To use the fabs function to the used type, instead of the double
variant. it fixes a build issue with clang:
./s_compoundn_template.c:64:14: error: absolute value function 'fabs' given an argument of type 'const long double' but has parameter of type 'double' which may cause truncation of value [-Werror,-Wabsolute-value]
64 | FLOAT pd = fabs (*(const FLOAT *) p);
| ^
./s_compoundn_template.c:64:14: note: use function 'fabsl' instead
64 | FLOAT pd = fabs (*(const FLOAT *) p);
| ^~~~
| fabsl
Reviewed-by: Collin Funk <collin.funk1@gmail.com>
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the compoundn functions, which compute (1+X) to the
power Y for integer Y (and X at least -1). The integer exponent has
type long long int in C23; it was intmax_t in TS 18661-4, and as with
other interfaces changed after their initial appearance in the TS, I
don't think we need to support the original version of the interface.
Note that these functions are "compoundn" with a trailing "n", *not*
"compound" (CORE-MATH has the wrong name, for example).
As with pown, I strongly encourage searching for worst cases for ulps
error for these implementations (necessarily non-exhaustively, given
the size of the input space). I also expect a custom implementation
for a given format could be much faster as well as more accurate (I
haven't tested or benchmarked the CORE-MATH implementation for
binary32); this is one of the more complicated and less efficient
functions to implement in a type-generic way.
As with exp2m1 and exp10m1, this showed up places where the
powerpc64le IFUNC setup is not as self-contained as one might hope (in
this case, without the changes specific to powerpc64le, there were
undefined references to __GI___expf128).
Tested for x86_64 and x86, and with build-many-glibcs.py.
Adhemerval Zanella
Joseph Myers