diff options
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 66 |
1 files changed, 37 insertions, 29 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 8020afffd45..106a4a71f93 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -795,14 +795,16 @@ static void computeKnownBitsFromAssume(const Value *V, KnownBits &Known, static void computeKnownBitsFromShiftOperator( const Operator *I, KnownBits &Known, KnownBits &Known2, unsigned Depth, const Query &Q, - function_ref<KnownBits(KnownBits, unsigned)> KBF) { + function_ref<APInt(const APInt &, unsigned)> KZF, + function_ref<APInt(const APInt &, unsigned)> KOF) { unsigned BitWidth = Known.getBitWidth(); if (auto *SA = dyn_cast<ConstantInt>(I->getOperand(1))) { unsigned ShiftAmt = SA->getLimitedValue(BitWidth-1); computeKnownBits(I->getOperand(0), Known, Depth + 1, Q); - Known = KBF(Known, ShiftAmt); + Known.Zero = KZF(Known.Zero, ShiftAmt); + Known.One = KOF(Known.One, ShiftAmt); // If the known bits conflict, this must be an overflowing left shift, so // the shift result is poison. We can return anything we want. Choose 0 for // the best folding opportunity. @@ -867,9 +869,8 @@ static void computeKnownBitsFromShiftOperator( continue; } - Known2 = KBF(Known2, ShiftAmt); - Known.Zero &= Known2.Zero; - Known.One &= Known2.One; + Known.Zero &= KZF(Known2.Zero, ShiftAmt); + Known.One &= KOF(Known2.One, ShiftAmt); } // If the known bits conflict, the result is poison. Return a 0 and hope the @@ -1067,46 +1068,53 @@ static void computeKnownBitsFromOperator(const Operator *I, KnownBits &Known, case Instruction::Shl: { // (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0 bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap(); - auto KBF = [NSW](const KnownBits &Known, unsigned ShiftAmt) { - KnownBits Result; - Result.Zero = Known.Zero << ShiftAmt; - Result.Zero.setLowBits(ShiftAmt); // Low bits known 0. - Result.One = Known.One << ShiftAmt; + auto KZF = [NSW](const APInt &KnownZero, unsigned ShiftAmt) { + APInt KZResult = KnownZero << ShiftAmt; + KZResult.setLowBits(ShiftAmt); // Low bits known 0. // If this shift has "nsw" keyword, then the result is either a poison // value or has the same sign bit as the first operand. - if (NSW && Known.isNonNegative()) - Result.Zero.setSignBit(); - if (NSW && Known.isNegative()) - Result.One.setSignBit(); - return Result; + if (NSW && KnownZero.isSignBitSet()) + KZResult.setSignBit(); + return KZResult; + }; + + auto KOF = [NSW](const APInt &KnownOne, unsigned ShiftAmt) { + APInt KOResult = KnownOne << ShiftAmt; + if (NSW && KnownOne.isSignBitSet()) + KOResult.setSignBit(); + return KOResult; }; - computeKnownBitsFromShiftOperator(I, Known, Known2, Depth, Q, KBF); + computeKnownBitsFromShiftOperator(I, Known, Known2, Depth, Q, KZF, KOF); break; } case Instruction::LShr: { // (lshr X, C1) & C2 == 0 iff (-1 >> C1) & C2 == 0 - auto KBF = [](const KnownBits &Known, unsigned ShiftAmt) { - KnownBits Result; - Result.Zero = Known.Zero.lshr(ShiftAmt); - Result.Zero.setHighBits(ShiftAmt); // High bits known zero. - Result.One = Known.One.lshr(ShiftAmt); - return Result; + auto KZF = [](const APInt &KnownZero, unsigned ShiftAmt) { + APInt KZResult = KnownZero.lshr(ShiftAmt); + // High bits known zero. + KZResult.setHighBits(ShiftAmt); + return KZResult; }; - computeKnownBitsFromShiftOperator(I, Known, Known2, Depth, Q, KBF); + auto KOF = [](const APInt &KnownOne, unsigned ShiftAmt) { + return KnownOne.lshr(ShiftAmt); + }; + + computeKnownBitsFromShiftOperator(I, Known, Known2, Depth, Q, KZF, KOF); break; } case Instruction::AShr: { // (ashr X, C1) & C2 == 0 iff (-1 >> C1) & C2 == 0 - auto KBF = [](const KnownBits &Known, unsigned ShiftAmt) { - KnownBits Result; - Result.Zero = Known.Zero.ashr(ShiftAmt); - Result.One = Known.One.ashr(ShiftAmt); - return Result; + auto KZF = [](const APInt &KnownZero, unsigned ShiftAmt) { + return KnownZero.ashr(ShiftAmt); + }; + + auto KOF = [](const APInt &KnownOne, unsigned ShiftAmt) { + return KnownOne.ashr(ShiftAmt); }; - computeKnownBitsFromShiftOperator(I, Known, Known2, Depth, Q, KBF); + computeKnownBitsFromShiftOperator(I, Known, Known2, Depth, Q, KZF, KOF); break; } case Instruction::Sub: { |