[Bug tree-optimization/49218] New: Incorrect optimization of a 'for' loop creates an infinite loop

[personal@e-maxx.ru]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49218

           Summary: Incorrect optimization of a 'for' loop creates an
                    infinite loop
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: personal@e-maxx.ru


Created attachment 24388
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24388
The program reads a number, and then it should output it back. After incorrect
optimization, however, the program hangs up

The following small program hangs up if compiled under gcc 4.6 with -O2.

The program reads a number (it can be any number, '5' for example), and then it
performs some silly for-loop, and then it should output the same number.

In gcc 4.6 with -O2, however, the program hangs up without outputting anything.
It looks like the loop (which can be doing less that 10 operations in reality)
is 'optimized' into an infinite loop.