From eb9066203f6e07128d42f771def4b7ad37b25dc1 Mon Sep 17 00:00:00 2001
From: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
Date: Mon, 24 May 2021 09:43:12 +0800
Subject: Use GCC builtins for roundeven functions if desired.

This patch is using the corresponding GCC builtin for roundevenf,
roundeven and roundevenl if the USE_FUNCTION_BUILTIN macros are defined
to one in math-use-builtins.h.

These builtin functions is supported since GCC 10.

The code of the generic implementation is not changed.

Signed-off-by: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
---
 sysdeps/ieee754/dbl-64/s_roundeven.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'sysdeps/ieee754/dbl-64')

diff --git a/sysdeps/ieee754/dbl-64/s_roundeven.c b/sysdeps/ieee754/dbl-64/s_roundeven.c
index 5deff3bb8a..88c051e9fe 100644
--- a/sysdeps/ieee754/dbl-64/s_roundeven.c
+++ b/sysdeps/ieee754/dbl-64/s_roundeven.c
@@ -21,6 +21,7 @@
 #include <math_private.h>
 #include <libm-alias-double.h>
 #include <stdint.h>
+#include <math-use-builtins.h>
 
 #define BIAS 0x3ff
 #define MANT_DIG 53
@@ -29,6 +30,9 @@
 double
 __roundeven (double x)
 {
+#if USE_ROUNDEVEN_BUILTIN
+  return __builtin_roundeven (x);
+#else
   uint64_t ix, ux;
   EXTRACT_WORDS64 (ix, x);
   ux = ix & 0x7fffffffffffffffULL;
@@ -66,6 +70,7 @@ __roundeven (double x)
     ix &= 0x8000000000000000ULL;
   INSERT_WORDS64 (x, ix);
   return x;
+#endif /* ! USE_ROUNDEVEN_BUILTIN  */
 }
 #ifndef __roundeven
 libm_alias_double (__roundeven, roundeven)
-- 
cgit 1.4.1