[patch, libgfortran] PR32611 Print sign of negative zero

[Jerry DeLisle]

Brooks Moses wrote:
> Jerry DeLisle wrote:
>> The attached patch provides a solution to this PR.
>>
>> The patch uses the signbit function to determine if a zero value is 
>> negative. If so, the sign is emitted.  If -std=legacy is specified at 
>> compile time, the negative sign for zero values is not emitted.
>>
>> This patch requires -std=legacy to be used to pass NIST.  This is 
>> because F77 explicitly prohibits printing the negative sign for zero 
>> values.
> [...]
>> OK for trunk?
> 
> This needs documenting, of course.
> 
> If you aren't sure of the best place to document it, feel free to create 
> a documentation PR about it and assign it to me, and I'll get to it 
> sometime in August when I have time to think again.  :)
> 
> In particular, note that this changes the meaning of the -std= option.
> Currently, it only affects what language features are accepted, 
> rejected, or warned about, but any program that compiles will have the 
> same behavior regardless of which -std= option was used to compile it.
> Your patch changes this, which is IMHO a fairly significant little change.
> 
> - Brooks
> 
> 
Do you think it better to have a separate compiler option like -fsign-zero?

Others please chime in.

Jerry