JIT: Improve strength reduction's prediction of loop reversal #104800
+200
−120
Conversation
This file contains 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
These primary IVs are not going to be removed by the downwards loop transformation, so if we do this we introduce additional primary IVs which (for now) it is the goal not to.
dotnet-issue-labeler
bot
added
the
area-CodeGen-coreclr
|
Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch |
This was referenced Jul 12, 2024
Open
jakobbotsch
changed the title
|
/azp run runtime-coreclr jitstress, runtime-coreclr libraries-jitstress |
|
Azure Pipelines successfully started running 2 pipeline(s). |
This was referenced Jul 17, 2024
|
Stress failures are #104449 and #102706. cc @dotnet/jit-contrib PTAL @AndyAyersMS Diffs with strength reduction enabled (mainly improvements because we strength reduce less...) |
AndyAyersMS
approved these changes
Jul 17, 2024
This was referenced Jul 17, 2024
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
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Outdated suggestions cannot be applied.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 current goal is to make sure strength reduction does not introduce new primary IVs. To do so we rely on the downwards-loop transformation to get rid of uses of the primary IV in the loop test.
This PR refines the checks that strength reduction was using to predict whether a use of the primary IV in a loop test will be removed. It should now be the exact same checks as the downwards-transformation uses.
Additionally, it means we can remove
CursorInfo::IsInsideExitTest; we now just avoid creating the cursor in the first place if we know the use will be removable.