// This is an extremely fast implementation of BigInteger.doubleValue(). JDK patch pending.
    BigInteger absX = x.abs();
    int exponent = absX.bitLength() - 1;
    // exponent == floor(log2(abs(x)))
    if (exponent < Long.SIZE - 1) {
      return x.longValue();
    } else if (exponent > MAX_EXPONENT) {
      return x.signum() * POSITIVE_INFINITY;
    }

    /*

    for (int i = 1; i <= 40; i++) {
      intValues.add(i);
    }
    // Now add values near 2^N for lots of values of N.
    for (int exponent : asList(2, 3, 4, 9, 15, 16, 17, 24, 25, 30)) {
      int x = 1 << exponent;
      intValues.add(x, x + 1, x - 1);
    }
    intValues.add(9999).add(10000).add(10001).add(1000000); // near powers of 10

    // This is an extremely fast implementation of BigInteger.doubleValue(). JDK patch pending.
    BigInteger absX = x.abs();
    int exponent = absX.bitLength() - 1;
    // exponent == floor(log2(abs(x)))
    if (exponent < Long.SIZE - 1) {
      return x.longValue();
    } else if (exponent > MAX_EXPONENT) {
      return x.signum() * POSITIVE_INFINITY;
    }

    /*

    return e.getDeclaringClass();
  }

  static int reduceIterationsIfGwt(int iterations) {
    return iterations;
  }

  static int reduceExponentIfGwt(int exponent) {
    return exponent;
  }

  private Platform() {}

    return e.getDeclaringClass();
  }

  static int reduceIterationsIfGwt(int iterations) {
    return iterations;
  }

  static int reduceExponentIfGwt(int exponent) {
    return exponent;
  }

  private Platform() {}

    return ******@****.***::getDeclaringClass()();
  }-*/;

  static int reduceIterationsIfGwt(int iterations) {
    return iterations / 10;
  }

  static int reduceExponentIfGwt(int exponent) {
    return exponent / 2;
  }

  private Platform() {}

            for (String expMarker : ImmutableList.of("p", "P")) {
              for (String exponent : ImmutableList.of("0", "-5", "+20", "52")) {
                for (String typePart : ImmutableList.of("", "D", "F", "d", "f")) {
                  checkTryParse(
                      signChar + hexPrefix + iPart + fPart + expMarker + exponent + typePart);
                }
              }
            }
          }
        }

            for (String expMarker : ImmutableList.of("p", "P")) {
              for (String exponent : ImmutableList.of("0", "-5", "+20", "52")) {
                for (String typePart : ImmutableList.of("", "D", "F", "d", "f")) {
                  checkTryParse(
                      signChar + hexPrefix + iPart + fPart + expMarker + exponent + typePart);
                }
              }
            }
          }
        }

   * time.
   *
   * @throws IllegalArgumentException if {@code k < 0}
   */
  @GwtIncompatible // TODO
  public static long pow(long b, int k) {
    checkNonNegative("exponent", k);
    if (-2 <= b && b <= 2) {
      switch ((int) b) {
        case 0:
          return (k == 0) ? 1 : 0;
        case 1:
          return 1;
        case -1:

            for (String expMarker : ImmutableList.of("p", "P")) {
              for (String exponent : ImmutableList.of("0", "-5", "+20", "52")) {
                for (String typePart : ImmutableList.of("", "D", "F", "d", "f")) {
                  checkTryParse(
                      signChar + hexPrefix + iPart + fPart + expMarker + exponent + typePart);
                }
              }
            }
          }
        }