g ++ inlined在调用always_inline“int _rdrand16_step（）”时失败

Posted 2021-04-11

我在Windows上使用英特尔功能_rdrand16_step()编写了一个代码（Visual Studio 2017），但在Linux（g ++）上我无法正常工作。我在我的代码中调用了这个函数2次：

#include <immintrin.h>
...
unsigned short val = 0;
if (_rdrand16_step(&val))
...
_rdrand16_step(&val);
...

和g ++输出：

/usr/lib/gcc/x86_64-linux-gnu/8/include/immintrin.h: In member function ‘int otp_s7c::crypt(std::__cxx11::string, std::__cxx11::string, long long unsigned int)’:
/usr/lib/gcc/x86_64-linux-gnu/8/include/immintrin.h:129:1: error: inlining failed in call to always_inline ‘int _rdrand16_step(short unsigned int*)’: target specific option mismatch
 _rdrand16_step (unsigned short *__P)
 ^~~~~~~~~~~~~~
otp_s7c.cpp:139:24: note: called from here
      if (_rdrand16_step(&val))
          ~~~~~~~~~~~~~~^~~~~~
/usr/lib/gcc/x86_64-linux-gnu/8/include/immintrin.h:129:1: error: inlining failed in call to always_inline ‘int _rdrand16_step(short unsigned int*)’: target specific option mismatch
 _rdrand16_step (unsigned short *__P)
 ^~~~~~~~~~~~~~
otp_s7c.cpp:148:23: note: called from here
         _rdrand16_step(&val);
         ~~~~~~~~~~~~~~^~~~~~

答案

这是一个有点误导性的错误消息，源于你实际上并没有告诉编译器你的目标架构支持RDRAND指令（据我所知，这里的重要部分是“目标特定选项不匹配”部分）在末尾）。

将-mrdrnd添加到编译器标志似乎可以解决问题。

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