RFR: 8285868: x86_64 intrinsics for floating point methods isNaN, isFinite and isInfinite [v8]

[Srinivas Vamsi Parasa]

> We develop optimized x86_64 intrinsics for the floating point class check methods `isNaN()`, `isFinite()` and `IsInfinite()` for Float and Double classes. JMH benchmarks show ~6x improvement for `isNan()`, ~2x improvement for `isInfinite()` and 40% gain for `isFinite()` using` vfpclasss(s/d)` instructions.
> 
> 
> JMH Benchmark (ns/op)	              Baseline	  This PR (WITH vfpclassss/sd)                      Speedup
> 		                               
> FloatClassCheck.testIsFinite	      0.559	                  0.4	                            1.4x
> FloatClassCheck.testIsInfinite	      0.828	                  0.386	                            2.15x
> FloatClassCheck.testIsNaN	      2.589	                  0.387	                            6.7x
> DoubleClassCheck.testIsFinite         0.568	                  0.414	                            1.37x
> DoubleClassCheck.testIsInfinite       0.836	                  0.395	                            2.11x
> DoubleClassCheck.testIsNaN	      2.592	                  0.393	                            6.6x
> 
> JMH Benchmark (ns/op)	              Baseline	  This PR (WITHOUT vfpclassss/sd)                   Speedup
> FloatClassCheck.testIsFinite	      0.561	                 0.468	                             1.2x
> FloatClassCheck.testIsInfinite	      0.793	                 0.491	                             1.61x
> FloatClassCheck.testIsNaN	      2.587	                 0.469	                             5.5x
> DoubleClassCheck.testIsFinite         0.561	                 0.592	                             0.94x
> DoubleClassCheck.testIsInfinite       0.828	                 0.592	                             1.4x
> DoubleClassCheck.testIsNaN	      2.593	                 0.594	                             4.4x

Srinivas Vamsi Parasa has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:

 - add comment for vfpclasss/d for isFinite()
 - Merge branch 'master' of https://git.openjdk.java.net/jdk into float
 - zero out the upper bits not written by setb
 - use 0x1 to be simpler
 - remove the redundant temp register
 - Split the macros using predicate
 - update jmh tests
 - Merge branch 'master' into float
 - 8285868: x86_64 intrinsics for floating point methods isNaN, isFinite and isInfinite

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Changes: https://git.openjdk.java.net/jdk/pull/8459/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8459&range=07
  Stats: 772 lines in 20 files changed: 770 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8459.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8459/head:pull/8459

PR: https://git.openjdk.java.net/jdk/pull/8459