[Bug middle-end/56231] warning traces have bogus line information when using LTO

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56231

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-02-07 13:54:20 UTC ---
To clarify, we are also switching between different translation-units main
filenames - but I don't think we can easily distinguish this from #includes.
Well, maybe we can, if at compile-time we can identify the "main" source
via libcpp.