RFR(S) 8029302: Performance regression in Math.pow intrinsic
David Chase
david.r.chase at oracle.com
Thu Apr 17 17:21:34 UTC 2014
As long as we are doing this as a constant-driven transform in the compiler,
it might not hurt to also consider the case of x**3. Cubes are common enough.
David
On 2014-04-17, at 11:45 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
> Niclas,
>
> Looking on __ieee754_pow() in sharedRuntimeTrans.cpp and it has other simple cases:
>
> x**0 = 1
> x**1 = x
> x**-1 = 1/x
> x**0.5 = sqrt(x)
>
> It would be nice to know which are frequently used and implement them too.
>
> Also there is check for NaN before all this cases except x**0 = 1:
>
> /* +-NaN return x+y */
>
> You need to test that new C2 code produces the same results for NaN values.
>
> Thanks,
> Vladimir
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