Fix negative shift left reported by UBSan#757
Merged
mayeut merged 1 commit intouclouvain:masterfrom Apr 26, 2016
Merged
Conversation
This shall have no performance impact on 2’s complement machine where the compiler replaces the multiplication by power of two (constant) by a left shift. Verified at least on MacOS Xcode 7.3, same assembly generated after fix.
mayeut
added a commit
to mayeut/openjpeg
that referenced
this pull request
Apr 27, 2016
Follow-up of uclouvain#757 This shall have no performance impact on 2’s complement machine where the compiler replaces the multiplication by power of two (constant) by a left shift. Verified at least on MacOS Xcode 7.3, same assembly generated after fix.
mayeut
added a commit
that referenced
this pull request
Apr 27, 2016
Follow-up of #757 This shall have no performance impact on 2’s complement machine where the compiler replaces the multiplication by power of two (constant) by a left shift. Verified at least on MacOS Xcode 7.3, same assembly generated after fix.
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
As @boxerab said, this shall have no performance impact on 2’s complement machine where
the compiler generates a left shift instruction for the signed multiplication by a positive constant power of two.
Verified at least on MacOS Xcode 7.3, same assembly generated after fix.
Update #718