Re: NULL pointer arithmetic issues

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Sun, Mar 08, 2020 at 03:30:02PM +0100, Kamil Rytarowski wrote:
> NULL+x is now miscompiled by Clang/LLVM after this commit:
> 
> https://reviews.llvm.org/rL369789
> 
> This broke various programs like:
> 
> "Performing base + offset pointer arithmetic is only allowed when base
> itself is not nullptr. In other words, the compiler is assumed to allow
> that base + offset is always non-null, which an upcoming compiler
> release will do in this case. The result is that CommandStream.cpp,
> which calls this in a loop until the result is nullptr, will never
> terminate (until it runs junk data and crashes)."

As you said, using a non-zero offset. Noone here argued that using
non-zero offsets is or should be valid since that would obviously create
a pointer outside the zero-sized object.

Joerg