[Bug middle-end/78786] GCC hangs/out of memory calling sprintf with large precision

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78786

--- Comment #2 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
With "%.*f", the problem comes from GMP (and possibly glibc) since MPFR calls
the GMP functions to handle non-MPFR format specifiers.

But the patch seems to use "%.*Rf", for which I cannot reproduce the problem
with MPFR 3.1.5.