From ab98b4c0725eb7c0f03d319ef3e22ae761b2698a Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 23 Sep 2022 13:39:31 +0100 Subject: [PATCH] libstdc++: Micro-optimizaion for std::bitset stream extraction Don't bother trying to copy any characters for bitset<0>. libstdc++-v3/ChangeLog: * include/std/bitset (operator>>): Do not copy for N==0. * testsuite/20_util/bitset/io/input.cc: Add comment. --- libstdc++-v3/include/std/bitset | 2 +- libstdc++-v3/testsuite/20_util/bitset/io/input.cc | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset index 83c6416b7706..6dbc58c6429e 100644 --- a/libstdc++-v3/include/std/bitset +++ b/libstdc++-v3/include/std/bitset @@ -1615,7 +1615,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER if (__tmp.empty() && _Nb) __state |= __ios_base::failbit; - else + else if _GLIBCXX17_CONSTEXPR (_Nb) __x._M_copy_from_string(__tmp, static_cast(0), _Nb, __zero, __one); if (__state) diff --git a/libstdc++-v3/testsuite/20_util/bitset/io/input.cc b/libstdc++-v3/testsuite/20_util/bitset/io/input.cc index 939861b171ea..0f22cefbb5b7 100644 --- a/libstdc++-v3/testsuite/20_util/bitset/io/input.cc +++ b/libstdc++-v3/testsuite/20_util/bitset/io/input.cc @@ -39,7 +39,7 @@ void test01() ss.clear(); ss.str("*"); ss >> b0; - VERIFY( ss.rdstate() == ios_base::goodbit ); + VERIFY( ss.rdstate() == ios_base::goodbit ); // LWG 3199 } int main() -- 2.47.3