[MemoryBanking] Add a new field to keep track values to be erased #8039
+95
−10
Conversation
This file contains hidden or 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
cgyurgyik
reviewed
Jan 8, 2025
lib/Transforms/MemoryBanking.cpp
Outdated
| auto defaultValue = rewriter.create<arith::ConstantOp>(loc, zeroAttr); | ||
| rewriter.create<scf::YieldOp>(loc, defaultValue.getResult()); | ||
|
|
||
| if (isa<BlockArgument>(loadOp.getMemref())) |
There was a problem hiding this comment.
We add loadOp.memref() to oldMemRefVals only when the value is a BlockArgument because only the BlockArgument will remain in the cleanUpOldMemRefs function; and the values that are not BlockArgument will all gets replaced and naturally no longer exists, thus not requiring any additional clean-ups.
It probably would be good to add this as a (bit more concise) comment here. It isn't clear otherwise to someone reading the code.
cgyurgyik
approved these changes
Jan 9, 2025
…sed because they will become dangling reference if their load operations are replaced
…tement; add more comments regarding old memref values
18ea55a to
a30e274
Compare
committing them, thanks for the review! |
TaoBi22
pushed a commit
to TaoBi22/circt
that referenced
this pull request
Jul 17, 2025
…ues that need to be cleaned up after memory banking is complete (llvm#8039)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.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 patch adds a new
oldMemRefValsfield to keep track of the originalmemrefvalues that should be erased, as opposed to the old approach that derivesoldMemRefValssimply frommemoryToBanksmap:circt/lib/Transforms/MemoryBanking.cpp
Line 382 in acc5075
The issue with the original approach is that some keys in the
memoryToBanksmap might become dangling references because they are replaced:circt/lib/Transforms/MemoryBanking.cpp
Line 182 in acc5075
We add
loadOp.memref()tooldMemRefValsonly when the value is aBlockArgumentbecause only theBlockArgumentwill remain in thecleanUpOldMemRefsfunction; and the values that are notBlockArgumentwill all gets replaced and naturally no longer exists, thus not requiring any additional clean-ups.