Rewrite For loop over IList to a ranged For loop for better unrolling. #597
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Rewrite For loop over IList to a ranged For loop for better unrolling. #597
IList to a ranged For loop for better unrolling. #597Conversation
weinbe58
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Ilist to a ranged For loop for better folding. IList to a ranged For loop for better folding.
weinbe58
changed the title
IList to a ranged For loop for better folding. IList to a ranged For loop for better unrolling.
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Pull request overview
This PR adds a new ilist rewrite rule that converts scf.For loops iterating over IList into index-based loops over a range(len(...))-style iterable, enabling subsequent rewrites/passes (notably HintLen + UnrollScf) to more reliably unroll such loops.
Changes:
- Add
ilist.rewrite.ToRangeForrewrite rule to transform element-iteration into range + getitem form. - Export the new rewrite rule from
kirin.dialects.ilist.rewrite. - Add a test that composes
ToRangeFor+HintLen+ folding +UnrollScf+ getitem inlining and validates the final simplified IR shape.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| test/dialects/test_ilist.py | Adds an end-to-end test validating the new rewrite enables unrolling and getitem inlining. |
| src/kirin/dialects/ilist/rewrite/to_range_loop.py | Implements the ToRangeFor rewrite that rewrites scf.For over IList to a range-based loop with an inserted getitem. |
| src/kirin/dialects/ilist/rewrite/init.py | Exports ToRangeFor from the ilist rewrite package. |
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Roger-luo
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…ng. (#597) In this PR I implement a rewrite that effectively rewrites: ```python for ele in ilist_value: ... ``` to ```python for i in range(len(ilist_value)): ele = ilist_value[i] ... ``` which is equivalent in terms of execution but is easier to massage into a state that can be unrolled by combining this rewrite with `HintLen` rewrite rule effectively allowing the `iterable` argument of the new `scf.For` statement to be known at compile time even if `ilist_value` is not a constant. The reason I think we should have this rule instead of implementing a specialization in the unroll of the for loop is that this rewrite is independent of the unroll rewrite and so you do not need to worry about a dependency between the unroll rule and the `ilist` dialect. --------- Co-authored-by: Xiu-zhe (Roger) Luo <rluo@quera.com> Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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In this PR I implement a rewrite that effectively rewrites:
to
which is equivalent in terms of execution but is easier to massage into a state that can be unrolled by combining this rewrite with
HintLenrewrite rule effectively allowing theiterableargument of the newscf.Forstatement to be known at compile time even ifilist_valueis not a constant.The reason I think we should have this rule instead of implementing a specialization in the unroll of the for loop is that this rewrite is independent of the unroll rewrite and so you do not need to worry about a dependency between the unroll rule and the
ilistdialect.