[PATCH 08/13] Use GCC builtins for rint functions if desired.

[Stefan Liebler <stli at linux dot ibm dot com>]

This patch is using the corresponding GCC builtin for rintf, rint,
rintl and rintf128 if the USE_FUNCTION_BUILTIN macros are defined to one
in math-use-builtins.h.

This is the case for s390 if build with at least --march=z196 --mzarch.
Otherwise the generic implementation is used.  The code of the generic
implementation is not changed except changes in code style.
---
 sysdeps/generic/math-use-builtins.h         |  5 ++
 sysdeps/ieee754/dbl-64/s_rint.c             | 11 +++-
 sysdeps/ieee754/float128/float128_private.h |  3 +
 sysdeps/ieee754/flt-32/s_rintf.c            | 57 ++++++++++++-------
 sysdeps/ieee754/ldbl-128/s_rintl.c          | 63 +++++++++++++--------
 sysdeps/s390/fpu/math-use-builtins.h        |  6 ++
 6 files changed, 97 insertions(+), 48 deletions(-)

diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
index e12490ed41..64b4a4bb5b 100644
--- a/sysdeps/generic/math-use-builtins.h
+++ b/sysdeps/generic/math-use-builtins.h
@@ -26,4 +26,9 @@
 #define USE_NEARBYINTL_BUILTIN 0
 #define USE_NEARBYINTF128_BUILTIN 0
 
+#define USE_RINT_BUILTIN 0
+#define USE_RINTF_BUILTIN 0
+#define USE_RINTL_BUILTIN 0
+#define USE_RINTF128_BUILTIN 0
+
 #endif /* math-use-builtins.h */
diff --git a/sysdeps/ieee754/dbl-64/s_rint.c b/sysdeps/ieee754/dbl-64/s_rint.c
index f96078c405..b09ed8fc06 100644
--- a/sysdeps/ieee754/dbl-64/s_rint.c
+++ b/sysdeps/ieee754/dbl-64/s_rint.c
@@ -23,16 +23,22 @@
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-double.h>
+#include <math-use-builtins.h>
 
+#if ! USE_RINT_BUILTIN
 static const double
 TWO52[2] = {
 	    4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
 	    -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
 };
+#endif
 
 double
 __rint (double x)
 {
+#if USE_RINT_BUILTIN
+  return __builtin_rint (x);
+#else
   int64_t i0, sx;
   int32_t j0;
   EXTRACT_WORDS64 (i0, x);
@@ -47,7 +53,7 @@ __rint (double x)
 	  EXTRACT_WORDS64 (i0, t);
 	  INSERT_WORDS64 (t, (i0 & UINT64_C (0x7fffffffffffffff))
 			  | (sx << 63));
-      return t;
+	  return t;
 	}
     }
   else
@@ -56,9 +62,10 @@ __rint (double x)
 	return x + x;			/* inf or NaN  */
       else
 	return x;			/* x is integral  */
-  }
+    }
   double w = TWO52[sx] + x;
   return w - TWO52[sx];
+#endif /* USE_RINT_BUILTIN  */
 }
 #ifndef __rint
 libm_alias_double (__rint, rint)
diff --git a/sysdeps/ieee754/float128/float128_private.h b/sysdeps/ieee754/float128/float128_private.h
index e96986a968..f458e7b85f 100644
--- a/sysdeps/ieee754/float128/float128_private.h
+++ b/sysdeps/ieee754/float128/float128_private.h
@@ -142,6 +142,8 @@
 #include <math-use-builtins.h>
 #undef USE_NEARBYINTL_BUILTIN
 #define USE_NEARBYINTL_BUILTIN USE_NEARBYINTF128_BUILTIN
+#undef USE_RINTL_BUILTIN
+#define USE_RINTL_BUILTIN USE_RINTF128_BUILTIN
 
 /* IEEE function renames.  */
 #define __ieee754_acoshl __ieee754_acoshf128
@@ -346,6 +348,7 @@
 #define __builtin_copysignl __builtin_copysignf128
 #define __builtin_signbitl __builtin_signbit
 #define __builtin_nearbyintl __builtin_nearbyintf128
+#define __builtin_rintl __builtin_rintf128
 
 /* Get the constant suffix from bits/floatn-compat.h.  */
 #define L(x) __f128 (x)
diff --git a/sysdeps/ieee754/flt-32/s_rintf.c b/sysdeps/ieee754/flt-32/s_rintf.c
index 0306dc21f4..7dbf991395 100644
--- a/sysdeps/ieee754/flt-32/s_rintf.c
+++ b/sysdeps/ieee754/flt-32/s_rintf.c
@@ -17,35 +17,48 @@
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-float.h>
+#include <math-use-builtins.h>
 
+#if ! USE_RINTF_BUILTIN
 static const float
-TWO23[2]={
-  8.3886080000e+06, /* 0x4b000000 */
- -8.3886080000e+06, /* 0xcb000000 */
+TWO23[2] = {
+	    8.3886080000e+06, /* 0x4b000000 */
+	    -8.3886080000e+06, /* 0xcb000000 */
 };
+#endif
 
 float
-__rintf(float x)
+__rintf (float x)
 {
-	int32_t i0,j0,sx;
-	float w,t;
-	GET_FLOAT_WORD(i0,x);
-	sx = (i0>>31)&1;
-	j0 = ((i0>>23)&0xff)-0x7f;
-	if(j0<23) {
-	    if(j0<0) {
-		w = TWO23[sx]+x;
-		t =  w-TWO23[sx];
-		GET_FLOAT_WORD(i0,t);
-		SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
-		return t;
-	    }
-	} else {
-	    if(j0==0x80) return x+x;	/* inf or NaN */
-	    else return x;		/* x is integral */
+#if USE_RINTF_BUILTIN
+  return __builtin_rintf (x);
+#else
+  int32_t i0, j0, sx;
+  float w, t;
+  GET_FLOAT_WORD (i0, x);
+  sx = (i0 >> 31) & 1;
+  j0 = ((i0 >> 23) & 0xff) - 0x7f;
+  if (j0 < 23)
+    {
+      if(j0 < 0)
+	{
+	  w = TWO23[sx] + x;
+	  t =  w - TWO23[sx];
+	  GET_FLOAT_WORD (i0, t);
+	  SET_FLOAT_WORD (t, (i0 & 0x7fffffff) | (sx << 31));
+	  return t;
 	}
-	w = TWO23[sx]+x;
-	return w-TWO23[sx];
+    }
+  else
+    {
+      if (j0 == 0x80)
+	return x + x;		/* inf or NaN  */
+      else
+	return x;		/* x is integral  */
+    }
+  w = TWO23[sx] + x;
+  return w - TWO23[sx];
+#endif /* USE_RINTF_BUILTIN  */
 }
 #ifndef __rintf
 libm_alias_float (__rint, rint)
diff --git a/sysdeps/ieee754/ldbl-128/s_rintl.c b/sysdeps/ieee754/ldbl-128/s_rintl.c
index b6337e1d8a..1c4eba566d 100644
--- a/sysdeps/ieee754/ldbl-128/s_rintl.c
+++ b/sysdeps/ieee754/ldbl-128/s_rintl.c
@@ -13,7 +13,9 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
+#include <math-use-builtins.h>
+
+#if ! USE_RINTL_BUILTIN && defined (LIBM_SCCS) && ! defined (lint)
 static char rcsid[] = "$NetBSD: $";
 #endif
 
@@ -32,33 +34,46 @@ static char rcsid[] = "$NetBSD: $";
 #include <math_private.h>
 #include <libm-alias-ldouble.h>
 
+#if ! USE_RINTL_BUILTIN
 static const _Float128
-TWO112[2]={
-  5.19229685853482762853049632922009600E+33L, /* 0x406F000000000000, 0 */
- -5.19229685853482762853049632922009600E+33L  /* 0xC06F000000000000, 0 */
+TWO112[2] = {
+	     5.19229685853482762853049632922009600E+33L, /* 0x406F000000000000, 0 */
+	     -5.19229685853482762853049632922009600E+33L  /* 0xC06F000000000000, 0 */
 };
+#endif
 
-_Float128 __rintl(_Float128 x)
+_Float128
+__rintl (_Float128 x)
 {
-	int64_t i0,j0,sx;
-	uint64_t i1 __attribute__ ((unused));
-	_Float128 w,t;
-	GET_LDOUBLE_WORDS64(i0,i1,x);
-	sx = (((uint64_t)i0)>>63);
-	j0 = ((i0>>48)&0x7fff)-0x3fff;
-	if(j0<112) {
-	    if(j0<0) {
-	        w = TWO112[sx]+x;
-	        t = w-TWO112[sx];
-		GET_LDOUBLE_MSW64(i0,t);
-		SET_LDOUBLE_MSW64(t,(i0&0x7fffffffffffffffLL)|(sx<<63));
-	        return t;
-	    }
-	} else {
-	    if(j0==0x4000) return x+x;	/* inf or NaN */
-	    else return x;		/* x is integral */
+#if USE_RINTL_BUILTIN
+  return __builtin_rintl (x);
+#else
+  int64_t i0, j0, sx;
+  uint64_t i1 __attribute__ ((unused));
+  _Float128 w, t;
+  GET_LDOUBLE_WORDS64 (i0, i1, x);
+  sx = (((uint64_t) i0) >> 63);
+  j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
+  if (j0 < 112)
+    {
+      if (j0 < 0)
+	{
+	  w = TWO112[sx] + x;
+	  t = w - TWO112[sx];
+	  GET_LDOUBLE_MSW64 (i0, t);
+	  SET_LDOUBLE_MSW64 (t, (i0 & 0x7fffffffffffffffLL) | (sx << 63));
+	  return t;
 	}
-	w = TWO112[sx]+x;
-	return w-TWO112[sx];
+    }
+  else
+    {
+      if (j0 == 0x4000)
+	return x + x;		/* inf or NaN  */
+      else
+	return x;		/* x is integral  */
+    }
+  w = TWO112[sx] + x;
+  return w - TWO112[sx];
+#endif /* USE_RINTL_BUILTIN  */
 }
 libm_alias_ldouble (__rint, rint)
diff --git a/sysdeps/s390/fpu/math-use-builtins.h b/sysdeps/s390/fpu/math-use-builtins.h
index fd9da8893e..15705fa74a 100644
--- a/sysdeps/s390/fpu/math-use-builtins.h
+++ b/sysdeps/s390/fpu/math-use-builtins.h
@@ -30,10 +30,16 @@
 # define USE_NEARBYINTF_BUILTIN 1
 # define USE_NEARBYINTL_BUILTIN 1
 
+# define USE_RINT_BUILTIN 1
+# define USE_RINTF_BUILTIN 1
+# define USE_RINTL_BUILTIN 1
+
 # if __GNUC_PREREQ (8, 1)
 #  define USE_NEARBYINTF128_BUILTIN 1
+#  define USE_RINTF128_BUILTIN 1
 # else
 #  define USE_NEARBYINTF128_BUILTIN 0
+#  define USE_RINTF128_BUILTIN 0
 # endif
 
 #else
-- 
2.19.1