[PATCH 3/4] math: signal underflow for fmaf results that are tiny before rounding

[Joseph Myers]

On Mon, 3 Aug 2026, Matt Turner wrote:

> fmaf computes the exact result as a double and lets the return convert
> it to float, so that conversion is the operation's single rounding and
> is what has to signal underflow.  Where the exact result is tiny but
> rounds up to the smallest normal float, architectures determining
> tininess after rounding do not signal it, because the value they examine
> is no longer tiny.

As with the previous patch, is this general for after-rounding 
architectures, or specific to an Alpha hardware bug?  In either case, I'd 
expect changes to be appropriately conditional to avoid executing 
unnecessary code on unaffected targets.

-- 
Joseph S. Myers
josmyers@redhat.com