Question

I’m currently working on an optimization of some C codes under MSVC, in which some sin() and cos() calculations are performed.

I use the SSE implementations like:

a = _mm_set_pd(cos(w),sin(w));

However, when I check disassembly codes later, I find that Microsoft compiler interpret cos(w) and sin(w) as follows:

call        __libm_sse2_cos 
...
call        __libm_sse2_sin 

In which cos and sin are called separately. But I would expect that compiler call __libm_sse2_sincos to calculate sin and cos with the same radian simultaneously.

So is it possible that I tell compiler to do this? or any interface to call them under MSVC? How about under Linux?

Thanks a lot for the help.

Answer 1

Why not just do this:

double s, c;

sincos(w, &s, &c);
a = _mm_set_pd(c, s);

?