From ae3577f607b50bf3ce9b0877e43ad2508c9da61b Mon Sep 17 00:00:00 2001
From: Stefan Liebler <stli@linux.ibm.com>
Date: Wed, 11 Dec 2019 15:09:18 +0100
Subject: Use GCC builtins for nearbyint functions if desired.

This patch is using the corresponding GCC builtin for nearbyintf, nearbyint,
nearbintl and nearbyintf128 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.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
 sysdeps/ieee754/dbl-64/s_nearbyint.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

(limited to 'sysdeps/ieee754/dbl-64/s_nearbyint.c')

diff --git a/sysdeps/ieee754/dbl-64/s_nearbyint.c b/sysdeps/ieee754/dbl-64/s_nearbyint.c
index c261885c5a..2deaeb2568 100644
--- a/sysdeps/ieee754/dbl-64/s_nearbyint.c
+++ b/sysdeps/ieee754/dbl-64/s_nearbyint.c
@@ -26,16 +26,20 @@
 #include <math_private.h>
 #include <fenv_private.h>
 #include <libm-alias-double.h>
-
-static const double
-TWO52[2] = {
-	    4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
-	    -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
-};
+#include <math-use-builtins.h>
 
 double
 __nearbyint (double x)
 {
+#if USE_NEARBYINT_BUILTIN
+  return __builtin_nearbyint (x);
+#else
+  /* Use generic implementation.  */
+  static const double
+    TWO52[2] = {
+		4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
+		-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
+  };
   fenv_t env;
   int64_t i0, sx;
   int32_t j0;
@@ -67,5 +71,6 @@ __nearbyint (double x)
   math_force_eval (t);
   libc_fesetenv (&env);
   return t;
+#endif /* ! USE_NEARBYINT_BUILTIN  */
 }
 libm_alias_double (__nearbyint, nearbyint)
-- 
cgit 1.4.1