math: Add math-use-builtinds-fmax.h

It allows the architecture to use the builtin instead of generic
implementation.

math/s_fmax_template.c

@@ -17,10 +17,14 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <math.h>
+#include <math-use-builtins.h>
 
 FLOAT
 M_DECL_FUNC (__fmax) (FLOAT x, FLOAT y)
 {
+#if M_USE_BUILTIN (FMAX)
+  return M_SUF (__builtin_fmax) (x, y);
+#else
   if (isgreaterequal (x, y))
     return x;
   else if (isless (x, y))
@@ -29,6 +33,7 @@ M_DECL_FUNC (__fmax) (FLOAT x, FLOAT y)
     return x + y;
   else
     return isnan (y) ? x : y;
+#endif
 }
 
 declare_mgen_alias (__fmax, fmax);

sysdeps/generic/math-type-macros-double.h

@@ -26,6 +26,7 @@
 #define FLOAT double
 #define CFLOAT _Complex double
 #define M_STRTO_NAN __strtod_nan
+#define M_USE_BUILTIN(c) USE_ ##c ##_BUILTIN
 
 #include <libm-alias-double.h>
 #include <math-nan-payload-double.h>

sysdeps/generic/math-type-macros-float.h

@@ -25,6 +25,7 @@
 #define FLOAT float
 #define CFLOAT _Complex float
 #define M_STRTO_NAN __strtof_nan
+#define M_USE_BUILTIN(c) USE_ ##c ##F_BUILTIN
 
 /* Standard/GNU macro literals do not exist for the float type.  Use
    the double macro constants.  */

sysdeps/generic/math-type-macros-float128.h

@@ -24,6 +24,7 @@
 #define M_SUF(c) c ## f128
 #define FLOAT _Float128
 #define M_STRTO_NAN __strtof128_nan
+#define M_USE_BUILTIN(c) USE_ ##c ##F128_BUILTIN
 
 #define CFLOAT __CFLOAT128
 

sysdeps/generic/math-type-macros-ldouble.h

@@ -26,6 +26,7 @@
 #define FLOAT long double
 #define CFLOAT _Complex long double
 #define M_STRTO_NAN __strtold_nan
+#define M_USE_BUILTIN(c) USE_ ##c ##L_BUILTIN
 
 #include <libm-alias-ldouble.h>
 #include <math-nan-payload-ldouble.h>

sysdeps/generic/math-use-builtins-fmax.h

@@ -0,0 +1,4 @@
+#define USE_FMAX_BUILTIN 0
+#define USE_FMAXF_BUILTIN 0
+#define USE_FMAXL_BUILTIN 0
+#define USE_FMAXF128_BUILTIN 0

sysdeps/generic/math-use-builtins.h

@@ -34,5 +34,6 @@
 #include <math-use-builtins-copysign.h>
 #include <math-use-builtins-sqrt.h>
 #include <math-use-builtins-fma.h>
+#include <math-use-builtins-fmax.h>
 
 #endif /* MATH_USE_BUILTINS_H  */