Version: 2.7.4 (and any prior 2.7-version. not tested with 3.x)
Compiler: VS 2008 Professional

If I compile Python using the batch 

> PCbuild\build_pgo.bat -2

Visual Studio fails to correctly collect profile information for the project "python27.dll". As a result, no real optimisation takes place.

The command "build_pgo.bat -2" runs the full test suite (..\lib\test\regrtest.py) to collect profile data. Experiments show, that several test cases (i.e. test_os and test_subprocess) break the collection of profile data. Probably the failure is related to the creation of sub-processes. I consider it a Visual Studio bug.

To work around this issue I created a list of good test cases and patched build_pgo.bat to run only the tests from this list.