From fa9d7d3b70bae40150022c469b6b50c001474e11 Mon Sep 17 00:00:00 2001 From: Paolo Carlini Date: Wed, 9 Jun 2010 09:15:51 +0000 Subject: re PR libstdc++/44413 (inefficient code for std::string::compare on x86-64) 2010-06-09 Paolo Carlini 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 db2c206..edb1519 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,9 @@ +2010-06-09 Paolo Carlini + + PR libstdc++/44413 + * include/ext/vstring_util.h (__vstring_utility<>::_S_compare): + Simplify, just return -1, 0, 1. + 2010-06-08 Paolo Carlini * 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 4042f70..a9c88d4 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::__max) - return __numeric_traits_integer::__max; - else if (__d < __numeric_traits_integer::__min) - return __numeric_traits_integer::__min; - else - return int(__d); + const difference_type __d = __n1 - __n2; + return __d == 0 ? 0 : (__d > 0 ? 1 : -1); } }; -- cgit v1.1