[jdk11u-dev] RFR: 8302191: Performance degradation for float/double modulo on Linux

[Jan Kratochvil]

Backport of [JDK-8302191](https://bugs.openjdk.java.net/browse/JDK-8302191). Applies cleanly. It is already committed in trunk.


build/linux-x86_64-normal-server-fastdebug/jdk/bin/java -jar ~/azul/jmh-jdk-microbenchmarks-git/micros-jdk8/target/micros-jdk8-1.0-SNAPSHOT.jar org.openjdk.bench.java.lang.FloatDoubleRem -i 2 -r 2 -wi 2 -f 2
unpatched:
Benchmark                            Mode  Cnt    Score    Error  Units
FloatDoubleRem.calcDoubleJava        avgt    4  103.219 ±  4.637  ns/op
FloatDoubleRem.calcFloatJava         avgt    4  106.588 ± 10.357  ns/op
FloatDoubleRem.cornercaseDoubleJava  avgt    4   11.822 ±  4.074  ns/op
FloatDoubleRem.cornercaseFloatJava   avgt    4   11.435 ±  1.355  ns/op
patched:
Benchmark                            Mode  Cnt   Score    Error  Units
FloatDoubleRem.calcDoubleJava        avgt    4  34.712 ± 22.532  ns/op
FloatDoubleRem.calcFloatJava         avgt    4  23.942 ±  5.177  ns/op
FloatDoubleRem.cornercaseDoubleJava  avgt    4   8.080 ±  1.004  ns/op
FloatDoubleRem.cornercaseFloatJava   avgt    4  10.647 ±  0.545  ns/op

-------------

Commit messages:
 - 8302191: Performance degradation for float/double modulo on Linux

Changes: https://git.openjdk.org/jdk11u-dev/pull/1824/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1824&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302191
  Stats: 267 lines in 3 files changed: 265 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1824.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/1824/head:pull/1824

PR: https://git.openjdk.org/jdk11u-dev/pull/1824