From fa9d7d3b70bae40150022c469b6b50c001474e11 Mon Sep 17 00:00:00 2001
From: Paolo Carlini <paolo.carlini@oracle.com>
Date: Wed, 9 Jun 2010 09:15:51 +0000
Subject: [PATCH] re PR libstdc++/44413 (inefficient code for
std::string::compare on x86-64)
2010-06-09 Paolo Carlini <paolo.carlini@oracle.com>
PR libstdc++/44413
* include/ext/vstring_util.h (__vstring_utility<>::_S_compare):
Simplify, just return -1, 0, 1.
From-SVN: r160456
---
libstdc++-v3/ChangeLog | 6 ++++++
libstdc++-v3/include/ext/vstring_util.h | 17 ++++++-----------
2 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index db2c20646dd1..edb1519046cc 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2010-06-09 Paolo Carlini <paolo.carlini@oracle.com>
+
+ PR libstdc++/44413
+ * include/ext/vstring_util.h (__vstring_utility<>::_S_compare):
+ Simplify, just return -1, 0, 1.
+
2010-06-08 Paolo Carlini <paolo.carlini@oracle.com>
* include/std/type_traits (has_nothrow_assign): Rename to
diff --git a/libstdc++-v3/include/ext/vstring_util.h b/libstdc++-v3/include/ext/vstring_util.h
index 4042f70692ed..a9c88d467a01 100644
--- a/libstdc++-v3/include/ext/vstring_util.h
+++ b/libstdc++-v3/include/ext/vstring_util.h
@@ -1,6 +1,7 @@
// Versatile string utility -*- C++ -*-
-// Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+// Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
+// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
@@ -50,10 +51,10 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
{
typedef typename _Alloc::template rebind<_CharT>::other _CharT_alloc_type;
- typedef _Traits traits_type;
+ typedef _Traits traits_type;
typedef typename _Traits::char_type value_type;
typedef typename _CharT_alloc_type::size_type size_type;
- typedef typename _CharT_alloc_type::difference_type difference_type;
+ typedef typename _CharT_alloc_type::difference_type difference_type;
typedef typename _CharT_alloc_type::pointer pointer;
typedef typename _CharT_alloc_type::const_pointer const_pointer;
@@ -164,14 +165,8 @@ _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
static int
_S_compare(size_type __n1, size_type __n2)
{
- const difference_type __d = difference_type(__n1 - __n2);
-
- if (__d > __numeric_traits_integer<int>::__max)
- return __numeric_traits_integer<int>::__max;
- else if (__d < __numeric_traits_integer<int>::__min)
- return __numeric_traits_integer<int>::__min;
- else
- return int(__d);
+ const difference_type __d = __n1 - __n2;
+ return __d == 0 ? 0 : (__d > 0 ? 1 : -1);
}
};
--
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