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Re: [patch, libgfortran] PR32611 Print sign of negative zero


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


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