This one might be a bit controversial since the terminology has been
introduced from the start but I think `FRACTION_LEN` is a better name
here. AFAICT it really is "the number of bits after the decimal dot when
the number is in normal form."
`MANTISSA_WIDTH` is less precise as it's unclear whether we take the
leading bit into account.
This patch also renames most of the properties to use the `_LEN` suffix
and fixes useless casts or variables.
Recent testing has uncovered some hard-to-find bugs in printf's long
double support. This patch adds an extra long double path to the fuzzer
with minimal extra effort. While a more thorough long double fuzzer
would be useful, it would need to handle the non-standard cases of 80
bit long doubles such as unnormal and pseudo-denormal numbers. For that
reason, a standalone long double fuzzer is left for future development.
To guarantee accuracy for all potential float values, this patch adds a
fuzzer to compare the results for float conversions from our printf
against MPFR's.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D156495
