JDK-8352635 : Improve inferencing of Float16 operations with constant inputs
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 25
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • CPU: generic
  • Submitted: 2025-03-21
  • Updated: 2025-07-21
  • Resolved: 2025-06-26
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JDK 26
26 b05Fixed
Related Reports
Causes :  
JDK-8361582 - AArch64: Some ConH values cannot be replicated with SVE
Causes :  
JDK-8362594 - Aarch64: Fix JTREG test - hotspot/jtreg/compiler/vectorization/TestFloat16VectorOperations.java failure on 256-bit SVE machines
Causes :  
JDK-8361037 - [ubsan] compiler/c2/irTests/TestFloat16ScalarOperations division by 0
Duplicate :  
JDK-8352154 - Folding optimizations for Float16
Relates :  
JDK-8342103 - C2 compiler support for Float16 type and associated scalar operations
Description
Currently, we do not infer Float16-specific IR for the following source pattern.

SRC = Float16.valueOf(src[i]);
RES = Float16.max(SRC, Float16.NaN)

The reason is that the current scheme to detect Float16 operations for some of the operations is based on generic pattern matching. In the above case, the second argument gets constant folded to a Float constant, thus bypassing the existing pattern, which expects the inputs to be ConvHF2F.
Comments
Changeset: a49ecb26 Branch: master Author: Jatin Bhateja <jbhateja@openjdk.org> Date: 2025-06-26 15:42:43 +0000 URL: https://git.openjdk.org/jdk/commit/a49ecb26c5ff2f949851937f3bb036d7946a103e
26-06-2025
A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jdk/pull/24179 Date: 2025-03-23 19:16:22 +0000
11-05-2025
Here is the link to draft PR https://github.com/openjdk/jdk/pull/24179
23-03-2025