Use GCC builtins for llrint functions if desired.

This patch is using the corresponding GCC builtin for llrintf, llrint,
llrintl and llrintf128 if the USE_FUNCTION_BUILTIN macros are defined to one
in math-use-builtins-function.h.

Co-Authored-By: Xi Ruoyao <xry111@xry111.site>

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

@@ -0,0 +1,4 @@
+#define USE_LLRINT_BUILTIN 0
+#define USE_LLRINTF_BUILTIN 0
+#define USE_LLRINTL_BUILTIN 0
+#define USE_LLRINTF128_BUILTIN 0

sysdeps/generic/math-use-builtins.h

@@ -38,5 +38,6 @@
 #include <math-use-builtins-fmin.h>
 #include <math-use-builtins-fabs.h>
 #include <math-use-builtins-lrint.h>
+#include <math-use-builtins-llrint.h>
 
 #endif /* MATH_USE_BUILTINS_H  */

sysdeps/ieee754/dbl-64/s_llrint.c

@@ -25,17 +25,22 @@
 #include <math_private.h>
 #include <libm-alias-double.h>
 #include <fix-fp-int-convert-overflow.h>
-
+#include <math-use-builtins.h>
-static const double two52[2] =
-{
-  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
- -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
-};
 
 
 long long int
 __llrint (double x)
 {
+#if USE_LLRINT_BUILTIN
+  return __builtin_llrint (x);
+#else
+  /* Use generic implementation.  */
+  static const double two52[2] =
+  {
+    4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
+   -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
+  };
+
   int32_t j0;
   uint32_t i1, i0;
   long long int result;
@@ -95,6 +100,7 @@ __llrint (double x)
     }
 
   return sx ? -result : result;
+#endif /* ! USE_LLRINT_BUILTIN  */
 }
 
 libm_alias_double (__llrint, llrint)

sysdeps/ieee754/float128/float128_private.h

@@ -163,6 +163,8 @@
 #define USE_FMAL_BUILTIN USE_FMAF128_BUILTIN
 #undef USE_LRINTL_BUILTIN
 #define USE_LRINTL_BUILTIN USE_LRINTF128_BUILTIN
+#undef USE_LLRINTL_BUILTIN
+#define USE_LLRINTL_BUILTIN USE_LLRINTF128_BUILTIN
 
 /* IEEE function renames.  */
 #define __ieee754_acoshl __ieee754_acoshf128

sysdeps/ieee754/flt-32/s_llrintf.c

@@ -25,17 +25,22 @@
 #include <math_private.h>
 #include <libm-alias-float.h>
 #include <fix-fp-int-convert-overflow.h>
-
+#include <math-use-builtins.h>
-static const float two23[2] =
-{
-  8.3886080000e+06, /* 0x4B000000 */
- -8.3886080000e+06, /* 0xCB000000 */
-};
 
 
 long long int
 __llrintf (float x)
 {
+#if USE_LLRINTF_BUILTIN
+  return __builtin_llrintf (x);
+#else
+  /* Use generic implementation.  */
+  static const float two23[2] =
+  {
+    8.3886080000e+06, /* 0x4B000000 */
+   -8.3886080000e+06, /* 0xCB000000 */
+  };
+
   int32_t j0;
   uint32_t i0;
   float w;
@@ -82,6 +87,7 @@ __llrintf (float x)
     }
 
   return sx ? -result : result;
+#endif /* ! USE_LLRINTF_BUILTIN  */
 }
 
 libm_alias_float (__llrint, llrint)

sysdeps/ieee754/ldbl-128/s_llrintl.c

@@ -24,16 +24,22 @@
 #include <math_private.h>
 #include <libm-alias-ldouble.h>
 #include <fix-fp-int-convert-overflow.h>
+#include <math-use-builtins.h>
 
-static const _Float128 two112[2] =
-{
-  L(5.19229685853482762853049632922009600E+33), /* 0x406F000000000000, 0 */
- L(-5.19229685853482762853049632922009600E+33)  /* 0xC06F000000000000, 0 */
-};
 
 long long int
 __llrintl (_Float128 x)
 {
+#if USE_LLRINTL_BUILTIN
+  return __builtin_round (x);
+#else
+  /* Use generic implementation.  */
+  static const _Float128 two112[2] =
+  {
+    L(5.19229685853482762853049632922009600E+33), /* 0x406F000000000000, 0 */
+   L(-5.19229685853482762853049632922009600E+33)  /* 0xC06F000000000000, 0 */
+  };
+
   int32_t j0;
   uint64_t i0,i1;
   _Float128 w;
@@ -102,6 +108,7 @@ __llrintl (_Float128 x)
     }
 
   return sx ? -result : result;
+#endif /* ! USE_LLRINTL_BUILTIN  */
 }
 
 libm_alias_ldouble (__llrint, llrint)