[llvm] r215647 - [Reassociation] Add support for reassociation with unsafe algebra.

Mehdi AMINI joker.eph at gmail.com
Thu Nov 6 02:37:05 PST 2014


Hi Chad,

After more digging, I found out that floating-point factorization is indeed
ok for fast-math operations.

The attached patch should fix the mixing of regular and fast operations
without break fast-math factorization.

Best,

Mehdi


2014-11-05 23:09 GMT-08:00 Mehdi Amini <joker.eph at gmail.com>:

> Hi Chad,
>
> This commit does not only bring reassociation but also factorization,
> which I am not sure is allowed for floating point even in fast-math.
> The attached patch disables floating point refactorization while keeping
> reassociation.
>
> Moreover I have a crash currently when mixing fast and regular operation,
> see test/Transforms/Reassociate/mixed-fast-nonfast-fp.ll in the patch.
>
> Best,
>
> Mehdi
>
>
>
>
> On 8/14/14, 8:23 AM, Chad Rosier wrote:
>
>> Author: mcrosier
>> Date: Thu Aug 14 10:23:01 2014
>> New Revision: 215647
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=215647&view=rev
>> Log:
>> [Reassociation] Add support for reassociation with unsafe algebra.
>>
>> Vector instructions are (still) not supported for either integer or
>> floating
>> point.  Hopefully, that work will be landed shortly.
>>
>> Added:
>>      llvm/trunk/test/Transforms/Reassociate/fast-AgressiveSubMove.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-ArrayOutOfBounds.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-MissedTree.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-ReassociateVector.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-SubReassociate.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-basictest.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-fp-commute.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-mightymul.ll
>>      llvm/trunk/test/Transforms/Reassociate/fast-multistep.ll
>> Modified:
>>      llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
>>
>> Modified: llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
>> Transforms/Scalar/Reassociate.cpp?rev=215647&r1=215646&r2=
>> 215647&view=diff
>> ============================================================
>> ==================
>> --- llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp (original)
>> +++ llvm/trunk/lib/Transforms/Scalar/Reassociate.cpp Thu Aug 14 10:23:01
>> 2014
>> @@ -240,6 +240,15 @@ static BinaryOperator *isReassociableOp(
>>     return nullptr;
>>   }
>>   +static BinaryOperator *isReassociableOp(Value *V, unsigned Opcode1,
>> +                                        unsigned Opcode2) {
>> +  if (V->hasOneUse() && isa<Instruction>(V) &&
>> +      (cast<Instruction>(V)->getOpcode() == Opcode1 ||
>> +       cast<Instruction>(V)->getOpcode() == Opcode2))
>> +    return cast<BinaryOperator>(V);
>> +  return nullptr;
>> +}
>> +
>>   static bool isUnmovableInstruction(Instruction *I) {
>>     switch (I->getOpcode()) {
>>     case Instruction::PHI:
>> @@ -304,8 +313,10 @@ unsigned Reassociate::getRank(Value *V)
>>       // If this is a not or neg instruction, do not count it for rank.
>> This
>>     // assures us that X and ~X will have the same rank.
>> -  if (!I->getType()->isIntegerTy() ||
>> -      (!BinaryOperator::isNot(I) && !BinaryOperator::isNeg(I)))
>> +  Type *Ty = V->getType();
>> +  if ((!Ty->isIntegerTy() && !Ty->isFloatingPointTy()) ||
>> +      (!BinaryOperator::isNot(I) && !BinaryOperator::isNeg(I) &&
>> +       !BinaryOperator::isFNeg(I)))
>>       ++Rank;
>>       //DEBUG(dbgs() << "Calculated Rank[" << V->getName() << "] = "
>> @@ -314,14 +325,50 @@ unsigned Reassociate::getRank(Value *V)
>>     return ValueRankMap[I] = Rank;
>>   }
>>   +static BinaryOperator *CreateAdd(Value *S1, Value *S2, const Twine
>> &Name,
>> +                                 Instruction *InsertBefore, Value
>> *FlagsOp) {
>> +  if (S1->getType()->isIntegerTy())
>> +    return BinaryOperator::CreateAdd(S1, S2, Name, InsertBefore);
>> +  else {
>> +    BinaryOperator *Res =
>> +        BinaryOperator::CreateFAdd(S1, S2, Name, InsertBefore);
>> +    Res->setFastMathFlags(cast<FPMathOperator>(FlagsOp)->
>> getFastMathFlags());
>> +    return Res;
>> +  }
>> +}
>> +
>> +static BinaryOperator *CreateMul(Value *S1, Value *S2, const Twine &Name,
>> +                                 Instruction *InsertBefore, Value
>> *FlagsOp) {
>> +  if (S1->getType()->isIntegerTy())
>> +    return BinaryOperator::CreateMul(S1, S2, Name, InsertBefore);
>> +  else {
>> +    BinaryOperator *Res =
>> +      BinaryOperator::CreateFMul(S1, S2, Name, InsertBefore);
>> +    Res->setFastMathFlags(cast<FPMathOperator>(FlagsOp)->
>> getFastMathFlags());
>> +    return Res;
>> +  }
>> +}
>> +
>> +static BinaryOperator *CreateNeg(Value *S1, const Twine &Name,
>> +                                 Instruction *InsertBefore, Value
>> *FlagsOp) {
>> +  if (S1->getType()->isIntegerTy())
>> +    return BinaryOperator::CreateNeg(S1, Name, InsertBefore);
>> +  else {
>> +    BinaryOperator *Res = BinaryOperator::CreateFNeg(S1, Name,
>> InsertBefore);
>> +    Res->setFastMathFlags(cast<FPMathOperator>(FlagsOp)->
>> getFastMathFlags());
>> +    return Res;
>> +  }
>> +}
>> +
>>   /// LowerNegateToMultiply - Replace 0-X with X*-1.
>>   ///
>>   static BinaryOperator *LowerNegateToMultiply(Instruction *Neg) {
>> -  Constant *Cst = Constant::getAllOnesValue(Neg->getType());
>> +  Type *Ty = Neg->getType();
>> +  Constant *NegOne = Ty->isIntegerTy() ? ConstantInt::getAllOnesValue(
>> Ty)
>> +                                       : ConstantFP::get(Ty, -1.0);
>>   -  BinaryOperator *Res =
>> -    BinaryOperator::CreateMul(Neg->getOperand(1), Cst, "",Neg);
>> -  Neg->setOperand(1, Constant::getNullValue(Neg->getType())); // Drop
>> use of op.
>> +  BinaryOperator *Res = CreateMul(Neg->getOperand(1), NegOne, "", Neg,
>> Neg);
>> +  Neg->setOperand(1, Constant::getNullValue(Ty)); // Drop use of op.
>>     Res->takeName(Neg);
>>     Neg->replaceAllUsesWith(Res);
>>     Res->setDebugLoc(Neg->getDebugLoc());
>> @@ -377,13 +424,14 @@ static void IncorporateWeight(APInt &LHS
>>       LHS = 0; // 1 + 1 === 0 modulo 2.
>>       return;
>>     }
>> -  if (Opcode == Instruction::Add) {
>> +  if (Opcode == Instruction::Add || Opcode == Instruction::FAdd) {
>>       // TODO: Reduce the weight by exploiting nsw/nuw?
>>       LHS += RHS;
>>       return;
>>     }
>>   -  assert(Opcode == Instruction::Mul && "Unknown associative
>> operation!");
>> +  assert((Opcode == Instruction::Mul || Opcode == Instruction::FMul) &&
>> +         "Unknown associative operation!");
>>     unsigned Bitwidth = LHS.getBitWidth();
>>     // If CM is the Carmichael number then a weight W satisfying W >=
>> CM+Bitwidth
>>     // can be replaced with W-CM.  That's because x^W=x^(W-CM) for every
>> Bitwidth
>> @@ -499,8 +547,7 @@ static bool LinearizeExprTree(BinaryOper
>>     DEBUG(dbgs() << "LINEARIZE: " << *I << '\n');
>>     unsigned Bitwidth = I->getType()->getScalarType()-
>> >getPrimitiveSizeInBits();
>>     unsigned Opcode = I->getOpcode();
>> -  assert(Instruction::isAssociative(Opcode) &&
>> -         Instruction::isCommutative(Opcode) &&
>> +  assert(I->isAssociative() && I->isCommutative() &&
>>            "Expected an associative and commutative operation!");
>>       // Visit all operands of the expression, keeping track of their
>> weight (the
>> @@ -619,15 +666,16 @@ static bool LinearizeExprTree(BinaryOper
>>           // If this is a multiply expression, turn any internal
>> negations into
>>         // multiplies by -1 so they can be reassociated.
>> -      BinaryOperator *BO = dyn_cast<BinaryOperator>(Op);
>> -      if (Opcode == Instruction::Mul && BO && BinaryOperator::isNeg(BO))
>> {
>> -        DEBUG(dbgs() << "MORPH LEAF: " << *Op << " (" << Weight << ") TO
>> ");
>> -        BO = LowerNegateToMultiply(BO);
>> -        DEBUG(dbgs() << *BO << 'n');
>> -        Worklist.push_back(std::make_pair(BO, Weight));
>> -        MadeChange = true;
>> -        continue;
>> -      }
>> +      if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op))
>> +        if ((Opcode == Instruction::Mul && BinaryOperator::isNeg(BO)) ||
>> +            (Opcode == Instruction::FMul && BinaryOperator::isFNeg(BO)))
>> {
>> +          DEBUG(dbgs() << "MORPH LEAF: " << *Op << " (" << Weight << ")
>> TO ");
>> +          BO = LowerNegateToMultiply(BO);
>> +          DEBUG(dbgs() << *BO << '\n');
>> +          Worklist.push_back(std::make_pair(BO, Weight));
>> +          MadeChange = true;
>> +          continue;
>> +        }
>>           // Failed to morph into an expression of the right type.  This
>> really is
>>         // a leaf.
>> @@ -798,6 +846,8 @@ void Reassociate::RewriteExprTree(Binary
>>         Constant *Undef = UndefValue::get(I->getType());
>>         NewOp = BinaryOperator::Create(Instruction::BinaryOps(Opcode),
>>                                        Undef, Undef, "", I);
>> +      if (NewOp->getType()->isFloatingPointTy())
>> +        NewOp->setFastMathFlags(I->getFastMathFlags());
>>       } else {
>>         NewOp = NodesToRewrite.pop_back_val();
>>       }
>> @@ -817,7 +867,14 @@ void Reassociate::RewriteExprTree(Binary
>>     // expression tree is dominated by all of Ops.
>>     if (ExpressionChanged)
>>       do {
>> -      ExpressionChanged->clearSubclassOptionalData();
>> +      // Preserve FastMathFlags.
>> +      if (isa<FPMathOperator>(I)) {
>> +        FastMathFlags Flags = I->getFastMathFlags();
>> +        ExpressionChanged->clearSubclassOptionalData();
>> +        ExpressionChanged->setFastMathFlags(Flags);
>> +      } else
>> +        ExpressionChanged->clearSubclassOptionalData();
>> +
>>         if (ExpressionChanged == I)
>>           break;
>>         ExpressionChanged->moveBefore(I);
>> @@ -834,6 +891,8 @@ void Reassociate::RewriteExprTree(Binary
>>   /// version of the value is returned, and BI is left pointing at the
>> instruction
>>   /// that should be processed next by the reassociation pass.
>>   static Value *NegateValue(Value *V, Instruction *BI) {
>> +  if (ConstantFP *C = dyn_cast<ConstantFP>(V))
>> +    return ConstantExpr::getFNeg(C);
>>     if (Constant *C = dyn_cast<Constant>(V))
>>       return ConstantExpr::getNeg(C);
>>   @@ -846,7 +905,8 @@ static Value *NegateValue(Value *V, Inst
>>     // the constants.  We assume that instcombine will clean up the mess
>> later if
>>     // we introduce tons of unnecessary negation instructions.
>>     //
>> -  if (BinaryOperator *I = isReassociableOp(V, Instruction::Add)) {
>> +  if (BinaryOperator *I =
>> +          isReassociableOp(V, Instruction::Add, Instruction::FAdd)) {
>>       // Push the negates through the add.
>>       I->setOperand(0, NegateValue(I->getOperand(0), BI));
>>       I->setOperand(1, NegateValue(I->getOperand(1), BI));
>> @@ -864,7 +924,8 @@ static Value *NegateValue(Value *V, Inst
>>     // Okay, we need to materialize a negated version of V with an
>> instruction.
>>     // Scan the use lists of V to see if we have one already.
>>     for (User *U : V->users()) {
>> -    if (!BinaryOperator::isNeg(U)) continue;
>> +    if (!BinaryOperator::isNeg(U) && !BinaryOperator::isFNeg(U))
>> +      continue;
>>         // We found one!  Now we have to make sure that the definition
>> dominates
>>       // this use.  We do this by moving it to the entry block (if it is a
>> @@ -894,27 +955,30 @@ static Value *NegateValue(Value *V, Inst
>>       // Insert a 'neg' instruction that subtracts the value from zero to
>> get the
>>     // negation.
>> -  return BinaryOperator::CreateNeg(V, V->getName() + ".neg", BI);
>> +  return CreateNeg(V, V->getName() + ".neg", BI, BI);
>>   }
>>     /// ShouldBreakUpSubtract - Return true if we should break up this
>> subtract of
>>   /// X-Y into (X + -Y).
>>   static bool ShouldBreakUpSubtract(Instruction *Sub) {
>>     // If this is a negation, we can't split it up!
>> -  if (BinaryOperator::isNeg(Sub))
>> +  if (BinaryOperator::isNeg(Sub) || BinaryOperator::isFNeg(Sub))
>>       return false;
>>       // Don't bother to break this up unless either the LHS is an
>> associable add or
>>     // subtract or if this is only used by one.
>> -  if (isReassociableOp(Sub->getOperand(0), Instruction::Add) ||
>> -      isReassociableOp(Sub->getOperand(0), Instruction::Sub))
>> +  Value *V0 = Sub->getOperand(0);
>> +  if (isReassociableOp(V0, Instruction::Add, Instruction::FAdd) ||
>> +      isReassociableOp(V0, Instruction::Sub, Instruction::FSub))
>>       return true;
>> -  if (isReassociableOp(Sub->getOperand(1), Instruction::Add) ||
>> -      isReassociableOp(Sub->getOperand(1), Instruction::Sub))
>> +  Value *V1 = Sub->getOperand(1);
>> +  if (isReassociableOp(V1, Instruction::Add, Instruction::FAdd) ||
>> +      isReassociableOp(V1, Instruction::Sub, Instruction::FSub))
>>       return true;
>> +  Value *VB = Sub->user_back();
>>     if (Sub->hasOneUse() &&
>> -      (isReassociableOp(Sub->user_back(), Instruction::Add) ||
>> -       isReassociableOp(Sub->user_back(), Instruction::Sub)))
>> +      (isReassociableOp(VB, Instruction::Add, Instruction::FAdd) ||
>> +       isReassociableOp(VB, Instruction::Sub, Instruction::FSub)))
>>       return true;
>>       return false;
>> @@ -931,8 +995,7 @@ static BinaryOperator *BreakUpSubtract(I
>>     // and set it as the RHS of the add instruction we just made.
>>     //
>>     Value *NegVal = NegateValue(Sub->getOperand(1), Sub);
>> -  BinaryOperator *New =
>> -    BinaryOperator::CreateAdd(Sub->getOperand(0), NegVal, "", Sub);
>> +  BinaryOperator *New = CreateAdd(Sub->getOperand(0), NegVal, "", Sub,
>> Sub);
>>     Sub->setOperand(0, Constant::getNullValue(Sub->getType())); // Drop
>> use of op.
>>     Sub->setOperand(1, Constant::getNullValue(Sub->getType())); // Drop
>> use of op.
>>     New->takeName(Sub);
>> @@ -988,15 +1051,16 @@ static Value *EmitAddTreeOfValues(Instru
>>     Value *V1 = Ops.back();
>>     Ops.pop_back();
>>     Value *V2 = EmitAddTreeOfValues(I, Ops);
>> -  return BinaryOperator::CreateAdd(V2, V1, "tmp", I);
>> +  return CreateAdd(V2, V1, "tmp", I, I);
>>   }
>>     /// RemoveFactorFromExpression - If V is an expression tree that is a
>>   /// multiplication sequence, and if this sequence contains a multiply
>> by Factor,
>>   /// remove Factor from the tree and return the new tree.
>>   Value *Reassociate::RemoveFactorFromExpression(Value *V, Value
>> *Factor) {
>> -  BinaryOperator *BO = isReassociableOp(V, Instruction::Mul);
>> -  if (!BO) return nullptr;
>> +  BinaryOperator *BO = isReassociableOp(V, Instruction::Mul,
>> Instruction::FMul);
>> +  if (!BO)
>> +    return nullptr;
>>       SmallVector<RepeatedValue, 8> Tree;
>>     MadeChange |= LinearizeExprTree(BO, Tree);
>> @@ -1018,13 +1082,25 @@ Value *Reassociate::RemoveFactorFromExpr
>>       }
>>         // If this is a negative version of this factor, remove it.
>> -    if (ConstantInt *FC1 = dyn_cast<ConstantInt>(Factor))
>> +    if (ConstantInt *FC1 = dyn_cast<ConstantInt>(Factor)) {
>>         if (ConstantInt *FC2 = dyn_cast<ConstantInt>(Factors[i].Op))
>>           if (FC1->getValue() == -FC2->getValue()) {
>>             FoundFactor = NeedsNegate = true;
>>             Factors.erase(Factors.begin()+i);
>>             break;
>>           }
>> +    } else if (ConstantFP *FC1 = dyn_cast<ConstantFP>(Factor)) {
>> +      if (ConstantFP *FC2 = dyn_cast<ConstantFP>(Factors[i].Op)) {
>> +        APFloat F1(FC1->getValueAPF());
>> +        APFloat F2(FC2->getValueAPF());
>> +        F2.changeSign();
>> +        if (F1.compare(F2) == APFloat::cmpEqual) {
>> +          FoundFactor = NeedsNegate = true;
>> +          Factors.erase(Factors.begin() + i);
>> +          break;
>> +        }
>> +      }
>> +    }
>>     }
>>       if (!FoundFactor) {
>> @@ -1046,7 +1122,7 @@ Value *Reassociate::RemoveFactorFromExpr
>>     }
>>       if (NeedsNegate)
>> -    V = BinaryOperator::CreateNeg(V, "neg", InsertPt);
>> +    V = CreateNeg(V, "neg", InsertPt, BO);
>>       return V;
>>   }
>> @@ -1058,7 +1134,7 @@ Value *Reassociate::RemoveFactorFromExpr
>>   static void FindSingleUseMultiplyFactors(Value *V,
>>                                            SmallVectorImpl<Value*>
>> &Factors,
>>                                          const
>> SmallVectorImpl<ValueEntry> &Ops) {
>> -  BinaryOperator *BO = isReassociableOp(V, Instruction::Mul);
>> +  BinaryOperator *BO = isReassociableOp(V, Instruction::Mul,
>> Instruction::FMul);
>>     if (!BO) {
>>       Factors.push_back(V);
>>       return;
>> @@ -1389,13 +1465,15 @@ Value *Reassociate::OptimizeAdd(Instruct
>>         ++NumFactor;
>>           // Insert a new multiply.
>> -      Value *Mul = ConstantInt::get(cast<IntegerType>(I->getType()),
>> NumFound);
>> -      Mul = BinaryOperator::CreateMul(TheOp, Mul, "factor", I);
>> +      Type *Ty = TheOp->getType();
>> +      Constant *C = Ty->isIntegerTy() ? ConstantInt::get(Ty, NumFound)
>> +                                      : ConstantFP::get(Ty, NumFound);
>> +      Instruction *Mul = CreateMul(TheOp, C, "factor", I, I);
>>           // Now that we have inserted a multiply, optimize it. This
>> allows us to
>>         // handle cases that require multiple factoring steps, such as
>> this:
>>         // (X*2) + (X*2) + (X*2) -> (X*2)*3 -> X*6
>> -      RedoInsts.insert(cast<Instruction>(Mul));
>> +      RedoInsts.insert(Mul);
>>           // If every add operand was a duplicate, return the multiply.
>>         if (Ops.empty())
>> @@ -1412,11 +1490,12 @@ Value *Reassociate::OptimizeAdd(Instruct
>>       }
>>         // Check for X and -X or X and ~X in the operand list.
>> -    if (!BinaryOperator::isNeg(TheOp) && !BinaryOperator::isNot(TheOp))
>> +    if (!BinaryOperator::isNeg(TheOp) && !BinaryOperator::isFNeg(TheOp)
>> &&
>> +        !BinaryOperator::isNot(TheOp))
>>         continue;
>>         Value *X = nullptr;
>> -    if (BinaryOperator::isNeg(TheOp))
>> +    if (BinaryOperator::isNeg(TheOp) || BinaryOperator::isFNeg(TheOp))
>>         X = BinaryOperator::getNegArgument(TheOp);
>>       else if (BinaryOperator::isNot(TheOp))
>>         X = BinaryOperator::getNotArgument(TheOp);
>> @@ -1426,7 +1505,8 @@ Value *Reassociate::OptimizeAdd(Instruct
>>         continue;
>>         // Remove X and -X from the operand list.
>> -    if (Ops.size() == 2 && BinaryOperator::isNeg(TheOp))
>> +    if (Ops.size() == 2 &&
>> +        (BinaryOperator::isNeg(TheOp) || BinaryOperator::isFNeg(TheOp)))
>>         return Constant::getNullValue(X->getType());
>>         // Remove X and ~X from the operand list.
>> @@ -1463,7 +1543,8 @@ Value *Reassociate::OptimizeAdd(Instruct
>>     unsigned MaxOcc = 0;
>>     Value *MaxOccVal = nullptr;
>>     for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
>> -    BinaryOperator *BOp = isReassociableOp(Ops[i].Op, Instruction::Mul);
>> +    BinaryOperator *BOp =
>> +        isReassociableOp(Ops[i].Op, Instruction::Mul, Instruction::FMul);
>>       if (!BOp)
>>         continue;
>>   @@ -1476,23 +1557,43 @@ Value *Reassociate::OptimizeAdd(Instruct
>>       SmallPtrSet<Value*, 8> Duplicates;
>>       for (unsigned i = 0, e = Factors.size(); i != e; ++i) {
>>         Value *Factor = Factors[i];
>> -      if (!Duplicates.insert(Factor)) continue;
>> +      if (!Duplicates.insert(Factor))
>> +        continue;
>>           unsigned Occ = ++FactorOccurrences[Factor];
>> -      if (Occ > MaxOcc) { MaxOcc = Occ; MaxOccVal = Factor; }
>> +      if (Occ > MaxOcc) {
>> +        MaxOcc = Occ;
>> +        MaxOccVal = Factor;
>> +      }
>>           // If Factor is a negative constant, add the negated value as a
>> factor
>>         // because we can percolate the negate out.  Watch for minint,
>> which
>>         // cannot be positivified.
>> -      if (ConstantInt *CI = dyn_cast<ConstantInt>(Factor))
>> +      if (ConstantInt *CI = dyn_cast<ConstantInt>(Factor)) {
>>           if (CI->isNegative() && !CI->isMinValue(true)) {
>>             Factor = ConstantInt::get(CI->getContext(), -CI->getValue());
>>             assert(!Duplicates.count(Factor) &&
>>                    "Shouldn't have two constant factors, missed a
>> canonicalize");
>> -
>>             unsigned Occ = ++FactorOccurrences[Factor];
>> -          if (Occ > MaxOcc) { MaxOcc = Occ; MaxOccVal = Factor; }
>> +          if (Occ > MaxOcc) {
>> +            MaxOcc = Occ;
>> +            MaxOccVal = Factor;
>> +          }
>>           }
>> +      } else if (ConstantFP *CF = dyn_cast<ConstantFP>(Factor)) {
>> +        if (CF->isNegative()) {
>> +          APFloat F(CF->getValueAPF());
>> +          F.changeSign();
>> +          Factor = ConstantFP::get(CF->getContext(), F);
>> +          assert(!Duplicates.count(Factor) &&
>> +                 "Shouldn't have two constant factors, missed a
>> canonicalize");
>> +          unsigned Occ = ++FactorOccurrences[Factor];
>> +          if (Occ > MaxOcc) {
>> +            MaxOcc = Occ;
>> +            MaxOccVal = Factor;
>> +          }
>> +        }
>> +      }
>>       }
>>     }
>>   @@ -1505,11 +1606,16 @@ Value *Reassociate::OptimizeAdd(Instruct
>>       // this, we could otherwise run into situations where removing a
>> factor
>>       // from an expression will drop a use of maxocc, and this can cause
>>       // RemoveFactorFromExpression on successive values to behave
>> differently.
>> -    Instruction *DummyInst = BinaryOperator::CreateAdd(MaxOccVal,
>> MaxOccVal);
>> +    Instruction *DummyInst =
>> +        I->getType()->isIntegerTy()
>> +            ? BinaryOperator::CreateAdd(MaxOccVal, MaxOccVal)
>> +            : BinaryOperator::CreateFAdd(MaxOccVal, MaxOccVal);
>> +
>>       SmallVector<WeakVH, 4> NewMulOps;
>>       for (unsigned i = 0; i != Ops.size(); ++i) {
>>         // Only try to remove factors from expressions we're allowed to.
>> -      BinaryOperator *BOp = isReassociableOp(Ops[i].Op,
>> Instruction::Mul);
>> +      BinaryOperator *BOp =
>> +          isReassociableOp(Ops[i].Op, Instruction::Mul,
>> Instruction::FMul);
>>         if (!BOp)
>>           continue;
>>   @@ -1542,7 +1648,7 @@ Value *Reassociate::OptimizeAdd(Instruct
>>         RedoInsts.insert(VI);
>>         // Create the multiply.
>> -    Instruction *V2 = BinaryOperator::CreateMul(V, MaxOccVal, "tmp", I);
>> +    Instruction *V2 = CreateMul(V, MaxOccVal, "tmp", I, I);
>>         // Rerun associate on the multiply in case the inner expression
>> turned into
>>       // a multiply.  We want to make sure that we keep things in
>> canonical form.
>> @@ -1632,7 +1738,10 @@ static Value *buildMultiplyTree(IRBuilde
>>       Value *LHS = Ops.pop_back_val();
>>     do {
>> -    LHS = Builder.CreateMul(LHS, Ops.pop_back_val());
>> +    if (LHS->getType()->isIntegerTy())
>> +      LHS = Builder.CreateMul(LHS, Ops.pop_back_val());
>> +    else
>> +      LHS = Builder.CreateFMul(LHS, Ops.pop_back_val());
>>     } while (!Ops.empty());
>>       return LHS;
>> @@ -1765,11 +1874,13 @@ Value *Reassociate::OptimizeExpression(B
>>       break;
>>       case Instruction::Add:
>> +  case Instruction::FAdd:
>>       if (Value *Result = OptimizeAdd(I, Ops))
>>         return Result;
>>       break;
>>       case Instruction::Mul:
>> +  case Instruction::FMul:
>>       if (Value *Result = OptimizeMul(I, Ops))
>>         return Result;
>>       break;
>> @@ -1810,8 +1921,7 @@ void Reassociate::OptimizeInst(Instructi
>>     if (!isa<BinaryOperator>(I))
>>       return;
>>   -  if (I->getOpcode() == Instruction::Shl &&
>> -      isa<ConstantInt>(I->getOperand(1)))
>> +  if (I->getOpcode() == Instruction::Shl && isa<ConstantInt>(I->
>> getOperand(1)))
>>       // If an operand of this shift is a reassociable multiply, or if
>> the shift
>>       // is used by a reassociable multiply or add, turn into a multiply.
>>       if (isReassociableOp(I->getOperand(0), Instruction::Mul) ||
>> @@ -1824,28 +1934,33 @@ void Reassociate::OptimizeInst(Instructi
>>         I = NI;
>>       }
>>   -  // Floating point binary operators are not associative, but we can
>> still
>> -  // commute (some) of them, to canonicalize the order of their operands.
>> -  // This can potentially expose more CSE opportunities, and makes
>> writing
>> -  // other transformations simpler.
>> -  if ((I->getType()->isFloatingPointTy() ||
>> I->getType()->isVectorTy())) {
>> -    // FAdd and FMul can be commuted.
>> -    if (I->getOpcode() != Instruction::FMul &&
>> -        I->getOpcode() != Instruction::FAdd)
>> -      return;
>> +  // Commute floating point binary operators, to canonicalize the order
>> of their
>> +  // operands.  This can potentially expose more CSE opportunities, and
>> makes
>> +  // writing other transformations simpler.
>> +  if (I->getType()->isFloatingPointTy() || I->getType()->isVectorTy()) {
>>   -    Value *LHS = I->getOperand(0);
>> -    Value *RHS = I->getOperand(1);
>> -    unsigned LHSRank = getRank(LHS);
>> -    unsigned RHSRank = getRank(RHS);
>> -
>> -    // Sort the operands by rank.
>> -    if (RHSRank < LHSRank) {
>> -      I->setOperand(0, RHS);
>> -      I->setOperand(1, LHS);
>> +    // FAdd and FMul can be commuted.
>> +    if (I->getOpcode() == Instruction::FMul ||
>> +        I->getOpcode() == Instruction::FAdd) {
>> +      Value *LHS = I->getOperand(0);
>> +      Value *RHS = I->getOperand(1);
>> +      unsigned LHSRank = getRank(LHS);
>> +      unsigned RHSRank = getRank(RHS);
>> +
>> +      // Sort the operands by rank.
>> +      if (RHSRank < LHSRank) {
>> +        I->setOperand(0, RHS);
>> +        I->setOperand(1, LHS);
>> +      }
>>       }
>>   -    return;
>> +    // FIXME: We should commute vector instructions as well.  However,
>> this
>> +    // requires further analysis to determine the effect on later passes.
>> +
>> +    // Don't try to optimize vector instructions or anything that
>> doesn't have
>> +    // unsafe algebra.
>> +    if (I->getType()->isVectorTy() || !I->hasUnsafeAlgebra())
>> +      return;
>>     }
>>       // Do not reassociate boolean (i1) expressions.  We want to
>> preserve the
>> @@ -1877,6 +1992,24 @@ void Reassociate::OptimizeInst(Instructi
>>           I = NI;
>>         }
>>       }
>> +  } else if (I->getOpcode() == Instruction::FSub) {
>> +    if (ShouldBreakUpSubtract(I)) {
>> +      Instruction *NI = BreakUpSubtract(I);
>> +      RedoInsts.insert(I);
>> +      MadeChange = true;
>> +      I = NI;
>> +    } else if (BinaryOperator::isFNeg(I)) {
>> +      // Otherwise, this is a negation.  See if the operand is a
>> multiply tree
>> +      // and if this is not an inner node of a multiply tree.
>> +      if (isReassociableOp(I->getOperand(1), Instruction::FMul) &&
>> +          (!I->hasOneUse() ||
>> +           !isReassociableOp(I->user_back(), Instruction::FMul))) {
>> +        Instruction *NI = LowerNegateToMultiply(I);
>> +        RedoInsts.insert(I);
>> +        MadeChange = true;
>> +        I = NI;
>> +      }
>> +    }
>>     }
>>       // If this instruction is an associative binary operator, process
>> it.
>> @@ -1894,11 +2027,16 @@ void Reassociate::OptimizeInst(Instructi
>>     if (BO->hasOneUse() && BO->getOpcode() == Instruction::Add &&
>>         cast<Instruction>(BO->user_back())->getOpcode() ==
>> Instruction::Sub)
>>       return;
>> +  if (BO->hasOneUse() && BO->getOpcode() == Instruction::FAdd &&
>> +      cast<Instruction>(BO->user_back())->getOpcode() ==
>> Instruction::FSub)
>> +    return;
>>       ReassociateExpression(BO);
>>   }
>>     void Reassociate::ReassociateExpression(BinaryOperator *I) {
>> +  assert(!I->getType()->isVectorTy() &&
>> +         "Reassociation of vector instructions is not supported.");
>>       // First, walk the expression tree, linearizing the tree,
>> collecting the
>>     // operand information.
>> @@ -1943,12 +2081,21 @@ void Reassociate::ReassociateExpression(
>>     // this is a multiply tree used only by an add, and the immediate is
>> a -1.
>>     // In this case we reassociate to put the negation on the outside so
>> that we
>>     // can fold the negation into the add: (-X)*Y + Z -> Z-X*Y
>> -  if (I->getOpcode() == Instruction::Mul && I->hasOneUse() &&
>> -      cast<Instruction>(I->user_back())->getOpcode() ==
>> Instruction::Add &&
>> -      isa<ConstantInt>(Ops.back().Op) &&
>> -      cast<ConstantInt>(Ops.back().Op)->isAllOnesValue()) {
>> -    ValueEntry Tmp = Ops.pop_back_val();
>> -    Ops.insert(Ops.begin(), Tmp);
>> +  if (I->hasOneUse()) {
>> +    if (I->getOpcode() == Instruction::Mul &&
>> +        cast<Instruction>(I->user_back())->getOpcode() ==
>> Instruction::Add &&
>> +        isa<ConstantInt>(Ops.back().Op) &&
>> +        cast<ConstantInt>(Ops.back().Op)->isAllOnesValue()) {
>> +      ValueEntry Tmp = Ops.pop_back_val();
>> +      Ops.insert(Ops.begin(), Tmp);
>> +    } else if (I->getOpcode() == Instruction::FMul &&
>> +               cast<Instruction>(I->user_back())->getOpcode() ==
>> +                   Instruction::FAdd &&
>> +               isa<ConstantFP>(Ops.back().Op) &&
>> +               cast<ConstantFP>(Ops.back().Op)->isExactlyValue(-1.0)) {
>> +      ValueEntry Tmp = Ops.pop_back_val();
>> +      Ops.insert(Ops.begin(), Tmp);
>> +    }
>>     }
>>       DEBUG(dbgs() << "RAOut:\t"; PrintOps(I, Ops); dbgs() << '\n');
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-AgressiveSubMove.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-AgressiveSubMove.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-AgressiveSubMove.ll
>> (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-AgressiveSubMove.ll Thu
>> Aug 14 10:23:01 2014
>> @@ -0,0 +1,24 @@
>> +; RUN: opt < %s -reassociate -S | FileCheck %s
>> +
>> +define float @test1(float %A) {
>> +; CHECK-LABEL: test1
>> +; CHECK-NEXT: %X = fadd float 1.000000e+00, %A
>> +; CHECK-NEXT: %Y = fadd float 1.000000e+00, %A
>> +; CHECK-NEXT: %r = fsub float %X, %Y
>> +; CHECK-NEXT: ret float %r
>> +
>> +  %X = fadd float %A, 1.000000e+00
>> +  %Y = fadd float %A, 1.000000e+00
>> +  %r = fsub float %X, %Y
>> +  ret float %r
>> +}
>> +
>> +define float @test2(float %A) {
>> +; CHECK-LABEL: test2
>> +; CHECK-NEXT: ret float 0.000000e+00
>> +
>> +  %X = fadd fast float 1.000000e+00, %A
>> +  %Y = fadd fast float 1.000000e+00, %A
>> +  %r = fsub fast float %X, %Y
>> +  ret float %r
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-ArrayOutOfBounds.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-ArrayOutOfBounds.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-ArrayOutOfBounds.ll
>> (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-ArrayOutOfBounds.ll Thu
>> Aug 14 10:23:01 2014
>> @@ -0,0 +1,65 @@
>> +; RUN: opt < %s -reassociate -instcombine -S | FileCheck %s
>> +
>> +; Not marked as fast, so must not change.
>> +define float @test1(float %a0, float %a1, float %a2, float %a3, float
>> %a4) {
>> +; CHECK-LABEL: test1
>> +; CHECK-NEXT: %tmp.2 = fadd float %a3, %a4
>> +; CHECK-NEXT: %tmp.4 = fadd float %tmp.2, %a2
>> +; CHECK-NEXT: %tmp.6 = fadd float %tmp.4, %a1
>> +; CHECK-NEXT: %tmp.8 = fadd float %tmp.6, %a0
>> +; CHECK-NEXT: %tmp.11 = fadd float %a2, %a3
>> +; CHECK-NEXT: %tmp.13 = fadd float %tmp.11, %a1
>> +; CHECK-NEXT: %tmp.15 = fadd float %tmp.13, %a0
>> +; CHECK-NEXT: %tmp.18 = fadd float %a1, %a2
>> +; CHECK-NEXT: %tmp.20 = fadd float %tmp.18, %a0
>> +; CHECK-NEXT: %tmp.23 = fadd float %a0, %a1
>> +; CHECK-NEXT: %tmp.26 = fsub float %tmp.8, %tmp.15
>> +; CHECK-NEXT: %tmp.28 = fadd float %tmp.20, %tmp.26
>> +; CHECK-NEXT: %tmp.30 = fsub float %tmp.28, %tmp.23
>> +; CHECK-NEXT: %tmp.32 = fsub float %tmp.30, %a4
>> +; CHECK-NEXT: %tmp.34 = fsub float %tmp.32, %a2
>> +; CHECK-NEXT: %T = fmul float %tmp.34, %tmp.34
>> +; CHECK-NEXT: ret float %T
>> +
>> +  %tmp.2 = fadd float %a4, %a3
>> +  %tmp.4 = fadd float %tmp.2, %a2
>> +  %tmp.6 = fadd float %tmp.4, %a1
>> +  %tmp.8 = fadd float %tmp.6, %a0
>> +  %tmp.11 = fadd float %a3, %a2
>> +  %tmp.13 = fadd float %tmp.11, %a1
>> +  %tmp.15 = fadd float %tmp.13, %a0
>> +  %tmp.18 = fadd float %a2, %a1
>> +  %tmp.20 = fadd float %tmp.18, %a0
>> +  %tmp.23 = fadd float %a1, %a0
>> +  %tmp.26 = fsub float %tmp.8, %tmp.15
>> +  %tmp.28 = fadd float %tmp.26, %tmp.20
>> +  %tmp.30 = fsub float %tmp.28, %tmp.23
>> +  %tmp.32 = fsub float %tmp.30, %a4
>> +  %tmp.34 = fsub float %tmp.32, %a2
>> +  %T = fmul float %tmp.34, %tmp.34
>> +  ret float %T
>> +}
>> +
>> +; Should be able to eliminate everything.
>> +define float @test2(float %a0, float %a1, float %a2, float %a3, float
>> %a4) {
>> +; CHECK-LABEL: test2
>> +; CHECK: ret float 0.000000e+00
>> +
>> +  %tmp.2 = fadd fast float %a4, %a3
>> +  %tmp.4 = fadd fast float %tmp.2, %a2
>> +  %tmp.6 = fadd fast float %tmp.4, %a1
>> +  %tmp.8 = fadd fast float %tmp.6, %a0
>> +  %tmp.11 = fadd fast float %a3, %a2
>> +  %tmp.13 = fadd fast float %tmp.11, %a1
>> +  %tmp.15 = fadd fast float %tmp.13, %a0
>> +  %tmp.18 = fadd fast float %a2, %a1
>> +  %tmp.20 = fadd fast float %tmp.18, %a0
>> +  %tmp.23 = fadd fast float %a1, %a0
>> +  %tmp.26 = fsub fast float %tmp.8, %tmp.15
>> +  %tmp.28 = fadd fast float %tmp.26, %tmp.20
>> +  %tmp.30 = fsub fast float %tmp.28, %tmp.23
>> +  %tmp.32 = fsub fast float %tmp.30, %a4
>> +  %tmp.34 = fsub fast float %tmp.32, %a2
>> +  %T = fmul fast float %tmp.34, %tmp.34
>> +  ret float %T
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-MissedTree.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-MissedTree.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-MissedTree.ll (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-MissedTree.ll Thu Aug 14
>> 10:23:01 2014
>> @@ -0,0 +1,11 @@
>> +; RUN: opt < %s -reassociate -instcombine -S | FileCheck %s
>> +
>> +define float @test1(float %A, float %B) {
>> +; CHECK-LABEL: test1
>> +; CHECK: %Z = fadd fast float %A, %B
>> +; CHECK: ret float %Z
>> +       %W = fadd fast float %B, -5.0
>> +       %Y = fadd fast float %A, 5.0
>> +       %Z = fadd fast float %W, %Y
>> +       ret float %Z
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-ReassociateVector.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-ReassociateVector.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-ReassociateVector.ll
>> (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-ReassociateVector.ll Thu
>> Aug 14 10:23:01 2014
>> @@ -0,0 +1,25 @@
>> +; RUN: opt < %s -reassociate -S | FileCheck %s
>> +
>> +; Don't handle floating point vector operations.
>> +define <4 x float> @test1() {
>> +; CHECK-LABEL: test1
>> +; CHECK-NEXT: %tmp1 = fsub fast <4 x float> zeroinitializer,
>> zeroinitializer
>> +; CHECK-NEXT: %tmp2 = fmul fast <4 x float> zeroinitializer, %tmp1
>> +
>> +  %tmp1 = fsub fast <4 x float> zeroinitializer, zeroinitializer
>> +  %tmp2 = fmul fast <4 x float> zeroinitializer, %tmp1
>> +  ret <4 x float> %tmp2
>> +}
>> +
>> +; We don't currently commute integer vector operations.
>> +define <2 x i32> @test2(<2 x i32> %x, <2 x i32> %y) {
>> +; CHECK-LABEL: test2
>> +; CHECK-NEXT: %tmp1 = add <2 x i32> %x, %y
>> +; CHECK-NEXT: %tmp2 = add <2 x i32> %y, %x
>> +; CHECK-NEXT: %tmp3 = add <2 x i32> %tmp1, %tmp2
>> +
>> +  %tmp1 = add <2 x i32> %x, %y
>> +  %tmp2 = add <2 x i32> %y, %x
>> +  %tmp3 = add <2 x i32> %tmp1, %tmp2
>> +  ret <2 x i32> %tmp3
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-SubReassociate.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-SubReassociate.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-SubReassociate.ll (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-SubReassociate.ll Thu
>> Aug 14 10:23:01 2014
>> @@ -0,0 +1,70 @@
>> +; RUN: opt < %s -reassociate -constprop -instcombine -S | FileCheck %s
>> +
>> +define float @test1(float %A, float %B) {
>> +; CHECK-LABEL: test1
>> +; CHECK-NEXT: %W = fadd float %B, 5.000000e+00
>> +; CHECK-NEXT: %X = fadd float %A, -7.000000e+00
>> +; CHECK-NEXT: %Y = fsub float %X, %W
>> +; CHECK-NEXT: %Z = fadd float %Y, 1.200000e+01
>> +; CHECK-NEXT: ret float %Z
>> +
>> +  %W = fadd float 5.0, %B
>> +  %X = fadd float -7.0, %A
>> +  %Y = fsub float %X, %W
>> +  %Z = fadd float %Y, 12.0
>> +  ret float %Z
>> +}
>> +
>> +; With sub reassociation, constant folding can eliminate all of the
>> constants.
>> +define float @test2(float %A, float %B) {
>> +; CHECK-LABEL: test2
>> +; CHECK-NEXT: %Z = fsub fast float %A, %B
>> +; CHECK-NEXT: ret float %Z
>> +
>> +  %W = fadd fast float %B, 5.000000e+00
>> +  %X = fadd fast float %A, -7.000000e+00
>> +  %Y = fsub fast float %X, %W
>> +  %Z = fadd fast float %Y, 1.200000e+01
>> +  ret float %Z
>> +
>> +}
>> +
>> +define float @test3(float %A, float %B, float %C, float %D) {
>> +; CHECK-LABEL: test3
>> +; CHECK-NEXT: %M = fadd float %A, 1.200000e+01
>> +; CHECK-NEXT: %N = fadd float %M, %B
>> +; CHECK-NEXT: %O = fadd float %N, %C
>> +; CHECK-NEXT: %P = fsub float %D, %O
>> +; CHECK-NEXT: %Q = fadd float %P, 1.200000e+01
>> +; CHECK-NEXT: ret float %Q
>> +
>> +  %M = fadd float %A, 1.200000e+01
>> +  %N = fadd float %M, %B
>> +  %O = fadd float %N, %C
>> +  %P = fsub float %D, %O
>> +  %Q = fadd float %P, 1.200000e+01
>> +  ret float %Q
>> +}
>> +
>> +; With sub reassociation, constant folding can eliminate the two 12
>> constants.
>> +define float @test4(float %A, float %B, float %C, float %D) {
>> +; CHECK-LABEL: test4
>> +; CHECK-NEXT: %B.neg = fsub fast float -0.000000e+00, %B
>> +; CHECK-NEXT: %O.neg = fsub fast float %B.neg, %A
>> +; CHECK-NEXT: %P = fsub fast float %O.neg, %C
>> +; CHECK-NEXT: %Q = fadd fast float %P, %D
>> +; CHECK-NEXT: ret float %Q
>> +
>> +; FIXME: InstCombine should be able to get us to the following:
>> +; %sum = fadd fast float %B, %A
>> +; %sum1 = fadd fast float %sum, %C
>> +; %Q = fsub fast float %D, %sum1
>> +; ret i32 %Q
>> +
>> +  %M = fadd fast float 1.200000e+01, %A
>> +  %N = fadd fast float %M, %B
>> +  %O = fadd fast float %N, %C
>> +  %P = fsub fast float %D, %O
>> +  %Q = fadd fast float 1.200000e+01, %P
>> +  ret float %Q
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-basictest.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-basictest.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-basictest.ll (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-basictest.ll Thu Aug 14
>> 10:23:01 2014
>> @@ -0,0 +1,285 @@
>> +; RUN: opt < %s -reassociate -gvn -instcombine -S | FileCheck %s
>> +
>> +; With reassociation, constant folding can eliminate the 12 and -12
>> constants.
>> +define float @test1(float %arg) {
>> +; CHECK-LABEL: @test1
>> +; CHECK-NEXT: fsub fast float -0.000000e+00, %arg
>> +; CHECK-NEXT: ret float
>> +
>> +  %tmp1 = fsub fast float -1.200000e+01, %arg
>> +  %tmp2 = fadd fast float %tmp1, 1.200000e+01
>> +  ret float %tmp2
>> +}
>> +
>> +define float @test2(float %reg109, float %reg1111) {
>> +; CHECK-LABEL: @test2
>> +; CHECK-NEXT: fadd float %reg109, -3.000000e+01
>> +; CHECK-NEXT: fadd float %reg115, %reg1111
>> +; CHECK-NEXT: fadd float %reg116, 3.000000e+01
>> +; CHECK-NEXT: ret float
>> +
>> +  %reg115 = fadd float %reg109, -3.000000e+01
>> +  %reg116 = fadd float %reg115, %reg1111
>> +  %reg117 = fadd float %reg116, 3.000000e+01
>> +  ret float %reg117
>> +}
>> +
>> +define float @test3(float %reg109, float %reg1111) {
>> +; CHECK-LABEL: @test3
>> +; CHECK-NEXT: %reg117 = fadd fast float %reg109, %reg1111
>> +; CHECK-NEXT:  ret float %reg117
>> +
>> +  %reg115 = fadd fast float %reg109, -3.000000e+01
>> +  %reg116 = fadd fast float %reg115, %reg1111
>> +  %reg117 = fadd fast float %reg116, 3.000000e+01
>> +  ret float %reg117
>> +}
>> +
>> + at fe = external global float
>> + at fa = external global float
>> + at fb = external global float
>> + at fc = external global float
>> + at ff = external global float
>> +
>> +define void @test4() {
>> +; CHECK-LABEL: @test4
>> +; CHECK: fadd fast float
>> +; CHECK: fadd fast float
>> +; CHECK-NOT: fadd fast float
>> +; CHECK: ret void
>> +
>> +  %A = load float* @fa
>> +  %B = load float* @fb
>> +  %C = load float* @fc
>> +  %t1 = fadd fast float %A, %B
>> +  %t2 = fadd fast float %t1, %C
>> +  %t3 = fadd fast float %C, %A
>> +  %t4 = fadd fast float %t3, %B
>> +  ; e = (a+b)+c;
>> +  store float %t2, float* @fe
>> +  ; f = (a+c)+b
>> +  store float %t4, float* @ff
>> +  ret void
>> +}
>> +
>> +define void @test5() {
>> +; CHECK-LABEL: @test5
>> +; CHECK: fadd fast float
>> +; CHECK: fadd fast float
>> +; CHECK-NOT: fadd
>> +; CHECK: ret void
>> +
>> +  %A = load float* @fa
>> +  %B = load float* @fb
>> +  %C = load float* @fc
>> +  %t1 = fadd fast float %A, %B
>> +  %t2 = fadd fast float %t1, %C
>> +  %t3 = fadd fast float %C, %A
>> +  %t4 = fadd fast float %t3, %B
>> +  ; e = c+(a+b)
>> +  store float %t2, float* @fe
>> +  ; f = (c+a)+b
>> +  store float %t4, float* @ff
>> +  ret void
>> +}
>> +
>> +define void @test6() {
>> +; CHECK-LABEL: @test6
>> +; CHECK: fadd fast float
>> +; CHECK: fadd fast float
>> +; CHECK-NOT: fadd
>> +; CHECK: ret void
>> +
>> +  %A = load float* @fa
>> +  %B = load float* @fb
>> +  %C = load float* @fc
>> +  %t1 = fadd fast float %B, %A
>> +  %t2 = fadd fast float %t1, %C
>> +  %t3 = fadd fast float %C, %A
>> +  %t4 = fadd fast float %t3, %B
>> +  ; e = c+(b+a)
>> +  store float %t2, float* @fe
>> +  ; f = (c+a)+b
>> +  store float %t4, float* @ff
>> +  ret void
>> +}
>> +
>> +define float @test7(float %A, float %B, float %C) {
>> +; CHECK-LABEL: @test7
>> +; CHECK-NEXT: fadd fast float %C, %B
>> +; CHECK-NEXT: fmul fast float %A, %A
>> +; CHECK-NEXT: fmul fast float %1, %tmp2
>> +; CHECK-NEXT: ret float
>> +
>> +  %aa = fmul fast float %A, %A
>> +  %aab = fmul fast float %aa, %B
>> +  %ac = fmul fast float %A, %C
>> +  %aac = fmul fast float %ac, %A
>> +  %r = fadd fast float %aab, %aac
>> +  ret float %r
>> +}
>> +
>> +define float @test8(float %X, float %Y, float %Z) {
>> +; CHECK-LABEL: @test8
>> +; CHECK-NEXT: fmul fast float %Y, %X
>> +; CHECK-NEXT: fsub fast float %Z
>> +; CHECK-NEXT: ret float
>> +
>> +  %A = fsub fast float 0.0, %X
>> +  %B = fmul fast float %A, %Y
>> +  ; (-X)*Y + Z -> Z-X*Y
>> +  %C = fadd fast float %B, %Z
>> +  ret float %C
>> +}
>> +
>> +define float @test9(float %X) {
>> +; CHECK-LABEL: @test9
>> +; CHECK-NEXT: fmul fast float %X, 9.400000e+01
>> +; CHECK-NEXT: ret float
>> +
>> +  %Y = fmul fast float %X, 4.700000e+01
>> +  %Z = fadd fast float %Y, %Y
>> +  ret float %Z
>> +}
>> +
>> +define float @test10(float %X) {
>> +; CHECK-LABEL: @test10
>> +; CHECK-NEXT: fmul fast float %X, 3.000000e+00
>> +; CHECK-NEXT: ret float
>> +
>> +  %Y = fadd fast float %X ,%X
>> +  %Z = fadd fast float %Y, %X
>> +  ret float %Z
>> +}
>> +
>> +define float @test11(float %W) {
>> +; CHECK-LABEL: test11
>> +; CHECK-NEXT: fmul fast float %W, 3.810000e+02
>> +; CHECK-NEXT: ret float
>> +
>> +  %X = fmul fast float %W, 127.0
>> +  %Y = fadd fast float %X ,%X
>> +  %Z = fadd fast float %Y, %X
>> +  ret float %Z
>> +}
>> +
>> +define float @test12(float %X) {
>> +; CHECK-LABEL: @test12
>> +; CHECK-NEXT: fmul fast float %X, -3.000000e+00
>> +; CHECK-NEXT: fadd fast float %factor, 6.000000e+00
>> +; CHECK-NEXT: ret float
>> +
>> +  %A = fsub fast float 1.000000e+00, %X
>> +  %B = fsub fast float 2.000000e+00, %X
>> +  %C = fsub fast float 3.000000e+00, %X
>> +  %Y = fadd fast float %A ,%B
>> +  %Z = fadd fast float %Y, %C
>> +  ret float %Z
>> +}
>> +
>> +define float @test13(float %X1, float %X2, float %X3) {
>> +; CHECK-LABEL: @test13
>> +; CHECK-NEXT: fsub fast float %X3, %X2
>> +; CHECK-NEXT: fmul fast float {{.*}}, %X1
>> +; CHECK-NEXT: ret float
>> +
>> +  %A = fsub fast float 0.000000e+00, %X1
>> +  %B = fmul fast float %A, %X2   ; -X1*X2
>> +  %C = fmul fast float %X1, %X3  ; X1*X3
>> +  %D = fadd fast float %B, %C    ; -X1*X2 + X1*X3 -> X1*(X3-X2)
>> +  ret float %D
>> +}
>> +
>> +define float @test14(float %X1, float %X2) {
>> +; CHECK-LABEL: @test14
>> +; CHECK-NEXT: fsub fast float %X1, %X2
>> +; CHECK-NEXT: fmul fast float %tmp, 4.700000e+01
>> +; CHECK-NEXT: ret float
>> +
>> +  %B = fmul fast float %X1, 47.   ; X1*47
>> +  %C = fmul fast float %X2, -47.  ; X2*-47
>> +  %D = fadd fast float %B, %C    ; X1*47 + X2*-47 -> 47*(X1-X2)
>> +  ret float %D
>> +}
>> +
>> +define float @test15(float %arg) {
>> +; CHECK-LABEL: test15
>> +; CHECK-NEXT: fmul fast float %arg, 1.440000e+02
>> +; CHECK-NEXT: ret float %tmp2
>> +
>> +  %tmp1 = fmul fast float 1.200000e+01, %arg
>> +  %tmp2 = fmul fast float %tmp1, 1.200000e+01
>> +  ret float %tmp2
>> +}
>> +
>> +; (b+(a+1234))+-a -> b+1234
>> +define float @test16(float %b, float %a) {
>> +; CHECK-LABEL: @test16
>> +; CHECK-NEXT: fadd fast float %b, 1.234000e+03
>> +; CHECK-NEXT: ret float
>> +
>> +  %1 = fadd fast float %a, 1234.0
>> +  %2 = fadd fast float %b, %1
>> +  %3 = fsub fast float 0.0, %a
>> +  %4 = fadd fast float %2, %3
>> +  ret float %4
>> +}
>> +
>> +; Test that we can turn things like X*-(Y*Z) -> X*-1*Y*Z.
>> +
>> +define float @test17(float %a, float %b, float %z) {
>> +; CHECK-LABEL: test17
>> +; CHECK-NEXT: fmul fast float %a, 1.234500e+04
>> +; CHECK-NEXT: fmul fast float %e, %b
>> +; CHECK-NEXT: fmul fast float %f, %z
>> +; CHECK-NEXT: ret float
>> +
>> +  %c = fsub fast float 0.000000e+00, %z
>> +  %d = fmul fast float %a, %b
>> +  %e = fmul fast float %c, %d
>> +  %f = fmul fast float %e, 1.234500e+04
>> +  %g = fsub fast float 0.000000e+00, %f
>> +  ret float %g
>> +}
>> +
>> +define float @test18(float %a, float %b, float %z) {
>> +; CHECK-LABEL: test18
>> +; CHECK-NEXT: fmul fast float %a, 4.000000e+01
>> +; CHECK-NEXT: fmul fast float %e, %z
>> +; CHECK-NEXT: ret float
>> +
>> +  %d = fmul fast float %z, 4.000000e+01
>> +  %c = fsub fast float 0.000000e+00, %d
>> +  %e = fmul fast float %a, %c
>> +  %f = fsub fast float 0.000000e+00, %e
>> +  ret float %f
>> +}
>> +
>> +; With sub reassociation, constant folding can eliminate the 12 and -12
>> constants.
>> +define float @test19(float %A, float %B) {
>> +; CHECK-LABEL: @test19
>> +; CHECK-NEXT: fsub fast float %A, %B
>> +; CHECK-NEXT: ret float
>> +  %X = fadd fast float -1.200000e+01, %A
>> +  %Y = fsub fast float %X, %B
>> +  %Z = fadd fast float %Y, 1.200000e+01
>> +  ret float %Z
>> +}
>> +
>> +; With sub reassociation, constant folding can eliminate the uses of %a.
>> +define float @test20(float %a, float %b, float %c) nounwind  {
>> +; CHECK-LABEL: @test20
>> +; CHECK-NEXT: fsub fast float -0.000000e+00, %b
>> +; CHECK-NEXT: fsub fast float %b.neg, %c
>> +; CHECK-NEXT: ret float
>> +
>> +; FIXME: Should be able to generate the below, which may expose more
>> +;        opportunites for FAdd reassociation.
>> +; %sum = fadd fast float %c, %b
>> +; %tmp7 = fsub fast float 0, %sum
>> +
>> +  %tmp3 = fsub fast float %a, %b
>> +  %tmp5 = fsub fast float %tmp3, %c
>> +  %tmp7 = fsub fast float %tmp5, %a
>> +  ret float %tmp7
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-fp-commute.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-fp-commute.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-fp-commute.ll (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-fp-commute.ll Thu Aug 14
>> 10:23:01 2014
>> @@ -0,0 +1,44 @@
>> +; RUN: opt -reassociate -S < %s | FileCheck %s
>> +
>> +declare void @use(float)
>> +
>> +define void @test1(float %x, float %y) {
>> +; CHECK-LABEL: test1
>> +; CHECK: fmul fast float %y, %x
>> +; CHECK: fmul fast float %y, %x
>> +; CHECK: fsub fast float %1, %2
>> +; CHECK: call void @use(float %{{.*}})
>> +; CHECK: call void @use(float %{{.*}})
>> +
>> +  %1 = fmul fast float %x, %y
>> +  %2 = fmul fast float %y, %x
>> +  %3 = fsub fast float %1, %2
>> +  call void @use(float %1)
>> +  call void @use(float %3)
>> +  ret void
>> +}
>> +
>> +define float @test2(float %x, float %y) {
>> +; CHECK-LABEL: test2
>> +; CHECK-NEXT: fmul fast float %y, %x
>> +; CHECK-NEXT: fmul fast float %y, %x
>> +; CHECK-NEXT: fsub fast float %1, %2
>> +; CHECK-NEXT: ret float %3
>> +
>> +  %1 = fmul fast float %x, %y
>> +  %2 = fmul fast float %y, %x
>> +  %3 = fsub fast float %1, %2
>> +  ret float %3
>> +}
>> +
>> +define float @test3(float %x, float %y) {
>> +; CHECK-LABEL: test3
>> +; CHECK-NEXT: %factor = fmul fast float 2.000000e+00, %y
>> +; CHECK-NEXT: %tmp1 = fmul fast float %factor, %x
>> +; CHECK-NEXT: ret float %tmp1
>> +
>> +  %1 = fmul fast float %x, %y
>> +  %2 = fmul fast float %y, %x
>> +  %3 = fadd fast float %1, %2
>> +  ret float %3
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-mightymul.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-mightymul.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-mightymul.ll (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-mightymul.ll Thu Aug 14
>> 10:23:01 2014
>> @@ -0,0 +1,35 @@
>> +; RUN: opt < %s -reassociate -disable-output
>> +; PR13021
>> +
>> +define float @test2(float %x) {
>> +  %t0 = fmul fast float %x, %x
>> +  %t1 = fmul fast float %t0, %t0
>> +  %t2 = fmul fast float %t1, %t1
>> +  %t3 = fmul fast float %t2, %t2
>> +  %t4 = fmul fast float %t3, %t3
>> +  %t5 = fmul fast float %t4, %t4
>> +  %t6 = fmul fast float %t5, %t5
>> +  %t7 = fmul fast float %t6, %t6
>> +  %t8 = fmul fast float %t7, %t7
>> +  %t9 = fmul fast float %t8, %t8
>> +  %t10 = fmul fast float %t9, %t9
>> +  %t11 = fmul fast float %t10, %t10
>> +  %t12 = fmul fast float %t11, %t11
>> +  %t13 = fmul fast float %t12, %t12
>> +  %t14 = fmul fast float %t13, %t13
>> +  %t15 = fmul fast float %t14, %t14
>> +  %t16 = fmul fast float %t15, %t15
>> +  %t17 = fmul fast float %t16, %t16
>> +  %t18 = fmul fast float %t17, %t17
>> +  %t19 = fmul fast float %t18, %t18
>> +  %t20 = fmul fast float %t19, %t19
>> +  %t21 = fmul fast float %t20, %t20
>> +  %t22 = fmul fast float %t21, %t21
>> +  %t23 = fmul fast float %t22, %t22
>> +  %t24 = fmul fast float %t23, %t23
>> +  %t25 = fmul fast float %t24, %t24
>> +  %t26 = fmul fast float %t25, %t25
>> +  %t27 = fmul fast float %t26, %t26
>> +  %t28 = fmul fast float %t27, %t27
>> +  ret float %t28
>> +}
>>
>> Added: llvm/trunk/test/Transforms/Reassociate/fast-multistep.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
>> Transforms/Reassociate/fast-multistep.ll?rev=215647&view=auto
>> ============================================================
>> ==================
>> --- llvm/trunk/test/Transforms/Reassociate/fast-multistep.ll (added)
>> +++ llvm/trunk/test/Transforms/Reassociate/fast-multistep.ll Thu Aug 14
>> 10:23:01 2014
>> @@ -0,0 +1,32 @@
>> +; RUN: opt < %s -reassociate -S | FileCheck %s
>> +
>> +define float @fmultistep1(float %a, float %b, float %c) {
>> +; Check that a*a*b+a*a*c is turned into a*(a*(b+c)).
>> +; CHECK-LABEL: @fmultistep1
>> +; CHECK-NEXT: fadd fast float %c, %b
>> +; CHECK-NEXT: fmul fast float %a, %tmp2
>> +; CHECK-NEXT: fmul fast float %tmp3, %a
>> +; CHECK-NEXT: ret float
>> +
>> +  %t0 = fmul fast float %a, %b
>> +  %t1 = fmul fast float %a, %t0 ; a*(a*b)
>> +  %t2 = fmul fast float %a, %c
>> +  %t3 = fmul fast float %a, %t2 ; a*(a*c)
>> +  %t4 = fadd fast float %t1, %t3
>> +  ret float %t4
>> +}
>> +
>> +define float @fmultistep2(float %a, float %b, float %c, float %d) {
>> +; Check that a*b+a*c+d is turned into a*(b+c)+d.
>> +; CHECK-LABEL: @fmultistep2
>> +; CHECK-NEXT: fadd fast float %c, %b
>> +; CHECK-NEXT: fmul fast float %tmp, %a
>> +; CHECK-NEXT: fadd fast float %tmp1, %d
>> +; CHECK-NEXT: ret float
>> +
>> +  %t0 = fmul fast float %a, %b
>> +  %t1 = fmul fast float %a, %c
>> +  %t2 = fadd fast float %t1, %d ; a*c+d
>> +  %t3 = fadd fast float %t0, %t2 ; a*b+(a*c+d)
>> +  ret float %t3
>> +}
>>
>>
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