RFR: 8352635: Improve inferencing of Float16 operations with constant inputs [v12]

[Emanuel Peter]

On Thu, 19 Jun 2025 07:44:39 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> This is a follow-up PR#22755 to improve Float16 operations inferencing.
>> 
>> The existing scheme to detect Float16 operations for some operations is based on pattern matching which expects to receive inputs through ConvHF2F IR, this patch extends matching to accept constant floating point inputs within the Float16 value range.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review resolution

src/hotspot/share/opto/subnode.cpp line 566:

> 564:   // applicable to other floating point types.
> 565:   if (t1->isa_half_float_constant() &&
> 566:       t2->isa_half_float_constant())  {

Suggestion:

  if (t1->isa_half_float_constant() != nullptr &&
      t2->isa_half_float_constant() != nullptr)  {

`src/hotspot/share/opto/type.hpp:298:21:  const TypeH      *isa_half_float_constant() const; // Returns null if not a FloatCon`

Same issue here

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PR Review Comment: https://git.openjdk.org/jdk/pull/24179#discussion_r2156368153