lib/Support/APInt.cpp

2996   APInt SQ = D.sqrt();
2998   APInt Q = SQ * SQ;
3000   // The calculated SQ may actually be greater than the exact (non-integer)
3001   // value. If that's the case, decrement SQ to get a value that is lower.
3003     SQ -= 1;
3008   // SQ is rounded down (i.e SQ * SQ <= D), so the roots may be inexact.
3010   // may be greater than the exact one, since we would be subtracting SQ.
3012   // one, subtract SQ+1 when calculating the low root (for inexact value
3013   // of SQ).
3015     APInt::sdivrem(-B - (SQ+InexactSQ), TwoA, X, Rem);
3017     APInt::sdivrem(-B + SQ, TwoA, X, Rem);
3029   assert((SQ*SQ).sle(D) && "SQ = |_sqrt(D)_|, so SQ*SQ <= D");
3030   // The exact value of the square root of D should be between SQ and SQ+1.
3032   // SQ (i.e. X) and that corresponding to SQ+1.