Since #130398, the below warning is emitted several times in case of MSVC release (or PGO) builds:

Include\internal\pycore_ceval.h(209): warning C4172: returning address of local variable or temporary : here

So the comment in the code

and then is "smart" enough to realize and warn about it.

See here https://godbolt.org/z/ooK5Poxo3 (btw gcc or clang won't do that https://godbolt.org/z/459f6hj9G).

__declspec(noinline) would help, but IMHO is an unneeded performance penalty.

I suggest to use #pragma warning(disable:4172) to silence the warning.
Since this is a code generation warning (4700-4999), we have to guard the whole
_Py_get_machine_stack_pointer and cannot just place it around line 209.

@colesbury had a much better idea: use _AddressOfReturnAddress which even gets rid of UB: see https://godbolt.org/z/7c9Gq9jzM and https://github.com/llvm/llvm-project/blob/llvmorg-10.0.0-rc1/clang/lib/Basic/Stack.cpp#L24.

Linked PRs

• GH-131288: use _AddressOfReturnAddress in _Py_get_machine_stack_pointer to silence MSVC warning in pycore_ceval.h for release builds #131289