RFR: 8341470: BigDecimal.stripTrailingZeros() optimization [v33]

[fabioromano1]

On Fri, 11 Oct 2024 19:45:23 GMT, fabioromano1 <duke at openjdk.org> wrote:

> This doesn't say much about `maxPowsOf5`, though. You are not using `intVal` but 2^`bitLength` > `intVal` in the computation of `maxPowsOf5`. So maybe the property you are looking for is `maxPowsOf5` - 1 <= log5(intVal) < `maxPowsOf5` || `maxPowsOf5` <= log5(intVal) < `maxPowsOf5` + 1

To clarify as much as possible, the weakest property that `maxPowsOf5` must satisfy is:
`maxPowsOf5 >= max{integer n : intVal % 5^n == 0}`.
Clearly, it is true that `max{integer n : 5^n <= intVal} >= max{integer n : intVal % 5^n == 0}`;
and since `floor(log5(intVal)) == max{integer n : 5^n <= intVal}`,
it follows that `maxPowsOf5 >= floor(log5(intVal)) ==> maxPowsOf5 >= max{integer n : intVal % 5^n == 0}.`

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PR Review Comment: https://git.openjdk.org/jdk/pull/21323#discussion_r1797381043