PR for llvm/llvm-project#64589 #580
Merged
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
(cherry picked from commit 59d558a)
D141386 changed the semantics of !range metadata to return poison on violation. If !range is combined with !noundef, violation is immediate UB instead, matching the old semantics. In theory, these IR semantics should also carry over into SDAG. In practice, DAGCombine has at least one key transform that is invalid in the presence of poison, namely the conversion of logical and/or to bitwise and/or (https://github.com/llvm/llvm-project/blob/c7b537bf0923df05254f9fa4722b298eb8f4790d/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp#L11252). Ideally, we would fix this transform, but this will require substantial work to avoid codegen regressions. In the meantime, avoid transferring !range metadata without !noundef, effectively restoring the old !range metadata semantics on the SDAG layer. Fixes llvm/llvm-project#64589. Differential Revision: https://reviews.llvm.org/D157685 (cherry picked from commit 9deee6b)
|
@arsenm What do you think about merging this PR to the release branch? |
|
ping @arsenm |
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Outdated suggestions cannot be applied.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.
resolves llvm/llvm-project#64589