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


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.



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