[Bug tree-optimization/56466] New: ICE in verify_loop_structure, at cfgloop.c:1629 (loop with header n not in loop tree !)

[antoine.balestrat at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56466

             Bug #: 56466
           Summary: ICE in verify_loop_structure, at cfgloop.c:1629 (loop
                    with header n not in loop tree !)
    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


Using GCC 4.8.0 as of 20130226 :

$ cat peel.c
int a, b, c;

void f(void)
{
    for(; b; b++)
    {
        if(0)
            for(; b < 0; b++)
                if(1 % 0)
                {
                    while(1)
                    {
                        a = 0;
lbl1:
                        c++;
                    }
lbl2:
                    ;
                }

        goto lbl1;
    }

    a = 0;
    goto lbl2;
}

$ xgcc -w -funroll-loops -O2 peel.c
peel.c: In function ‘f’:
peel.c:26:1: error: loop with header 6 not in loop tree
 }
 ^
peel.c:26:1: internal compiler error: in verify_loop_structure, at
cfgloop.c:1629
0x60ffb5 verify_loop_structure()
    ../../srcdir/gcc/cfgloop.c:1629
0x7f70af peel_loops_completely
    ../../srcdir/gcc/loop-unroll.c:310
0x7f70af unroll_and_peel_loops(int)
    ../../srcdir/gcc/loop-unroll.c:215
0x7eaed7 rtl_unroll_and_peel_loops
    ../../srcdir/gcc/loop-init.c:492
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