && isa<Instruction>(m) &&
- visited.count(m) == 0)
- stack.push_back(m);
- else {
- vec.push_back(e);
- visited.insert(e);
- stack.pop_back();
- }
-
- // Handle vararg ops
- } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(e)) {
- Value* p = find_leader(set, VN.lookup(U->getPointerOperand()));
-
- if (p != 0 && isa<Instruction>(p) &&
- visited.count(p) == 0)
- stack.push_back(p);
- else {
- bool push_va = false;
- for (GetElementPtrInst::op_iterator I = U->idx_begin(),
- E = U->idx_end(); I != E; ++I) {
- Value * v = find_leader(set, VN.lookup(*I));
- if (v != 0 && isa<Instruction>(v) && visited.count(v) == 0) {
- stack.push_back(v);
- push_va = true;
- }
- }
-
- if (!push_va) {
- vec.push_back(e);
- visited.insert(e);
- stack.pop_back();
- }
- }
-
- // Handle opaque ops
- } else {
- visited.insert(e);
- vec.push_back(e);
- stack.pop_back();
- }
- }
-
- stack.clear();
- }
-}
-
-/// dump - Dump a set of values to standard error
-void GVNPRE::dump(ValueNumberedSet& s) const {
- DEBUG(errs() << "{ ");
- for (ValueNumberedSet::iterator I = s.begin(), E = s.end();
- I != E; ++I) {
- DEBUG(errs() << "" << VN.lookup(*I) << ": ");
- DEBUG((*I)->dump());
- }
- DEBUG(errs() << "}\n\n");
-}
-
-/// elimination - Phase 3 of the main algorithm. Perform full redundancy
-/// elimination by walking the dominator tree and removing any instruction that
-/// is dominated by another instruction with the same value number.
-bool GVNPRE::elimination() {
- bool changed_function = false;
-
- SmallVector<std::pair<Instruction*, Value*>, 8> replace;
- SmallVector<Instruction*, 8> erase;
-
- DominatorTree& DT = getAnalysis<DominatorTree>();
-
- for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
- E = df_end(DT.getRootNode()); DI != E; ++DI) {
- BasicBlock* BB = DI->getBlock();
-
- for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
- BI != BE; ++BI) {
-
- if (isa<BinaryOperator>(BI) || isa<CmpInst>(BI) ||
- isa<ShuffleVectorInst>(BI) || isa<InsertElementInst>(BI) ||
- isa<ExtractElementInst>(BI) || isa<SelectInst>(BI) ||
- isa<CastInst>(BI) || isa<GetElementPtrInst>(BI)) {
-
- if (availableOut[BB].test(VN.lookup(BI)) &&
- !availableOut[BB].count(BI)) {
- Value *leader = find_leader(availableOut[BB], VN.lookup(BI));
- if (Instruction* Instr = dyn_cast<Instruction>(leader))
- if (Instr->getParent() != 0 && Instr != BI) {
- replace.push_back(std::make_pair(BI, leader));
- erase.push_back(BI);
- ++NumEliminated;
- }
- }
- }
- }
- }
-
- while (!replace.empty()) {
- std::pair<Instruction*, Value*> rep = replace.back();
- replace.pop_back();
- rep.first->replaceAllUsesWith(rep.second);
- changed_function = true;
- }
-
- for (SmallVector<Instruction*, 8>::iterator I = erase.begin(),
- E = erase.end(); I != E; ++I)
- (*I)->eraseFromParent();
-
- return changed_function;
-}
-
-/// cleanup - Delete any extraneous values that were created to represent
-/// expressions without leaders.
-void GVNPRE::cleanup() {
- while (!createdExpressions.empty()) {
- Instruction* I = createdExpressions.back();
- createdExpressions.pop_back();
-
- delete I;
- }
-}
-
-/// buildsets_availout - When calculating availability, handle an instruction
-/// by inserting it into the appropriate sets
-void GVNPRE::buildsets_availout(BasicBlock::iterator I,
- ValueNumberedSet& currAvail,
- ValueNumberedSet& currPhis,
- ValueNumberedSet& currExps,
- SmallPtrSet<Value*, 16>& currTemps) {
- // Handle PHI nodes
- if (PHINode* p = dyn_cast<PHINode>(I)) {
- unsigned num = VN.lookup_or_add(p);
-
- currPhis.insert(p);
- currPhis.set(num);
-
- // Handle unary ops
- } else if (CastInst* U = dyn_cast<CastInst>(I)) {
- Value* leftValue = U->getOperand(0);
-
- unsigned num = VN.lookup_or_add(U);
-
- if (isa<Instruction>(leftValue))
- if (!currExps.test(VN.lookup(leftValue))) {
- currExps.insert(leftValue);
- currExps.set(VN.lookup(leftValue));
- }
-
- if (!currExps.test(num)) {
- currExps.insert(U);
- currExps.set(num);
- }
-
- // Handle binary ops
- } else if (isa<BinaryOperator>(I) || isa<CmpInst>(I) ||
- isa<ExtractElementInst>(I)) {
- User* U = cast<User>(I);
- Value* leftValue = U->getOperand(0);
- Value* rightValue = U->getOperand(1);
-
- unsigned num = VN.lookup_or_add(U);
-
- if (isa<Instruction>(leftValue))
- if (!currExps.test(VN.lookup(leftValue))) {
- currExps.insert(leftValue);
- currExps.set(VN.lookup(leftValue));
- }
-
- if (isa<Instruction>(rightValue))
- if (!currExps.test(VN.lookup(rightValue))) {
- currExps.insert(rightValue);
- currExps.set(VN.lookup(rightValue));
- }
-
- if (!currExps.test(num)) {
- currExps.insert(U);
- currExps.set(num);
- }
-
- // Handle ternary ops
- } else if (isa<InsertElementInst>(I) || isa<ShuffleVectorInst>(I) ||
- isa<SelectInst>(I)) {
- User* U = cast<User>(I);
- Value* leftValue = U->getOperand(0);
- Value* rightValue = U->getOperand(1);
- Value* thirdValue = U->getOperand(2);
-
- VN.lookup_or_add(U);
-
- unsigned num = VN.lookup_or_add(U);
-
- if (isa<Instruction>(leftValue))
- if (!currExps.test(VN.lookup(leftValue))) {
- currExps.insert(leftValue);
- currExps.set(VN.lookup(leftValue));
- }
- if (isa<Instruction>(rightValue))
- if (!currExps.test(VN.lookup(rightValue))) {
- currExps.insert(rightValue);
- currExps.set(VN.lookup(rightValue));
- }
- if (isa<Instruction>(thirdValue))
- if (!currExps.test(VN.lookup(thirdValue))) {
- currExps.insert(thirdValue);
- currExps.set(VN.lookup(thirdValue));
- }
-
- if (!currExps.test(num)) {
- currExps.insert(U);
- currExps.set(num);
- }
-
- // Handle vararg ops
- } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(I)) {
- Value* ptrValue = U->getPointerOperand();
-
- VN.lookup_or_add(U);
-
- unsigned num = VN.lookup_or_add(U);
-
- if (isa<Instruction>(ptrValue))
- if (!currExps.test(VN.lookup(ptrValue))) {
- currExps.insert(ptrValue);
- currExps.set(VN.lookup(ptrValue));
- }
-
- for (GetElementPtrInst::op_iterator OI = U->idx_begin(), OE = U->idx_end();
- OI != OE; ++OI)
- if (isa<Instruction>(*OI) && !currExps.test(VN.lookup(*OI))) {
- currExps.insert(*OI);
- currExps.set(VN.lookup(*OI));
- }
-
- if (!currExps.test(VN.lookup(U))) {
- currExps.insert(U);
- currExps.set(num);
- }
-
- // Handle opaque ops
- } else if (!I->isTerminator()){
- VN.lookup_or_add(I);
-
- currTemps.insert(I);
- }
-
- if (!I->isTerminator())
- if (!currAvail.test(VN.lookup(I))) {
- currAvail.insert(I);
- currAvail.set(VN.lookup(I));
- }
-}
-
-/// buildsets_anticout - When walking the postdom tree, calculate the ANTIC_OUT
-/// set as a function of the ANTIC_IN set of the block's predecessors
-bool GVNPRE::buildsets_anticout(BasicBlock* BB,
- ValueNumberedSet& anticOut,
- SmallPtrSet<BasicBlock*, 8>& visited) {
- if (BB->getTerminator()->getNumSuccessors() == 1) {
- if (BB->getTerminator()->getSuccessor(0) != BB &&
- visited.count(BB->getTerminator()->getSuccessor(0)) == 0) {
- return true;
- }
- else {
- phi_translate_set(anticipatedIn[BB->getTerminator()->getSuccessor(0)],
- BB, BB->getTerminator()->getSuccessor(0), anticOut);
- }
- } else if (BB->getTerminator()->getNumSuccessors() > 1) {
- BasicBlock* first = BB->getTerminator()->getSuccessor(0);
- for (ValueNumberedSet::iterator I = anticipatedIn[first].begin(),
- E = anticipatedIn[first].end(); I != E; ++I) {
- anticOut.insert(*I);
- anticOut.set(VN.lookup(*I));
- }
-
- for (unsigned i = 1; i < BB->getTerminator()->getNumSuccessors(); ++i) {
- BasicBlock* currSucc = BB->getTerminator()->getSuccessor(i);
- ValueNumberedSet& succAnticIn = anticipatedIn[currSucc];
-
- SmallVector<Value*, 16> temp;
-
- for (ValueNumberedSet::iterator I = anticOut.begin(),
- E = anticOut.end(); I != E; ++I)
- if (!succAnticIn.test(VN.lookup(*I)))
- temp.push_back(*I);
-
- for (SmallVector<Value*, 16>::iterator I = temp.begin(), E = temp.end();
- I != E; ++I) {
- anticOut.erase(*I);
- anticOut.reset(VN.lookup(*I));
- }
- }
- }
-
- return false;
-}
-
-/// buildsets_anticin - Walk the postdom tree, calculating ANTIC_OUT for
-/// each block. ANTIC_IN is then a function of ANTIC_OUT and the GEN
-/// sets populated in buildsets_availout
-unsigned GVNPRE::buildsets_anticin(BasicBlock* BB,
- ValueNumberedSet& anticOut,
- ValueNumberedSet& currExps,
- SmallPtrSet<Value*, 16>& currTemps,
- SmallPtrSet<BasicBlock*, 8>& visited) {
- ValueNumberedSet& anticIn = anticipatedIn[BB];
- unsigned old = anticIn.size();
-
- bool defer = buildsets_anticout(BB, anticOut, visited);
- if (defer)
- return 0;
-
- anticIn.clear();
-
- for (ValueNumberedSet::iterator I = anticOut.begin(),
- E = anticOut.end(); I != E; ++I) {
- anticIn.insert(*I);
- anticIn.set(VN.lookup(*I));
- }
- for (ValueNumberedSet::iterator I = currExps.begin(),
- E = currExps.end(); I != E; ++I) {
- if (!anticIn.test(VN.lookup(*I))) {
- anticIn.insert(*I);
- anticIn.set(VN.lookup(*I));
- }
- }
-
- for (SmallPtrSet<Value*, 16>::iterator I = currTemps.begin(),
- E = currTemps.end(); I != E; ++I) {
- anticIn.erase(*I);
- anticIn.reset(VN.lookup(*I));
- }
-
- clean(anticIn);
- anticOut.clear();
-
- if (old != anticIn.size())
- return 2;
- else
- return 1;
-}
-
-/// buildsets - Phase 1 of the main algorithm. Construct the AVAIL_OUT
-/// and the ANTIC_IN sets.
-void GVNPRE::buildsets(Function& F) {
- DenseMap<BasicBlock*, ValueNumberedSet> generatedExpressions;
- DenseMap<BasicBlock*, SmallPtrSet<Value*, 16> > generatedTemporaries;
-
- DominatorTree &DT = getAnalysis<DominatorTree>();
-
- // Phase 1, Part 1: calculate AVAIL_OUT
-
- // Top-down walk of the dominator tree
- for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
- E = df_end(DT.getRootNode()); DI != E; ++DI) {
-
- // Get the sets to update for this block
- ValueNumberedSet& currExps = generatedExpressions[DI->getBlock()];
- ValueNumberedSet& currPhis = generatedPhis[DI->getBlock()];
- SmallPtrSet<Value*, 16>& currTemps = generatedTemporaries[DI->getBlock()];
- ValueNumberedSet& currAvail = availableOut[DI->getBlock()];
-
- BasicBlock* BB = DI->getBlock();
-
- // A block inherits AVAIL_OUT from its dominator
- if (DI->getIDom() != 0)
- currAvail = availableOut[DI->getIDom()->getBlock()];
-
- for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
- BI != BE; ++BI)
- buildsets_availout(BI, currAvail, currPhis, currExps,
- currTemps);
-
- }
-
- // Phase 1, Part 2: calculate ANTIC_IN
-
- SmallPtrSet<BasicBlock*, 8> visited;
- SmallPtrSet<BasicBlock*, 4> block_changed;
- for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
- block_changed.insert(FI);
-
- bool changed = true;
- unsigned iterations = 0;
-
- while (changed) {
- changed = false;
- ValueNumberedSet anticOut;
-
- // Postorder walk of the CFG
- for (po_iterator<BasicBlock*> BBI = po_begin(&F.getEntryBlock()),
- BBE = po_end(&F.getEntryBlock()); BBI != BBE; ++BBI) {
- BasicBlock* BB = *BBI;
-
- if (block_changed.count(BB) != 0) {
- unsigned ret = buildsets_anticin(BB, anticOut,generatedExpressions[BB],
- generatedTemporaries[BB], visited);
-
- if (ret == 0) {
- changed = true;
- continue;
- } else {
- visited.insert(BB);
-
- if (ret == 2)
- for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
- PI != PE; ++PI) {
- block_changed.insert(*PI);
- }
- else
- block_changed.erase(BB);
-
- changed |= (ret == 2);
- }
- }
- }
-
- iterations++;
- }
-}
-
-/// insertion_pre - When a partial redundancy has been identified, eliminate it
-/// by inserting appropriate values into the predecessors and a phi node in
-/// the main block
-void GVNPRE::insertion_pre(Value* e, BasicBlock* BB,
- DenseMap<BasicBlock*, Value*>& avail,
- std::map<BasicBlock*, ValueNumberedSet>& new_sets) {
- for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
- Value* e2 = avail[*PI];
- if (!availableOut[*PI].test(VN.lookup(e2))) {
- User* U = cast<User>(e2);
-
- Value* s1 = 0;
- if (isa<BinaryOperator>(U->getOperand(0)) ||
- isa<CmpInst>(U->getOperand(0)) ||
- isa<ShuffleVectorInst>(U->getOperand(0)) ||
- isa<ExtractElementInst>(U->getOperand(0)) ||
- isa<InsertElementInst>(U->getOperand(0)) ||
- isa<SelectInst>(U->getOperand(0)) ||
- isa<CastInst>(U->getOperand(0)) ||
- isa<GetElementPtrInst>(U->getOperand(0)))
- s1 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(0)));
- else
- s1 = U->getOperand(0);
-
- Value* s2 = 0;
-
- if (isa<BinaryOperator>(U) ||
- isa<CmpInst>(U) ||
- isa<ShuffleVectorInst>(U) ||
- isa<ExtractElementInst>(U) ||
- isa<InsertElementInst>(U) ||
- isa<SelectInst>(U)) {
- if (isa<BinaryOperator>(U->getOperand(1)) ||
- isa<CmpInst>(U->getOperand(1)) ||
- isa<ShuffleVectorInst>(U->getOperand(1)) ||
- isa<ExtractElementInst>(U->getOperand(1)) ||
- isa<InsertElementInst>(U->getOperand(1)) ||
- isa<SelectInst>(U->getOperand(1)) ||
- isa<CastInst>(U->getOperand(1)) ||
- isa<GetElementPtrInst>(U->getOperand(1))) {
- s2 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(1)));
- } else {
- s2 = U->getOperand(1);
- }
- }
-
- // Ternary Operators
- Value* s3 = 0;
- if (isa<ShuffleVectorInst>(U) ||
- isa<InsertElementInst>(U) ||
- isa<SelectInst>(U)) {
- if (isa<BinaryOperator>(U->getOperand(2)) ||
- isa<CmpInst>(U->getOperand(2)) ||
- isa<ShuffleVectorInst>(U->getOperand(2)) ||
- isa<ExtractElementInst>(U->getOperand(2)) ||
- isa<InsertElementInst>(U->getOperand(2)) ||
- isa<SelectInst>(U->getOperand(2)) ||
- isa<CastInst>(U->getOperand(2)) ||
- isa<GetElementPtrInst>(U->getOperand(2))) {
- s3 = find_leader(availableOut[*PI], VN.lookup(U->getOperand(2)));
- } else {
- s3 = U->getOperand(2);
- }
- }
-
- // Vararg operators
- SmallVector<Value*, 4> sVarargs;
- if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U)) {
- for (GetElementPtrInst::op_iterator OI = G->idx_begin(),
- OE = G->idx_end(); OI != OE; ++OI) {
- if (isa<BinaryOperator>(*OI) ||
- isa<CmpInst>(*OI) ||
- isa<ShuffleVectorInst>(*OI) ||
- isa<ExtractElementInst>(*OI) ||
- isa<InsertElementInst>(*OI) ||
- isa<SelectInst>(*OI) ||
- isa<CastInst>(*OI) ||
- isa<GetElementPtrInst>(*OI)) {
- sVarargs.push_back(find_leader(availableOut[*PI],
- VN.lookup(*OI)));
- } else {
- sVarargs.push_back(*OI);
- }
- }
- }
-
- Value* newVal = 0;
- if (BinaryOperator* BO = dyn_cast<BinaryOperator>(U))
- newVal = BinaryOperator::Create(BO->getOpcode(), s1, s2,
- BO->getName()+".gvnpre",
- (*PI)->getTerminator());
- else if (CmpInst* C = dyn_cast<CmpInst>(U))
- newVal = CmpInst::Create(C->getOpcode(),
- C->getPredicate(), s1, s2,
- C->getName()+".gvnpre",
- (*PI)->getTerminator());
- else if (ShuffleVectorInst* S = dyn_cast<ShuffleVectorInst>(U))
- newVal = new ShuffleVectorInst(s1, s2, s3, S->getName()+".gvnpre",
- (*PI)->getTerminator());
- else if (InsertElementInst* S = dyn_cast<InsertElementInst>(U))
- newVal = InsertElementInst::Create(s1, s2, s3, S->getName()+".gvnpre",
- (*PI)->getTerminator());
- else if (ExtractElementInst* S = dyn_cast<ExtractElementInst>(U))
- newVal = ExtractElementInst::Create(s1, s2, S->getName()+".gvnpre",
- (*PI)->getTerminator());
- else if (SelectInst* S = dyn_cast<SelectInst>(U))
- newVal = SelectInst::Create(s1, s2, s3, S->getName()+".gvnpre",
- (*PI)->getTerminator());
- else if (CastInst* C = dyn_cast<CastInst>(U))
- newVal = CastInst::Create(C->getOpcode(), s1, C->getType(),
- C->getName()+".gvnpre",
- (*PI)->getTerminator());
- else if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(U))
- newVal = GetElementPtrInst::Create(s1, sVarargs.begin(), sVarargs.end(),
- G->getName()+".gvnpre",
- (*PI)->getTerminator());
-
- VN.add(newVal, VN.lookup(U));
-
- ValueNumberedSet& predAvail = availableOut[*PI];
- val_replace(predAvail, newVal);
- val_replace(new_sets[*PI], newVal);
- predAvail.set(VN.lookup(newVal));
-
- DenseMap<BasicBlock*, Value*>::iterator av = avail.find(*PI);
- if (av != avail.end())
- avail.erase(av);
- avail.insert(std::make_pair(*PI, newVal));
-
- ++NumInsertedVals;
- }
- }
-
- PHINode* p = 0;
-
- for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
- if (p == 0)
- p = PHINode::Create(avail[*PI]->getType(), "gvnpre-join", BB->begin());
-
- p->addIncoming(avail[*PI], *PI);
- }
-
- VN.add(p, VN.lookup(e));
- val_replace(availableOut[BB], p);
- availableOut[BB].set(VN.lookup(e));
- generatedPhis[BB].insert(p);
- generatedPhis[BB].set(VN.lookup(e));
- new_sets[BB].insert(p);
- new_sets[BB].set(VN.lookup(e));
-
- ++NumInsertedPhis;
-}
-
-/// insertion_mergepoint - When walking the dom tree, check at each merge
-/// block for the possibility of a partial redundancy. If present, eliminate it
-unsigned GVNPRE::insertion_mergepoint(SmallVector<Value*, 8>& workList,
- df_iterator<DomTreeNode*>& D,
- std::map<BasicBlock*, ValueNumberedSet >& new_sets) {
- bool changed_function = false;
- bool new_stuff = false;
-
- BasicBlock* BB = D->getBlock();
- for (unsigned i = 0; i < workList.size(); ++i) {
- Value* e = workList[i];
-
- if (isa<BinaryOperator>(e) || isa<CmpInst>(e) ||
- isa<ExtractElementInst>(e) || isa<InsertElementInst>(e) ||
- isa<ShuffleVectorInst>(e) || isa<SelectInst>(e) || isa<CastInst>(e) ||
- isa<GetElementPtrInst>(e)) {
- if (availableOut[D->getIDom()->getBlock()].test(VN.lookup(e)))
- continue;
-
- DenseMap<BasicBlock*, Value*> avail;
- bool by_some = false;
- bool all_same = true;
- Value * first_s = 0;
-
- for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;
- ++PI) {
- Value *e2 = phi_translate(e, *PI, BB);
- Value *e3 = find_leader(availableOut[*PI], VN.lookup(e2));
-
- if (e3 == 0) {
- DenseMap<BasicBlock*, Value*>::iterator av = avail.find(*PI);
- if (av != avail.end())
- avail.erase(av);
- avail.insert(std::make_pair(*PI, e2));
- all_same = false;
- } else {
- DenseMap<BasicBlock*, Value*>::iterator av = avail.find(*PI);
- if (av != avail.end())
- avail.erase(av);
- avail.insert(std::make_pair(*PI, e3));
-
- by_some = true;
- if (first_s == 0)
- first_s = e3;
- else if (first_s != e3)
- all_same = false;
- }
- }
-
- if (by_some && !all_same &&
- !generatedPhis[BB].test(VN.lookup(e))) {
- insertion_pre(e, BB, avail, new_sets);
-
- changed_function = true;
- new_stuff = true;
- }
- }
- }
-
- unsigned retval = 0;
- if (changed_function)
- retval += 1;
- if (new_stuff)
- retval += 2;
-
- return retval;
-}
-
-/// insert - Phase 2 of the main algorithm. Walk the dominator tree looking for
-/// merge points. When one is found, check for a partial redundancy. If one is
-/// present, eliminate it. Repeat this walk until no changes are made.
-bool GVNPRE::insertion(Function& F) {
- bool changed_function = false;
-
- DominatorTree &DT = getAnalysis<DominatorTree>();
-
- std::map<BasicBlock*, ValueNumberedSet> new_sets;
- bool new_stuff = true;
- while (new_stuff) {
- new_stuff = false;
- for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
- E = df_end(DT.getRootNode()); DI != E; ++DI) {
- BasicBlock* BB = DI->getBlock();
-
- if (BB == 0)
- continue;
-
- ValueNumberedSet& availOut = availableOut[BB];
- ValueNumberedSet& anticIn = anticipatedIn[BB];
-
- // Replace leaders with leaders inherited from dominator
- if (DI->getIDom() != 0) {
- ValueNumberedSet& dom_set = new_sets[DI->getIDom()->getBlock()];
- for (ValueNumberedSet::iterator I = dom_set.begin(),
- E = dom_set.end(); I != E; ++I) {
- val_replace(new_sets[BB], *I);
- val_replace(availOut, *I);
- }
- }
-
- // If there is more than one predecessor...
- if (pred_begin(BB) != pred_end(BB) && ++pred_begin(BB) != pred_end(BB)) {
- SmallVector<Value*, 8> workList;
- workList.reserve(anticIn.size());
- topo_sort(anticIn, workList);
-
- unsigned result = insertion_mergepoint(workList, DI, new_sets);
- if (result & 1)
- changed_function = true;
- if (result & 2)
- new_stuff = true;
- }
- }
- }
-
- return changed_function;
-}
-
-// GVNPRE::runOnFunction - This is the main transformation entry point for a
-// function.
-//
-bool GVNPRE::runOnFunction(Function &F) {
- // Clean out global sets from any previous functions
- VN.clear();
- createdExpressions.clear();
- availableOut.clear();
- anticipatedIn.clear();
- generatedPhis.clear();
-
- bool changed_function = false;
-
- // Phase 1: BuildSets
- // This phase calculates the AVAIL_OUT and ANTIC_IN sets
- buildsets(F);
-
- // Phase 2: Insert
- // This phase inserts values to make partially redundant values
- // fully redundant
- changed_function |= insertion(F);
-
- // Phase 3: Eliminate
- // This phase performs trivial full redundancy elimination
- changed_function |= elimination();
-
- // Phase 4: Cleanup
- // This phase cleans up values that were created solely
- // as leaders for expressions
- cleanup();
-
- return changed_function;
-}
projects / oota-llvm.git / commitdiff