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In function ComputeMaskedBits():
1. Replace getSignedMinValue() with getSignBit() for better code readability. 2. Replace APIntOps::shl() with operator<<= for convenience. 3. Make APInt construction more effective. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35060 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -695,7 +695,7 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero,
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// If the sign bit of the input is known set or clear, then we know the
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// top bits of the result.
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APInt InSignBit(APInt::getSignedMinValue(SrcTy->getBitWidth()));
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APInt InSignBit(APInt::getSignBit(SrcTy->getBitWidth()));
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InSignBit.zextOrTrunc(BitWidth);
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if ((KnownZero & InSignBit) != 0) { // Input sign bit known zero
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KnownZero |= NewBits;
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@ -716,8 +716,8 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero,
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Mask = APIntOps::lshr(Mask, ShiftAmt);
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ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, Depth+1);
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assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
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KnownZero = APIntOps::shl(KnownZero, ShiftAmt);
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KnownOne = APIntOps::shl(KnownOne, ShiftAmt);
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KnownZero <<= ShiftAmt;
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KnownOne <<= ShiftAmt;
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KnownZero |= APInt(BitWidth, 1ULL).shl(ShiftAmt)-1; // low bits known zero.
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return;
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}
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@ -730,7 +730,7 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero,
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APInt HighBits(APInt::getAllOnesValue(BitWidth).shl(BitWidth-ShiftAmt));
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// Unsigned shift right.
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Mask = APIntOps::shl(Mask, ShiftAmt);
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Mask <<= ShiftAmt;
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ComputeMaskedBits(I->getOperand(0), Mask, KnownZero,KnownOne,Depth+1);
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assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
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KnownZero = APIntOps::lshr(KnownZero, ShiftAmt);
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@ -747,14 +747,14 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero,
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APInt HighBits(APInt::getAllOnesValue(BitWidth).shl(BitWidth-ShiftAmt));
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// Signed shift right.
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Mask = APIntOps::shl(Mask, ShiftAmt);
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Mask <<= ShiftAmt;
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ComputeMaskedBits(I->getOperand(0), Mask, KnownZero,KnownOne,Depth+1);
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assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
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KnownZero = APIntOps::lshr(KnownZero, ShiftAmt);
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KnownOne = APIntOps::lshr(KnownOne, ShiftAmt);
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// Handle the sign bits and adjust to where it is now in the mask.
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APInt SignBit = APInt::getSignedMinValue(BitWidth).lshr(ShiftAmt);
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APInt SignBit(APInt::getSignBit(BitWidth).lshr(ShiftAmt));
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if ((KnownZero & SignBit) != 0) { // New bits are known zero.
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KnownZero |= HighBits;
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