[Bug lto/50620] New: "undefined reference" errors / csmith lto testing

["markus at trippelsdorf dot de" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50620

             Bug #: 50620
           Summary: "undefined reference" errors / csmith lto testing
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: markus@trippelsdorf.de


Created attachment 25421
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25421
preprocessed testfile

I ran csmith's compiler_test.pl ( http://embed.cs.utah.edu/csmith/ ) overnight:

 % cat compiler_test
gcc -O2 -Wfatal-errors -w -flto
 % compiler_test.pl 0 compiler_test
...

This produces roughly one "crash" file every 20 minutes. All files show
linker errors of the same type e.g.:

 % gcc -O2 -Wfatal-errors -w -flto test.i
/tmp/ccYdYNxC.ltrans1.ltrans.o:ccYdYNxC.ltrans1.o:function func_1.2254: error:
undefined reference to 'g_331.2321.2276'
collect2: error: ld returned 1 exit status

Running without "-flto" or adding "-flto-partition=1to1" resolves the issue.

I've attached one preprocessed file, that was reduced with delta.