Fix #79595: zend_init_fpu() alters FPU precision #5621
Closed
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
On startup, PHP deliberately changes the floating point control word to enforce binary64 format for the calculations for best consistency across platforms. However, this is unnessary for x86_64 architectures, because in this case SSE instructions are used by default, and there is no good reason to pass `-mfpmath=i387` or such. Therefore, we can skip the modification, which has the benefit that system libraries are free to work in the mode of their liking.
nikic
approved these changes
May 26, 2020
|
Thanks! Applied as 879004d. |
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Outdated suggestions cannot be applied.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.
On startup, PHP deliberately changes the floating point control word to
enforce binary64 format for the calculations for best consistency
across platforms. However, this is unnessary for x86_64 architectures,
because in this case SSE instructions are used by default, and there is
no good reason to pass
-mfpmath=i387or such.Therefore, we can skip the modification, which has the benefit that
system libraries are free to work in the mode of their liking.
This is supposed to supersede PR #5602. I've targeted master to have the i386 tests running.