Fix #79595: zend_init_fpu() alters FPU precision #5621
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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. |
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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.