c - inlining failed in call to always_inline ‘_mm_mullo_epi32’: target specific option mismatch

Question

I am trying to compile a C program using cmake which uses SIMD intrinsics. When I try to compile it, I get two errors

/usr/lib/gcc/x86_64-linux-gnu/5/include/smmintrin.h:326:1: error: inlining failed in call to always_inline ‘_mm_mullo_epi32’: target specific option mismatch _mm_mullo_epi32 (__m128i __X, __m128i __Y)

/usr/lib/gcc/x86_64-linux-gnu/5/include/tmmintrin.h:136:1: error: inlining failed in call to always_inline ‘_mm_shuffle_epi8’: target specific option mismatch _mm_shuffle_epi8 (__m128i __X, __m128i __Y)

This issue has already been solved here StackOverflow by setting

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.1")

I try the very same and many other options. But my project still fails to compile.

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.1")  
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -sse4_1")  
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=nehalem")  
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.1 -msse4.2")  
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")  
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ssse3")  

Answer 1

Since you are compiling C code, not C++, you need:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -msse4.1")

You can get rid of all the other -march XXX and -msseXXX settings.

If you're using a mix of C and C++ then you could also add:

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse4.1")