}
}
+ // B * (uitofp i1 C) -> select C, B, 0
+ if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
+ Value *LHS = Op0, *RHS = Op1;
+ Value *B, *C;
+ if (!match(RHS, m_UIToFP(m_Value(C))))
+ std::swap(LHS, RHS);
+
+ if (match(RHS, m_UIToFP(m_Value(C))) && C->getType()->isIntegerTy(1)) {
+ B = LHS;
+ Value *Zero = ConstantFP::getNegativeZero(B->getType());
+ return SelectInst::Create(C, B, Zero);
+ }
+ }
+
+ // A * (1 - uitofp i1 C) -> select C, 0, A
+ if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
+ Value *LHS = Op0, *RHS = Op1;
+ Value *A, *C;
+ if (!match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))))
+ std::swap(LHS, RHS);
+
+ if (match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))) &&
+ C->getType()->isIntegerTy(1)) {
+ A = LHS;
+ Value *Zero = ConstantFP::getNegativeZero(A->getType());
+ return SelectInst::Create(C, Zero, A);
+ }
+ }
+
if (!isa<Constant>(Op1))
std::swap(Opnd0, Opnd1);
else
return 0;
}
+namespace {
const unsigned MaxDepth = 6;
+typedef Instruction *(*FoldUDivOperandCb)(Value *Op0, Value *Op1,
+ const BinaryOperator &I,
+ InstCombiner &IC);
+
+/// \brief Used to maintain state for visitUDivOperand().
+struct UDivFoldAction {
+ FoldUDivOperandCb FoldAction; ///< Informs visitUDiv() how to fold this
+ ///< operand. This can be zero if this action
+ ///< joins two actions together.
+
+ Value *OperandToFold; ///< Which operand to fold.
+ union {
+ Instruction *FoldResult; ///< The instruction returned when FoldAction is
+ ///< invoked.
+
+ size_t SelectLHSIdx; ///< Stores the LHS action index if this action
+ ///< joins two actions together.
+ };
+
+ UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand)
+ : FoldAction(FA), OperandToFold(InputOperand), FoldResult(0) {}
+ UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand, size_t SLHS)
+ : FoldAction(FA), OperandToFold(InputOperand), SelectLHSIdx(SLHS) {}
+};
+}
+
+// X udiv 2^C -> X >> C
+static Instruction *foldUDivPow2Cst(Value *Op0, Value *Op1,
+ const BinaryOperator &I, InstCombiner &IC) {
+ const APInt &C = cast<Constant>(Op1)->getUniqueInteger();
+ BinaryOperator *LShr = BinaryOperator::CreateLShr(
+ Op0, ConstantInt::get(Op0->getType(), C.logBase2()));
+ if (I.isExact()) LShr->setIsExact();
+ return LShr;
+}
+
+// X udiv C, where C >= signbit
+static Instruction *foldUDivNegCst(Value *Op0, Value *Op1,
+ const BinaryOperator &I, InstCombiner &IC) {
+ Value *ICI = IC.Builder->CreateICmpULT(Op0, cast<ConstantInt>(Op1));
+
+ return SelectInst::Create(ICI, Constant::getNullValue(I.getType()),
+ ConstantInt::get(I.getType(), 1));
+}
+
+// X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2)
+static Instruction *foldUDivShl(Value *Op0, Value *Op1, const BinaryOperator &I,
+ InstCombiner &IC) {
+ Instruction *ShiftLeft = cast<Instruction>(Op1);
+ if (isa<ZExtInst>(ShiftLeft))
+ ShiftLeft = cast<Instruction>(ShiftLeft->getOperand(0));
+
+ const APInt &CI =
+ cast<Constant>(ShiftLeft->getOperand(0))->getUniqueInteger();
+ Value *N = ShiftLeft->getOperand(1);
+ if (CI != 1)
+ N = IC.Builder->CreateAdd(N, ConstantInt::get(N->getType(), CI.logBase2()));
+ if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1))
+ N = IC.Builder->CreateZExt(N, Z->getDestTy());
+ BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, N);
+ if (I.isExact()) LShr->setIsExact();
+ return LShr;
+}
// \brief Recursively visits the possible right hand operands of a udiv
// instruction, seeing through select instructions, to determine if we can
// replace the udiv with something simpler. If we find that an operand is not
// able to simplify the udiv, we abort the entire transformation.
-//
-// Inserts any intermediate instructions used for the simplification into
-// NewInstrs and returns a new instruction that depends upon them.
-static Instruction *visitUDivOperand(Value *Op0, Value *Op1,
- const BinaryOperator &I,
- SmallVectorImpl<Instruction *> &NewInstrs,
- unsigned Depth = 0) {
- {
- // X udiv 2^C -> X >> C
- // Check to see if this is an unsigned division with an exact power of 2,
- // if so, convert to a right shift.
- const APInt *C;
- if (match(Op1, m_Power2(C))) {
- BinaryOperator *LShr = BinaryOperator::CreateLShr(
- Op0, ConstantInt::get(Op0->getType(), C->logBase2()));
- if (I.isExact()) LShr->setIsExact();
- return LShr;
- }
+static size_t visitUDivOperand(Value *Op0, Value *Op1, const BinaryOperator &I,
+ SmallVectorImpl<UDivFoldAction> &Actions,
+ unsigned Depth = 0) {
+ // Check to see if this is an unsigned division with an exact power of 2,
+ // if so, convert to a right shift.
+ if (match(Op1, m_Power2())) {
+ Actions.push_back(UDivFoldAction(foldUDivPow2Cst, Op1));
+ return Actions.size();
}
- if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) {
+ if (ConstantInt *C = dyn_cast<ConstantInt>(Op1))
// X udiv C, where C >= signbit
if (C->getValue().isNegative()) {
- ICmpInst *IC = new ICmpInst(ICmpInst::ICMP_ULT, Op0, C);
- NewInstrs.push_back(IC);
-
- return SelectInst::Create(IC, Constant::getNullValue(I.getType()),
- ConstantInt::get(I.getType(), 1));
+ Actions.push_back(UDivFoldAction(foldUDivNegCst, C));
+ return Actions.size();
}
- }
// X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2)
- { const APInt *CI; Value *N;
- if (match(Op1, m_Shl(m_Power2(CI), m_Value(N))) ||
- match(Op1, m_ZExt(m_Shl(m_Power2(CI), m_Value(N))))) {
- if (*CI != 1) {
- N = BinaryOperator::CreateAdd(
- N, ConstantInt::get(N->getType(), CI->logBase2()));
- NewInstrs.push_back(cast<Instruction>(N));
- }
- if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1)) {
- N = new ZExtInst(N, Z->getDestTy());
- NewInstrs.push_back(cast<Instruction>(N));
- }
- BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, N);
- if (I.isExact()) LShr->setIsExact();
- return LShr;
- }
+ if (match(Op1, m_Shl(m_Power2(), m_Value())) ||
+ match(Op1, m_ZExt(m_Shl(m_Power2(), m_Value())))) {
+ Actions.push_back(UDivFoldAction(foldUDivShl, Op1));
+ return Actions.size();
}
// The remaining tests are all recursive, so bail out if we hit the limit.
return 0;
if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
- if (Instruction *LHS =
- visitUDivOperand(Op0, SI->getOperand(1), I, NewInstrs)) {
- NewInstrs.push_back(LHS);
- if (Instruction *RHS =
- visitUDivOperand(Op0, SI->getOperand(2), I, NewInstrs)) {
- NewInstrs.push_back(RHS);
- return SelectInst::Create(SI->getCondition(), LHS, RHS);
+ if (size_t LHSIdx = visitUDivOperand(Op0, SI->getOperand(1), I, Actions))
+ if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions)) {
+ Actions.push_back(UDivFoldAction((FoldUDivOperandCb)0, Op1, LHSIdx-1));
+ return Actions.size();
}
- }
return 0;
}
I.getType());
// (LHS udiv (select (select (...)))) -> (LHS >> (select (select (...))))
- SmallVector<Instruction *, 4> NewInstrs;
- Instruction *RetI = visitUDivOperand(Op0, Op1, I, NewInstrs);
- for (unsigned i = 0, e = NewInstrs.size(); i != e; i++)
- // If we managed to replace the UDiv completely, insert the new intermediate
- // instructions before where the UDiv was.
- // If we couldn't, we must clean up after ourselves by deleting the new
- // instructions.
- if (RetI)
- NewInstrs[i]->insertBefore(&I);
- else
- delete NewInstrs[i];
- if (RetI)
- return RetI;
+ SmallVector<UDivFoldAction, 6> UDivActions;
+ if (visitUDivOperand(Op0, Op1, I, UDivActions))
+ for (unsigned i = 0, e = UDivActions.size(); i != e; ++i) {
+ FoldUDivOperandCb Action = UDivActions[i].FoldAction;
+ Value *ActionOp1 = UDivActions[i].OperandToFold;
+ Instruction *Inst;
+ if (Action)
+ Inst = Action(Op0, ActionOp1, I, *this);
+ else {
+ // This action joins two actions together. The RHS of this action is
+ // simply the last action we processed, we saved the LHS action index in
+ // the joining action.
+ size_t SelectRHSIdx = i - 1;
+ Value *SelectRHS = UDivActions[SelectRHSIdx].FoldResult;
+ size_t SelectLHSIdx = UDivActions[i].SelectLHSIdx;
+ Value *SelectLHS = UDivActions[SelectLHSIdx].FoldResult;
+ Inst = SelectInst::Create(cast<SelectInst>(ActionOp1)->getCondition(),
+ SelectLHS, SelectRHS);
+ }
+
+ // If this is the last action to process, return it to the InstCombiner.
+ // Otherwise, we insert it before the UDiv and record it so that we may
+ // use it as part of a joining action (i.e., a SelectInst).
+ if (e - i != 1) {
+ Inst->insertBefore(&I);
+ UDivActions[i].FoldResult = Inst;
+ } else
+ return Inst;
+ }
return 0;
}
if (Value *V = SimplifyFDivInst(Op0, Op1, TD))
return ReplaceInstUsesWith(I, V);
+ if (isa<Constant>(Op0))
+ if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
+ if (Instruction *R = FoldOpIntoSelect(I, SI))
+ return R;
+
bool AllowReassociate = I.hasUnsafeAlgebra();
bool AllowReciprocal = I.hasAllowReciprocal();
if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
+ if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+ if (Instruction *R = FoldOpIntoSelect(I, SI))
+ return R;
+
if (AllowReassociate) {
ConstantFP *C1 = 0;
ConstantFP *C2 = Op1C;
return BinaryOperator::CreateAnd(Op0, Add);
}
+ // 1 urem X -> zext(X != 1)
+ if (match(Op0, m_One())) {
+ Value *Cmp = Builder->CreateICmpNE(Op1, Op0);
+ Value *Ext = Builder->CreateZExt(Cmp, I.getType());
+ return ReplaceInstUsesWith(I, Ext);
+ }
+
return 0;
}
projects / oota-llvm.git / blobdiff