8357551: RISC-V: support CMoveF/D vectorization

[Hamlin-Li]

Hi,

This pr add CMoveF/D on riscv, which enable vectorization of statement like: op_1 bop op_2 ? res_f_d_1 : res_f_d_2 in a loop.

This pr is also a preparation for further vectorization in #28231.

Previously it's #25341, but at that time, C2 SLP has some issue with unsigned comparison, which is now fixed, so it's good to continue the work.

Test

Jtreg

in progress...

Performance

Column names meanings:

• p: with patch
• p+v: with patch, -XX:+UseVectorCmov -XX:+UseCMoveUnconditionally turned on
• m: without patch
• m+v: without patch, -XX:+UseVectorCmov -XX:+UseCMoveUnconditionally turned on

Average improvement

NOTE: With only this PR, it brings performance benefit in case of CMoveF+CmpF, CMoveD+ComD, CMoveF+CmpI, CMoveD+CmpL. The data below is based on fullly implmenting the vectorization of CMoveI/L/F/D+CmpI/L/F/D, which will be achieved by #28231.

For details, check the performance data in #25341 on riscv.

Opt (m/p)	Opt (m+v/p+v)	Opt (p/p+v)	Opt (m/p+v)
1.022782609	2.198717391	2.162673913	2.199

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8357551: RISC-V: support CMoveF/D vectorization (Enhancement - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/28309/head:pull/28309
$ git checkout pull/28309

Update a local copy of the PR:
$ git checkout pull/28309
$ git pull https://git.openjdk.org/jdk.git pull/28309/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 28309

View PR using the GUI difftool:
$ git pr show -t 28309

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/28309.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back mli! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

⚠️ @Hamlin-Li This pull request contains merges that bring in commits not present in the target repository. Since this is not a "merge style" pull request, these changes will be squashed when this pull request in integrated. If this is your intention, then please ignore this message. If you want to preserve the commit structure, you must change the title of this pull request to Merge <project>:<branch> where <project> is the name of another project in the OpenJDK organization (for example Merge jdk:master).

[openjdk]

@Hamlin-Li The following labels will be automatically applied to this pull request:

• core-libs
• hotspot

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 04: Full - Incremental (572a7b74)
• 03: Full - Incremental (cf9168a2)
• 02: Full - Incremental (51451ab5)
• 01: Full - Incremental (5c0d645d)
• 00: Full (ec0d8cc4)

[eme64]

/label add hotspot-compiler

[openjdk]

@eme64
The hotspot-compiler label was successfully added.

[eme64]

I won't be able to review the RISCV part, so you'll have to find someone else there. I just dropped 2 drive-by comments about the tests :)