On Monday 2009-08-10 10:54, Patrick McHardy wrote:
>Jan Engelhardt wrote:
>> The use of memcmp should enable architecture-preferred comparison
>> methods, for example 64-bit comparisons that would complete in [more
>> than] half the time than inspecting just each u32/char.
>
>I don't object to the change as cleanup, but that reasoning makes
>no sense. memcmp can't assume alignment,
Right, memcmp itself cannot, and there is usually a prealignment check
in libcs that clears a few bytes and advances the pointer until it is
aligned.
>so unless there's a
>version checking for compile-time known alignment, this won't happen.
static void func(int r)
{
static int q = 1234;
memcmp(&q, &r, sizeof(q));
}
There is GCC's __builtin_memcmp, which should generally have
knowledge about alignment. q and r are known here.
>Please fix up the changelog and label this as cleanup.
Will do.
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