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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100361

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #2)
> Patrick, is the table an optimization, or essential? We might be able to
> avoid it, but he functions would be much slower.

The tables are essential for Ryu's d2exp_buffered_n and d2fixed_buffered_n
routines, which we use for fast explicit-precision formatting of float/doub=
le.

>=20
> Maybe we should just disable the floating-point to_chars for 16-bit targe=
ts.

Agreed.. though in theory we could just go through printf as a fallback for
d2exp_buffered_n and d2fixed_buffered_n on these targets.

Btw, we already disable the floating-point to_chars on targets without a
binary64 double.  So is our test for detecting binary64 not accurate enough=
, or
are these 16-bit targets whose double type really is binary64?=