On Fri, 11 Oct 2024 18:41:50 GMT, Raffaello Giulietti <rgiulie...@openjdk.org> wrote:
>> If the mathematical value v of the product and its floating-point value fp >> are separated by an integer i in such a way that fp < i < v, we are in >> trouble: the ceilings will be different, even if the values are very close >> to each other. > > One might prove that this cannot happen for a specific approximation of > log5(2), like `LOG_5_OF_2` and for all bit length, but I don't think it is > worthwhile to put too much effort on this, given the performance figures. > If the mathematical value v of the product and its floating-point value fp > are separated by an integer i in such a way that fp < i < v, we are in > trouble: the ceilings will be different, even if the values are very close to > each other. In that unlikely case, we would have `maxPowsOf5 >= floor(log5(intVal))`, which is still acceptable as an upper bound. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21323#discussion_r1797319077
