Re: [PATCH]: x86_64: Remove unnecessary cast in prefetch()

[Serge Belyshev]

Andi Kleen <andi@xxxxxxxxxxxxxx> writes:

...
>> to make kernel work with GCC 4.3 and above.  (Also note that gcc 4.2 already
>> smart enough to break that code, but kernel is just lucky currently).
>
> How would it break the code exactly?  It more sounded like an optimization
> to me. Would it generate incorrect code without it?


See http://gcc.gnu.org/PR33294 for testcase which fails if compiled with gcc 4.2
and above.  Yes, incorrect code can be generated without the patch as demonstrated by
testcase, but i didn't analyze why kernel appears to work with 4.2 currently.
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