RFR: JDK-8068803:Performance of LocalDate.plusDays could be better

[Stephen Colebourne]

I updated the benchmark with this change and another one:
https://github.com/ThreeTen/threeten-bench/blob/master/src/main/java/org/threeten/LocalDateBenchmark.java

Marginally fastest is this pattern as it avoids one if statement:

  if (dom > 0) {
    if (dom <= 28) { // same month
      return ...
    }
    if (dom <= 59) { // 59th Jan is 28th Feb
      return ...
    }
  }

Rather than doing:
  return LocalDate.of(year, month, (int) dom);
we can also do
  return new LocalDate(year, month, (int) dom);

This is safe, because we know that the year, month and day are valid.
(I can't easily test the performance of this change, but it should be
noticeable as it avoids a lot of unnecessary checks).

I'd like a few more test cases. Addition around 27/28/29/30 from the
first of Jan/Feb, and of 13/14/15/16 from the 15th of Jan and 15th of
Feb.

Stephen



On 7 January 2016 at 09:20, nadeesh tv <nadeesh.tv at oracle.com> wrote:
> Hi ,
> Please see the updated webrev
> http://cr.openjdk.java.net/~ntv/8068803/webrev.01/
> Thanks and regards,
> Nadeesh
>
> On 1/6/2016 12:11 AM, Roger Riggs wrote:
>
> Hi Nadeesh,
>
> LocalDate.java: +1374:
>   For the most common case of dom > 0 && <= 28, I would have explicitly and
> immediately returned the new LocalDate.
>
>      if (dom > 0 && dom <= 28) {
>           return LocalDate.of(year, month, (int) dom);
>      }
>      ...
>
>
> TCKLocalDate.java:
>  - Since the test_plusDays_normal is being replaced, its test case should be
> included in the DataProvider
>
>       {LocalDate.of(2007, 7, 15), 1, LocalDate.of(2007, 7, 16)}
>
> Thanks, Roger
>
> On 1/5/2016 1:05 PM, nadeesh tv wrote:
>
> Hi all,
>
> Please review  a  fix for https://bugs.openjdk.java.net/browse/JDK-8068803
>  web rev :   http://cr.openjdk.java.net/~ntv/8068803/webrev.00/
>
> Special thanks for Stephen for  providing the source code patch
>
>
>
> --
> Thanks and Regards,
> Nadeesh TV
>