[PATCH] Define 3-argument overloads of std::hypot for C++17 (P0030R1)

[Jonathan Wakely]

On 29/09/16 14:37 +0100, Andre Vieira (lists) wrote:
>Hi Jonathan,
>
>On 27/09/16 16:11, Jonathan Wakely wrote:
>>
>> The test might not be very good, but tests some small integer values
>> and some other values where accuracy is lost for one or other of the
>> alternative implementations mentioned above. If this FAILs for some
>> 32-bit targets we might need to adjust the tolerances or the
>> dg-options.
>
>On arm-none-eabi I'm seeing a failure for the long double type and inputs:
>{ 1e-2l, 1e-4l, 1e-4l, 0.010000999950004999375l }
>
>The abs(frac) is higher than the toler: 1.73455e-16 vs 1e-16. Is that a
>reasonable difference? Should we raise toler3 to 1e-15?
>
>The last line is also too high:
>  { 2147483647.l, 2147483647.l, 2147483647.l, 3719550785.027307813987l }
>Yields a frac of: 1.28198e-16
>
>Those are the only ones that pass the 1e-16 threshold.

Yes, it makes sense to raise it, although Ed's reworking the code and
tests anyway.