Re: [PATCH] Fix do_div() for all architectures

[Dale Johannesen]

On Thursday, July 10, 2003, at 12:31  PM, Bernardo Innocenti wrote:
>
>  The compiler could easily tell what memory can be clobbered by a 
> pointer
> by applying type-based aliasing rules. For example, a function taking a
> "char *" can't clobber memory objects declared as "long bar" or
> "struct foo".

No, for two reasons.  First, anything can be aliased by a char.  Second,
the restriction is on the type of the eventual memory reference,
not on the type of the pointer.  Assuming an int* p, you can still do 
*((char*)p) and
that may alias anything.  So you must check each dereference; this 
can't be
done easily at function entry.