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From: "dhazeghi at yahoo dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/56448] New: cc1 hangs on volatile array with -O or above
Date: Mon, 25 Feb 2013 21:11:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56448

             Bug #: 56448
           Summary: cc1 hangs on volatile array with -O or above
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: dhazeghi@yahoo.com


The following snippet (reduced from a larger test case) causes top-of-trunk cc1
to hang (infinite loop) on x86_64-linux using -O or above.  This is a
regression from 4.7.2 which does not have this issue.

$ cat volatile.c
volatile int a[1];
int b;
void fn1 ()
{
    for (;;)
    {
        int *c[3][6] =
        { 0, 0, 0, &b, 0, 0, 0, 0, &b, 0, 0, 0, 0, 0, 0, 0, &b, (int *)&a[0] };
        b = *c[2][5];
    }
}
$ gcc-trunk --version
gcc-trunk (GCC) 4.8.0 20130225 (experimental) [trunk revision 196255]
$ gcc-4.7 -O -c volatile.c
$ gcc-trunk -c volatile.c
$ gcc-trunk -O -c volatile.c
<hangs>