C++: Remove big-step relation in flow-through code #3857
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This relation was originally introduced to improve performance but may no longer be necessary. The `localFlowStepPlus` predicate had an explosion of tuples on oneapi-src/oneDNN for C++.
In this non-linear recursion, a `#prev` relation was joined earlier than the `#prev_delta` relation. As a result, each iteration of the predicate processes every tuple from previous iterations. This quadratic behavior caused severe slowdowns on oneapi-src/oneDNN.
Contributor
Author
aschackmull
approved these changes
Jul 1, 2020
Contributor
Author
hvitved
approved these changes
Jul 1, 2020
Contributor
Contributor
|
Java as well, those two results can for some reason not be matched, so they show up as removed and re-introduced in every single Java-Differences. |
max-schaefer
pushed a commit
to max-schaefer/codeql-go
that referenced
this pull request
Jul 1, 2020
max-schaefer
pushed a commit
to max-schaefer/codeql-go
that referenced
this pull request
Jul 2, 2020
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The first commit makes it feasible to run C++ IR data-flow queries on oneapi-src/oneDNN, and the second makes it fast.
The second commit works around a join order problem that I've reported as https://github.com/github/codeql-coreql-team/issues/453.
I'll take this PR out of draft mode if *-Differences show no performance regressions.