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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.


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