[FIRRTL] Improve Layer Merge Performance #7552
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
|
To me it might be a bit more natural to do this as a backwards walk and shift everything downward into the first found block, slightly because you never violate the use before def when modifying the code |
I switched to this. Interestingly, this still uses Algorithm is much cleaner now. Nice suggestion. |
Fix a performance issue in the `LayerMerge` pass. Apparently, repeated use of `inlineBlockBefore` with a forward walk can be a performance issue. Fix this, by reversing the iteration order. h/t @youngar for algorithmic suggestions. Fixes #7551. Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>
Superficial cleanup of LayerMerge to make the variable names make more sense. Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>
seldridge
force-pushed
the
dev/seldridge/issue-7551-layer-merge
branch
from
55b3706
to
66122eb
Compare
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Outdated suggestions cannot be applied.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.
Fix a performance issue in the
LayerMergepass [1]. Apparently, repeated use ofinlineBlockBeforecan be a performance issue. Fix this, by usingmergeBlockswhich will append at the end of a block as opposed to prepend. This requires an additional move, however, this empirically doesn't matter.For details of the algorithm, see the updated comments in the pass.
h/t @youngar for algorithmic suggestions.