musl/include/tgmath.h

#ifndef _TGMATH_H
#define _TGMATH_H

/*
the return types are only correct with gcc (__GNUC__)
otherwise they are long double or long double complex

the long double version of a function is never chosen when
sizeof(double) == sizeof(long double)
(but the return type is set correctly with gcc)
*/

#include <math.h>
#include <complex.h>

#define __IS_FP(x) !!((1?1:(x))/2)
#define __IS_CX(x) (__IS_FP(x) && sizeof(x) == sizeof((x)+I))
#define __IS_REAL(x) (__IS_FP(x) && 2*sizeof(x) == sizeof((x)+I))

#define __FLT(x) (__IS_REAL(x) && sizeof(x) == sizeof(float))
#define __LDBL(x) (__IS_REAL(x) && sizeof(x) == sizeof(long double) && sizeof(long double) != sizeof(double))

#define __FLTCX(x) (__IS_CX(x) && sizeof(x) == sizeof(float complex))
#define __DBLCX(x) (__IS_CX(x) && sizeof(x) == sizeof(double complex))
#define __LDBLCX(x) (__IS_CX(x) && sizeof(x) == sizeof(long double complex) && sizeof(long double) != sizeof(double))

/* return type */

#ifdef __GNUC__
/* cast to double when x is integral, otherwise use typeof(x) */
#define __RETCAST(x) (__typeof__(*( \
	0 ? (__typeof__(0 ? (double *)0 : (void *)__IS_FP(x)))0 : \
	    (__typeof__(0 ? (__typeof__(x) *)0 : (void *)!__IS_FP(x)))0 )))
/* 2 args case, consider complex types (for cpow) */
#define __RETCAST_2(x, y) (__typeof__(*( \
	0 ? (__typeof__(0 ? (double *)0 : \
		(void *)!((!__IS_FP(x) || !__IS_FP(y)) && __FLT((x)+(y)+1.0f))))0 : \
	0 ? (__typeof__(0 ? (double complex *)0 : \
		(void *)!((!__IS_FP(x) || !__IS_FP(y)) && __FLTCX((x)+(y)))))0 : \
	    (__typeof__(0 ? (__typeof__((x)+(y)) *)0 : \
		(void *)((!__IS_FP(x) || !__IS_FP(y)) && (__FLT((x)+(y)+1.0f) || __FLTCX((x)+(y))))))0 )))
/* 3 args case, don't consider complex types (fma only) */
#define __RETCAST_3(x, y, z) (__typeof__(*( \
	0 ? (__typeof__(0 ? (double *)0 : \
		(void *)!((!__IS_FP(x) || !__IS_FP(y) || !__IS_FP(z)) && __FLT((x)+(y)+(z)+1.0f))))0 : \
	    (__typeof__(0 ? (__typeof__((x)+(y)) *)0 : \
		(void *)((!__IS_FP(x) || !__IS_FP(y) || !__IS_FP(z)) && __FLT((x)+(y)+(z)+1.0f))))0 )))
/* drop complex from the type of x */
#define __TO_REAL(x) *( \
	0 ? (__typeof__(0 ? (double *)0 : (void *)!__DBLCX(x)))0 : \
	0 ? (__typeof__(0 ? (float *)0 : (void *)!__FLTCX(x)))0 : \
	0 ? (__typeof__(0 ? (long double *)0 : (void *)!__LDBLCX(x)))0 : \
	    (__typeof__(0 ? (__typeof__(x) *)0 : (void *)__IS_CX(x)))0 )
#else
#define __RETCAST(x)
#define __RETCAST_2(x, y)
#define __RETCAST_3(x, y, z)
#endif

/* function selection */

#define __tg_real(fun, x) (__RETCAST(x)( \
	__FLT(x) ? fun ## f (x) : \
	__LDBL(x) ? fun ## l (x) : \
	fun(x) ))

#define __tg_real_2_1(fun, x, y) (__RETCAST(x)( \
	__FLT(x) ? fun ## f (x, y) : \
	__LDBL(x) ? fun ## l (x, y) : \
	fun(x, y) ))

#define __tg_real_2(fun, x, y) (__RETCAST_2(x, y)( \
	__FLT(x) && __FLT(y) ? fun ## f (x, y) : \
	__LDBL((x)+(y)) ? fun ## l (x, y) : \
	fun(x, y) ))

#define __tg_complex(fun, x) (__RETCAST((x)+I)( \
	__FLTCX((x)+I) && __IS_FP(x) ? fun ## f (x) : \
	__LDBLCX((x)+I) ? fun ## l (x) : \
	fun(x) ))

#define __tg_complex_retreal(fun, x) (__RETCAST(__TO_REAL(x))( \
	__FLTCX((x)+I) && __IS_FP(x) ? fun ## f (x) : \
	__LDBLCX((x)+I) ? fun ## l (x) : \
	fun(x) ))

#define __tg_real_complex(fun, x) (__RETCAST(x)( \
	__FLTCX(x) ? c ## fun ## f (x) : \
	__DBLCX(x) ? c ## fun (x) : \
	__LDBLCX(x) ? c ## fun ## l (x) : \
	__FLT(x) ? fun ## f (x) : \
	__LDBL(x) ? fun ## l (x) : \
	fun(x) ))

/* special cases */

#define __tg_real_remquo(x, y, z) (__RETCAST_2(x, y)( \
	__FLT(x) && __FLT(y) ? remquof(x, y, z) : \
	__LDBL((x)+(y)) ? remquol(x, y, z) : \
	remquo(x, y, z) ))

#define __tg_real_fma(x, y, z) (__RETCAST_3(x, y, z)( \
	__FLT(x) && __FLT(y) && __FLT(z) ? fmaf(x, y, z) : \
	__LDBL((x)+(y)+(z)) ? fmal(x, y, z) : \
	fma(x, y, z) ))

#define __tg_real_complex_pow(x, y) (__RETCAST_2(x, y)( \
	__FLTCX((x)+(y)) && __IS_FP(x) && __IS_FP(y) ? cpowf(x, y) : \
	__FLTCX((x)+(y)) ? cpow(x, y) : \
	__DBLCX((x)+(y)) ? cpow(x, y) : \
	__LDBLCX((x)+(y)) ? cpowl(x, y) : \
	__FLT(x) && __FLT(y) ? powf(x, y) : \
	__LDBL((x)+(y)) ? powl(x, y) : \
	pow(x, y) ))

#define __tg_real_complex_fabs(x) (__RETCAST(__TO_REAL(x))( \
	__FLTCX(x) ? cabsf(x) : \
	__DBLCX(x) ? cabs(x) : \
	__LDBLCX(x) ? cabsl(x) : \
	__FLT(x) ? fabsf(x) : \
	__LDBL(x) ? fabsl(x) : \
	fabs(x) ))

/* tg functions */

#define acos(x)         __tg_real_complex(acos, (x))
#define acosh(x)        __tg_real_complex(acosh, (x))
#define asin(x)         __tg_real_complex(asin, (x))
#define asinh(x)        __tg_real_complex(asinh, (x))
#define atan(x)         __tg_real_complex(atan, (x))
#define atan2(x,y)      __tg_real_2(atan2, (x), (y))
#define atanh(x)        __tg_real_complex(atanh, (x))
#define carg(x)         __tg_complex_retreal(carg, (x))
#define cbrt(x)         __tg_real(cbrt, (x))
#define ceil(x)         __tg_real(ceil, (x))
#define cimag(x)        __tg_complex_retreal(cimag, (x))
#define conj(x)         __tg_complex(conj, (x))
#define copysign(x,y)   __tg_real_2(copysign, (x), (y))
#define cos(x)          __tg_real_complex(cos, (x))
#define cosh(x)         __tg_real_complex(cosh, (x))
#define cproj(x)        __tg_complex(cproj, (x))
#define creal(x)        __tg_complex_retreal(creal, (x))
#define erf(x)          __tg_real(erf, (x))
#define erfc(x)         __tg_real(erfc, (x))
#define exp(x)          __tg_real_complex(exp, (x))
#define exp2(x)         __tg_real(exp2, (x))
#define expm1(x)        __tg_real(expm1, (x))
#define fabs(x)         __tg_real_complex_fabs(x)
#define fdim(x,y)       __tg_real_2(fdim, (x), (y))
#define floor(x)        __tg_real(floor, (x))
#define fma(x,y,z)      __tg_real_fma((x), (y), (z))
#define fmax(x,y)       __tg_real_2(fmax, (x), (y))
#define fmin(x,y)       __tg_real_2(fmin, (x), (y))
#define fmod(x,y)       __tg_real_2(fmod, (x), (y))
#define frexp(x,y)      __tg_real_2_1(frexp, (x), (y))
#define hypot(x,y)      __tg_real_2(hypot, (x), (y))
#define ilogb(x)        __tg_real(ilogb, (x))
#define ldexp(x,y)      __tg_real_2_1(ldexp, (x), (y))
#define lgamma(x)       __tg_real(lgamma, (x))
#define llrint(x)       __tg_real(llrint, (x))
#define llround(x)      __tg_real(llround, (x))
#define log(x)          __tg_real_complex(log, (x))
#define log10(x)        __tg_real(log10, (x))
#define log1p(x)        __tg_real(log1p, (x))
#define log2(x)         __tg_real(log2, (x))
#define logb(x)         __tg_real(logb, (x))
#define lrint(x)        __tg_real(lrint, (x))
#define lround(x)       __tg_real(lround, (x))
#define nearbyint(x)    __tg_real(nearbyint, (x))
#define nextafter(x,y)  __tg_real_2(nextafter, (x), (y)
#define nexttoward(x,y) __tg_real_2(nexttoward, (x), (y))
#define pow(x,y)        __tg_real_complex_pow((x), (y))
#define remainder(x,y)  __tg_real_2(remainder, (x), (y))
#define remquo(x,y,z)   __tg_real_remquo((x), (y), (z))
#define rint(x)         __tg_real(rint, (x))
#define round(x)        __tg_real(round, (x))
#define scalbln(x,y)    __tg_real_2_1(scalbln, (x), (y))
#define scalbn(x,y)     __tg_real_2_1(scalbn, (x), (y))
#define sin(x)          __tg_real_complex(sin, (x))
#define sinh(x)         __tg_real_complex(sinh, (x))
#define sqrt(x)         __tg_real_complex(sqrt, (x))
#define tan(x)          __tg_real_complex(tan, (x))
#define tanh(x)         __tg_real_complex(tanh, (x))
#define tgamma(x)       __tg_real(tgamma, (x))
#define trunc(x)        __tg_real(trunc, (x))

#endif