http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54645
--- Comment #1 from Bernd Schmidt <bernds at gcc dot gnu.org> 2012-09-20 19:19:05 UTC --- gcc.dg/pch and g++.dg/pch just completed here without problems. I don't see how a scheduler patch could cause primarily PCH failures. Can you check your bisection, and can you run tests with stage1 to see if you have a later miscompilation of the compiler? It would help to include sample excess error messages in a bug report if there are failures of that type.