RFR: 8325438: Add exhaustive tests for Math.round intrinsics [v9]

[Andrew Haley]

On Fri, 5 Apr 2024 10:26:06 GMT, Hamlin Li <mli at openjdk.org> wrote:

>>> > There's no need for randomness or arrays or special values in the 32-bit case. You can, and should, test the entire 32-bit range in a few lines of code by using floatBitsToInt.
>>> 
>>> In previous discussion, there are several reasons why it's implemented in this way:
>>> 
>>> 1. test the whole range of 32 bits is slow, and even slow for a 64 ranges double.
>> 
>> I guess we could try it for 32 bit floats. But it would take a while. If we can make sure it does not take much more than one minute, we can do that. But of course 64 bit doubles would be infeasible.
>
> As I remember, that's not the case in my local environment, i.e. it will take longer time.

If it takes longer than a few seconds, there's something wrong with your computer or your compiler. It's only 4G tests. I get


          6,255.47 msec task-clock:u                     #    1.057 CPUs utilized             
    19,681,407,235      cycles:u                         #    3.146 GHz                         (95.55%)
   110,397,691,854      instructions:u                   #    5.61  insn per cycle              (95.55%)

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PR Review Comment: https://git.openjdk.org/jdk/pull/17753#discussion_r1557235952