Fix pow (0.0, -Inf) (bug 14241)

[Andreas Jaeger]

On 06/15/2012 01:17 PM, Joseph S. Myers wrote:
> On Fri, 15 Jun 2012, Andreas Jaeger wrote:
>
>> -    if (ABS(y) > 1.0e20) return (y>0)?0:INF.x;
>> +    if (ABS(y) > 1.0e20) return (y>0)?0:1.0/ABS(x);
>>       k = checkint(y);
>>       if (k == -1)
>>         return y < 0 ? 1.0/x : x;
>>
>> Can't we just revert this - just using INF.x in both places? Why do we need
>> the division here?
>
> When y is finite, the divide-by-zero exception is required, which means
> the division must be executed.  It's the case of infinite y where ideally
> there would be no exception (as per the IEEE 754 semantics that
> divide-by-zero exceptions are for exact infinities as results for
> operations on *finite* operands) and C11 makes the exception optional.

thanks for the explanation. In that case your changes is fine.

Andreas
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