On Thu, Apr 07, 2016 at 08:31:09AM +0200, Dmitry Vyukov wrote:
> Hweight custom calling convention caused crashes with KCOV coverage.
> We had to disable instrumentation of the file.
I guess we can do something like this:
if (likely(static_cpu_has(X86_FEATURE_POPCNT)))
asm volatile(POPCNT32
: "="REG_OUT (res)
: REG_IN (w));
else
res = __sw_hweight32(w);
and get rid of the custom calling convention.
Along with some numbers showing that the change doesn't cause any
noticeable slowdown...
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284
(AG Nürnberg)
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