[issue45116] Performance regression 3.10b1 and later on Windows

[neonene]

neonene <nicesalmon at gmail.com> added the comment:

According to:
https://docs.microsoft.com/en-us/cpp/build/profile-guided-optimizations?view=msvc-160

PGO seems to override /Ob3.
Around this issue, I posted benchmark on issue44381.
On python building, /Ob3 works for only non-pgo-supported dlls like,

_ctypes_test
_freeze_importlib
_msi
_testbuffer
_testcapi
_testconsole
_testembed
_testimportmultiple
_testinternalcapi
_testmultiphase
_uuid
liblzma
pylauncher
pyshellext
pywlauncher
sqlite3
venvlauncher
venvwlauncher
winsound

I use this option in _msvccompiler.py for my pyd.
I will try and report when PGO with /Ob3 makes difference in the log.

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue45116>
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