RFR: 8360116: Add support for AVX10 floating point minmax instruction [v3]

[Jatin Bhateja]

> Intel@ AVX10 ISA [1] extensions added new floating point MIN/MAX instructions which comply with definitions in IEEE-754-2019 standard section 9.6 and can directly emulate Math.min/max semantics without the need for any special handling for NaN, +0.0 or -0.0 detection.
> 
> **The following pseudo-code describes the existing algorithm for min/max[FD]:**
> 
> Move the non-negative value to the second operand; this will ensure that we correctly handle 0.0 and -0.0 values, if values being compared are both 0.0s (of either sign), the value in the second operand (source operand) is returned. Existing MINPS and MAXPS semantics only check for NaN as the second operand; hence, we need special handling to check for NaN at the first operand.
> 
>   btmp = (b < +0.0) ? a : b
>   atmp = (b < +0.0) ? b : a
>   Tmp = Max_Float(atmp , btmp)
>   Res = (atmp == NaN) ? atmp : Tmp
> 
> For min[FD] we need a small tweak in the above algorithm, i.e., move the non-negative value to the first operand, this will ensure that we correctly select -0.0 if both the operands being compared are 0.0 or -0.0.
> 
>   btmp = (b < +0.0) ? b : a
>   atmp = (b < +0.0) ? a : b
>   Tmp = Max_Float(atmp , btmp)
>   Res = (atmp == NaN) ? atmp : Tmp
> 
> Thus, we need additional special handling for NaNs and +/-0.0 to compute floating-point min/max values to comply with the semantics of Math.max/min APIs using existing MINPS / MAXPS instructions. AVX10.2 added a new instruction, VPMINMAX[SH,SS,SD]/[PH,PS,PD], which comprehensively handles special cases, thereby eliminating the need for special handling.
> 
> Patch emits new instructions for reduction and non-reduction operations for single, double, and Float16 type.
> 
> Kindly review and share your feedback.
> 
> Best Regards,
> Jatin
> 
> [1] https://www.intel.com/content/www/us/en/content-details/856721/intel-advanced-vector-extensions-10-2-intel-avx10-2-architecture-specification.html?wapkw=AVX10

Jatin Bhateja has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Review comments resolutions
 - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8360116
 - Update comments
 - Extending the patch to cover reduction operations
 - 8360116: Add support for AVX10 floating point minmax instruction

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25914/files
  - new: https://git.openjdk.org/jdk/pull/25914/files/b6e55157..382c9b9e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25914&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25914&range=01-02

  Stats: 6650 lines in 365 files changed: 3468 ins; 1485 del; 1697 mod
  Patch: https://git.openjdk.org/jdk/pull/25914.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25914/head:pull/25914

PR: https://git.openjdk.org/jdk/pull/25914