[Custom Descriptors] CFP: Fix nullable descriptors #7928
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
tlively
reviewed
Sep 26, 2025
| ;; function result is non-nullable. | ||
| (ref.get_desc $A | ||
| (struct.new_default $A | ||
| (ref.null none) |
There was a problem hiding this comment.
We could do even better in this case by ignoring null writes to the descriptor in the first place. Then if there is another location that writes a real value, we can still optimize all the reads to return the real value.
However, we'll still need the current code to fix up the case where the single written value is a nullable global, but the output of the ref.get_cast is required to be non-null.
There was a problem hiding this comment.
Makes sense, I added a TODO
tlively
approved these changes
Sep 26, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 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Outdated suggestions cannot be applied.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.
We can write a null (it would trap, but it looks like a write in the opt), but
cannot read a null, so we must cast.