Fixed LTO issue on no discard variable#1761
Merged
Merged
Conversation
2100c61 to
675d242
Compare
LebedevRI
reviewed
Mar 5, 2024
LebedevRI
reviewed
Mar 5, 2024
LebedevRI
reviewed
Mar 5, 2024
|
|
||
| // FIXME: Verify if LTO still messes this up? | ||
| void UseCharPointer(char const volatile* const v) { | ||
| //forces compiler to issue instruction by assigning dummy value to a volatile preventing LTO |
Collaborator
There was a problem hiding this comment.
// We want to escape the pointer `v` so that the compiler can not eliminate computations
// that produced it. To do that, we escape the pointer by storing it into a volatile variable,
// since generally, volatile store, is not something the compiler is allowed to elide.
LebedevRI
approved these changes
Mar 5, 2024
LebedevRI
left a comment
Collaborator
There was a problem hiding this comment.
I think this works, at least better than the original: https://godbolt.org/z/v1493hd81
Collaborator
|
I'll merge after #1761 unbreaks the CI... |
Contributor
Author
|
Yes, I was having an issue where my code was optimized away and the benchmark::DoNotOptimize failed to prevent optimization. With this it works for my case, now my statistics are more accurate. |
Collaborator
|
@tmiguelf thank you! |
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Fixed LTO issue on no discard variable.
Tested on MSVC