Transforms/InstCombine/InstCombineSimplifyDemanded.cpp

102 /// expression. Known.Zero contains all the bits that are known to be zero in
106 /// Known.One and Known.Zero always follow the invariant that:
107 ///   Known.One & Known.Zero == 0.
109 /// Known.Zero may only be accurate for those bits set in DemandedMask. Note
110 /// also that the bitwidth of V, DemandedMask, Known.Zero and Known.One must all
168     // If either the LHS or the RHS are Zero, the result is zero.
170         SimplifyDemandedBits(I, 0, DemandedMask & ~RHSKnown.Zero, LHSKnown,
177     APInt IKnownZero = RHSKnown.Zero | LHSKnown.Zero;
188     if (DemandedMask.isSubsetOf(LHSKnown.Zero | RHSKnown.One))
190     if (DemandedMask.isSubsetOf(RHSKnown.Zero | LHSKnown.One))
194     if (ShrinkDemandedConstant(I, 1, DemandedMask & ~LHSKnown.Zero))
197     Known.Zero = std::move(IKnownZero);
211     APInt IKnownZero = RHSKnown.Zero & LHSKnown.Zero;
222     if (DemandedMask.isSubsetOf(LHSKnown.One | RHSKnown.Zero))
224     if (DemandedMask.isSubsetOf(RHSKnown.One | LHSKnown.Zero))
231     Known.Zero = std::move(IKnownZero);
243     APInt IKnownZero = (RHSKnown.Zero & LHSKnown.Zero) |
246     APInt IKnownOne =  (RHSKnown.Zero & LHSKnown.One) |
247                        (RHSKnown.One & LHSKnown.Zero);
256     if (DemandedMask.isSubsetOf(RHSKnown.Zero))
258     if (DemandedMask.isSubsetOf(LHSKnown.Zero))
264     if (DemandedMask.isSubsetOf(RHSKnown.Zero | LHSKnown.Zero)) {
275     if (DemandedMask.isSubsetOf(RHSKnown.Zero|RHSKnown.One) &&
313     Known.Zero = std::move(IKnownZero);
387     Known.Zero = RHSKnown.Zero & LHSKnown.Zero;
480     if (DemandedFromOps.isSubsetOf(RHSKnown.Zero))
486         DemandedFromOps.isSubsetOf(LHSKnown.Zero))
518       Known.Zero <<= ShiftAmt;
522         Known.Zero.setLowBits(ShiftAmt);
542       Known.Zero.lshrInPlace(ShiftAmt);
545         Known.Zero.setHighBits(ShiftAmt);  // high bits known zero.
591       Known.Zero.lshrInPlace(ShiftAmt);
597       if (Known.Zero[BitWidth-ShiftAmt-1] ||
625       Known.Zero.setHighBits(std::min(
626           BitWidth, LHSKnown.Zero.countLeadingOnes() + RHSTrailingZeros));
647         Known.Zero = LHSKnown.Zero & LowBits;
652         if (LHSKnown.isNonNegative() || LowBits.isSubsetOf(LHSKnown.Zero))
653           Known.Zero |= ~LowBits;
682     Known.Zero = APInt::getHighBitsSet(BitWidth, Leaders) & DemandedMask;
739         Known.Zero = LHSKnown.Zero.shl(ShiftAmt) |
740                      RHSKnown.Zero.lshr(BitWidth - ShiftAmt);
770         Known.Zero.setBitsFrom(ArgWidth);
774         Known.Zero.setBitsFrom(32);
784   if (DemandedMask.isSubsetOf(Known.Zero|Known.One))
809     // If either the LHS or the RHS are Zero, the result is zero.
815     APInt IKnownZero = RHSKnown.Zero | LHSKnown.Zero;
827     if (DemandedMask.isSubsetOf(LHSKnown.Zero | RHSKnown.One))
829     if (DemandedMask.isSubsetOf(RHSKnown.Zero | LHSKnown.One))
832     Known.Zero = std::move(IKnownZero);
846     APInt IKnownZero = RHSKnown.Zero & LHSKnown.Zero;
858     if (DemandedMask.isSubsetOf(LHSKnown.One | RHSKnown.Zero))
860     if (DemandedMask.isSubsetOf(RHSKnown.One | LHSKnown.Zero))
863     Known.Zero = std::move(IKnownZero);
876     APInt IKnownZero = (RHSKnown.Zero & LHSKnown.Zero) |
879     APInt IKnownOne =  (RHSKnown.Zero & LHSKnown.One) |
880                        (RHSKnown.One & LHSKnown.Zero);
889     if (DemandedMask.isSubsetOf(RHSKnown.Zero))
891     if (DemandedMask.isSubsetOf(LHSKnown.Zero))
895     Known.Zero = std::move(IKnownZero);
906     if (DemandedMask.isSubsetOf(Known.Zero|Known.One))
951   Known.Zero.setLowBits(ShlAmt - 1);
952   Known.Zero &= DemandedMask;