Make specialization of x64 zend_safe_address() for nmemb==1 #19203
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There are typically 3 forms of calls to this function: 1. nmemb>1, offset=0||size=0 2. nmemb=1, size>0, offset>0 3. nmemb>1, size>0, offset>0 This specializes the second form.
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iluuu1994
approved these changes
Jul 21, 2025
| "adc $0,%1" | ||
| : "+r"(res), "+r" (m_overflow) | ||
| : "rm"(offset) | ||
| : "cc"); |
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Do we not need this clobber hint for the other branches?
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This also surprised me, I think we actually do need it. I don't know why it isn't there.
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Might make sense to backport that part.
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There are typically 3 forms of calls to this function:
This specializes the second form: it avoids the multiplication.
For clang, which has trouble with the
rmconstraint, it also avoids some spills in some cases.