enum { RecursionLimit = 3 };
STATISTIC(NumExpand, "Number of expansions");
-STATISTIC(NumFactor , "Number of factorizations");
STATISTIC(NumReassoc, "Number of reassociations");
struct Query {
return nullptr;
}
-/// FactorizeBinOp - Simplify "LHS Opcode RHS" by factorizing out a common term
-/// using the operation OpCodeToExtract. For example, when Opcode is Add and
-/// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
-/// Returns the simplified value, or null if no simplification was performed.
-static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
- unsigned OpcToExtract, const Query &Q,
- unsigned MaxRecurse) {
- Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
- // Recursion is always used, so bail out at once if we already hit the limit.
- if (!MaxRecurse--)
- return nullptr;
-
- BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
- BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
-
- if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
- !Op1 || Op1->getOpcode() != OpcodeToExtract)
- return nullptr;
-
- // The expression has the form "(A op' B) op (C op' D)".
- Value *A = Op0->getOperand(0), *B = Op0->getOperand(1);
- Value *C = Op1->getOperand(0), *D = Op1->getOperand(1);
-
- // Use left distributivity, i.e. "X op' (Y op Z) = (X op' Y) op (X op' Z)".
- // Does the instruction have the form "(A op' B) op (A op' D)" or, in the
- // commutative case, "(A op' B) op (C op' A)"?
- if (A == C || (Instruction::isCommutative(OpcodeToExtract) && A == D)) {
- Value *DD = A == C ? D : C;
- // Form "A op' (B op DD)" if it simplifies completely.
- // Does "B op DD" simplify?
- if (Value *V = SimplifyBinOp(Opcode, B, DD, Q, MaxRecurse)) {
- // It does! Return "A op' V" if it simplifies or is already available.
- // If V equals B then "A op' V" is just the LHS. If V equals DD then
- // "A op' V" is just the RHS.
- if (V == B || V == DD) {
- ++NumFactor;
- return V == B ? LHS : RHS;
- }
- // Otherwise return "A op' V" if it simplifies.
- if (Value *W = SimplifyBinOp(OpcodeToExtract, A, V, Q, MaxRecurse)) {
- ++NumFactor;
- return W;
- }
- }
- }
-
- // Use right distributivity, i.e. "(X op Y) op' Z = (X op' Z) op (Y op' Z)".
- // Does the instruction have the form "(A op' B) op (C op' B)" or, in the
- // commutative case, "(A op' B) op (B op' D)"?
- if (B == D || (Instruction::isCommutative(OpcodeToExtract) && B == C)) {
- Value *CC = B == D ? C : D;
- // Form "(A op CC) op' B" if it simplifies completely..
- // Does "A op CC" simplify?
- if (Value *V = SimplifyBinOp(Opcode, A, CC, Q, MaxRecurse)) {
- // It does! Return "V op' B" if it simplifies or is already available.
- // If V equals A then "V op' B" is just the LHS. If V equals CC then
- // "V op' B" is just the RHS.
- if (V == A || V == CC) {
- ++NumFactor;
- return V == A ? LHS : RHS;
- }
- // Otherwise return "V op' B" if it simplifies.
- if (Value *W = SimplifyBinOp(OpcodeToExtract, V, B, Q, MaxRecurse)) {
- ++NumFactor;
- return W;
- }
- }
- }
-
- return nullptr;
-}
-
/// SimplifyAssociativeBinOp - Generic simplifications for associative binary
/// operations. Returns the simpler value, or null if none was found.
static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
MaxRecurse))
return V;
- // Mul distributes over Add. Try some generic simplifications based on this.
- if (Value *V = FactorizeBinOp(Instruction::Add, Op0, Op1, Instruction::Mul,
- Q, MaxRecurse))
- return V;
-
// Threading Add over selects and phi nodes is pointless, so don't bother.
// Threading over the select in "A + select(cond, B, C)" means evaluating
// "A+B" and "A+C" and seeing if they are equal; but they are equal if and
if (Op0 == Op1)
return Constant::getNullValue(Op0->getType());
- // (X*2) - X -> X
- // (X<<1) - X -> X
- Value *X = nullptr;
- if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
- match(Op0, m_Shl(m_Specific(Op1), m_One())))
- return Op1;
-
// (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
// For example, (X + Y) - Y -> X; (Y + X) - Y -> X
- Value *Y = nullptr, *Z = Op1;
+ Value *X = nullptr, *Y = nullptr, *Z = Op1;
if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
// See if "V === Y - Z" simplifies.
if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1))
if (Constant *Result = computePointerDifference(Q.DL, X, Y))
return ConstantExpr::getIntegerCast(Result, Op0->getType(), true);
- // Mul distributes over Sub. Try some generic simplifications based on this.
- if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
- Q, MaxRecurse))
- return V;
-
// i1 sub -> xor.
if (MaxRecurse && Op0->getType()->isIntegerTy(1))
if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
return X;
+ // Arithmetic shifting an all-sign-bit value is a no-op.
+ unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL);
+ if (NumSignBits == Op0->getType()->getScalarSizeInBits())
+ return Op0;
+
return nullptr;
}
Q, MaxRecurse))
return V;
- // Or distributes over And. Try some generic simplifications based on this.
- if (Value *V = FactorizeBinOp(Instruction::And, Op0, Op1, Instruction::Or,
- Q, MaxRecurse))
- return V;
-
// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
MaxRecurse))
return V;
- // And distributes over Or. Try some generic simplifications based on this.
- if (Value *V = FactorizeBinOp(Instruction::Or, Op0, Op1, Instruction::And,
- Q, MaxRecurse))
- return V;
-
// If the operation is with the result of a select instruction, check whether
// operating on either branch of the select always yields the same value.
if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
MaxRecurse))
return V;
+ // (A & C)|(B & D)
+ Value *C = nullptr, *D = nullptr;
+ if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
+ match(Op1, m_And(m_Value(B), m_Value(D)))) {
+ ConstantInt *C1 = dyn_cast<ConstantInt>(C);
+ ConstantInt *C2 = dyn_cast<ConstantInt>(D);
+ if (C1 && C2 && (C1->getValue() == ~C2->getValue())) {
+ // (A & C1)|(B & C2)
+ // If we have: ((V + N) & C1) | (V & C2)
+ // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
+ // replace with V+N.
+ Value *V1, *V2;
+ if ((C2->getValue() & (C2->getValue() + 1)) == 0 && // C2 == 0+1+
+ match(A, m_Add(m_Value(V1), m_Value(V2)))) {
+ // Add commutes, try both ways.
+ if (V1 == B && MaskedValueIsZero(V2, C2->getValue()))
+ return A;
+ if (V2 == B && MaskedValueIsZero(V1, C2->getValue()))
+ return A;
+ }
+ // Or commutes, try both ways.
+ if ((C1->getValue() & (C1->getValue() + 1)) == 0 &&
+ match(B, m_Add(m_Value(V1), m_Value(V2)))) {
+ // Add commutes, try both ways.
+ if (V1 == A && MaskedValueIsZero(V2, C1->getValue()))
+ return B;
+ if (V2 == A && MaskedValueIsZero(V1, C1->getValue()))
+ return B;
+ }
+ }
+ }
+
// If the operation is with the result of a phi instruction, check whether
// operating on all incoming values of the phi always yields the same value.
if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
MaxRecurse))
return V;
- // And distributes over Xor. Try some generic simplifications based on this.
- if (Value *V = FactorizeBinOp(Instruction::Xor, Op0, Op1, Instruction::And,
- Q, MaxRecurse))
- return V;
-
// Threading Xor over selects and phi nodes is pointless, so don't bother.
// Threading over the select in "A ^ select(cond, B, C)" means evaluating
// "A^B" and "A^C" and seeing if they are equal; but they are equal if and
if (!CI2->isZero())
Upper = NegOne.udiv(CI2->getValue()) + 1;
} else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
- // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
- Upper = CI2->getValue().abs() + 1;
- Lower = (-Upper) + 1;
+ if (CI2->isMinSignedValue()) {
+ // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
+ Lower = CI2->getValue();
+ Upper = Lower.lshr(1) + 1;
+ } else {
+ // 'sdiv CI2, x' produces [-|CI2|, |CI2|].
+ Upper = CI2->getValue().abs() + 1;
+ Lower = (-Upper) + 1;
+ }
} else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
- // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
APInt IntMin = APInt::getSignedMinValue(Width);
APInt IntMax = APInt::getSignedMaxValue(Width);
- APInt Val = CI2->getValue().abs();
- if (!Val.isMinValue()) {
+ APInt Val = CI2->getValue();
+ if (Val.isAllOnesValue()) {
+ // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
+ // where CI2 != -1 and CI2 != 0 and CI2 != 1
+ Lower = IntMin + 1;
+ Upper = IntMax + 1;
+ } else if (Val.countLeadingZeros() < Width - 1) {
+ // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2]
+ // where CI2 != -1 and CI2 != 0 and CI2 != 1
Lower = IntMin.sdiv(Val);
- Upper = IntMax.sdiv(Val) + 1;
+ Upper = IntMax.sdiv(Val);
+ if (Lower.sgt(Upper))
+ std::swap(Lower, Upper);
+ Upper = Upper + 1;
+ assert(Upper != Lower && "Upper part of range has wrapped!");
}
} else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
// 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
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