Free-threaded builds with PGO fail to build on Windows

[mdboom]

Bug report

Bug description:

I don't consider this a high-priority bug, since free threading remains experimental, however it does prevent us from getting accurate benchmarking figures for free-threaded builds on Windows.

Building with

PCbuild\build.bat --pgo   --disable-gil -c Release

currently fails with an internal compiler error:

C:\actions-runner\_work\benchmarking\benchmarking\cpython\Python\ceval.c(761): fatal error C1001: Internal compiler error. [C:\actions-runner\_work\benchmarking\benchmarking\cpython\PCbuild\pythoncore.vcxproj]
(compiler file 'D:\a\_work\1\s\src\vctools\Compiler\Utc\src\p2\main.c', line 224)
    To work around this problem, try simplifying or changing the program near the locations listed above.
   If possible please provide a repro here: https://developercommunity.visualstudio.com 
   Please choose the Technical Support command on the Visual C++ 
    Help menu, or open the Technical Support help file for more information
     link!InvokeCompilerPass()+0x10e636
     link!InvokeCompilerPass()+0x10e636
     link!InvokeCompilerPass()+0x10e373
     link!InvokeCompilerPass()+0x10b310
     link!InvokeCompilerPass()+0x10b215
     link!InvokeCompilerPass()+0x102cea

Full build log here

CPython versions tested on:

CPython main branch

Operating systems tested on:

Windows

Linked PRs

• gh-123153: Fix PGO builds with free-threading on Windows #125607

[colesbury]

Given that it's an Internal compiler error, maybe worth reporting the bug to Visual Studio?

[mdboom]

Given that it's an Internal compiler error, maybe worth reporting the bug to Visual Studio?

Sorry, I should have said so, but I plan to.