https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78196
Bug ID: 78196 Summary: GCC self-test breaks native Windows builds Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: other Assignee: unassigned at gcc dot gnu.org Reporter: tamar.christina at arm dot com Target Milestone: --- The GCC self-test added in r237144 breaks the native Windows builds (e.g. mingw-w64). The test essentially does `-xc -S -c /dev/null -fself-test` `/dev/null` is then converted into the Windows null device `nul` by the MSYS shell, which is correct. But then the driver adds a filename to the name, trying to write the output to `nul.s`. `nul` is a reserved filename on Windows. As such it's invalid to create this file and the call always fails using CreateFile. This makes you unable to make native windows builds of GCC 7.