SSE2 instruction support with /CLR switch.

Question

Why isn't the SSE2 enhanced instruction set optimization available for C++ programs compiled with the /clr switch?

Answer 1

It is the job of the JIT compiler to generate the machine code. It will do so based on the architecture of the processor it runs on. Yes, it will use SSE instructions when appropriate, the x64 JITter uses them heavily.

If you want to use SSE2 in your code then you'll have to compile it separately without /clr. Or use the #pragma managed directive to switch to machine code generation so you can use the intrinsics.