为什么我无法在 GCC 13.x 版本中使用 #pragma GCC target(...) 声明字符串类型变量

Question

我刚刚将 GCC 编译器版本从 11.4 更新到 13.1。我发现以下代码曾经在我的旧 GCC 11.4 上运行，但不再在 GCC 13.1 上运行。

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")

#include <iostream>

int main() {
    string s = "Hello World!";
    cout << s << endl;
}

这是编译器消息：

====================[ Build | run | Debug ]=====================================
"C:\Program Files\JetBrains\CLion 2023.3.2\bin\cmake\win\x64\bin\cmake.exe" --build C:\Users\zyk\CLionProjects\run\cmake-build-debug --target run -j 18
[1/2] Building CXX object CMakeFiles/run.dir/main.cpp.obj
FAILED: CMakeFiles/run.dir/main.cpp.obj 
C:\PROGRA~1\JETBRA~1\CLION2~1.2\bin\mingw\bin\G__~1.EXE   -g -fdiagnostics-color=always -MD -MT CMakeFiles/run.dir/main.cpp.obj -MF CMakeFiles\run.dir\main.cpp.obj.d -o CMakeFiles/run.dir/main.cpp.obj -c C:/Users/zyk/CLionProjects/run/main.cpp
In file included from C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/string:43,
                 from C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/bits/locale_classes.h:40,
                 from C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/bits/ios_base.h:41,
                 from C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/ios:44,
                 from C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/ostream:40,
                 from C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/iostream:41,
                 from C:/Users/zyk/CLionProjects/run/main.cpp:3:
C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/bits/allocator.h: In destructor 'std::__cxx11::basic_string<char>::_Alloc_hider::~_Alloc_hider()':
C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/bits/allocator.h:184:7: error: inlining failed in call to 'always_inline' 'std::allocator< <template-parameter-1-1> >::~allocator() noexcept [with _Tp = char]': target specific option mismatch
  184 |       ~allocator() _GLIBCXX_NOTHROW { }
      |       ^
In file included from C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/string:54:
C:/Program Files/JetBrains/CLion 2023.3.2/bin/mingw/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/bits/basic_string.h:192:14: note: called from here
  192 |       struct _Alloc_hider : allocator_type // TODO check __is_final
      |              ^~~~~~~~~~~~
ninja: build stopped: subcommand failed.

通过删除

#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")

甚至简单地不声明任何字符串类型变量，我可以让代码再次工作。但有时由于某些原因我需要那行代码。

这是我在编译器资源管理器上的代码的链接：https://godbolt.org/z/r4rxr6Efn

UPD： 使用最小的工作示例进行了更新，没有

using namespace std;

和

bit/stdc++.h

头文件。

Answer 1

target

编译指示适用于文件中稍后定义的所有函数。 切勿将其放在

#include

指令前面；否则，您尝试将

target

编译指示放在标准库函数上，但这是不受支持的。

以下代码编译（https://godbolt.org/z/efxThx51e）：

#include <iostream>
#include <string>

#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")

int main() {
    std::string s = "Hello World!";
    std::cout << s << std::endl;
}