On Mon, 27 Apr 2026 13:00:28 GMT, Emanuel Peter <[email protected]> wrote:
>> Found while working on JDK-8369699. >> >> In general, the Vector API documentation is a bit vague around part numbers. >> There was considerable confusion around expansion/contraction: are we >> talking about logical, physical or output expansion/contraction? >> Confusingly, in some places we called expansions things that go from more to >> fewer bits, and we called contractions that went from fewer to more bits. >> >> And exception messages are not very helpful, for example they don't provide >> the legal range. >> >> @rose00 took a first stab at improving things >> (https://github.com/openjdk/jdk/pull/29306), and I eventually took over the >> project. >> >> -------------------------------------- >> >> Principles: >> - Expansion means fewer->more bits. >> - Contraction means more->fewer bits. >> - Be clear about input, logical result and output. >> - We primarily use: >> - conversion lanewise expansion (logical) >> - conversion lanewise contraction (logical) >> - conversion lanewise in-place (logical) >> - reinterpret (logical) >> - select, for truncation (output) >> - insert, for padding (output) >> - in-place, logical fits output (output) >> >> Please review this PR in this order: >> - Changes in the "Expansions, contractions, and partial results" section of >> `Vector.java`. We must first agree on the definitions here, before we go and >> disagree elsewhere ;) >> - Changes in affected methods `convertShape`, `convert`, and >> `reinterpretShape`. >> - Internal changes in `AbstractVector.java`: adjust nomenclature and >> exception message. >> - New test. I think it is necessary, I caught some mistakes I made. And when >> I wanted to add tests for `unslice` I realized that it does not throw for >> out of bounds `part`. So I think it is justified. >> >> In general, I'm a bit worried that the documentation is a bit too long, and >> feels a bit heavy/overwhelming. >> To a large degree, this is due to the complexity of part numbers. >> We could drop some paragraphs and some repetition. Let me know what you >> think is too much. >> More explanations may help make things clearer, but also risk being too much >> and overwhelming. >> I'm open to cut things down more, and any other constructive suggestions ;) >> >> ----------------------- >> >> While reading the documentation and testing for `unslice`, I found out that >> https://github.com/openjdk/jdk/pull/3804 accidentally removed the bounds >> checks for `part`. But we did not notice, because there were no tests for >> it. I'm adding the bounds check back in and adding tests ... > > Emanuel Peter 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 46 additional > commits since the last revision: > > - Merge branch 'master' into > JDK-8375631-part-number-exception-and-documentation > - fix resut->result typo for John > - after merge with master: fix fuzzer for unslice out of bounds exception > - Merge branch 'master' into > JDK-8375631-part-number-exception-and-documentation > - small update for Paul > - more for Paul > - fix reinterpret examples in table, suggested by Paul > - Apply suggestions from code review > > Co-authored-by: Paul Sandoz <[email protected]> > - fix small typo > - update and restructure resizing list > - ... and 36 more: https://git.openjdk.org/jdk/compare/0be44237...7c5d35cf Marked as reviewed by psandoz (Reviewer). ------------- PR Review: https://git.openjdk.org/jdk/pull/30113#pullrequestreview-4182449780
