Re: use ARM intrinsics in pg_lfind32() where available

On Mon, Aug 29, 2022 at 3:19 PM John Naylor
<john(dot)naylor(at)enterprisedb(dot)com> wrote:
>
> It turns out MSVC animal drongo doesn't like this cast -- on x86 they
> are the same underlying type. Will look into that as more results come
> in.

Here's the simplest fix I can think of:

/*
* Exactly like vector8_is_highbit_set except for the input type, so
it still looks
* at each _byte_ separately.
*
* XXX x86 uses the same underlying type for vectors with 8-bit,
16-bit, and 32-bit
* integer elements, but Arm does not, hence the need for a separate function.
* We could instead adopt the behavior of Arm's vmaxvq_u32(), i.e. check each
* 32-bit element, but that would require an additional mask operation on x86.
*/
static inline bool
vector32_is_highbit_set(const Vector32 v)
{
#if defined(USE_NEON)
return vector8_is_highbit_set((Vector8) v);
#else
return vector8_is_highbit_set(v);
#endif
}

--
John Naylor
EDB: http://www.enterprisedb.com