JDK-8367389 : C2 SuperWord: refactor VTransform to model the whole loop instead of just the basic block
  • Type: Sub-task
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 26
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2025-09-11
  • Updated: 2025-12-10
  • Resolved: 2025-10-08
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JDK 26
26 b19Fixed
Related Reports
Causes :  
JDK-8373453 - C2 SuperWord: assert(_inputs.at(alias_idx) == nullptr || _inputs.at(alias_idx) == load->in(1)) failed: not yet touched or the same input
Causes :  
JDK-8371603 - C2: Missing Ideal optimizations for load and store vectors on SVE
Relates :  
JDK-8366969 - C2 SuperWord: ensure that all new nodes have node notes copied
Description
We are doing this step from the parent task:

3. Model whole loop instead of only basic block (allows VTransform optimizations like moving reduction out of loop)
  - Instead of VTransformGraph::apply_memops_reordering_with_schedule that reorders the old graph,
  - I want to build the new loop body from the VTransform directly.
  - That means we are less constrained by the old shape of the loop.
Comments
Changeset: 2ac24bf1 Branch: master Author: Emanuel Peter <epeter@openjdk.org> Date: 2025-10-08 03:06:29 +0000 URL: https://git.openjdk.org/jdk/commit/2ac24bf1bac9c32704ebd72b93a75819b9404063
08-10-2025
A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jdk/pull/27208 Date: 2025-09-11 06:52:19 +0000
12-09-2025