将__m256i设置为两个__m128i值的值 [英] Setting __m256i to the value of two __m128i values

问题描述

因此，AVX具有 immintrin.h 中的功能，该功能应允许将两个 __ m128i 值的串联存储到单个 __ m256i 中价值.功能是

So, AVX has a function from immintrin.h, which should allow to store the concatenation of two __m128i values into a single __m256i value. The function is

__m256i _mm256_set_m128i (__m128i hi, __m128i lo)

但是，当我使用它时，就像这样:

However, when I use it, like so:

__m256i as[2]; __m128i s[4]; as[0] = _mm256_setr_m128i(s[0], s[1]);

我收到编译错误:

error: incompatible types when assigning to type ‘__m256i’ from type ‘int’

我真的不明白为什么会这样.任何帮助，我们将不胜感激！

I don't really understand why this happens. Any help is greatly appreciated!

推荐答案

并不是所有的编译器似乎都具有 _mm256_setr_m128i ，甚至没有在 immintrin中定义的 _mm256_set_m128i .h .因此，通常我只需要根据需要定义宏，并在适当的 #ifdef 后面加上括号，以测试编译器和版本:

Not all compilers seem to have _mm256_setr_m128i, or even _mm256_set_m128i, defined in immintrin.h. So I usually just define macros as needed, bracketed with suitable #ifdefs which test for compiler and version:

#define _mm256_set_m128i(v0, v1)  _mm256_insertf128_si256(_mm256_castsi128_si256(v1), (v0), 1)

#define _mm256_setr_m128i(v0, v1) _mm256_set_m128i((v1), (v0))

• Intel ICC 11.1和更高版本同时具有 _mm256_set_m128i 和 _mm256_setr_m128i .

  MSVC 2012及更高版本仅具有 _mm256_set_m128i .

  MSVC 2012 and later has just _mm256_set_m128i.

  gcc/clang似乎也没有，尽管我还没有检查最新版本以查看是否已解决.

  gcc/clang don't seem to have either, although I haven't checked recent versions to see if this has been fixed yet.

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