-
Notifications
You must be signed in to change notification settings - Fork 5.3k
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Improve copy-propagation and DCE for memory operations #4592
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
I just want to say I really appreciate having a table detailing the size improvements. 👍 |
IGI-111
previously approved these changes
May 31, 2023
tritao
previously approved these changes
May 31, 2023
IGI-111
approved these changes
May 31, 2023
tritao
approved these changes
May 31, 2023
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Outdated suggestions cannot be applied.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.
Description
This PR adds a new copy-propagation for memory operations and also enhances the DCE pass to eliminate dead stores and
memcpy
s.Closes #4345. This doesn't do a full data-flow analysis for the function as mentioned in the Issue description (that would be quite compile-time heavy). Instead it tracks data-flow (available
memcpy
s per block and optimizes when safe).This does not remove the existing ad-hoc copy-propagation for memory operations (which is now called
local_copy_prop_prememcpy
) yet. More testing and benchmarking needs to be done before that is removed.This PR introduces an escaped symbols analysis pass (also used by DCE now) to figure out symbols (locals / args) that escape out of our purview, and hence deemed unsafe to touch for any optimization.
Code size reduction with this PR is tabulated below. (note that the gtf intrinsic test code size has increased, that's because the test itself has been modified to ensure that code isn't DCE'd).
Table
Checklist
Breaking*
orNew Feature
labels where relevant.