// 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 a very
+// live ranges, and should be used with caution on platforms that are very
// sensitive to register pressure.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Scalar.h"
#include "llvm/Instructions.h"
#include "llvm/Function.h"
+#include "llvm/DerivedTypes.h"
#include "llvm/Analysis/Dominators.h"
-#include "llvm/Analysis/PostDominators.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/Compiler.h"
+#include "llvm/Support/Debug.h"
#include <algorithm>
+#include <deque>
#include <map>
-#include <set>
-#include <cstdio>
using namespace llvm;
-namespace {
+//===----------------------------------------------------------------------===//
+// ValueTable Class
+//===----------------------------------------------------------------------===//
- class VISIBILITY_HIDDEN GVNPRE : public FunctionPass {
- bool runOnFunction(Function &F);
- public:
- static char ID; // Pass identification, replacement for typeid
- GVNPRE() : FunctionPass((intptr_t)&ID) { nextValueNumber = 0; }
+/// 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.
- private:
- uint32_t nextValueNumber;
+struct Expression {
+ enum ExpressionOpcode { ADD, SUB, MUL, 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;
- struct Expression {
- char opcode;
- Value* value;
- uint32_t lhs;
- uint32_t rhs;
-
- bool operator<(const Expression& other) const {
- if (opcode < other.opcode)
- return true;
- else if (other.opcode < opcode)
- return false;
-
- if (opcode == 0) {
- if (value < other.value)
- return true;
- else
- return false;
- } else {
- if (lhs < other.lhs)
- return true;
- else if (other.lhs < lhs)
- return true;
- else if (rhs < other.rhs)
- return true;
- else
- return false;
- }
- }
+ Expression() { }
+ 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;
- bool operator==(const Expression& other) const {
- if (opcode != other.opcode)
- return false;
-
- if (value != other.value)
- return false;
-
- if (lhs != other.lhs)
- return false;
-
- if (rhs != other.rhs)
+ 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 VISIBILITY_HIDDEN 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 DenseMapKeyInfo<Expression> {
+ static inline Expression getEmptyKey() {
+ return Expression(Expression::EMPTY);
+ }
- typedef std::map<Expression, uint32_t> ValueTable;
+ 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 isPod() { return true; }
+};
+}
+
+//===----------------------------------------------------------------------===//
+// ValueTable Internal Functions
+//===----------------------------------------------------------------------===//
+Expression::ExpressionOpcode
+ ValueTable::getOpcode(BinaryOperator* BO) {
+ switch(BO->getOpcode()) {
+ case Instruction::Add:
+ return Expression::ADD;
+ case Instruction::Sub:
+ return Expression::SUB;
+ case Instruction::Mul:
+ return Expression::MUL;
+ 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:
+ assert(0 && "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:
+ assert(0 && "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:
+ assert(0 && "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:
+ assert(0 && "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
+ assert(0 && "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;
+}
+
+//===----------------------------------------------------------------------===//
+// 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 VISIBILITY_HIDDEN GVNPRE : public FunctionPass {
+ bool runOnFunction(Function &F);
+ public:
+ static char ID; // Pass identification, replacement for typeid
+ GVNPRE() : FunctionPass((intptr_t)&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>();
- AU.addRequired<PostDominatorTree>();
}
// Helper fuctions
// FIXME: eliminate or document these better
- void dump(ValueTable& VN, std::set<Expression>& s);
- void clean(ValueTable VN, std::set<Expression>& set);
- Expression add(ValueTable& VN, std::set<Expression>& MS, Instruction* V);
- ValueTable::iterator lookup(ValueTable& VN, Value* V);
- Expression buildExpression(ValueTable& VN, Value* V);
- std::set<Expression>::iterator find_leader(ValueTable VN,
- std::set<Expression>& vals,
- uint32_t v);
- void phi_translate(ValueTable& VN,
- std::set<Expression>& anticIn, BasicBlock* B,
- std::set<Expression>& out);
-
- // For a given block, calculate the generated expressions, temporaries,
- // and the AVAIL_OUT set
- void CalculateAvailOut(ValueTable& VN, std::set<Expression>& MS,
- DominatorTree::Node* DI,
- std::set<Expression>& currExps,
- std::set<PHINode*>& currPhis,
- std::set<Expression>& currTemps,
- std::set<Expression>& currAvail,
- std::map<BasicBlock*, std::set<Expression> > availOut);
+ 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) ;
};
}
+// createGVNPREPass - The public interface to this file...
FunctionPass *llvm::createGVNPREPass() { return new GVNPRE(); }
-RegisterPass<GVNPRE> X("gvnpre",
- "Global Value Numbering/Partial Redundancy Elimination");
-
-// Given a Value, build an Expression to represent it
-GVNPRE::Expression GVNPRE::buildExpression(ValueTable& VN, Value* V) {
- if (Instruction* I = dyn_cast<Instruction>(V)) {
- Expression e;
-
- switch (I->getOpcode()) {
- case 7:
- e.opcode = 1; // ADD
- break;
- case 8:
- e.opcode = 2; // SUB
- break;
- case 9:
- e.opcode = 3; // MUL
- break;
- case 10:
- e.opcode = 4; // UDIV
- break;
- case 11:
- e.opcode = 5; // SDIV
- break;
- case 12:
- e.opcode = 6; // FDIV
- break;
- case 13:
- e.opcode = 7; // UREM
- break;
- case 14:
- e.opcode = 8; // SREM
- break;
- case 15:
- e.opcode = 9; // FREM
- break;
- default:
- e.opcode = 0; // OPAQUE
- e.lhs = 0;
- e.rhs = 0;
- e.value = V;
- return e;
- }
-
- e.value = 0;
-
- ValueTable::iterator lhs = lookup(VN, I->getOperand(0));
- if (lhs == VN.end()) {
- Expression lhsExp = buildExpression(VN, I->getOperand(0));
- VN.insert(std::make_pair(lhsExp, nextValueNumber));
- e.lhs = nextValueNumber;
- nextValueNumber++;
- } else
- e.lhs = lhs->second;
- ValueTable::iterator rhs = lookup(VN, I->getOperand(1));
- if (rhs == VN.end()) {
- Expression rhsExp = buildExpression(VN, I->getOperand(1));
- VN.insert(std::make_pair(rhsExp, nextValueNumber));
- e.rhs = nextValueNumber;
- nextValueNumber++;
- } else
- e.rhs = rhs->second;
-
- return e;
- } else {
- Expression e;
- e.opcode = 0;
- e.value = V;
- e.lhs = 0;
- e.rhs = 0;
-
- return e;
- }
-}
+static RegisterPass<GVNPRE> X("gvnpre",
+ "Global Value Numbering/Partial Redundancy Elimination");
-GVNPRE::Expression GVNPRE::add(ValueTable& VN, std::set<Expression>& MS,
- Instruction* V) {
- Expression e = buildExpression(VN, V);
- if (VN.insert(std::make_pair(e, nextValueNumber)).second)
- nextValueNumber++;
- if (e.opcode != 0 || (e.opcode == 0 && isa<PHINode>(e.value)))
- MS.insert(e);
- return e;
+
+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;
+
+ assert(0 && "No leader found, but present bit is set?");
+ return 0;
}
-GVNPRE::ValueTable::iterator GVNPRE::lookup(ValueTable& VN, Value* V) {
- Expression e = buildExpression(VN, V);
- return VN.find(e);
+/// 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);
}
-std::set<GVNPRE::Expression>::iterator GVNPRE::find_leader(GVNPRE::ValueTable VN,
- std::set<GVNPRE::Expression>& vals,
- uint32_t v) {
- for (std::set<Expression>::iterator I = vals.begin(), E = vals.end();
- I != E; ++I)
- if (VN[*I] == v)
- return I;
+/// 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;
- return vals.end();
+ uint32_t num = VN.lookup(v);
+ Value* leader = find_leader(s, num);
+ if (leader != 0)
+ s.erase(leader);
+ s.insert(v);
+ s.set(num);
}
-void GVNPRE::phi_translate(GVNPRE::ValueTable& VN,
- std::set<GVNPRE::Expression>& anticIn, BasicBlock* B,
- std::set<GVNPRE::Expression>& out) {
- BasicBlock* succ = B->getTerminator()->getSuccessor(0);
+/// 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;
- for (std::set<Expression>::iterator I = anticIn.begin(), E = anticIn.end();
- I != E; ++I) {
- if (I->opcode == 0) {
- Value *v = I->value;
- if (PHINode* p = dyn_cast<PHINode>(v))
- if (p->getParent() == succ) {
- out.insert(buildExpression(VN, p->getIncomingValueForBlock(B)));
- continue;
- }
+ // 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;
+ }
}
- //out.insert(*I);
+
+ // 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 = new ExtractElementInst(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 = new InsertElementInst(newOp1, newOp2, newOp3,
+ I->getName()+".expr");
+ else if (SelectInst* I = dyn_cast<SelectInst>(U))
+ newVal = new SelectInst(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 = new GetElementPtrInst(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;
}
-// Remove all expressions whose operands are not themselves in the set
-void GVNPRE::clean(GVNPRE::ValueTable VN, std::set<GVNPRE::Expression>& set) {
- unsigned size = set.size();
- unsigned old = 0;
-
- while (size != old) {
- old = size;
+/// 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);
- std::vector<Expression> worklist(set.begin(), set.end());
- while (!worklist.empty()) {
- Expression e = worklist.back();
- worklist.pop_back();
+ for (unsigned i = 0; i < worklist.size(); ++i) {
+ Value* v = worklist[i];
- if (e.opcode == 0) // OPAQUE
- continue;
+ // 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));
- bool lhsValid = false;
- for (std::set<Expression>::iterator I = set.begin(), E = set.end();
+ 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 (VN[*I] == e.lhs);
- lhsValid = true;
+ 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;
+ }
+ }
- bool rhsValid = false;
- for (std::set<Expression>::iterator I = set.begin(), E = set.end();
- I != E; ++I)
- if (VN[*I] == e.rhs);
- rhsValid = true;
+ if (!push_va) {
+ vec.push_back(e);
+ visited.insert(e);
+ stack.pop_back();
+ }
+ }
- if (!lhsValid || !rhsValid)
- set.erase(e);
+ // Handle opaque ops
+ } else {
+ visited.insert(e);
+ vec.push_back(e);
+ stack.pop_back();
+ }
}
- size = set.size();
+ stack.clear();
}
}
-void GVNPRE::dump(GVNPRE::ValueTable& VN, std::set<GVNPRE::Expression>& s) {
- printf("{ ");
- for (std::set<Expression>::iterator I = s.begin(), E = s.end(); I != E; ++I) {
- printf("(%d, %s, value.%d, value.%d) ", I->opcode, I->value == 0 ? "0" : I->value->getName().c_str(), I->lhs, I->rhs);
+/// dump - Dump a set of values to standard error
+void GVNPRE::dump(ValueNumberedSet& s) const {
+ DOUT << "{ ";
+ for (ValueNumberedSet::iterator I = s.begin(), E = s.end();
+ I != E; ++I) {
+ DOUT << "" << VN.lookup(*I) << ": ";
+ DEBUG((*I)->dump());
}
- printf("}\n\n");
+ DOUT << "}\n\n";
}
-void GVNPRE::CalculateAvailOut(GVNPRE::ValueTable& VN, std::set<Expression>& MS,
- DominatorTree::Node* DI,
- std::set<Expression>& currExps,
- std::set<PHINode*>& currPhis,
- std::set<Expression>& currTemps,
- std::set<Expression>& currAvail,
- std::map<BasicBlock*, std::set<Expression> > availOut) {
+/// 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;
+ }
+ }
+ }
+ }
+ }
- BasicBlock* BB = DI->getBlock();
+ 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();
- // A block inherits AVAIL_OUT from its dominator
- if (DI->getIDom() != 0)
- currAvail.insert(availOut[DI->getIDom()->getBlock()].begin(),
- availOut[DI->getIDom()->getBlock()].end());
+ 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);
- for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
- BI != BE; ++BI) {
-
- // Handle PHI nodes...
- if (PHINode* p = dyn_cast<PHINode>(BI)) {
- add(VN, MS, p);
- currPhis.insert(p);
+ currPhis.insert(p);
+ currPhis.set(num);
+
+ // Handle unary ops
+ } else if (CastInst* U = dyn_cast<CastInst>(I)) {
+ Value* leftValue = U->getOperand(0);
- // Handle binary ops...
- } else if (BinaryOperator* BO = dyn_cast<BinaryOperator>(BI)) {
- Expression leftValue = buildExpression(VN, BO->getOperand(0));
- Expression rightValue = buildExpression(VN, BO->getOperand(1));
+ unsigned num = VN.lookup_or_add(U);
- Expression e = add(VN, MS, BO);
+ 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);
- currExps.insert(leftValue);
- currExps.insert(rightValue);
- currExps.insert(e);
+ 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);
- currTemps.insert(e);
-
- // Handle unsupported ops
- } else {
- Expression e = add(VN, MS, BI);
- currTemps.insert(e);
+ 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();
- currAvail.insert(buildExpression(VN, BI));
+ 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));
+ }
}
-bool GVNPRE::runOnFunction(Function &F) {
- ValueTable VN;
- std::set<Expression> maximalSet;
+/// 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;
+}
- std::map<BasicBlock*, std::set<Expression> > generatedExpressions;
- std::map<BasicBlock*, std::set<PHINode*> > generatedPhis;
- std::map<BasicBlock*, std::set<Expression> > generatedTemporaries;
- std::map<BasicBlock*, std::set<Expression> > availableOut;
- std::map<BasicBlock*, std::set<Expression> > anticipatedIn;
+/// 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>();
- // First Phase of BuildSets - calculate AVAIL_OUT
+ // Phase 1, Part 1: calculate AVAIL_OUT
// Top-down walk of the dominator tree
- for (df_iterator<DominatorTree::Node*> DI = df_begin(DT.getRootNode()),
+ 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
- std::set<Expression>& currExps = generatedExpressions[DI->getBlock()];
- std::set<PHINode*>& currPhis = generatedPhis[DI->getBlock()];
- std::set<Expression>& currTemps = generatedTemporaries[DI->getBlock()];
- std::set<Expression>& currAvail = availableOut[DI->getBlock()];
+ ValueNumberedSet& currExps = generatedExpressions[DI->getBlock()];
+ ValueNumberedSet& currPhis = generatedPhis[DI->getBlock()];
+ SmallPtrSet<Value*, 16>& currTemps = generatedTemporaries[DI->getBlock()];
+ ValueNumberedSet& currAvail = availableOut[DI->getBlock()];
- CalculateAvailOut(VN, maximalSet, *DI, currExps, currPhis,
- currTemps, currAvail, availableOut);
- }
+ BasicBlock* BB = DI->getBlock();
- PostDominatorTree &PDT = getAnalysis<PostDominatorTree>();
+ // 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
- // Second Phase of BuildSets - 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;
- std::set<Expression> anticOut;
-
- // Top-down walk of the postdominator tree
- for (df_iterator<PostDominatorTree::Node*> PDI =
- df_begin(PDT.getRootNode()), E = df_end(DT.getRootNode());
- PDI != E; ++PDI) {
- BasicBlock* BB = PDI->getBlock();
-
- std::set<Expression>& anticIn = anticipatedIn[BB];
- std::set<Expression> old (anticIn.begin(), anticIn.end());
-
- if (BB->getTerminator()->getNumSuccessors() == 1) {
- phi_translate(VN, maximalSet, BB, anticOut);
- } else if (BB->getTerminator()->getNumSuccessors() > 1) {
- for (unsigned i = 0; i < BB->getTerminator()->getNumSuccessors(); ++i) {
- BasicBlock* currSucc = BB->getTerminator()->getSuccessor(i);
- std::set<Expression> temp;
- if (i == 0)
- temp.insert(maximalSet.begin(), maximalSet.end());
+ 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
- temp.insert(anticIn.begin(), anticIn.end());
-
- anticIn.clear();
- std::insert_iterator<std::set<Expression> > ai_ins(anticIn,
- anticIn.begin());
-
- std::set_difference(anticipatedIn[currSucc].begin(),
- anticipatedIn[currSucc].end(),
- temp.begin(),
- temp.end(),
- ai_ins);
+ 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);
- std::set<Expression> S;
- std::insert_iterator<std::set<Expression> > s_ins(S, S.begin());
- std::set_union(anticOut.begin(), anticOut.end(),
- generatedExpressions[BB].begin(),
- generatedExpressions[BB].end(),
- s_ins);
-
- anticIn.clear();
- std::insert_iterator<std::set<Expression> > antic_ins(anticIn,
- anticIn.begin());
- std::set_difference(S.begin(), S.end(),
- generatedTemporaries[BB].begin(),
- generatedTemporaries[BB].end(),
- antic_ins);
+ 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);
- clean(VN, anticIn);
+ 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);
+ }
- if (old != anticIn)
- changed = true;
+ // 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);
+ }
+ }
+ }
- anticOut.clear();
+ 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 = new InsertElementInst(s1, s2, s3, S->getName()+".gvnpre",
+ (*PI)->getTerminator());
+ else if (ExtractElementInst* S = dyn_cast<ExtractElementInst>(U))
+ newVal = new ExtractElementInst(s1, s2, S->getName()+".gvnpre",
+ (*PI)->getTerminator());
+ else if (SelectInst* S = dyn_cast<SelectInst>(U))
+ newVal = new SelectInst(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 = new GetElementPtrInst(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 = new PHINode(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;
+ }
}
- iterations++;
}
- printf("Iterations: %d\n", iterations);
-
- for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
- printf("Name: ");
- printf(I->getName().c_str());
- printf("\nTMP_GEN: ");
- dump(VN, generatedTemporaries[I]);
- printf("\nEXP_GEN: ");
- dump(VN, generatedExpressions[I]);
- //printf("\nANTIC_OUT: ");
- //dump(VN, anticipatedOut[I]);
- printf("\nANTIC_IN: \n");
- dump(VN, anticipatedIn[I]);
- printf("\n");
+ 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 false;
+ 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 / blobdiff