RFR: 8302191: Performance degradation for float/double modulo on Linux

[David Holmes]

On Fri, 10 Feb 2023 09:06:56 GMT, Jan Kratochvil <duke at openjdk.org> wrote:

> I have OCA already processed/approved. I am not Author but my Author request is being processed these days (sent to Rob McKenna).
> I did regression test x86_64 OpenJDK-8. I will leave other regression testing on GHA.
> The patch (and former GCC performance regression) affects only x86_64+i686.

Thanks for doing the benchmark. Could you please include it in the PR by adding to test/micro/org/openjdk/bench/vm/floating-point.

The code still needs to be factored out into an x86 specific file e.g. src/hotspot/cpu/x86/sharedRuntime_x86.cpp. You can either name it `SharedRuntime::frem` and ifdef out the "shared" version; or else define `SharedRuntime::frem_x86` and call it from `SharedRuntime::frem` (similar to the Windows `fmod_winx64`). It should suffice to use X86 as the conditional rather than the compiler(?) macros `__x86_64_` and `__i386_`.

Thanks

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PR: https://git.openjdk.org/jdk/pull/12508