Re: [PATCH] lib: Avoid redundant sizeof checking in __bitmap_weight() calculation.

From: Rakib Mullick
Date: Tue Nov 14 2017 - 03:59:18 EST


On Tue, Nov 14, 2017 at 1:23 PM, Rasmus Villemoes
<linux@xxxxxxxxxxxxxxxxxx> wrote:
>
> hint: sizeof() very rarely evaluates to zero... So this is the same as
> "is32 = 1". So the patch as-is is broken (and may explain the 1-byte
> delta in vmlinux). But even if this condition is fixed, the patch
> doesn't change anything, since the sizeof() evaluation is done at
> compile-time, regardless of whether it happens inside the inlined
> hweight_long or outside. So it is certainly not worth it to duplicate
> the loop.
>
Right, no need to duplicate the loop. Checking the objdump output, it
didn't changed anything at all. Fixed condition nullifies the vmlinux
size advantage also. Drop it.

Thanks,
Rakib.