[Python-Dev] mingw32 and gc-header weirdness

[Neil Hodgson]

Martin v. Löwis:

> Yes: alignof(PyGC_HEAD) would be specified as being the maximum
> alignment on a platform; sizeof(PyGC_HEAD) would be frozen.

   Maximum alignment currently on x86 is 16 bytes for SSE vector
types. Next year AVX will add 32 byte types and while they are
supposed to work OK with 16 byte alignment, performance will be better
with 32 byte alignment.

   It is possible that some use could be found for vector instructions
in core Python but it is more likely that they will only be used in
specialized extensions that can take care of alignment issues for
their own cases.

http://en.wikipedia.org/wiki/Advanced_Vector_Extensions
http://software.intel.com/en-us/forums/intel-avx-and-cpu-instructions/topic/61891/

   Neil