RFR: 8279508: Auto-vectorize Math.round API [v6]

[Jatin Bhateja]

> Summary of changes:
> - Intrinsify Math.round(float) and Math.round(double) APIs.
> - Extend auto-vectorizer to infer vector operations on encountering scalar IR nodes for above intrinsics.
> - Test creation using new IR testing framework.
> 
> Following are the performance number of a JMH micro included with the patch 
> 
> Test System: Intel(R) Xeon(R) Platinum 8380 CPU @ 2.30GHz (Icelake Server)
> 
> 
> TESTSIZE | Baseline AVX3 (ops/ms) | Withopt AVX3 (ops/ms) | Gain ratio | Baseline AVX2 (ops/ms) | Withopt AVX2 (ops/ms) | Gain ratio
> -- | -- | -- | -- | -- | -- | --
> 1024.00 | 510.41 | 1811.66 | 3.55 | 510.40 | 502.65 | 0.98
> 2048.00 | 293.52 | 984.37 | 3.35 | 304.96 | 177.88 | 0.58
> 1024.00 | 825.94 | 3387.64 | 4.10 | 750.77 | 1925.15 | 2.56
> 2048.00 | 411.91 | 1942.87 | 4.72 | 412.22 | 1034.13 | 2.51
> 
> 
> Kindly review and share your feedback.
> 
> Best Regards,
> Jatin

Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:

  8279508: Fixing for windows failure.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7094/files
  - new: https://git.openjdk.java.net/jdk/pull/7094/files/73674fe4..f35ed9cf

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7094&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7094&range=04-05

  Stats: 6 lines in 1 file changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7094.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7094/head:pull/7094

PR: https://git.openjdk.java.net/jdk/pull/7094