From: Jonathan Wakely <jwakely@redhat.com>
Date: Mon, 12 May 2025 11:56:17 +0000 (+0100)
Subject: libstdc++: Micro-optimization in std::arg overload for scalars
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=270d23c5b201c8e000f60e05d17577498f409441;p=thirdparty%2Fgcc.git

libstdc++: Micro-optimization in std::arg overload for scalars

Use __builtin_signbit directly instead of std::signbit.

libstdc++-v3/ChangeLog:

	* include/std/complex (arg(T)): Use __builtin_signbit instead of
	std::signbit.

Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
---

diff --git a/libstdc++-v3/include/std/complex b/libstdc++-v3/include/std/complex
index 67f37d4ec2b..d9d2d8afda8 100644
--- a/libstdc++-v3/include/std/complex
+++ b/libstdc++-v3/include/std/complex
@@ -2532,8 +2532,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       typedef typename __gnu_cxx::__promote<_Tp>::__type __type;
 #if (_GLIBCXX11_USE_C99_MATH && !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC)
-      return std::signbit(__x) ? __type(3.1415926535897932384626433832795029L)
-	                       : __type();
+      return __builtin_signbit(__type(__x))
+	       ? __type(3.1415926535897932384626433832795029L) : __type();
 #else
       return std::arg(std::complex<__type>(__x));
 #endif