Revert rL303923 since it broke the sanitizer bootstrap build bot.

llvm-svn: 303969

Author: wmi-11

llvm/include/llvm/Transforms/Scalar/GVN.h

@@ -68,24 +68,6 @@ class GVN : public PassInfoMixin<GVN> {
   class ValueTable {
     DenseMap<Value *, uint32_t> valueNumbering;
     DenseMap<Expression, uint32_t> expressionNumbering;
-
-    // Expressions is the vector of Expression. ExprIdx is the mapping from
-    // value number to the index of Expression in Expressions. We use it
-    // instead of a DenseMap because filling such mapping is faster than
-    // filling a DenseMap and the compile time is a little better.
-    uint32_t nextExprNumber;
-    std::vector<Expression> Expressions;
-    std::vector<uint32_t> ExprIdx;
-    // Value number to PHINode mapping. Used for phi-translate in scalarpre.
-    DenseMap<uint32_t, PHINode *> NumberingPhi;
-    // Cache for phi-translate in scalarpre.
-    typedef DenseMap<std::pair<uint32_t, const BasicBlock *>, uint32_t>
-        PhiTranslateMap;
-    PhiTranslateMap PhiTranslateTable;
-    // Map the block to reversed postorder traversal number. It is used to
-    // find back edge easily.
-    DenseMap<const BasicBlock *, uint32_t> BlockRPONumber;
-
     AliasAnalysis *AA;
     MemoryDependenceResults *MD;
     DominatorTree *DT;
@@ -97,10 +79,6 @@ class GVN : public PassInfoMixin<GVN> {
                              Value *LHS, Value *RHS);
     Expression createExtractvalueExpr(ExtractValueInst *EI);
     uint32_t lookupOrAddCall(CallInst *C);
-    uint32_t phiTranslateImpl(const BasicBlock *BB, const BasicBlock *PhiBlock,
-                              uint32_t Num, GVN &Gvn);
-    std::pair<uint32_t, bool> assignExpNewValueNum(Expression &exp);
-    bool areAllValsInBB(uint32_t num, const BasicBlock *BB, GVN &Gvn);
 
   public:
     ValueTable();
@@ -109,12 +87,9 @@ class GVN : public PassInfoMixin<GVN> {
     ~ValueTable();
 
     uint32_t lookupOrAdd(Value *V);
-    uint32_t lookup(Value *V, bool Verify = true) const;
+    uint32_t lookup(Value *V) const;
     uint32_t lookupOrAddCmp(unsigned Opcode, CmpInst::Predicate Pred,
                             Value *LHS, Value *RHS);
-    uint32_t phiTranslate(const BasicBlock *BB, const BasicBlock *PhiBlock,
-                          uint32_t Num, GVN &Gvn);
-    void assignBlockRPONumber(Function &F);
     bool exists(Value *V) const;
     void add(Value *V, uint32_t num);
     void clear();

llvm/lib/Transforms/Scalar/GVN.cpp

@@ -80,10 +80,9 @@ MaxRecurseDepth("max-recurse-depth", cl::Hidden, cl::init(1000), cl::ZeroOrMore,
 struct llvm::GVN::Expression {
   uint32_t opcode;
   Type *type;
-  bool commutative;
   SmallVector<uint32_t, 4> varargs;
 
-  Expression(uint32_t o = ~2U) : opcode(o), commutative(false) {}
+  Expression(uint32_t o = ~2U) : opcode(o) {}
 
   bool operator==(const Expression &other) const {
     if (opcode != other.opcode)
@@ -247,7 +246,6 @@ GVN::Expression GVN::ValueTable::createExpr(Instruction *I) {
     assert(I->getNumOperands() == 2 && "Unsupported commutative instruction!");
     if (e.varargs[0] > e.varargs[1])
       std::swap(e.varargs[0], e.varargs[1]);
-    e.commutative = true;
   }
 
   if (CmpInst *C = dyn_cast<CmpInst>(I)) {
@@ -258,7 +256,6 @@ GVN::Expression GVN::ValueTable::createExpr(Instruction *I) {
       Predicate = CmpInst::getSwappedPredicate(Predicate);
     }
     e.opcode = (C->getOpcode() << 8) | Predicate;
-    e.commutative = true;
   } else if (InsertValueInst *E = dyn_cast<InsertValueInst>(I)) {
     for (InsertValueInst::idx_iterator II = E->idx_begin(), IE = E->idx_end();
          II != IE; ++II)
@@ -284,7 +281,6 @@ GVN::Expression GVN::ValueTable::createCmpExpr(unsigned Opcode,
     Predicate = CmpInst::getSwappedPredicate(Predicate);
   }
   e.opcode = (Opcode << 8) | Predicate;
-  e.commutative = true;
   return e;
 }
 
@@ -352,25 +348,25 @@ GVN::ValueTable::~ValueTable() = default;
 /// add - Insert a value into the table with a specified value number.
 void GVN::ValueTable::add(Value *V, uint32_t num) {
   valueNumbering.insert(std::make_pair(V, num));
-  if (PHINode *PN = dyn_cast<PHINode>(V))
-    NumberingPhi[num] = PN;
 }
 
 uint32_t GVN::ValueTable::lookupOrAddCall(CallInst *C) {
   if (AA->doesNotAccessMemory(C)) {
     Expression exp = createExpr(C);
-    uint32_t e = assignExpNewValueNum(exp).first;
+    uint32_t &e = expressionNumbering[exp];
+    if (!e) e = nextValueNumber++;
     valueNumbering[C] = e;
     return e;
   } else if (AA->onlyReadsMemory(C)) {
     Expression exp = createExpr(C);
-    auto ValNum = assignExpNewValueNum(exp);
-    if (ValNum.second) {
-      valueNumbering[C] = ValNum.first;
-      return ValNum.first;
+    uint32_t &e = expressionNumbering[exp];
+    if (!e) {
+      e = nextValueNumber++;
+      valueNumbering[C] = e;
+      return e;
     }
     if (!MD) {
-      uint32_t e = assignExpNewValueNum(exp).first;
+      e = nextValueNumber++;
       valueNumbering[C] = e;
       return e;
     }
@@ -526,29 +522,23 @@ uint32_t GVN::ValueTable::lookupOrAdd(Value *V) {
     case Instruction::ExtractValue:
       exp = createExtractvalueExpr(cast<ExtractValueInst>(I));
       break;
-    case Instruction::PHI:
-      valueNumbering[V] = nextValueNumber;
-      NumberingPhi[nextValueNumber] = cast<PHINode>(V);
-      return nextValueNumber++;
     default:
       valueNumbering[V] = nextValueNumber;
       return nextValueNumber++;
   }
 
-  uint32_t e = assignExpNewValueNum(exp).first;
+  uint32_t& e = expressionNumbering[exp];
+  if (!e) e = nextValueNumber++;
   valueNumbering[V] = e;
   return e;
 }
 
 /// Returns the value number of the specified value. Fails if
 /// the value has not yet been numbered.
-uint32_t GVN::ValueTable::lookup(Value *V, bool Verify) const {
+uint32_t GVN::ValueTable::lookup(Value *V) const {
   DenseMap<Value*, uint32_t>::const_iterator VI = valueNumbering.find(V);
-  if (Verify) {
-    assert(VI != valueNumbering.end() && "Value not numbered?");
-    return VI->second;
-  }
-  return (VI != valueNumbering.end()) ? VI->second : 0;
+  assert(VI != valueNumbering.end() && "Value not numbered?");
+  return VI->second;
 }
 
 /// Returns the value number of the given comparison,
@@ -559,29 +549,21 @@ uint32_t GVN::ValueTable::lookupOrAddCmp(unsigned Opcode,
                                          CmpInst::Predicate Predicate,
                                          Value *LHS, Value *RHS) {
   Expression exp = createCmpExpr(Opcode, Predicate, LHS, RHS);
-  return assignExpNewValueNum(exp).first;
+  uint32_t& e = expressionNumbering[exp];
+  if (!e) e = nextValueNumber++;
+  return e;
 }
 
 /// Remove all entries from the ValueTable.
 void GVN::ValueTable::clear() {
   valueNumbering.clear();
   expressionNumbering.clear();
-  NumberingPhi.clear();
-  PhiTranslateTable.clear();
-  BlockRPONumber.clear();
   nextValueNumber = 1;
-  Expressions.clear();
-  ExprIdx.clear();
-  nextExprNumber = 0;
 }
 
 /// Remove a value from the value numbering.
 void GVN::ValueTable::erase(Value *V) {
-  uint32_t Num = valueNumbering.lookup(V);
   valueNumbering.erase(V);
-  // If V is PHINode, V <--> value number is an one-to-one mapping.
-  if (isa<PHINode>(V))
-    NumberingPhi.erase(Num);
 }
 
 /// verifyRemoved - Verify that the value is removed from all internal data
@@ -1469,97 +1451,6 @@ bool GVN::processLoad(LoadInst *L) {
   return false;
 }
 
-/// Return a pair the first field showing the value number of \p Exp and the
-/// second field showing whether it is a value number newly created.
-std::pair<uint32_t, bool>
-GVN::ValueTable::assignExpNewValueNum(Expression &Exp) {
-  uint32_t &e = expressionNumbering[Exp];
-  bool CreateNewValNum = !e;
-  if (CreateNewValNum) {
-    Expressions.push_back(Exp);
-    if (ExprIdx.size() < nextValueNumber + 1)
-      ExprIdx.resize(nextValueNumber * 2);
-    e = nextValueNumber;
-    ExprIdx[nextValueNumber++] = nextExprNumber++;
-  }
-  return {e, CreateNewValNum};
-}
-
-void GVN::ValueTable::assignBlockRPONumber(Function &F) {
-  uint32_t NextBlockNumber = 1;
-  ReversePostOrderTraversal<Function *> RPOT(&F);
-  for (BasicBlock *BB : RPOT)
-    BlockRPONumber[BB] = NextBlockNumber++;
-}
-
-/// Return whether all the values related with the same \p num are
-/// defined in \p BB.
-bool GVN::ValueTable::areAllValsInBB(uint32_t Num, const BasicBlock *BB,
-                                     GVN &Gvn) {
-  LeaderTableEntry *Vals = &Gvn.LeaderTable[Num];
-  while (Vals && Vals->BB == BB)
-    Vals = Vals->Next;
-  return !Vals;
-}
-
-/// Wrap phiTranslateImpl to provide caching functionality.
-uint32_t GVN::ValueTable::phiTranslate(const BasicBlock *Pred,
-                                       const BasicBlock *PhiBlock, uint32_t Num,
-                                       GVN &Gvn) {
-  auto FindRes = PhiTranslateTable.find({Num, Pred});
-  if (FindRes != PhiTranslateTable.end())
-    return FindRes->second;
-  uint32_t NewNum = phiTranslateImpl(Pred, PhiBlock, Num, Gvn);
-  PhiTranslateTable.insert({{Num, Pred}, NewNum});
-  return NewNum;
-}
-
-/// Translate value number \p Num using phis, so that it has the values of
-/// the phis in BB.
-uint32_t GVN::ValueTable::phiTranslateImpl(const BasicBlock *Pred,
-                                           const BasicBlock *PhiBlock,
-                                           uint32_t Num, GVN &Gvn) {
-  if (PHINode *PN = NumberingPhi[Num]) {
-    if (BlockRPONumber[Pred] >= BlockRPONumber[PhiBlock])
-      return Num;
-    for (unsigned i = 0; i != PN->getNumIncomingValues(); ++i) {
-      if (PN->getParent() == PhiBlock && PN->getIncomingBlock(i) == Pred)
-        if (uint32_t TransVal = lookup(PN->getIncomingValue(i), false))
-          return TransVal;
-    }
-    return Num;
-  }
-
-  // If there is any value related with Num is defined in a BB other than
-  // PhiBlock, it cannot depend on a phi in PhiBlock without going through
-  // a backedge. We can do an early exit in that case to save compile time.
-  if (!areAllValsInBB(Num, PhiBlock, Gvn))
-    return Num;
-
-  if (ExprIdx[Num] == 0 || Num >= ExprIdx.size())
-    return Num;
-  Expression Exp = Expressions[ExprIdx[Num]];
-
-  for (unsigned i = 0; i < Exp.varargs.size(); i++)
-    Exp.varargs[i] = phiTranslate(Pred, PhiBlock, Exp.varargs[i], Gvn);
-
-  if (Exp.commutative) {
-    assert(Exp.varargs.size() == 2 && "Unsupported commutative expression!");
-    if (Exp.varargs[0] > Exp.varargs[1]) {
-      std::swap(Exp.varargs[0], Exp.varargs[1]);
-      uint32_t Opcode = Exp.opcode >> 8;
-      if (Opcode == Instruction::ICmp || Opcode == Instruction::FCmp)
-        Exp.opcode = (Opcode << 8) |
-                     CmpInst::getSwappedPredicate(
-                         static_cast<CmpInst::Predicate>(Exp.opcode & 255));
-    }
-  }
-
-  if (uint32_t NewNum = expressionNumbering[Exp])
-    return NewNum;
-  return Num;
-}
-
 // In order to find a leader for a given value number at a
 // specific basic block, we first obtain the list of all Values for that number,
 // and then scan the list to find one whose block dominates the block in
@@ -1965,7 +1856,6 @@ bool GVN::runImpl(Function &F, AssumptionCache &RunAC, DominatorTree &RunDT,
     // Fabricate val-num for dead-code in order to suppress assertion in
     // performPRE().
     assignValNumForDeadCode();
-    VN.assignBlockRPONumber(F);
     bool PREChanged = true;
     while (PREChanged) {
       PREChanged = performPRE(F);
@@ -2055,9 +1945,7 @@ bool GVN::performScalarPREInsertion(Instruction *Instr, BasicBlock *Pred,
       success = false;
       break;
     }
-    uint32_t TValNo =
-        VN.phiTranslate(Pred, Instr->getParent(), VN.lookup(Op), *this);
-    if (Value *V = findLeader(Pred, TValNo)) {
+    if (Value *V = findLeader(Pred, VN.lookup(Op))) {
       Instr->setOperand(i, V);
     } else {
       success = false;
@@ -2074,12 +1962,10 @@ bool GVN::performScalarPREInsertion(Instruction *Instr, BasicBlock *Pred,
   Instr->insertBefore(Pred->getTerminator());
   Instr->setName(Instr->getName() + ".pre");
   Instr->setDebugLoc(Instr->getDebugLoc());
-
-  unsigned Num = VN.lookupOrAdd(Instr);
-  VN.add(Instr, Num);
+  VN.add(Instr, ValNo);
 
   // Update the availability map to include the new instruction.
-  addToLeaderTable(Num, Instr, Pred);
+  addToLeaderTable(ValNo, Instr, Pred);
   return true;
 }
 
@@ -2128,8 +2014,7 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
       break;
     }
 
-    uint32_t TValNo = VN.phiTranslate(P, CurrentBlock, ValNo, *this);
-    Value *predV = findLeader(P, TValNo);
+    Value *predV = findLeader(P, ValNo);
     if (!predV) {
       predMap.push_back(std::make_pair(static_cast<Value *>(nullptr), P));
       PREPred = P;