RFR: 8332265: RISC-V: Materialize pointers faster by using a temp register [v3]

[Robbin Ehn]

> Hi, please consider!
> 
> Materializing a 48-bit pointer, using an additional register, we can do with:
> lui + lui + slli + add + addi
> This 15% faster both on VF2 and in CPU models, compared to movptr().
> 
> As we often materialize during calls there is free registers.
> 
> I have choose just a few spot to use it, many more can use.
> E.g. la() with tmp register can use li48 instead of movptr.
> 
> Running tests now (so far so good), as if I screwed up IC calls it should be seen fast.
> And benchmarks when hardware is free.

Robbin Ehn has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Merge branch 'master' into 8332265
 - Small review update
 - li48 -> movptr
 - Merge branch 'master' into 8332265
 - li48

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19246/files
  - new: https://git.openjdk.org/jdk/pull/19246/files/edfdda28..c406294a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19246&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19246&range=01-02

  Stats: 1130 lines in 62 files changed: 557 ins; 502 del; 71 mod
  Patch: https://git.openjdk.org/jdk/pull/19246.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19246/head:pull/19246

PR: https://git.openjdk.org/jdk/pull/19246