[SYCL] Make internal device_global pointer mutable #8780
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
The implementation of device_global allows it to be const. However, for cases where the device_global is shared between programs, the value of the device_global is defined through a USM pointer inside the device_global. Since this pointer is seen as const when the device_global is const-qualified, the compiler may chose to optimize it out, potentially causing invalid accesses on device. To avoid this, this commit marks the underlying pointer member as mutable which prevents this potential optimization. Signed-off-by: Larsen, Steffen <[email protected]>
steffenlarsen
force-pushed
the
steffen/mutable_dg_ptr
branch
from
a8c70a8 to
7847203
Compare
sergey-semenov
approved these changes
Mar 27, 2023
| @@ -44,7 +44,7 @@ template <typename T, typename PropertyListT, typename = void> | |||
| class device_global_base { | |||
| protected: | |||
| using pointer_t = typename decorated_global_ptr<T>::pointer; | |||
| pointer_t usmptr{}; | |||
| mutable pointer_t usmptr{}; | |||
There was a problem hiding this comment.
I think it would be useful to have a comment here that briefly mentions why this has to be mutable.
There was a problem hiding this comment.
Good idea! It has been added.
Signed-off-by: Larsen, Steffen <[email protected]>
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Outdated suggestions cannot be applied.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.
The implementation of device_global allows it to be const. However, for cases where the device_global is shared between programs, the value of the device_global is defined through a USM pointer inside the device_global. Since this pointer is seen as const when the device_global is const-qualified, the compiler may chose to optimize it out, potentially causing invalid accesses on device. To avoid this, this commit marks the underlying pointer member as mutable which prevents this potential optimization.