[ARM64] Fix lifting of mrs xzr, ... to not reference the xzr register #7220
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
plafosse
approved these changes
Aug 5, 2025
ARM64 lifting replaces references to the zero register with constant zeroes. The zero register is not intended to appear in any lifted IL. In the case of the `mrs` instruction, the destination being a zero register means the system register is accessed only for a side-effect, and is not stored anywhere. The lifting is updated to specify no output registers for the intrinsic in that case.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
ARM64 lifting replaces references to the zero register with constant zeroes. The zero register is not intended to appear in any lifted IL.
In the case of the
mrsinstruction, the destination being a zero register means the system register is accessed only for a side-effect, and is not stored anywhere. The lifting is updated to specify no output registers for the intrinsic in that case.