这个问题是在编写一些与计算机图形相关的代码时发现的，代码的简化版本如下所示：

#include <bits/stdc++.h>

#define __AVX__ 1
#define __AVX2__ 1
#pragma GCC target("avx,avx2,popcnt,tune=native")
#include <immintrin.h>

namespace with_avx {
class vec {
   public:
    vec(double x = 0, double y = 0, double z = 0, double t = 0) {
        vec_data = _mm256_set_pd(t, z, y, x);
    }
    __m256d vec_data;
};
}  // namespace with_avx

namespace without_avx {
class vec {
   public:
    vec(double x = 0, double y = 0, double z = 0, double t = 0) {
        vec_data[0] = x, vec_data[1] = y, vec_data[2] = z, vec_data[3] = t;
    }
    double vec_data[4];
};
}  // namespace without_avx

#ifdef USE_AVX
using namespace with_avx;
#else
using namespace without_avx;
#endif

vec same(vec x) { return x; }
std::function<vec(vec)> stdfunc = same;

int main() { 
    vec rand_vec(rand(), rand(), rand());
    vec ret = stdfunc(rand_vec);
    std::cout<<(double)ret.vec_data[0];
}

如果我编译带有USE_AVX标志的代码，如下所示：

g++-12 stdfunction_test.cpp -o ../build/unit_test -D USE_AVX -g

g++将输出一些警告：

In file included from /usr/include/c++/12/functional:59,
                 from /usr/include/x86_64-linux-gnu/c++/12/bits/stdc++.h:71,
                 from stdfunction_test.cpp:2:
/usr/include/c++/12/bits/std_function.h: In member function ‘_Res std::function<_Res(_ArgTypes ...)>::operator()(_ArgTypes ...) const [with _Res = with_avx::vec; _ArgTypes = {with_avx::vec}]’:
/usr/include/c++/12/bits/std_function.h:587:7: note: the ABI for passing parameters with 32-byte alignment has changed in GCC 4.6
  587 |       operator()(_ArgTypes... __args) const
      |       ^~~~~~~~

然后，如果我运行代码，有时会导致分段错误，输出如下：

[1]    12710 segmentation fault  ../build/unit_test

有时会抛出bad_function_call，并显示以下输出：

terminate called after throwing an instance of 'std::bad_function_call'
  what():  bad_function_call
[1]    12678 IOT instruction  ../build/unit_test

当执行此行时，会发生这两个错误：

vec ret = stdfunc(rand_vec);

然后我使用gdb进行回溯：

(gdb) bt
#0  0x00007ffff7e35521 in __cxa_throw () from /lib/x86_64-linux-gnu/libstdc++.so.6
#1  0x00007ffff7e2c6f4 in std::__throw_bad_function_call() () from /lib/x86_64-linux-gnu/libstdc++.so.6
#2  0x000055555555558b in std::function<with_avx::vec (with_avx::vec)>::operator()(with_avx::vec) const (this=0x7fffffffda74,
    __args#0=...) at /usr/include/c++/12/bits/std_function.h:590
#3  0x000055555555528d in main () at stdfunction_test.cpp:39

但是，如果我不添加标志，代码将正常运行。
我想这可能是由某种对齐问题引起的，比如警告说我不知道如何解决这个问题。
下面列出了我的环境，希望它们会有用：

• g++版本：g++-12 (Ubuntu 12-20220319-1ubuntu1) 12.0.1 20220319 (experimental) [master r12-7719-g8ca61ad148f]
• 操作系统：Ubuntu