Andro Nuxx <gitinit...@gmail.com> added the comment:
Py_MEMCPY() has a special case for small blocks on Windows to work around an
ancient performance issue in MSVC. Can we safely assume that recent MSVC
properly optimize memcpy()? See #28055
/* Py_MEMCPY can be used instead of memcpy in cases where the copied blocks
* are often very short. While most platforms have highly optimized code for
* large transfers, the setup costs for memcpy are often quite high. MEMCPY
* solves this by doing short copies "in line".
*/
#if defined(_MSC_VER)
#define Py_MEMCPY(target, source, length) do { \
size_t i_, n_ = (length); \
char *t_ = (void*) (target); \
const char *s_ = (void*) (source); \
if (n_ >= 16) \
memcpy(t_, s_, n_); \
else \
for (i_ = 0; i_ < n_; i_++) \
t_[i_] = s_[i_]; \
} while (0)
#else
#define Py_MEMCPY memcpy
#endif
----------
nosy: +gitinit...@gmail.com
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Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue28126>
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