http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52996

             Bug #: 52996
           Summary: ice in verify_loop_structure, at cfgloop.c:1567
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: reg...@cs.utah.edu
                CC: cheny...@cs.utah.edu


[regehr@dyson r33]$ current-gcc -O3 -c small.c
small.c: In function 'fn1':
small.c:29:1: error: edge from 18 to 19 should be marked irreducible
 }
 ^
small.c:29:1: error: basic block 19 should be marked irreducible
 }
 ^
small.c:29:1: error: edge from 19 to 11 should be marked irreducible
 }
 ^
small.c:29:1: internal compiler error: in verify_loop_structure, at
cfgloop.c:1567
 }
 ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


[regehr@dyson r33]$ cat small.c
int a, b, c, d, e, f;
void
fn1 ()
{
    int g, h;
lbl_173:
    if (a)
        c++;
lbl_158:
    e = 0;
    h = 0;
    for (; h > -8; h--)
    {
        g = 0;
        for (; g <= 0; g += 1)
        {
            d = 1;
            for (; d >= 0; d -= 1)
                a = 1;
            if (b)
                break;
            if (f)
                return;
            if (h)
                goto lbl_158;
        }
    }
    goto lbl_173;
}


[regehr@dyson r33]$ current-gcc -v
Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/uusoc/exports/scratch/regehr/z/compiler-install/gcc-r186455-install/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.8.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --with-libelf=/usr/local --enable-lto
--prefix=/home/regehr/z/compiler-install/gcc-r186455-install
--program-prefix=r186455- --enable-languages=c,c++
Thread model: posix
gcc version 4.8.0 20120414 (experimental) (GCC)

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