[8u-dev] Request for backport approval: 8145913: PPC64: add Montgomery multiply intrinsic

[Gustavo Serra Scalet]

Hi,


Original Bug: https://bugs.openjdk.java.net/browse/JDK-8145913
Jdk9 change: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/ce0dacc26f3d
Jdk9 review thread: http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2015-December/020534.html

Unfortunately the Jdk9 change doesn't apply cleanly. Below the are reasons for the adaptations:

1) This stub call uses integer type on a 64 bits register so a conversion to long was additionally needed.
2) Avoid changing the ppc.ad file as some interfaces were not existing.

My changes are available on: https://gut.github.io/openjdk/webrev/JDK-8145913/webrev/index.html

This change also belongs to 8u102 backport of https://bugs.openjdk.java.net/browse/JDK-8150152


Thanks to this change, SpecJVM2008's crypto.rsa benchmark had a speedup of 3.1 on ppc64le!

Gustavo Serra Scalet