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Re: [AArch64] Add precision choices for the reciprocal square root approximation
- From: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- To: Evandro Menezes <e dot menezes at samsung dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: James Greenhalgh <James dot Greenhalgh at arm dot com>, Andrew Pinski <pinskia at gmail dot com>, nd <nd at arm dot com>
- Date: Fri, 1 Apr 2016 13:47:05 +0000
- Subject: Re: [AArch64] Add precision choices for the reciprocal square root approximation
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Evandro Menezes wrote:
>
> Ping^1
I haven't seen a newer version that incorporates my feedback. To recap what
I'd like to see is a more general way to select approximations based on mode.
I don't believe that looking at the inner mode works in general, and it doesn't
make sense to add internal tune flags for all possible combinations.
To give an idea what I mean, it would be easiest to add a single field to the CPU
tuning structure that contains a mask for all the combinations. Then we call a
single function with approximation kind ie. sqrt, rsqrt, div (x/y), recip (1/x) and
mode which uses the CPU tuning field to decide whether it should be inlined.
Cheers,
Wilco