[Chapel Merge] Make 'proc sgn' and 'proc bigint.sgn' overloads unstable

Branch: refs/heads/main
Revision: 7660c5faaa3cceb94b834a5d8ab40c6cdf469207
Author: mppf
Link: Make 'proc sgn' and 'proc bigint.sgn' overloads unstable by mppf · Pull Request #24582 · chapel-lang/chapel · GitHub
Log Message:
Make 'proc sgn' and 'proc bigint.sgn' overloads unstable (#24582)

This PR makes proc sgn and proc bigint.sgn unstable based upon
discussion in

. The discussion there is focused on being able to get a floating-point
NaN result from sgn(NaN), which is not possible with the current
return type of int(8) for the real overload.

This PR makes the integer and bigint overloads unstable in addition to
the real overload in order to leave room for reconsideration of the
entire family of functions. This might include changing the name or
making the return type always match the argument type.

Issue #24583 asks how these functions should be adjusted in order to
become stable.

  • full comm=none testing

Reviewed by @ShreyasKhandekar - thanks!

Compare: Comparing 052dbb03a577619ba5fef160fa0f03f1a235f6a3...4f7cbb35196a0bc805a20dc1f6d64f633e259e75 · chapel-lang/chapel · GitHub

Diff:
M modules/standard/AutoMath.chpl
M modules/standard/BigInteger.chpl
A test/unstable/BigInteger/unstable-sgn-bigint.chpl
A test/unstable/BigInteger/unstable-sgn-bigint.good
A test/unstable/unstable-sgn.chpl
A test/unstable/unstable-sgn.good
https://github.com/chapel-lang/chapel/pull/24582.diff