On Tue, Dec 21, 2021 at 05:13:08PM +0100, Adrian Moreno via Gcc-help wrote: > On 12/21/21 17:05, Stefan Ring wrote: > >On Tue, Dec 21, 2021 at 4:40 PM Adrian Moreno via Gcc-help > ><gcc-help@xxxxxxxxxxx> wrote: > >> > >>I'd really appreciate any hint or idea to try to understand this problem. > > > >I guess the compiler doesn't like the dereferencing of uninitialized > >pointers (in the sizeof expressions). I am not 100% sure that this > >counts as dereferencing, but I would assume so. Because of this the > >compiler will be free to behave however it likes to. > > I agree that doesn't look good. Replacing them by sizeof (struct ___) > expressions does not change the behavior though. As required by C. 6.3.2.1/2: Except when it is the operand of the sizeof operator, [...], an lvalue that does not have array type is converted to the value stored in the designated object (and is no longer an lvalue); this is called lvalue conversion. There is no dereferencing. Segher
