//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "instsimplify"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/Operator.h"
-#include "llvm/Support/ConstantRange.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
-#include "llvm/Support/PatternMatch.h"
-#include "llvm/Support/ValueHandle.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/IR/ValueHandle.h"
using namespace llvm;
using namespace llvm::PatternMatch;
+#define DEBUG_TYPE "instsimplify"
+
enum { RecursionLimit = 3 };
STATISTIC(NumExpand, "Number of expansions");
-STATISTIC(NumFactor , "Number of factorizations");
STATISTIC(NumReassoc, "Number of reassociations");
struct Query {
Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
- return 0;
+ return nullptr;
// Check whether the expression has the form "(A op' B) op C".
if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS))
}
}
- return 0;
-}
-
-/// 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 0;
-
- BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
- BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
-
- if (!Op0 || Op0->getOpcode() != OpcodeToExtract ||
- !Op1 || Op1->getOpcode() != OpcodeToExtract)
- return 0;
-
- // 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 0;
+ return nullptr;
}
/// SimplifyAssociativeBinOp - Generic simplifications for associative binary
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
- return 0;
+ return nullptr;
BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS);
BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS);
// The remaining transforms require commutativity as well as associativity.
if (!Instruction::isCommutative(Opcode))
- return 0;
+ return nullptr;
// Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
if (Op0 && Op0->getOpcode() == Opcode) {
}
}
- return 0;
+ return nullptr;
}
/// ThreadBinOpOverSelect - In the case of a binary operation with a select
const Query &Q, unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
- return 0;
+ return nullptr;
SelectInst *SI;
if (isa<SelectInst>(LHS)) {
}
}
- return 0;
+ return nullptr;
}
/// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
- return 0;
+ return nullptr;
// Make sure the select is on the LHS.
if (!isa<SelectInst>(LHS)) {
// It didn't simplify. However if "cmp TV, RHS" is equal to the select
// condition then we can replace it with 'true'. Otherwise give up.
if (!isSameCompare(Cond, Pred, TV, RHS))
- return 0;
+ return nullptr;
TCmp = getTrue(Cond->getType());
}
// It didn't simplify. However if "cmp FV, RHS" is equal to the select
// condition then we can replace it with 'false'. Otherwise give up.
if (!isSameCompare(Cond, Pred, FV, RHS))
- return 0;
+ return nullptr;
FCmp = getFalse(Cond->getType());
}
// The remaining cases only make sense if the select condition has the same
// type as the result of the comparison, so bail out if this is not so.
if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy())
- return 0;
+ return nullptr;
// If the false value simplified to false, then the result of the compare
// is equal to "Cond && TCmp". This also catches the case when the false
// value simplified to false and the true value to true, returning "Cond".
Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
/// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
const Query &Q, unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
- return 0;
+ return nullptr;
PHINode *PI;
if (isa<PHINode>(LHS)) {
PI = cast<PHINode>(LHS);
// Bail out if RHS and the phi may be mutually interdependent due to a loop.
if (!ValueDominatesPHI(RHS, PI, Q.DT))
- return 0;
+ return nullptr;
} else {
assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
PI = cast<PHINode>(RHS);
// Bail out if LHS and the phi may be mutually interdependent due to a loop.
if (!ValueDominatesPHI(LHS, PI, Q.DT))
- return 0;
+ return nullptr;
}
// Evaluate the BinOp on the incoming phi values.
- Value *CommonValue = 0;
+ Value *CommonValue = nullptr;
for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
Value *Incoming = PI->getIncomingValue(i);
// If the incoming value is the phi node itself, it can safely be skipped.
// If the operation failed to simplify, or simplified to a different value
// to previously, then give up.
if (!V || (CommonValue && V != CommonValue))
- return 0;
+ return nullptr;
CommonValue = V;
}
const Query &Q, unsigned MaxRecurse) {
// Recursion is always used, so bail out at once if we already hit the limit.
if (!MaxRecurse--)
- return 0;
+ return nullptr;
// Make sure the phi is on the LHS.
if (!isa<PHINode>(LHS)) {
// Bail out if RHS and the phi may be mutually interdependent due to a loop.
if (!ValueDominatesPHI(RHS, PI, Q.DT))
- return 0;
+ return nullptr;
// Evaluate the BinOp on the incoming phi values.
- Value *CommonValue = 0;
+ Value *CommonValue = nullptr;
for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
Value *Incoming = PI->getIncomingValue(i);
// If the incoming value is the phi node itself, it can safely be skipped.
// If the operation failed to simplify, or simplified to a different value
// to previously, then give up.
if (!V || (CommonValue && V != CommonValue))
- return 0;
+ return nullptr;
CommonValue = V;
}
// X + (Y - X) -> Y
// (Y - X) + X -> Y
// Eg: X + -X -> 0
- Value *Y = 0;
+ Value *Y = nullptr;
if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
return Y;
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
// "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
// for threading over phi nodes.
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
// If LHS and RHS are not related via constant offsets to the same base
// value, there is nothing we can do here.
if (LHS != RHS)
- return 0;
+ return nullptr;
// Otherwise, the difference of LHS - RHS can be computed as:
// LHS - RHS
if (Op0 == Op1)
return Constant::getNullValue(Op0->getType());
- // (X*2) - X -> X
- // (X<<1) - X -> X
- Value *X = 0;
- if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
- match(Op0, m_Shl(m_Specific(Op1), m_One())))
- return Op1;
+ // X - (0 - Y) -> X if the second sub is NUW.
+ // If Y != 0, 0 - Y is a poison value.
+ // If Y == 0, 0 - Y simplifies to 0.
+ if (BinaryOperator::isNeg(Op1)) {
+ if (const auto *BO = dyn_cast<BinaryOperator>(Op1)) {
+ assert(BO->getOpcode() == Instruction::Sub &&
+ "Expected a subtraction operator!");
+ if (BO->hasNoUnsignedWrap())
+ return Op0;
+ }
+ }
// (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 = 0, *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))
// "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
// for threading over phi nodes.
- return 0;
+ return nullptr;
}
Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
// fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
// where nnan and ninf have to occur at least once somewhere in this
// expression
- Value *SubOp = 0;
+ Value *SubOp = nullptr;
if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
SubOp = Op1;
else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
return Constant::getNullValue(Op0->getType());
}
- return 0;
+ return nullptr;
}
/// Given operands for an FSub, see if we can fold the result. If not, this
if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1)
return Constant::getNullValue(Op0->getType());
- return 0;
+ return nullptr;
}
/// Given the operands for an FMul, see if we can fold the result
if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
return Op1;
- return 0;
+ return nullptr;
}
/// SimplifyMulInst - Given operands for a Mul, see if we can
return Op0;
// (X / Y) * Y -> X if the division is exact.
- Value *X = 0;
+ Value *X = nullptr;
if (match(Op0, m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y
match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0))))) // Y * (X / Y)
return X;
MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
return ConstantInt::get(Op0->getType(), 1);
// (X * Y) / Y -> X if the multiplication does not overflow.
- Value *X = 0, *Y = 0;
+ Value *X = nullptr, *Y = nullptr;
if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
/// SimplifySDivInst - Given operands for an SDiv, see if we can
if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
if (match(Op1, m_Undef()))
return Op1;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const DataLayout *DL,
if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
/// SimplifySRemInst - Given operands for an SRem, see if we can
if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const DataLayout *DL,
if (match(Op1, m_Undef()))
return Op1;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const DataLayout *DL,
if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
/// SimplifyShlInst - Given operands for an Shl, see if we can
Value *X;
if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
return X;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
return X;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
return X;
- return 0;
+ // 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;
}
Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
return Constant::getNullValue(Op0->getType());
// (A | ?) & A = A
- Value *A = 0, *B = 0;
+ Value *A = nullptr, *B = nullptr;
if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
(A == Op1 || B == Op1))
return Op1;
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;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout *DL,
return Constant::getAllOnesValue(Op0->getType());
// (A & ?) | A = A
- Value *A = 0, *B = 0;
+ Value *A = nullptr, *B = nullptr;
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
(A == Op1 || B == Op1))
return 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))
if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const DataLayout *DL,
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
// "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
// for threading over phi nodes.
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const DataLayout *DL,
Value *LHS, Value *RHS) {
SelectInst *SI = dyn_cast<SelectInst>(V);
if (!SI)
- return 0;
+ return nullptr;
CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
if (!Cmp)
- return 0;
+ return nullptr;
Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
return Cmp;
if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
LHS == CmpRHS && RHS == CmpLHS)
return Cmp;
- return 0;
+ return nullptr;
}
// A significant optimization not implemented here is assuming that alloca
// We can only fold certain predicates on pointer comparisons.
switch (Pred) {
default:
- return 0;
+ return nullptr;
// Equality comaprisons are easy to fold.
case CmpInst::ICMP_EQ:
}
// Otherwise, fail.
- return 0;
+ return nullptr;
}
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
// Many binary operators with constant RHS have easy to compute constant
// range. Use them to check whether the comparison is a tautology.
- uint32_t Width = CI->getBitWidth();
+ unsigned Width = CI->getBitWidth();
APInt Lower = APInt(Width, 0);
APInt Upper = APInt(Width, 0);
ConstantInt *CI2;
APInt NegOne = APInt::getAllOnesValue(Width);
if (!CI2->isZero())
Upper = NegOne.udiv(CI2->getValue()) + 1;
+ } else if (match(LHS, m_SDiv(m_ConstantInt(CI2), m_Value()))) {
+ 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_NUWShl(m_ConstantInt(CI2), m_Value()))) {
+ // 'shl nuw CI2, x' produces [CI2, CI2 << CLZ(CI2)]
+ Lower = CI2->getValue();
+ Upper = Lower.shl(Lower.countLeadingZeros()) + 1;
+ } else if (match(LHS, m_NSWShl(m_ConstantInt(CI2), m_Value()))) {
+ if (CI2->isNegative()) {
+ // 'shl nsw CI2, x' produces [CI2 << CLO(CI2)-1, CI2]
+ unsigned ShiftAmount = CI2->getValue().countLeadingOnes() - 1;
+ Lower = CI2->getValue().shl(ShiftAmount);
+ Upper = CI2->getValue() + 1;
+ } else {
+ // 'shl nsw CI2, x' produces [CI2, CI2 << CLZ(CI2)-1]
+ unsigned ShiftAmount = CI2->getValue().countLeadingZeros() - 1;
+ Lower = CI2->getValue();
+ Upper = CI2->getValue().shl(ShiftAmount) + 1;
}
} else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
// 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
APInt NegOne = APInt::getAllOnesValue(Width);
if (CI2->getValue().ult(Width))
Upper = NegOne.lshr(CI2->getValue()) + 1;
+ } else if (match(LHS, m_LShr(m_ConstantInt(CI2), m_Value()))) {
+ // 'lshr CI2, x' produces [CI2 >> (Width-1), CI2].
+ unsigned ShiftAmount = Width - 1;
+ if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
+ ShiftAmount = CI2->getValue().countTrailingZeros();
+ Lower = CI2->getValue().lshr(ShiftAmount);
+ Upper = CI2->getValue() + 1;
} else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
// 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
APInt IntMin = APInt::getSignedMinValue(Width);
Lower = IntMin.ashr(CI2->getValue());
Upper = IntMax.ashr(CI2->getValue()) + 1;
}
+ } else if (match(LHS, m_AShr(m_ConstantInt(CI2), m_Value()))) {
+ unsigned ShiftAmount = Width - 1;
+ if (!CI2->isZero() && cast<BinaryOperator>(LHS)->isExact())
+ ShiftAmount = CI2->getValue().countTrailingZeros();
+ if (CI2->isNegative()) {
+ // 'ashr CI2, x' produces [CI2, CI2 >> (Width-1)]
+ Lower = CI2->getValue();
+ Upper = CI2->getValue().ashr(ShiftAmount) + 1;
+ } else {
+ // 'ashr CI2, x' produces [CI2 >> (Width-1), CI2]
+ Lower = CI2->getValue().ashr(ShiftAmount);
+ Upper = CI2->getValue() + 1;
+ }
} else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
// 'or x, CI2' produces [CI2, UINT_MAX].
Lower = CI2->getValue();
}
}
+ // If a bit is known to be zero for A and known to be one for B,
+ // then A and B cannot be equal.
+ if (ICmpInst::isEquality(Pred)) {
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
+ uint32_t BitWidth = CI->getBitWidth();
+ APInt LHSKnownZero(BitWidth, 0);
+ APInt LHSKnownOne(BitWidth, 0);
+ computeKnownBits(LHS, LHSKnownZero, LHSKnownOne);
+ APInt RHSKnownZero(BitWidth, 0);
+ APInt RHSKnownOne(BitWidth, 0);
+ computeKnownBits(RHS, RHSKnownZero, RHSKnownOne);
+ if (((LHSKnownOne & RHSKnownZero) != 0) ||
+ ((LHSKnownZero & RHSKnownOne) != 0))
+ return (Pred == ICmpInst::ICMP_EQ)
+ ? ConstantInt::getFalse(CI->getContext())
+ : ConstantInt::getTrue(CI->getContext());
+ }
+ }
+
// Special logic for binary operators.
BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
if (MaxRecurse && (LBO || RBO)) {
// Analyze the case when either LHS or RHS is an add instruction.
- Value *A = 0, *B = 0, *C = 0, *D = 0;
+ Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr;
// LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
if (LBO && LBO->getOpcode() == Instruction::Add) {
}
}
+ // 0 - (zext X) pred C
+ if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) {
+ if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) {
+ if (RHSC->getValue().isStrictlyPositive()) {
+ if (Pred == ICmpInst::ICMP_SLT)
+ return ConstantInt::getTrue(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_SGE)
+ return ConstantInt::getFalse(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_EQ)
+ return ConstantInt::getFalse(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_NE)
+ return ConstantInt::getTrue(RHSC->getContext());
+ }
+ if (RHSC->getValue().isNonNegative()) {
+ if (Pred == ICmpInst::ICMP_SLE)
+ return ConstantInt::getTrue(RHSC->getContext());
+ if (Pred == ICmpInst::ICMP_SGT)
+ return ConstantInt::getFalse(RHSC->getContext());
+ }
+ }
+ }
+
// icmp pred (urem X, Y), Y
if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
bool KnownNonNegative, KnownNegative;
return getTrue(ITy);
}
+ // handle:
+ // CI2 << X == CI
+ // CI2 << X != CI
+ //
+ // where CI2 is a power of 2 and CI isn't
+ if (auto *CI = dyn_cast<ConstantInt>(RHS)) {
+ const APInt *CI2Val, *CIVal = &CI->getValue();
+ if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) &&
+ CI2Val->isPowerOf2()) {
+ if (!CIVal->isPowerOf2()) {
+ // CI2 << X can equal zero in some circumstances,
+ // this simplification is unsafe if CI is zero.
+ //
+ // We know it is safe if:
+ // - The shift is nsw, we can't shift out the one bit.
+ // - The shift is nuw, we can't shift out the one bit.
+ // - CI2 is one
+ // - CI isn't zero
+ if (LBO->hasNoSignedWrap() || LBO->hasNoUnsignedWrap() ||
+ *CI2Val == 1 || !CI->isZero()) {
+ if (Pred == ICmpInst::ICMP_EQ)
+ return ConstantInt::getFalse(RHS->getContext());
+ if (Pred == ICmpInst::ICMP_NE)
+ return ConstantInt::getTrue(RHS->getContext());
+ }
+ }
+ if (CIVal->isSignBit() && *CI2Val == 1) {
+ if (Pred == ICmpInst::ICMP_UGT)
+ return ConstantInt::getFalse(RHS->getContext());
+ if (Pred == ICmpInst::ICMP_ULE)
+ return ConstantInt::getTrue(RHS->getContext());
+ }
+ }
+ }
+
if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
LBO->getOperand(1) == RBO->getOperand(1)) {
switch (LBO->getOpcode()) {
if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
return TrueVal;
- return 0;
+ return nullptr;
}
Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
static Value *SimplifyGEPInst(ArrayRef<Value *> Ops, const Query &Q, unsigned) {
// The type of the GEP pointer operand.
PointerType *PtrTy = cast<PointerType>(Ops[0]->getType()->getScalarType());
+ unsigned AS = PtrTy->getAddressSpace();
// getelementptr P -> P.
if (Ops.size() == 1)
return Ops[0];
- if (isa<UndefValue>(Ops[0])) {
- // Compute the (pointer) type returned by the GEP instruction.
- Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
- Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
- if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
- GEPTy = VectorType::get(GEPTy, VT->getNumElements());
+ // Compute the (pointer) type returned by the GEP instruction.
+ Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, Ops.slice(1));
+ Type *GEPTy = PointerType::get(LastType, AS);
+ if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType()))
+ GEPTy = VectorType::get(GEPTy, VT->getNumElements());
+
+ if (isa<UndefValue>(Ops[0]))
return UndefValue::get(GEPTy);
- }
if (Ops.size() == 2) {
// getelementptr P, 0 -> P.
if (match(Ops[1], m_Zero()))
return Ops[0];
- // getelementptr P, N -> P if P points to a type of zero size.
- if (Q.DL) {
- Type *Ty = PtrTy->getElementType();
- if (Ty->isSized() && Q.DL->getTypeAllocSize(Ty) == 0)
+
+ Type *Ty = PtrTy->getElementType();
+ if (Q.DL && Ty->isSized()) {
+ Value *P;
+ uint64_t C;
+ uint64_t TyAllocSize = Q.DL->getTypeAllocSize(Ty);
+ // getelementptr P, N -> P if P points to a type of zero size.
+ if (TyAllocSize == 0)
return Ops[0];
+
+ // The following transforms are only safe if the ptrtoint cast
+ // doesn't truncate the pointers.
+ if (Ops[1]->getType()->getScalarSizeInBits() ==
+ Q.DL->getPointerSizeInBits(AS)) {
+ auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
+ if (match(P, m_Zero()))
+ return Constant::getNullValue(GEPTy);
+ Value *Temp;
+ if (match(P, m_PtrToInt(m_Value(Temp))))
+ if (Temp->getType() == GEPTy)
+ return Temp;
+ return nullptr;
+ };
+
+ // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
+ if (TyAllocSize == 1 &&
+ match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
+ if (Value *R = PtrToIntOrZero(P))
+ return R;
+
+ // getelementptr V, (ashr (sub P, V), C) -> Q
+ // if P points to a type of size 1 << C.
+ if (match(Ops[1],
+ m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
+ m_ConstantInt(C))) &&
+ TyAllocSize == 1ULL << C)
+ if (Value *R = PtrToIntOrZero(P))
+ return R;
+
+ // getelementptr V, (sdiv (sub P, V), C) -> Q
+ // if P points to a type of size C.
+ if (match(Ops[1],
+ m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
+ m_SpecificInt(TyAllocSize))))
+ if (Value *R = PtrToIntOrZero(P))
+ return R;
+ }
}
}
// Check to see if this is constant foldable.
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
if (!isa<Constant>(Ops[i]))
- return 0;
+ return nullptr;
return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
}
return Agg;
}
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
static Value *SimplifyPHINode(PHINode *PN, const Query &Q) {
// If all of the PHI's incoming values are the same then replace the PHI node
// with the common value.
- Value *CommonValue = 0;
+ Value *CommonValue = nullptr;
bool HasUndefInput = false;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *Incoming = PN->getIncomingValue(i);
continue;
}
if (CommonValue && Incoming != CommonValue)
- return 0; // Not the same, bail out.
+ return nullptr; // Not the same, bail out.
CommonValue = Incoming;
}
// instruction, we cannot return X as the result of the PHI node unless it
// dominates the PHI block.
if (HasUndefInput)
- return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : 0;
+ return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
return CommonValue;
}
if (Constant *C = dyn_cast<Constant>(Op))
return ConstantFoldInstOperands(Instruction::Trunc, Ty, C, Q.DL, Q.TLI);
- return 0;
+ return nullptr;
}
Value *llvm::SimplifyTruncInst(Value *Op, Type *Ty, const DataLayout *DL,
if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, Q, MaxRecurse))
return V;
- return 0;
+ return nullptr;
}
}
const Query &Q, unsigned MaxRecurse) {
// Perform idempotent optimizations
if (!IsIdempotent(IID))
- return 0;
+ return nullptr;
// Unary Ops
if (std::distance(ArgBegin, ArgEnd) == 1)
if (II->getIntrinsicID() == IID)
return II;
- return 0;
+ return nullptr;
}
template <typename IterTy>
Function *F = dyn_cast<Function>(V);
if (!F)
- return 0;
+ return nullptr;
if (unsigned IID = F->getIntrinsicID())
if (Value *Ret =
return Ret;
if (!canConstantFoldCallTo(F))
- return 0;
+ return nullptr;
SmallVector<Constant *, 4> ConstantArgs;
ConstantArgs.reserve(ArgEnd - ArgBegin);
for (IterTy I = ArgBegin, E = ArgEnd; I != E; ++I) {
Constant *C = dyn_cast<Constant>(*I);
if (!C)
- return 0;
+ return nullptr;
ConstantArgs.push_back(C);
}
// If we have an explicit value to collapse to, do that round of the
// simplification loop by hand initially.
if (SimpleV) {
- for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
- ++UI)
- if (*UI != I)
- Worklist.insert(cast<Instruction>(*UI));
+ for (User *U : I->users())
+ if (U != I)
+ Worklist.insert(cast<Instruction>(U));
// Replace the instruction with its simplified value.
I->replaceAllUsesWith(SimpleV);
// Stash away all the uses of the old instruction so we can check them for
// recursive simplifications after a RAUW. This is cheaper than checking all
// uses of To on the recursive step in most cases.
- for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
- ++UI)
- Worklist.insert(cast<Instruction>(*UI));
+ for (User *U : I->users())
+ Worklist.insert(cast<Instruction>(U));
// Replace the instruction with its simplified value.
I->replaceAllUsesWith(SimpleV);
const DataLayout *DL,
const TargetLibraryInfo *TLI,
const DominatorTree *DT) {
- return replaceAndRecursivelySimplifyImpl(I, 0, DL, TLI, DT);
+ return replaceAndRecursivelySimplifyImpl(I, nullptr, DL, TLI, DT);
}
bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV,
projects / oota-llvm.git / blobdiff