RFR: 8295159: DSO created with -ffast-math breaks Java floating-point arithmetic [v7]

[Andrew Haley]

On Tue, 25 Oct 2022 13:29:52 GMT, Andrew Haley <aph at openjdk.org> wrote:

> Enabling `-XX:+RestoreMXCSROnJNICalls` makes the overhead much worse:
> 
> ```
> Benchmark                          Mode  Cnt   Score   Error  Units
> CallOverheadConstant.jni_blank     avgt   40  14.741 ± 0.031  ns/op
> CallOverheadConstant.panama_blank  avgt   40  14.620 ± 0.022  ns/op
> ```

This is Zen+, by the way: Latency of stmxcsr ≤18. Better than some x86_64, worse than others.

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PR: https://git.openjdk.org/jdk/pull/10661