[release/5.0] Fix an over-constrained use of a byte reg #41642
Merged
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
![github-actions[bot]](https://avatars.githubusercontent.com/in/15368?s=60&v=4){kind=small}
Dotnet-GitSync-Bot
added
the
area-CodeGen-coreclr
sandreenko
approved these changes
Sep 1, 2020
ghost
locked as resolved and limited conversation to collaborators
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Outdated suggestions cannot be applied.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.
Backport of #41004 to release/5.0
/cc @CarolEidt
Customer Impact
This is a rare case, introduced by new struct copy code that has 4 incoming source registers and requires a byteable temp register for the odd byte-count case. It was found in stress testing, but if it occurs it is a silent bad codegen bug.
Testing
Caught by outerloop stress testing. Backporting this fix will support clean outerloop testing in this branch.
Risk
The fix is low risk, and narrowly targeted.