http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56463
--- Comment #5 from Cristóbal Camarero <nakacristo at hotmail dot com> 2013-02-27 08:19:04 UTC --- Dominique, I think the test I found is more problematic than yours. Since in mine, the huge value is completely independent of the ending condition. Hence most people would expect the loop to end without care of what happens to the accumulator variable 'a'. Exploring the intermediate steps of my test (with gcc test.c -O2 -fdump-tree-all) I see that in test.c.119t.ivopts the condition of the loop is changed from 'ivtmp.8_3 != 0' to 'a_25 != 1267128320', which would be correct considering overflow. From here the situation must be similar to Dominique's examples. In test.c.123t.vrp2 we see that the Value Range Propagation has decided that the ending condition never happens, probably because the ranges have no modular considerations. The ending condition and the printf are eliminated. In a later stage the infinite loop is substituted by an empty infinite loop. I suppose that this is not technically a bug. However, the lack of warning IS a bug. And a coherent behaviour would still being a good enhancement.
