using namespace llvm;
using namespace PatternMatch;
+#define DEBUG_TYPE "instcombine"
+
Instruction *InstCombiner::commonShiftTransforms(BinaryOperator &I) {
assert(I.getOperand(1)->getType() == I.getOperand(0)->getType());
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
return &I;
}
- return 0;
+ return nullptr;
}
/// CanEvaluateShifted - See if we can compute the specified value, but shifted
// if the needed bits are already zero in the input. This allows us to reuse
// the value which means that we don't care if the shift has multiple uses.
// TODO: Handle opposite shift by exact value.
- ConstantInt *CI = 0;
+ ConstantInt *CI = nullptr;
if ((isLeftShift && match(I, m_LShr(m_Value(), m_ConstantInt(CI)))) ||
(!isLeftShift && match(I, m_Shl(m_Value(), m_ConstantInt(CI))))) {
if (CI->getZExtValue() == NumBits) {
case Instruction::Shl: {
// We can often fold the shift into shifts-by-a-constant.
CI = dyn_cast<ConstantInt>(I->getOperand(1));
- if (CI == 0) return false;
+ if (!CI) return false;
// We can always fold shl(c1)+shl(c2) -> shl(c1+c2).
if (isLeftShift) return true;
case Instruction::LShr: {
// We can often fold the shift into shifts-by-a-constant.
CI = dyn_cast<ConstantInt>(I->getOperand(1));
- if (CI == 0) return false;
+ if (!CI) return false;
// We can always fold lshr(c1)+lshr(c2) -> lshr(c1+c2).
if (!isLeftShift) return true;
GetShiftedValue(Op0, COp1->getZExtValue(), isLeftShift, *this));
}
-
// See if we can simplify any instructions used by the instruction whose sole
// purpose is to compute bits we don't care about.
uint32_t TypeBits = Op0->getType()->getScalarSizeInBits();
- // shl i32 X, 32 = 0 and srl i8 Y, 9 = 0, ... just don't eliminate
- // a signed shift.
- //
- if (COp1->uge(TypeBits)) {
- if (I.getOpcode() != Instruction::AShr)
- return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
- // ashr i32 X, 32 --> ashr i32 X, 31
- I.setOperand(1, ConstantInt::get(I.getType(), TypeBits-1));
- return &I;
- }
+ assert(!COp1->uge(TypeBits) &&
+ "Shift over the type width should have been removed already");
// ((X*C1) << C2) == (X * (C1 << C2))
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
if (BO->getOpcode() == Instruction::Mul && isLeftShift)
if (Constant *BOOp = dyn_cast<Constant>(BO->getOperand(1)))
return BinaryOperator::CreateMul(BO->getOperand(0),
- ConstantExpr::getShl(BOOp, COp1));
+ ConstantExpr::getShl(BOOp, Op1));
// Try to fold constant and into select arguments.
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), YS, V1,
Op0BO->getOperand(1)->getName());
uint32_t Op1Val = COp1->getLimitedValue(TypeBits);
- return BinaryOperator::CreateAnd(X, ConstantInt::get(I.getContext(),
- APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
+
+ APInt Bits = APInt::getHighBitsSet(TypeBits, TypeBits - Op1Val);
+ Constant *Mask = ConstantInt::get(I.getContext(), Bits);
+ if (VectorType *VT = dyn_cast<VectorType>(X->getType()))
+ Mask = ConstantVector::getSplat(VT->getNumElements(), Mask);
+ return BinaryOperator::CreateAnd(X, Mask);
}
// Turn (Y + ((X >> C) & CC)) << C -> ((X & (CC << C)) + (Y << C))
Value *X = Builder->CreateBinOp(Op0BO->getOpcode(), V1, YS,
Op0BO->getOperand(0)->getName());
uint32_t Op1Val = COp1->getLimitedValue(TypeBits);
- return BinaryOperator::CreateAnd(X, ConstantInt::get(I.getContext(),
- APInt::getHighBitsSet(TypeBits, TypeBits-Op1Val)));
+
+ APInt Bits = APInt::getHighBitsSet(TypeBits, TypeBits - Op1Val);
+ Constant *Mask = ConstantInt::get(I.getContext(), Bits);
+ if (VectorType *VT = dyn_cast<VectorType>(X->getType()))
+ Mask = ConstantVector::getSplat(VT->getNumElements(), Mask);
+ return BinaryOperator::CreateAnd(X, Mask);
}
// Turn (((X >> C)&CC) + Y) << C -> (X + (Y << C)) & (CC << C)
}
- // If the operand is an bitwise operator with a constant RHS, and the
+ // If the operand is a bitwise operator with a constant RHS, and the
// shift is the only use, we can pull it out of the shift.
if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) {
bool isValid = true; // Valid only for And, Or, Xor
// Find out if this is a shift of a shift by a constant.
BinaryOperator *ShiftOp = dyn_cast<BinaryOperator>(Op0);
if (ShiftOp && !ShiftOp->isShift())
- ShiftOp = 0;
+ ShiftOp = nullptr;
if (ShiftOp && isa<ConstantInt>(ShiftOp->getOperand(1))) {
uint32_t ShiftAmt1 = ShiftAmt1C->getLimitedValue(TypeBits);
uint32_t ShiftAmt2 = COp1->getLimitedValue(TypeBits);
assert(ShiftAmt2 != 0 && "Should have been simplified earlier");
- if (ShiftAmt1 == 0) return 0; // Will be simplified in the future.
+ if (ShiftAmt1 == 0) return nullptr; // Will be simplified in the future.
Value *X = ShiftOp->getOperand(0);
IntegerType *Ty = cast<IntegerType>(I.getType());
}
}
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitShl(BinaryOperator &I) {
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyShlInst(I.getOperand(0), I.getOperand(1),
I.hasNoSignedWrap(), I.hasNoUnsignedWrap(),
DL))
match(I.getOperand(1), m_Constant(C2)))
return BinaryOperator::CreateShl(ConstantExpr::getShl(C1, C2), A);
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitLShr(BinaryOperator &I) {
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyLShrInst(I.getOperand(0), I.getOperand(1),
I.isExact(), DL))
return ReplaceInstUsesWith(I, V);
}
}
- return 0;
+ return nullptr;
}
Instruction *InstCombiner::visitAShr(BinaryOperator &I) {
+ if (Value *V = SimplifyVectorOp(I))
+ return ReplaceInstUsesWith(I, V);
+
if (Value *V = SimplifyAShrInst(I.getOperand(0), I.getOperand(1),
I.isExact(), DL))
return ReplaceInstUsesWith(I, V);
// have a sign-extend idiom.
Value *X;
if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1)))) {
- // If the left shift is just shifting out partial signbits, delete the
- // extension.
- if (cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
- return ReplaceInstUsesWith(I, X);
-
// If the input is an extension from the shifted amount value, e.g.
// %x = zext i8 %A to i32
// %y = shl i32 %x, 24
APInt::getSignBit(I.getType()->getScalarSizeInBits())))
return BinaryOperator::CreateLShr(Op0, Op1);
- // Arithmetic shifting an all-sign-bit value is a no-op.
- unsigned NumSignBits = ComputeNumSignBits(Op0);
- if (NumSignBits == Op0->getType()->getScalarSizeInBits())
- return ReplaceInstUsesWith(I, Op0);
-
- return 0;
+ return nullptr;
}
-
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