[Bug tree-optimization/61502] == comparison on "one-past" pointer gives wrong result

[ch3root at openwall dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61502

--- Comment #19 from Alexander Cherepanov <ch3root at openwall dot com> ---
(In reply to jos...@codesourcery.com from comment #3)
> Except within a larger object, I'm not aware of any reason the cases of 
> two objects following or not following each other in memory must be 
> mutually exclusive.

Apparently some folks use linker scripts to get a specific arrangement of
objects.

A fresh example is a problem in Linux -- https://lkml.org/lkml/2016/6/25/77 . A
simplified example from http://pastebin.com/4Qc6pUAA :

extern int __start[];
extern int __end[];

extern void bar(int *);

void foo()
{
    for (int *x = __start; x != __end; ++x)
        bar(x);
}

This is optimized into an infinite loop by gcc 7 at -O.