RFR: 8350896: Integer/Long.compress gets wrong type from CompressBitsNode::Value [v2]

Jatin Bhateja jbhateja at openjdk.org
Wed Apr 2 07:39:02 UTC 2025


> Hi All,
> 
> This bugfix patch fixes incorrect value computation for Integer/Long. compress APIs.
> 
> Problems occur with a constant input and variable mask where the input's value is equal to the lower bound of the mask value., In this case, an erroneous value range estimation results in a constant value. Existing value routine first attempts to constant fold the compression operation if both input and compression mask are constant values; otherwise, it attempts to constrain the value range of result based on the upper and lower bounds of mask type.
> 
> New IR test covers the issue reported in the bug report along with a case for value range based logic pruning.
> 
> Kindly review and share your feedback.
> 
> Best Regards,
> Jatin

Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:

  Review comments resolutions

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/23947/files
  - new: https://git.openjdk.org/jdk/pull/23947/files/ee67ee22..ae48895b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23947&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23947&range=00-01

  Stats: 189 lines in 2 files changed: 160 ins; 4 del; 25 mod
  Patch: https://git.openjdk.org/jdk/pull/23947.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23947/head:pull/23947

PR: https://git.openjdk.org/jdk/pull/23947


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