[lworld] RFR: 8235914: [lworld] Profile acmp bytecode [v4]

[Roland Westrelin]

> This includes:
> - a new ProfileData structure to profile both inputs to acmp
> - profile collection at acmp in the interpreter on x86
> - profile collection at acmp in c1 generated code on x86
> - changes to c2's acmp implementation to leverage profiling (both existing profiling through type speculation and new
>   profile data at acmp)
> - small tweaks to the assembly code generated for acmp
> - a change to the implementation of LIRGenerator::profile_null_free_array() so it doesn't use a branch (which is
>   dangerous given the register allocator is not aware of branches added at the LIR level)
> - new tests
> 
> Profile collection happens unconditionally. Leveraging profiling at acmp is under UseACmpProfile which is false by
> default.

Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:

  review

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

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/185/files
  - new: https://git.openjdk.java.net/valhalla/pull/185/files/01b00395..b88029c6

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=185&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=185&range=02-03

  Stats: 58 lines in 7 files changed: 0 ins; 2 del; 56 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/185.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/185/head:pull/185

PR: https://git.openjdk.java.net/valhalla/pull/185