[Bug middle-end/115570] array subscript 'long unsigned int[0]' is partly outside array bounds of 'unsigned char[4]'

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115570

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |INVALID
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The warning is correct.
sizeof(long) on x86_64 is 8 rather than 4 that it was on i686.
So when you do this:

    unsigned char cValue[4];
    unsigned long *value = 0;
    value = (unsigned long *)cValue;

*value & 0xffffffff

You get undefined behavior because you are reading 8 bytes from a 4 byte array.