------- Comment #10 from dada1 at cosmosbay dot com 2007-09-20 08:17 ------- > > What happens is that ivopts decide to use val as the variable to use in the > exit compare; they compute what its final value will be (67305984), and > replace > the exit test by val != 67305984. > > There is not much I can do with that in ivopts. I could make ivopts avoid > preserving signed variables appearing in the source code that provably > overflow; but I do not think we want to introduce this kind of hacks to handle > code with undefined behavior. >
This code is valid. Integer overflows of a counter may happen in any program. i = 0x7fffffff, i += 1; /* IS VALID */ /* Here, gcc-4.1.2 can emit some infinite loop because programmer is lazy ! */ At very least, gcc should emit a BIG WARNING or ERROR The integer overflow is not a excuse for a compiler to generate an infinite loop. int i; int some_int = 0; for (i = 0 ; i < 100 ; i++) { some_func(some_int); some_int += 0x40000000; /* yes, it can 'overflow'... big deal */ } Are you telling me that *any* integer overflow allows a compiler to generate a buggy code without any notice ? Interesting. -- dada1 at cosmosbay dot com changed: What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |REOPENED Resolution|INVALID | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33498