[Bug rtl-optimization/56181] New: ICE in verify_loop_structure, at cfgloop.c:1581 with -ftracer

[antoine.balestrat at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56181

             Bug #: 56181
           Summary: ICE in verify_loop_structure, at cfgloop.c:1581 with
                    -ftracer
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: antoine.balestrat@gmail.com


Using GCC 4.8.0 as of 20130202 :

$ cat loop.c
int a, b;

void f(void)
{
    if(a++)
    {
        for(a = 0; a < 1;)
        {
            for(b = 0; b < 1; b++)
            {
                while(a++ < 0);
lbl:
                ;
            }

            if(a)
                goto lbl;
        }

        goto lbl;
    }
}

$ xgcc -w -O2 -ftracer loop.c
loop.c: In function ‘f’:
loop.c:3:6: error: size of loop 3 should be 0, not 3
 void f(void)
      ^
loop.c:3:6: error: bb 8 does not belong to loop 3
loop.c:3:6: error: bb 10 does not belong to loop 3
loop.c:3:6: error: bb 9 does not belong to loop 3
loop.c:3:6: error: bb 8 has father loop 2, should be loop 3
loop.c:3:6: error: bb 10 has father loop 2, should be loop 3
loop.c:3:6: error: bb 9 has father loop 2, should be loop 3
loop.c:3:6: error: loop 3’s header does not belong directly to it
loop.c:3:6: internal compiler error: in verify_loop_structure, at
cfgloop.c:1581
0x5f8564 verify_loop_structure()
    ../../srcdir/gcc/cfgloop.c:1581
0x8defcd tracer
    ../../srcdir/gcc/tracer.c:385
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

It looks like PR55270, and after bisection, it appears that it started with
http://gcc.gnu.org/viewcvs?view=revision&revision=185913 too.