#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/GlobalsModRef.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
}
#ifndef NDEBUG
-/// PrintOps - Print out the expression identified in the Ops list.
+/// Print out the expression identified in the Ops list.
///
static void PrintOps(Instruction *I, const SmallVectorImpl<ValueEntry> &Ops) {
Module *M = I->getParent()->getParent()->getParent();
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
+ AU.addPreserved<GlobalsAAWrapperPass>();
}
private:
void BuildRankMap(Function &F);
unsigned getRank(Value *V);
+ void canonicalizeOperands(Instruction *I);
void ReassociateExpression(BinaryOperator *I);
void RewriteExprTree(BinaryOperator *I, SmallVectorImpl<ValueEntry> &Ops);
Value *OptimizeExpression(BinaryOperator *I,
Value *OptimizeMul(BinaryOperator *I, SmallVectorImpl<ValueEntry> &Ops);
Value *RemoveFactorFromExpression(Value *V, Value *Factor);
void EraseInst(Instruction *I);
- void optimizeFAddNegExpr(ConstantFP *ConstOperand, Instruction *I,
- int OperandNr);
void OptimizeInst(Instruction *I);
+ Instruction *canonicalizeNegConstExpr(Instruction *I);
};
}
// Public interface to the Reassociate pass
FunctionPass *llvm::createReassociatePass() { return new Reassociate(); }
-/// isReassociableOp - Return true if V is an instruction of the specified
-/// opcode and if it only has one use.
+/// Return true if V is an instruction of the specified opcode and if it
+/// only has one use.
static BinaryOperator *isReassociableOp(Value *V, unsigned Opcode) {
if (V->hasOneUse() && isa<Instruction>(V) &&
cast<Instruction>(V)->getOpcode() == Opcode &&
return nullptr;
}
-static bool isUnmovableInstruction(Instruction *I) {
- switch (I->getOpcode()) {
- case Instruction::PHI:
- case Instruction::LandingPad:
- case Instruction::Alloca:
- case Instruction::Load:
- case Instruction::Invoke:
- case Instruction::UDiv:
- case Instruction::SDiv:
- case Instruction::FDiv:
- case Instruction::URem:
- case Instruction::SRem:
- case Instruction::FRem:
- return true;
- case Instruction::Call:
- return !isa<DbgInfoIntrinsic>(I);
- default:
- return false;
- }
-}
-
void Reassociate::BuildRankMap(Function &F) {
unsigned i = 2;
- // Assign distinct ranks to function arguments
- for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
+ // Assign distinct ranks to function arguments.
+ for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) {
ValueRankMap[&*I] = ++i;
+ DEBUG(dbgs() << "Calculated Rank[" << I->getName() << "] = " << i << "\n");
+ }
ReversePostOrderTraversal<Function*> RPOT(&F);
for (ReversePostOrderTraversal<Function*>::rpo_iterator I = RPOT.begin(),
// we cannot move. This ensures that the ranks for these instructions are
// all different in the block.
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
- if (isUnmovableInstruction(I))
+ if (mayBeMemoryDependent(*I))
ValueRankMap[&*I] = ++BBRank;
}
}
// 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.
- Type *Ty = V->getType();
- if ((!Ty->isIntegerTy() && !Ty->isFloatingPointTy()) ||
- (!BinaryOperator::isNot(I) && !BinaryOperator::isNeg(I) &&
- !BinaryOperator::isFNeg(I)))
+ if (!BinaryOperator::isNot(I) && !BinaryOperator::isNeg(I) &&
+ !BinaryOperator::isFNeg(I))
++Rank;
- //DEBUG(dbgs() << "Calculated Rank[" << V->getName() << "] = "
- // << Rank << "\n");
+ DEBUG(dbgs() << "Calculated Rank[" << V->getName() << "] = " << Rank << "\n");
return ValueRankMap[I] = Rank;
}
+// Canonicalize constants to RHS. Otherwise, sort the operands by rank.
+void Reassociate::canonicalizeOperands(Instruction *I) {
+ assert(isa<BinaryOperator>(I) && "Expected binary operator.");
+ assert(I->isCommutative() && "Expected commutative operator.");
+
+ Value *LHS = I->getOperand(0);
+ Value *RHS = I->getOperand(1);
+ unsigned LHSRank = getRank(LHS);
+ unsigned RHSRank = getRank(RHS);
+
+ if (isa<Constant>(RHS))
+ return;
+
+ if (isa<Constant>(LHS) || RHSRank < LHSRank)
+ cast<BinaryOperator>(I)->swapOperands();
+}
+
static BinaryOperator *CreateAdd(Value *S1, Value *S2, const Twine &Name,
Instruction *InsertBefore, Value *FlagsOp) {
- if (S1->getType()->isIntegerTy())
+ if (S1->getType()->isIntOrIntVectorTy())
return BinaryOperator::CreateAdd(S1, S2, Name, InsertBefore);
else {
BinaryOperator *Res =
static BinaryOperator *CreateMul(Value *S1, Value *S2, const Twine &Name,
Instruction *InsertBefore, Value *FlagsOp) {
- if (S1->getType()->isIntegerTy())
+ if (S1->getType()->isIntOrIntVectorTy())
return BinaryOperator::CreateMul(S1, S2, Name, InsertBefore);
else {
BinaryOperator *Res =
static BinaryOperator *CreateNeg(Value *S1, const Twine &Name,
Instruction *InsertBefore, Value *FlagsOp) {
- if (S1->getType()->isIntegerTy())
+ if (S1->getType()->isIntOrIntVectorTy())
return BinaryOperator::CreateNeg(S1, Name, InsertBefore);
else {
BinaryOperator *Res = BinaryOperator::CreateFNeg(S1, Name, InsertBefore);
}
}
-/// LowerNegateToMultiply - Replace 0-X with X*-1.
-///
+/// Replace 0-X with X*-1.
static BinaryOperator *LowerNegateToMultiply(Instruction *Neg) {
Type *Ty = Neg->getType();
- Constant *NegOne = Ty->isIntegerTy() ? ConstantInt::getAllOnesValue(Ty)
- : ConstantFP::get(Ty, -1.0);
+ Constant *NegOne = Ty->isIntOrIntVectorTy() ?
+ ConstantInt::getAllOnesValue(Ty) : ConstantFP::get(Ty, -1.0);
BinaryOperator *Res = CreateMul(Neg->getOperand(1), NegOne, "", Neg, Neg);
Neg->setOperand(1, Constant::getNullValue(Ty)); // Drop use of op.
return Res;
}
-/// CarmichaelShift - Returns k such that lambda(2^Bitwidth) = 2^k, where lambda
-/// is the Carmichael function. This means that x^(2^k) === 1 mod 2^Bitwidth for
+/// Returns k such that lambda(2^Bitwidth) = 2^k, where lambda is the Carmichael
+/// function. This means that x^(2^k) === 1 mod 2^Bitwidth for
/// every odd x, i.e. x^(2^k) = 1 for every odd x in Bitwidth-bit arithmetic.
/// Note that 0 <= k < Bitwidth, and if Bitwidth > 3 then x^(2^k) = 0 for every
/// even x in Bitwidth-bit arithmetic.
return Bitwidth - 2;
}
-/// IncorporateWeight - Add the extra weight 'RHS' to the existing weight 'LHS',
+/// Add the extra weight 'RHS' to the existing weight 'LHS',
/// reducing the combined weight using any special properties of the operation.
/// The existing weight LHS represents the computation X op X op ... op X where
/// X occurs LHS times. The combined weight represents X op X op ... op X with
typedef std::pair<Value*, APInt> RepeatedValue;
-/// LinearizeExprTree - Given an associative binary expression, return the leaf
+/// Given an associative binary expression, return the leaf
/// nodes in Ops along with their weights (how many times the leaf occurs). The
/// original expression is the same as
/// (Ops[0].first op Ops[0].first op ... Ops[0].first) <- Ops[0].second times
// ways to get to it.
SmallVector<std::pair<BinaryOperator*, APInt>, 8> Worklist; // (Op, Weight)
Worklist.push_back(std::make_pair(I, APInt(Bitwidth, 1)));
- bool MadeChange = false;
+ bool Changed = false;
// Leaves of the expression are values that either aren't the right kind of
// operation (eg: a constant, or a multiply in an add tree), or are, but have
// If this is a binary operation of the right kind with only one use then
// add its operands to the expression.
if (BinaryOperator *BO = isReassociableOp(Op, Opcode)) {
- assert(Visited.insert(Op) && "Not first visit!");
+ assert(Visited.insert(Op).second && "Not first visit!");
DEBUG(dbgs() << "DIRECT ADD: " << *Op << " (" << Weight << ")\n");
Worklist.push_back(std::make_pair(BO, Weight));
continue;
LeafMap::iterator It = Leaves.find(Op);
if (It == Leaves.end()) {
// Not in the leaf map. Must be the first time we saw this operand.
- assert(Visited.insert(Op) && "Not first visit!");
+ assert(Visited.insert(Op).second && "Not first visit!");
if (!Op->hasOneUse()) {
// This value has uses not accounted for by the expression, so it is
// not safe to modify. Mark it as being a leaf.
// exactly one such use, drop this new use of the leaf.
assert(!Op->hasOneUse() && "Only one use, but we got here twice!");
I->setOperand(OpIdx, UndefValue::get(I->getType()));
- MadeChange = true;
+ Changed = true;
// If the leaf is a binary operation of the right kind and we now see
// that its multiple original uses were in fact all by nodes belonging
BO = LowerNegateToMultiply(BO);
DEBUG(dbgs() << *BO << '\n');
Worklist.push_back(std::make_pair(BO, Weight));
- MadeChange = true;
+ Changed = true;
continue;
}
if (Ops.empty()) {
Constant *Identity = ConstantExpr::getBinOpIdentity(Opcode, I->getType());
assert(Identity && "Associative operation without identity!");
- Ops.push_back(std::make_pair(Identity, APInt(Bitwidth, 1)));
+ Ops.emplace_back(Identity, APInt(Bitwidth, 1));
}
- return MadeChange;
+ return Changed;
}
-// RewriteExprTree - Now that the operands for this expression tree are
-// linearized and optimized, emit them in-order.
+/// Now that the operands for this expression tree are
+/// linearized and optimized, emit them in-order.
void Reassociate::RewriteExprTree(BinaryOperator *I,
SmallVectorImpl<ValueEntry> &Ops) {
assert(Ops.size() > 1 && "Single values should be used directly!");
Constant *Undef = UndefValue::get(I->getType());
NewOp = BinaryOperator::Create(Instruction::BinaryOps(Opcode),
Undef, Undef, "", I);
- if (NewOp->getType()->isFloatingPointTy())
+ if (NewOp->getType()->isFPOrFPVectorTy())
NewOp->setFastMathFlags(I->getFastMathFlags());
} else {
NewOp = NodesToRewrite.pop_back_val();
RedoInsts.insert(NodesToRewrite[i]);
}
-/// NegateValue - Insert instructions before the instruction pointed to by BI,
+/// Insert instructions before the instruction pointed to by BI,
/// that computes the negative version of the value specified. The negative
/// 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))
+ if (Constant *C = dyn_cast<Constant>(V)) {
+ if (C->getType()->isFPOrFPVectorTy()) {
+ return ConstantExpr::getFNeg(C);
+ }
return ConstantExpr::getNeg(C);
+ }
+
// We are trying to expose opportunity for reassociation. One of the things
// that we want to do to achieve this is to push a negation as deep into an
// Push the negates through the add.
I->setOperand(0, NegateValue(I->getOperand(0), BI));
I->setOperand(1, NegateValue(I->getOperand(1), BI));
+ if (I->getOpcode() == Instruction::Add) {
+ I->setHasNoUnsignedWrap(false);
+ I->setHasNoSignedWrap(false);
+ }
// We must move the add instruction here, because the neg instructions do
// not dominate the old add instruction in general. By moving it, we are
if (Instruction *InstInput = dyn_cast<Instruction>(V)) {
if (InvokeInst *II = dyn_cast<InvokeInst>(InstInput)) {
InsertPt = II->getNormalDest()->begin();
+ } else if (auto *CPI = dyn_cast<CatchPadInst>(InstInput)) {
+ InsertPt = CPI->getNormalDest()->begin();
} else {
InsertPt = InstInput;
++InsertPt;
InsertPt = TheNeg->getParent()->getParent()->getEntryBlock().begin();
}
TheNeg->moveBefore(InsertPt);
+ if (TheNeg->getOpcode() == Instruction::Sub) {
+ TheNeg->setHasNoUnsignedWrap(false);
+ TheNeg->setHasNoSignedWrap(false);
+ } else {
+ TheNeg->andIRFlags(BI);
+ }
return TheNeg;
}
return CreateNeg(V, V->getName() + ".neg", BI, BI);
}
-/// ShouldBreakUpSubtract - Return true if we should break up this subtract of
-/// X-Y into (X + -Y).
+/// 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) || BinaryOperator::isFNeg(Sub))
return false;
}
-/// BreakUpSubtract - If we have (X-Y), and if either X is an add, or if this is
-/// only used by an add, transform this into (X+(0-Y)) to promote better
-/// reassociation.
+/// If we have (X-Y), and if either X is an add, or if this is only used by an
+/// add, transform this into (X+(0-Y)) to promote better reassociation.
static BinaryOperator *BreakUpSubtract(Instruction *Sub) {
// Convert a subtract into an add and a neg instruction. This allows sub
// instructions to be commuted with other add instructions.
return New;
}
-/// ConvertShiftToMul - If this is a shift of a reassociable multiply or is used
-/// by one, change this into a multiply by a constant to assist with further
-/// reassociation.
+/// If this is a shift of a reassociable multiply or is used by one, change
+/// this into a multiply by a constant to assist with further reassociation.
static BinaryOperator *ConvertShiftToMul(Instruction *Shl) {
Constant *MulCst = ConstantInt::get(Shl->getType(), 1);
MulCst = ConstantExpr::getShl(MulCst, cast<Constant>(Shl->getOperand(1)));
BinaryOperator::CreateMul(Shl->getOperand(0), MulCst, "", Shl);
Shl->setOperand(0, UndefValue::get(Shl->getType())); // Drop use of op.
Mul->takeName(Shl);
+
+ // Everyone now refers to the mul instruction.
Shl->replaceAllUsesWith(Mul);
Mul->setDebugLoc(Shl->getDebugLoc());
+
+ // We can safely preserve the nuw flag in all cases. It's also safe to turn a
+ // nuw nsw shl into a nuw nsw mul. However, nsw in isolation requires special
+ // handling.
+ bool NSW = cast<BinaryOperator>(Shl)->hasNoSignedWrap();
+ bool NUW = cast<BinaryOperator>(Shl)->hasNoUnsignedWrap();
+ if (NSW && NUW)
+ Mul->setHasNoSignedWrap(true);
+ Mul->setHasNoUnsignedWrap(NUW);
return Mul;
}
-/// FindInOperandList - Scan backwards and forwards among values with the same
-/// rank as element i to see if X exists. If X does not exist, return i. This
-/// is useful when scanning for 'x' when we see '-x' because they both get the
-/// same rank.
+/// Scan backwards and forwards among values with the same rank as element i
+/// to see if X exists. If X does not exist, return i. This is useful when
+/// scanning for 'x' when we see '-x' because they both get the same rank.
static unsigned FindInOperandList(SmallVectorImpl<ValueEntry> &Ops, unsigned i,
Value *X) {
unsigned XRank = Ops[i].Rank;
return i;
}
-/// EmitAddTreeOfValues - Emit a tree of add instructions, summing Ops together
+/// Emit a tree of add instructions, summing Ops together
/// and returning the result. Insert the tree before I.
static Value *EmitAddTreeOfValues(Instruction *I,
SmallVectorImpl<WeakVH> &Ops){
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,
+/// 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, Instruction::FMul);
return V;
}
-/// FindSingleUseMultiplyFactors - If V is a single-use multiply, recursively
-/// add its operands as factors, otherwise add V to the list of factors.
+/// If V is a single-use multiply, recursively add its operands as factors,
+/// otherwise add V to the list of factors.
///
/// Ops is the top-level list of add operands we're trying to factor.
static void FindSingleUseMultiplyFactors(Value *V,
FindSingleUseMultiplyFactors(BO->getOperand(0), Factors, Ops);
}
-/// OptimizeAndOrXor - Optimize a series of operands to an 'and', 'or', or 'xor'
-/// instruction. This optimizes based on identities. If it can be reduced to
-/// a single Value, it is returned, otherwise the Ops list is mutated as
-/// necessary.
+/// Optimize a series of operands to an 'and', 'or', or 'xor' instruction.
+/// This optimizes based on identities. If it can be reduced to a single Value,
+/// it is returned, otherwise the Ops list is mutated as necessary.
static Value *OptimizeAndOrXor(unsigned Opcode,
SmallVectorImpl<ValueEntry> &Ops) {
// Scan the operand lists looking for X and ~X pairs, along with X,X pairs.
return nullptr;
}
-/// OptimizeAdd - Optimize a series of operands to an 'add' instruction. This
+/// Optimize a series of operands to an 'add' instruction. This
/// optimizes based on identities. If it can be reduced to a single Value, it
/// is returned, otherwise the Ops list is mutated as necessary.
Value *Reassociate::OptimizeAdd(Instruction *I,
++NumFound;
} while (i != Ops.size() && Ops[i].Op == TheOp);
- DEBUG(errs() << "\nFACTORING [" << NumFound << "]: " << *TheOp << '\n');
+ DEBUG(dbgs() << "\nFACTORING [" << NumFound << "]: " << *TheOp << '\n');
++NumFactor;
// Insert a new multiply.
Type *Ty = TheOp->getType();
- Constant *C = Ty->isIntegerTy() ? ConstantInt::get(Ty, NumFound)
- : ConstantFP::get(Ty, NumFound);
+ Constant *C = Ty->isIntOrIntVectorTy() ?
+ 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
SmallPtrSet<Value*, 8> Duplicates;
for (unsigned i = 0, e = Factors.size(); i != e; ++i) {
Value *Factor = Factors[i];
- if (!Duplicates.insert(Factor))
+ if (!Duplicates.insert(Factor).second)
continue;
unsigned Occ = ++FactorOccurrences[Factor];
// If any factor occurred more than one time, we can pull it out.
if (MaxOcc > 1) {
- DEBUG(errs() << "\nFACTORING [" << MaxOcc << "]: " << *MaxOccVal << '\n');
+ DEBUG(dbgs() << "\nFACTORING [" << MaxOcc << "]: " << *MaxOccVal << '\n');
++NumFactor;
// Create a new instruction that uses the MaxOccVal twice. If we don't do
// from an expression will drop a use of maxocc, and this can cause
// RemoveFactorFromExpression on successive values to behave differently.
Instruction *DummyInst =
- I->getType()->isIntegerTy()
+ I->getType()->isIntOrIntVectorTy()
? BinaryOperator::CreateAdd(MaxOccVal, MaxOccVal)
: BinaryOperator::CreateFAdd(MaxOccVal, MaxOccVal);
Value *LHS = Ops.pop_back_val();
do {
- if (LHS->getType()->isIntegerTy())
+ if (LHS->getType()->isIntOrIntVectorTy())
LHS = Builder.CreateMul(LHS, Ops.pop_back_val());
else
LHS = Builder.CreateFMul(LHS, Ops.pop_back_val());
return nullptr;
}
-/// EraseInst - Zap the given instruction, adding interesting operands to the
-/// work list.
+/// Zap the given instruction, adding interesting operands to the work list.
void Reassociate::EraseInst(Instruction *I) {
assert(isInstructionTriviallyDead(I) && "Trivially dead instructions only!");
SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
// and add that since that's where optimization actually happens.
unsigned Opcode = Op->getOpcode();
while (Op->hasOneUse() && Op->user_back()->getOpcode() == Opcode &&
- Visited.insert(Op))
+ Visited.insert(Op).second)
Op = Op->user_back();
RedoInsts.insert(Op);
}
}
-void Reassociate::optimizeFAddNegExpr(ConstantFP *ConstOperand, Instruction *I,
- int OperandNr) {
+// Canonicalize expressions of the following form:
+// x + (-Constant * y) -> x - (Constant * y)
+// x - (-Constant * y) -> x + (Constant * y)
+Instruction *Reassociate::canonicalizeNegConstExpr(Instruction *I) {
+ if (!I->hasOneUse() || I->getType()->isVectorTy())
+ return nullptr;
+
+ // Must be a fmul or fdiv instruction.
+ unsigned Opcode = I->getOpcode();
+ if (Opcode != Instruction::FMul && Opcode != Instruction::FDiv)
+ return nullptr;
+
+ auto *C0 = dyn_cast<ConstantFP>(I->getOperand(0));
+ auto *C1 = dyn_cast<ConstantFP>(I->getOperand(1));
+
+ // Both operands are constant, let it get constant folded away.
+ if (C0 && C1)
+ return nullptr;
+
+ ConstantFP *CF = C0 ? C0 : C1;
+
+ // Must have one constant operand.
+ if (!CF)
+ return nullptr;
+
+ // Must be a negative ConstantFP.
+ if (!CF->isNegative())
+ return nullptr;
+
+ // User must be a binary operator with one or more uses.
+ Instruction *User = I->user_back();
+ if (!isa<BinaryOperator>(User) || !User->hasNUsesOrMore(1))
+ return nullptr;
+
+ unsigned UserOpcode = User->getOpcode();
+ if (UserOpcode != Instruction::FAdd && UserOpcode != Instruction::FSub)
+ return nullptr;
+
+ // Subtraction is not commutative. Explicitly, the following transform is
+ // not valid: (-Constant * y) - x -> x + (Constant * y)
+ if (!User->isCommutative() && User->getOperand(1) != I)
+ return nullptr;
+
// Change the sign of the constant.
- APFloat Val = ConstOperand->getValueAPF();
+ APFloat Val = CF->getValueAPF();
Val.changeSign();
- I->setOperand(0, ConstantFP::get(ConstOperand->getContext(), Val));
-
- assert(I->hasOneUse() && "Only a single use can be replaced.");
- Instruction *Parent = I->user_back();
+ I->setOperand(C0 ? 0 : 1, ConstantFP::get(CF->getContext(), Val));
- Value *OtherOperand = Parent->getOperand(1 - OperandNr);
+ // Canonicalize I to RHS to simplify the next bit of logic. E.g.,
+ // ((-Const*y) + x) -> (x + (-Const*y)).
+ if (User->getOperand(0) == I && User->isCommutative())
+ cast<BinaryOperator>(User)->swapOperands();
- unsigned Opcode = Parent->getOpcode();
- assert(Opcode == Instruction::FAdd ||
- (Opcode == Instruction::FSub && Parent->getOperand(1) == I));
+ Value *Op0 = User->getOperand(0);
+ Value *Op1 = User->getOperand(1);
+ BinaryOperator *NI;
+ switch (UserOpcode) {
+ default:
+ llvm_unreachable("Unexpected Opcode!");
+ case Instruction::FAdd:
+ NI = BinaryOperator::CreateFSub(Op0, Op1);
+ NI->setFastMathFlags(cast<FPMathOperator>(User)->getFastMathFlags());
+ break;
+ case Instruction::FSub:
+ NI = BinaryOperator::CreateFAdd(Op0, Op1);
+ NI->setFastMathFlags(cast<FPMathOperator>(User)->getFastMathFlags());
+ break;
+ }
- BinaryOperator *NI = Opcode == Instruction::FAdd
- ? BinaryOperator::CreateFSub(OtherOperand, I)
- : BinaryOperator::CreateFAdd(OtherOperand, I);
- NI->setFastMathFlags(cast<FPMathOperator>(Parent)->getFastMathFlags());
- NI->insertBefore(Parent);
- NI->setName(Parent->getName() + ".repl");
- Parent->replaceAllUsesWith(NI);
+ NI->insertBefore(User);
+ NI->setName(User->getName());
+ User->replaceAllUsesWith(NI);
NI->setDebugLoc(I->getDebugLoc());
+ RedoInsts.insert(I);
MadeChange = true;
+ return NI;
}
-/// OptimizeInst - Inspect and optimize the given instruction. Note that erasing
+/// Inspect and optimize the given instruction. Note that erasing
/// instructions is not allowed.
void Reassociate::OptimizeInst(Instruction *I) {
// Only consider operations that we understand.
I = NI;
}
- // 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()) {
-
- // FAdd and FMul can be commuted.
- unsigned Opcode = I->getOpcode();
- if (Opcode == Instruction::FMul || Opcode == 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);
- }
- }
+ // Canonicalize negative constants out of expressions.
+ if (Instruction *Res = canonicalizeNegConstExpr(I))
+ I = Res;
- // Reassociate: x + -ConstantFP * y -> x - ConstantFP * y
- // The FMul can also be an FDiv, and FAdd can be a FSub.
- if (Opcode == Instruction::FMul || Opcode == Instruction::FDiv) {
- if (ConstantFP *LHSConst = dyn_cast<ConstantFP>(I->getOperand(0))) {
- if (LHSConst->isNegative() && I->hasOneUse()) {
- Instruction *Parent = I->user_back();
- if (Parent->getOpcode() == Instruction::FAdd) {
- if (Parent->getOperand(0) == I)
- optimizeFAddNegExpr(LHSConst, I, 0);
- else if (Parent->getOperand(1) == I)
- optimizeFAddNegExpr(LHSConst, I, 1);
- } else if (Parent->getOpcode() == Instruction::FSub)
- if (Parent->getOperand(1) == I)
- optimizeFAddNegExpr(LHSConst, I, 1);
- }
- }
- }
+ // Commute binary operators, to canonicalize the order of their operands.
+ // This can potentially expose more CSE opportunities, and makes writing other
+ // transformations simpler.
+ if (I->isCommutative())
+ canonicalizeOperands(I);
- // FIXME: We should commute vector instructions as well. However, this
- // requires further analysis to determine the effect on later passes.
+ // TODO: We should optimize vector Xor instructions, but they are
+ // currently unsupported.
+ if (I->getType()->isVectorTy() && I->getOpcode() == Instruction::Xor)
+ return;
- // Don't try to optimize vector instructions or anything that doesn't have
- // unsafe algebra.
- if (I->getType()->isVectorTy() || !I->hasUnsafeAlgebra())
- return;
- }
+ // Don't optimize floating point instructions that don't have unsafe algebra.
+ if (I->getType()->isFloatingPointTy() && !I->hasUnsafeAlgebra())
+ return;
// Do not reassociate boolean (i1) expressions. We want to preserve the
// original order of evaluation for short-circuited comparisons that
}
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.
SmallVector<RepeatedValue, 8> Tree;
// the vector.
std::stable_sort(Ops.begin(), Ops.end());
- // OptimizeExpression - Now that we have the expression tree in a convenient
+ // Now that we have the expression tree in a convenient
// sorted form, optimize it globally if possible.
if (Value *V = OptimizeExpression(I, Ops)) {
if (V == I)
projects / oota-llvm.git / blobdiff