title: Why do I get this compile error with GCC 5 and cilk-plus?
body: <p>For some reason cilk_spawn does not work with x86 intrinsics.  I get an error every time I try to combine the two in the body of the same function.  (Note that cilk_for works fine).  If I remove all of the SIMD instructions it compiles and runs fine.</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;x86intrin.h&gt;
  #include &lt;math.h&gt;
  #include &lt;cilk/cilk.h&gt;
  
  int main()
  {
      int w = cilk_spawn sqrt(10);
      __m128i x = _mm_set_epi64x(1, 1);
      x = _mm_add_epi64(x, x);
      cilk_sync;
      printf("%d\n", w);
      return 0;
  }
  </code></pre>
  
  <p>here is gcc ouput:</p>
  
  <pre><code>gcc-4.9 -std=c99 -march=native -fcilkplus -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"main.d" -MT"main.d" -o "main.o" "../main.c"
  In file included from /usr/lib/gcc/x86_64-linux-gnu/4.9/include/xmmintrin.h:1258:0,
                   from /usr/lib/gcc/x86_64-linux-gnu/4.9/include/x86intrin.h:31,
                   from ../main.c:2:
  ../main.c: In function ‘main’:
  /usr/lib/gcc/x86_64-linux-gnu/4.9/include/emmintrin.h:581:1: error: inlining failed in call to always_inline ‘_mm_set_epi64x’: function not inlinable
   _mm_set_epi64x (long long __q1, long long __q0)
   ^
  ../main.c:9:10: error: called from here
    __m128i x = _mm_set_epi64x(1, 1);
            ^
  In file included from /usr/lib/gcc/x86_64-linux-gnu/4.9/include/xmmintrin.h:1258:0,
                   from /usr/lib/gcc/x86_64-linux-gnu/4.9/include/x86intrin.h:31,
                   from ../main.c:2:
  /usr/lib/gcc/x86_64-linux-gnu/4.9/include/emmintrin.h:1025:1: error: inlining failed in call to always_inline ‘_mm_add_epi64’: function not inlinable
   _mm_add_epi64 (__m128i __A, __m128i __B)
   ^
  subdir.mk:18: recipe for target 'main.o' failed
  ../main.c:10:4: error: called from here
    x = _mm_add_epi64(x, x);
      ^
  make: *** [main.o] Error 1
  </code></pre>
  
  <p>I just noticed that that was with GCC 4.9 but the error message is the same with GCC 5.</p>