[layout] Pack slot indexes before register allocation#62
Merged
Conversation
Applies: llvm#66334 llvm#67038 Packing the slot indexes before register allocation is useful for us because it evens the gaps between slots after all the optimization passes that happen before `greedy` and may have removed a different number of instructions between AArch64 and X86. This leads to different slot gaps and, hence, slightly different regalloc in some cases. We backport the above patches for our LLVM, with the main difference being the absence of some convenient data structure iterators, which we had to convert to be compatible with our ADT infrastructure. We add the `-pack-indexes` flag to activate this. Addressses: systems-nuts/unifico#291
|
Would you care to comment on the upstream PR? Not too many people have taken an interest in it. Thanks. |
Owner
Author
|
@jayfoad Sure, I'll try to have a look today! |
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
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Applies LLVM patches/PRs:
66334
67038
Packing the slot indexes before register allocation is useful for us because it evens the gaps between slots after all the optimization passes that happen before
greedyand may have removed a different number of instructions between AArch64 and X86. This leads to different slot gaps and, hence, slightly different regalloc in some cases.We backport the above patches for our LLVM, with the main difference being the absence of some convenient data structure iterators, which we had to convert to be compatible with our ADT infrastructure.
We add the
-pack-indexesflag to activate this.Addressses: systems-nuts/unifico#291