[Bug tree-optimization/56035] New: ICE in verify_loop_structure, at cfgloop.c:1581 (loop n’s header does not belong directly to it !)

[antoine.balestrat at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56035

             Bug #: 56035
           Summary: ICE in verify_loop_structure, at cfgloop.c:1581 (loop
                    n’s header does not belong directly to it !)
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: antoine.balest...@gmail.com


Hi !
Using GCC 4.8.0 as of 20130118 :

$ cat bb.c
short a, c, *p;

void f(void)
{
    int b;

    if(c)
lbl1:
        for(a = 0; a < 1; a++)
        {
            for(c = 0; c < 1; c++)
            {
                goto lbl1;
                while (*p++)
lbl2:
                    ;
            }
        }

    for(;; b++)
    {
        if(c)
            goto lbl2;
lbl3:
        for(c = 0; c < 9; c++)
            for(c = -17; c < 2; c++)
                if(*p)
                    goto lbl3;
    }
}

$ xgcc -w -O1 -ftree-vectorize -fcse-follow-jumps -fstrict-overflow bb.c
bb.c: In function ‘f’:
bb.c:30:1: error: size of loop 4 should be 0, not 2
 }
 ^
bb.c:30:1: error: bb 6 do not belong to loop 4
bb.c:30:1: error: bb 5 do not belong to loop 4
bb.c:30:1: error: bb 6 has father loop 1, should be loop 4
bb.c:30:1: error: bb 5 has father loop 1, should be loop 4
bb.c:30:1: error: loop 4’s header does not belong directly to it
bb.c:30:1: internal compiler error: in verify_loop_structure, at cfgloop.c:1581
0x5f8788 verify_loop_structure()
    ../../srcdir/gcc/cfgloop.c:1581
0xcb7b2e cleanup_cfg(int)
    ../../srcdir/gcc/cfgcleanup.c:3026
0xcdf29e rest_of_handle_cse
    ../../srcdir/gcc/cse.c:7443
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