[mypyc] Provide an easier way to define IR-to-IR transforms #16998
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Outdated suggestions cannot be applied.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.
This makes it easy to define simple IR-to-IR transforms by subclassing
IRTansform
and overriding some visit methods.Add an implementation of a simple copy propagation optimization as an example.
This will be used by the implementation of mypyc/mypyc#854, and this can also be used for various optimizations.
The IR transform preserves the identities of ops that are not modified. This means that the old IR is no longer valid after the transform, but the transform can be fast since we don't need to allocate many objects if only a small subset of ops will be modified by a transform.