[PATCH] D87835: [APFloat] prevent NaN morphing into Inf on conversion (PR43907)

[Steve Canon via Phabricator via llvm-commits]

scanon added a comment.

If we can do it without complication, it would be best to preserve signaling-ness, because that's the more faithful interpretation of IEEE 754 (even though it _doesn't_ match what the HW does, because the HW can signal and APFloat can't). A general principle (imperfectly adhered to) of IEEE 754 is that conversions on signaling NaNs should _either_ signal and produce a quiet NaN (if possible), or should produce a signaling NaN if no signal is possible.

We _certainly_ shouldn't produce infinity, so any movement here is a big improvement.


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https://reviews.llvm.org/D87835