RFR: 8327661: C1: Make RBP allocatable on x64 when PreserveFramePointer is disabled [v3]

[Denghui Dong]

> Hi,
> 
> Could I have a review of this change that makes RBP allocatable in c1 register allocation when PreserveFramePointer is not enabled.
> 
> There seems no reason that RBP cannot be used. Although the performance of c1 jit code is not very critical, in my opinion, this change will not add overhead of compilation. So maybe it is acceptable.
> 
> I am not very sure if I have changed all the places that should be.
> 
> Testing: fastdebug tier1-4 on Linux x64

Denghui Dong has updated the pull request incrementally with one additional commit since the last revision:

  delete jmh

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/18167/files
  - new: https://git.openjdk.org/jdk/pull/18167/files/a6270736..972b12ee

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18167&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18167&range=01-02

  Stats: 74 lines in 1 file changed: 0 ins; 74 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18167.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18167/head:pull/18167

PR: https://git.openjdk.org/jdk/pull/18167