[8u-dev, ppc] RFR for (almost clean) backport of 8185696: PPC64: Improve VSR support to use up to 64 registers

[Kazunori Ogata]

Hi,

I'm requesting backport of 8185696: PPC64: Improve VSR support to use up 
to 64 registers to jdk8u-dev.  This patch can be applied almost cleanly, 
but one chunk failed (other than a copyright year conflict) because the 
definition of MTVSRWA_OPCODE is missing in 
src/cpu/ppc/vm/assembler_ppc.hpp.

MTVSRWA_OPCODE was added in 8144019: PPC64 C1: Introduce Client Compiler 
[1], which added tiered compilation feature in JDK9.  Since JDK8 does not 
support tiered compilation, we cannot apply this change set.

So I manually applied the failed chunk by skipping the MTVSRWA_OPCODE 
definition because no code in this changeset and other changesets I'm 
going to backport uses this opcode.  I'll leave it to the future backport 
that really needs this opcode.

Is this fix acceptable for backport request?  If there is no objection in 
a few days, I'll go forward to add jdk8u-fix-request tag in the original 
bug report.  I verified I can build both fastdebug and release version, 
and no degradation in jtreg.


Original bug report:
https://bugs.openjdk.java.net/browse/JDK-8185969

Webrev:
http://cr.openjdk.java.net/~horii/jdk8u_aes_be/8185969/webrev.02/

Refs:
[1] https://bugs.openjdk.java.net/browse/JDK-8144019