[LLVMdev] APFloat renaming isNormal => isFiniteNonZero and isIEEENormal => isNormal

Michael Gottesman
Wed, 19 Jun 2013 01:47:43 -0000

It seems like there is a consensus that this is a good change. Any nay sayers?

Michael

On Jun 18, 2013, at 5:07 PM, Eric Christopher <echristo at gmail.com>
wrote:

> LGTM (and you've already gotten other positive feedback as well).
>
> -eric
>
> On Tue, Jun 18, 2013 at 3:45 PM, Michael Gottesman <mgottesman at
apple.com> wrote:
>> IEEE-754R defines a normal floating point number as:
>>
>> 2.1.38 normal number: For a particular format, a finite non-zero
>> floating-point number with magnitude greater than or equal to a minimum
>> bemin value, where b is the radix. Normal numbers can use the full
precision
>> available in a format. In this standard, zero is neither normal nor
>> subnormal.
>>
>> This implies that a denormal is not a normal number.
>>
>> In contrast, the current implementation of isNormal in APFloat does
treat
>> denormal numbers as normal numbers breaking this definition. This is
not
>> just a predicate that has a name that differs from IEEE-754R (which I
am
>> fine with), but is an actual name collision with IEEE-754R with a
different
>> semantic meaning. This could easily lead to programmer error and thus
in my
>> humble opinion is worth the hassle/trouble of fixing.
>>
>> Does anyone have any thoughts/suggestions/objections with my renaming
>> isNormal => isFiniteNonZero (and making all the relevant changes in
the
>> relevant codebases) and isIEEENormal => isNormal?
>>
>> Awaiting the flames,
>> Michael
>>
>>
>>
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