[Bug bootstrap/78817] stage2 bootstrap failure in vec.h:1613:5: error: argument 1 null where non-null expected after r243661

["jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78817

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Note, users that want this to be diagnosed reliably already can use
-fsanitize={returns-,}nonnull-attribute
So I think it is better to warn only about the obvious cases with very low
false positive rate, and leave the rest to the runtime.  Because there is
really nothing wrong on the testcases from profiledbootstrap (which is meant to
be supported without --disable-werror), and more importantly it is hard to
figure out what actually might be wrong and how to work around the false
positives.
The
        PR bootstrap/78817
        * vec.h (vec<T, A, vl_embed>::quick_grow_cleared): Assert
postcondition.
        ( vec<T, va_heap, vl_ptr>::safe_grow_cleared): Ditto.           
patch looks like alchemy, slows things actually down (and will not help with
--disable-checking anyway).