#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();
Factor(Value *Base, unsigned Power) : Base(Base), Power(Power) {}
- /// \brief Sort factors by their Base.
- struct BaseSorter {
- bool operator()(const Factor &LHS, const Factor &RHS) {
- return LHS.Base < RHS.Base;
- }
- };
-
- /// \brief Compare factors for equal bases.
- struct BaseEqual {
- bool operator()(const Factor &LHS, const Factor &RHS) {
- return LHS.Base == RHS.Base;
- }
- };
-
/// \brief Sort factors in descending order by their power.
struct PowerDescendingSorter {
bool operator()(const Factor &LHS, const Factor &RHS) {
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
+ AU.addPreserved<GlobalsAAWrapperPass>();
}
private:
void BuildRankMap(Function &F);
// 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;
// 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;
}
}
}
}
-/// 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->isIntOrIntVectorTy() ?
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
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 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!");
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.
// 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 = ++InstInput->getIterator();
}
while (isa<PHINode>(InsertPt)) ++InsertPt;
} else {
InsertPt = TheNeg->getParent()->getParent()->getEntryBlock().begin();
}
- TheNeg->moveBefore(InsertPt);
+ 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)));
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 nullptr;
}
- BasicBlock::iterator InsertPt = BO; ++InsertPt;
+ BasicBlock::iterator InsertPt = ++BO->getIterator();
// If this was just a single multiply, remove the multiply and return the only
// remaining operand.
}
if (NeedsNegate)
- V = CreateNeg(V, "neg", InsertPt, BO);
+ V = CreateNeg(V, "neg", &*InsertPt, BO);
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,
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());
if (!I->hasOneUse() || I->getType()->isVectorTy())
return nullptr;
- // Must be a mul, fmul, or fdiv instruction.
+ // Must be a fmul or fdiv instruction.
unsigned Opcode = I->getOpcode();
- if (Opcode != Instruction::Mul && Opcode != Instruction::FMul &&
- Opcode != Instruction::FDiv)
+ 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;
- // Must have at least one constant operand.
- Constant *C0 = dyn_cast<Constant>(I->getOperand(0));
- Constant *C1 = dyn_cast<Constant>(I->getOperand(1));
- if (!C0 && !C1)
+ ConstantFP *CF = C0 ? C0 : C1;
+
+ // Must have one constant operand.
+ if (!CF)
return nullptr;
- // Must be a negative ConstantInt or ConstantFP.
- Constant *C = C0 ? C0 : C1;
- unsigned ConstIdx = C0 ? 0 : 1;
- if (auto *CI = dyn_cast<ConstantInt>(C)) {
- if (!CI->isNegative() || CI->isMinValue(true))
- return nullptr;
- } else if (auto *CF = dyn_cast<ConstantFP>(C)) {
- if (!CF->isNegative())
- return nullptr;
- } else
+ // 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->getNumUses())
+ if (!isa<BinaryOperator>(User) || !User->hasNUsesOrMore(1))
return nullptr;
unsigned UserOpcode = User->getOpcode();
- if (UserOpcode != Instruction::Add && UserOpcode != Instruction::FAdd &&
- UserOpcode != Instruction::Sub && UserOpcode != Instruction::FSub)
+ if (UserOpcode != Instruction::FAdd && UserOpcode != Instruction::FSub)
return nullptr;
// Subtraction is not commutative. Explicitly, the following transform is
return nullptr;
// Change the sign of the constant.
- if (ConstantInt *CI = dyn_cast<ConstantInt>(C))
- I->setOperand(ConstIdx, ConstantInt::get(CI->getContext(), -CI->getValue()));
- else {
- ConstantFP *CF = cast<ConstantFP>(C);
- APFloat Val = CF->getValueAPF();
- Val.changeSign();
- I->setOperand(ConstIdx, ConstantFP::get(CF->getContext(), Val));
- }
+ APFloat Val = CF->getValueAPF();
+ Val.changeSign();
+ I->setOperand(C0 ? 0 : 1, ConstantFP::get(CF->getContext(), Val));
// Canonicalize I to RHS to simplify the next bit of logic. E.g.,
// ((-Const*y) + x) -> (x + (-Const*y)).
Value *Op0 = User->getOperand(0);
Value *Op1 = User->getOperand(1);
BinaryOperator *NI;
- switch(UserOpcode) {
+ switch (UserOpcode) {
default:
llvm_unreachable("Unexpected Opcode!");
- case Instruction::Add:
- NI = BinaryOperator::CreateSub(Op0, Op1);
- break;
- case Instruction::Sub:
- NI = BinaryOperator::CreateAdd(Op0, Op1);
- break;
case Instruction::FAdd:
NI = BinaryOperator::CreateFSub(Op0, Op1);
NI->setFastMathFlags(cast<FPMathOperator>(User)->getFastMathFlags());
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.
// 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)
for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
// Optimize every instruction in the basic block.
for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE; )
- if (isInstructionTriviallyDead(II)) {
- EraseInst(II++);
+ if (isInstructionTriviallyDead(&*II)) {
+ EraseInst(&*II++);
} else {
- OptimizeInst(II);
+ OptimizeInst(&*II);
assert(II->getParent() == BI && "Moved to a different block!");
++II;
}
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