[ControlOverlay] Introduce dma_placeholder to preserve connection ops from Dead-Code Elimination
#1111
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
Yu-Zhewen
changed the title
dma_placeholder to preserve connection operation from Dead-Code Eliminationdma_placeholder to preserve connection ops from Dead-Code Elimination
Yu-Zhewen
changed the title
dma_placeholder to preserve connection ops from Dead-Code Eliminationdma_placeholder to preserve connection ops from Dead-Code Elimination
Yu-Zhewen
changed the title
dma_placeholder to preserve connection ops from Dead-Code Eliminationdma_placeholder to preserve connection ops from Dead-Code Elimination
Yu-Zhewen
requested review from
MaheshRavishankar,
nirvedhmeshram,
yzhang93,
Abhishek-Varma and
jtuyls
as code owners
jtuyls
approved these changes
Feb 16, 2025
Comment on lines
607
to
609
| if (failed(isCtrlFlow)) | ||
| return connectionOp.emitOpError() | ||
| << "could not determine if flow is control"; |
There was a problem hiding this comment.
Suggested change
| if (failed(isCtrlFlow)) | |
| return connectionOp.emitOpError() | |
| << "could not determine if flow is control"; | |
| if (failed(isCtrlFlow)) { | |
| return connectionOp.emitOpError() | |
| << "could not determine if flow is control"; | |
| } |
Comment on lines
592
to
594
| This operation acts as a placeholder user for those `amdaie.connection` operations | ||
| that represent control flows, to prevent them from being dead-code eliminated. | ||
| This operation does not have any side effects on control code size. |
There was a problem hiding this comment.
I would write this a bit more generally as there could be potential other uses for this placeholder in the future.
Suggested change
| This operation acts as a placeholder user for those `amdaie.connection` operations | |
| that represent control flows, to prevent them from being dead-code eliminated. | |
| This operation does not have any side effects on control code size. | |
| This operation acts as a placeholder user for `amdaie.connection` operations to prevent | |
| them from being dead-code eliminated. This is used for control flow connections that are | |
| inserted before control packets are generated because they need to be taken into account | |
| together with data connections for routing. This operation does not have any side effects | |
| on control code size. |
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.
Following the discussion in #1063,
connectionops generated for the control overlay do not initially have DMA users, as these are only added later when the content of control packets is determined. However, sinceconnectionops are marked as pure in the IR, they can be wrongly eliminated by CSE and Canonicalization if they have no users at that stage.