RFR: 8325438: Add exhaustive tests for Math.round intrinsics

[Vladimir Kozlov]

On Wed, 7 Feb 2024 16:07:02 GMT, Hamlin Li <mli at openjdk.org> wrote:

> HI,
> Can you have a look at this patch adding some tests for Math.round instrinsics?
> Thanks!
> 
> ### FYI:
> During the development of RoundVF/RoundF, we faced the issues which were only spotted by running test exhaustively against 32/64 bits range of int/long.
> It's helpful to add these exhaustive tests in jdk for future possible usage, rather than build it everytime when needed.
> Of course, we need to put it in `manual` mode, so it's not run when `-automatic` jtreg option is specified which I guess is the mode CI used, please correct me if I'm assume incorrectly.

test/hotspot/jtreg/compiler/c2/cr6340864/TestDoubleVectManual.java line 100:

> 98:           for (int sign = 0; sign < 2; sign++) {
> 99:             int idx = ei*2+sign;
> 100:             if (res[idx] != Math.round(input[idx])) {

You are comparing `Math.round()` with `Math.round()` results.  It is possible that C2 will compile `test()` too as OSR.
I would suggest to move code which creates "golden" values into a separate method and exclude it from compilation. To run code in Interpreter.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17753#discussion_r1483393241