[PATCH 09/13] Use GCC builtins for floor functions if desired.

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

This patch is using the corresponding GCC builtin for floorf, floor,
floorl and floorf128 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_floor.c            |  5 ++
 sysdeps/ieee754/float128/float128_private.h |  3 +
 sysdeps/ieee754/flt-32/s_floorf.c           | 60 ++++++++-----
 sysdeps/ieee754/ldbl-128/s_floorl.c         | 97 ++++++++++++++-------
 sysdeps/s390/fpu/math-use-builtins.h        |  6 ++
 6 files changed, 121 insertions(+), 55 deletions(-)

diff --git a/sysdeps/generic/math-use-builtins.h b/sysdeps/generic/math-use-builtins.h
index 64b4a4bb5b..e1c5df62e4 100644
--- a/sysdeps/generic/math-use-builtins.h
+++ b/sysdeps/generic/math-use-builtins.h
@@ -31,4 +31,9 @@
 #define USE_RINTL_BUILTIN 0
 #define USE_RINTF128_BUILTIN 0
 
+#define USE_FLOOR_BUILTIN 0
+#define USE_FLOORF_BUILTIN 0
+#define USE_FLOORL_BUILTIN 0
+#define USE_FLOORF128_BUILTIN 0
+
 #endif /* math-use-builtins.h */
diff --git a/sysdeps/ieee754/dbl-64/s_floor.c b/sysdeps/ieee754/dbl-64/s_floor.c
index ce0c42bdb6..0ed22795ed 100644
--- a/sysdeps/ieee754/dbl-64/s_floor.c
+++ b/sysdeps/ieee754/dbl-64/s_floor.c
@@ -35,6 +35,7 @@
 #include <math_private.h>
 #include <stdint.h>
 #include <libm-alias-double.h>
+#include <math-use-builtins.h>
 
 /*
  * floor(x)
@@ -47,6 +48,9 @@
 double
 __floor (double x)
 {
+#if USE_FLOOR_BUILTIN
+  return __builtin_floor (x);
+#else
   int64_t i0;
   EXTRACT_WORDS64 (i0, x);
   int32_t j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
@@ -74,6 +78,7 @@ __floor (double x)
   else if (j0 == 0x400)
     return x + x;			/* inf or NaN */
   return x;
+#endif /* USE_FLOOR_BUILTIN  */
 }
 #ifndef __floor
 libm_alias_double (__floor, floor)
diff --git a/sysdeps/ieee754/float128/float128_private.h b/sysdeps/ieee754/float128/float128_private.h
index f458e7b85f..8c8a74a12c 100644
--- a/sysdeps/ieee754/float128/float128_private.h
+++ b/sysdeps/ieee754/float128/float128_private.h
@@ -144,6 +144,8 @@
 #define USE_NEARBYINTL_BUILTIN USE_NEARBYINTF128_BUILTIN
 #undef USE_RINTL_BUILTIN
 #define USE_RINTL_BUILTIN USE_RINTF128_BUILTIN
+#undef USE_FLOORL_BUILTIN
+#define USE_FLOORL_BUILTIN USE_FLOORF128_BUILTIN
 
 /* IEEE function renames.  */
 #define __ieee754_acoshl __ieee754_acoshf128
@@ -349,6 +351,7 @@
 #define __builtin_signbitl __builtin_signbit
 #define __builtin_nearbyintl __builtin_nearbyintf128
 #define __builtin_rintl __builtin_rintf128
+#define __builtin_floorl __builtin_floorf128
 
 /* Get the constant suffix from bits/floatn-compat.h.  */
 #define L(x) __f128 (x)
diff --git a/sysdeps/ieee754/flt-32/s_floorf.c b/sysdeps/ieee754/flt-32/s_floorf.c
index b34d967f01..39bb570d10 100644
--- a/sysdeps/ieee754/flt-32/s_floorf.c
+++ b/sysdeps/ieee754/flt-32/s_floorf.c
@@ -24,32 +24,48 @@
 #include <math.h>
 #include <math_private.h>
 #include <libm-alias-float.h>
+#include <math-use-builtins.h>
 
 float
-__floorf(float x)
+__floorf (float x)
 {
-	int32_t i0,j0;
-	uint32_t i;
-	GET_FLOAT_WORD(i0,x);
-	j0 = ((i0>>23)&0xff)-0x7f;
-	if(j0<23) {
-	    if(j0<0) {
-		/* return 0*sign(x) if |x|<1 */
-		if(i0>=0) {i0=0;}
-		else if((i0&0x7fffffff)!=0)
-		  { i0=0xbf800000;}
-	    } else {
-		i = (0x007fffff)>>j0;
-		if((i0&i)==0) return x; /* x is integral */
-		if(i0<0) i0 += (0x00800000)>>j0;
-		i0 &= (~i);
-	    }
-	} else {
-	    if(__builtin_expect(j0==0x80, 0)) return x+x; /* inf or NaN */
-	    else return x;		/* x is integral */
+#if USE_FLOORF_BUILTIN
+  return __builtin_floorf (x);
+#else
+  int32_t i0, j0;
+  uint32_t i;
+  GET_FLOAT_WORD (i0, x);
+  j0 = ((i0 >> 23) & 0xff) - 0x7f;
+  if (j0 < 23)
+    {
+      if (j0 < 0)
+	{
+	  /* return 0 * sign (x) if |x| < 1  */
+	  if (i0 >= 0)
+	    i0 = 0;
+	  else if ((i0 & 0x7fffffff) != 0)
+	    i0 = 0xbf800000;
 	}
-	SET_FLOAT_WORD(x,i0);
-	return x;
+      else
+	{
+	  i = (0x007fffff) >> j0;
+	  if ((i0 & i) == 0)
+	    return x;		/* x is integral  */
+	  if (i0 < 0)
+	    i0 += (0x00800000) >> j0;
+	  i0 &= (~i);
+	}
+    }
+  else
+    {
+      if (__glibc_unlikely (j0 == 0x80))
+	return x + x;		/* inf or NaN  */
+      else
+	return x;		/* x is integral  */
+    }
+  SET_FLOAT_WORD (x, i0);
+  return x;
+#endif /* USE_FLOORF_BUILTIN  */
 }
 #ifndef __floorf
 libm_alias_float (__floor, floor)
diff --git a/sysdeps/ieee754/ldbl-128/s_floorl.c b/sysdeps/ieee754/ldbl-128/s_floorl.c
index f340a3fbca..8d20a79fec 100644
--- a/sysdeps/ieee754/ldbl-128/s_floorl.c
+++ b/sysdeps/ieee754/ldbl-128/s_floorl.c
@@ -13,7 +13,9 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
+#include <math-use-builtins.h>
+
+#if ! USE_FLOORL_BUILTIN && defined (LIBM_SCCS) && ! defined (lint)
 static char rcsid[] = "$NetBSD: $";
 #endif
 
@@ -29,41 +31,70 @@ static char rcsid[] = "$NetBSD: $";
 #include <math_private.h>
 #include <libm-alias-ldouble.h>
 
-_Float128 __floorl(_Float128 x)
+_Float128
+__floorl (_Float128 x)
 {
-	int64_t i0,i1,j0;
-	uint64_t i,j;
-	GET_LDOUBLE_WORDS64(i0,i1,x);
-	j0 = ((i0>>48)&0x7fff)-0x3fff;
-	if(j0<48) {
-	    if(j0<0) {
-		/* return 0*sign(x) if |x|<1 */
-		if(i0>=0) {i0=i1=0;}
-		else if(((i0&0x7fffffffffffffffLL)|i1)!=0)
-		    { i0=0xbfff000000000000ULL;i1=0;}
-	    } else {
-		i = (0x0000ffffffffffffULL)>>j0;
-		if(((i0&i)|i1)==0) return x; /* x is integral */
-		if(i0<0) i0 += (0x0001000000000000LL)>>j0;
-		i0 &= (~i); i1=0;
+#if USE_FLOORL_BUILTIN
+  return __builtin_floorl (x);
+#else
+  int64_t i0, i1, j0;
+  uint64_t i, j;
+  GET_LDOUBLE_WORDS64 (i0, i1, x);
+  j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
+  if (j0 < 48)
+    {
+      if (j0 < 0)
+	{
+	  /* return 0 * sign (x) if |x| < 1 */
+	  if (i0 >= 0)
+	    {
+	      i0 = i1 = 0;
+	    }
+	  else if (((i0 & 0x7fffffffffffffffLL) | i1) != 0)
+	    {
+	      i0 = 0xbfff000000000000ULL;
+	      i1 = 0;
 	    }
-	} else if (j0>111) {
-	    if(j0==0x4000) return x+x;	/* inf or NaN */
-	    else return x;		/* x is integral */
-	} else {
-	    i = -1ULL>>(j0-48);
-	    if((i1&i)==0) return x;	/* x is integral */
-	    if(i0<0) {
-		if(j0==48) i0+=1;
-		else {
-		    j = i1+(1LL<<(112-j0));
-		    if(j<i1) i0 +=1 ; 	/* got a carry */
-		    i1=j;
-		}
+	}
+      else
+	{
+	  i = (0x0000ffffffffffffULL) >> j0;
+	  if (((i0 & i) | i1) == 0)
+	    return x;		/* x is integral  */
+	  if (i0 < 0)
+	    i0 += (0x0001000000000000LL) >> j0;
+	  i0 &= (~i);
+	  i1 = 0;
+	}
+    }
+  else if (j0 > 111)
+    {
+      if (j0 == 0x4000)
+	return x + x;		/* inf or NaN  */
+      else
+	return x;		/* x is integral  */
+    }
+  else
+    {
+      i = -1ULL >> (j0 - 48);
+      if ((i1 & i) == 0)
+	return x;		/* x is integral  */
+      if (i0 < 0)
+	{
+	  if (j0 == 48)
+	    i0 += 1;
+	  else
+	    {
+	      j = i1 + (1LL << (112 - j0));
+	      if (j < i1)
+		i0 += 1 ;	/* got a carry */
+	      i1 = j;
 	    }
-	    i1 &= (~i);
 	}
-	SET_LDOUBLE_WORDS64(x,i0,i1);
-	return x;
+      i1 &= (~i);
+    }
+  SET_LDOUBLE_WORDS64 (x, i0, i1);
+  return x;
+#endif /* USE_FLOORL_BUILTIN  */
 }
 libm_alias_ldouble (__floor, floor)
diff --git a/sysdeps/s390/fpu/math-use-builtins.h b/sysdeps/s390/fpu/math-use-builtins.h
index 15705fa74a..63cc9d7a23 100644
--- a/sysdeps/s390/fpu/math-use-builtins.h
+++ b/sysdeps/s390/fpu/math-use-builtins.h
@@ -34,12 +34,18 @@
 # define USE_RINTF_BUILTIN 1
 # define USE_RINTL_BUILTIN 1
 
+# define USE_FLOOR_BUILTIN 1
+# define USE_FLOORF_BUILTIN 1
+# define USE_FLOORL_BUILTIN 1
+
 # if __GNUC_PREREQ (8, 1)
 #  define USE_NEARBYINTF128_BUILTIN 1
 #  define USE_RINTF128_BUILTIN 1
+#  define USE_FLOORF128_BUILTIN 1
 # else
 #  define USE_NEARBYINTF128_BUILTIN 0
 #  define USE_RINTF128_BUILTIN 0
+#  define USE_FLOORF128_BUILTIN 0
 # endif
 
 #else
-- 
2.19.1