Just write some SIMD code instead of making the compiler generate the SIMD code automatically, but how do I enable the icc compiler to compile with the code?
Write inline SSE assembly and compile it with Intel compiler.
If you don't want to go down the path of writing in assembly language, there is also same kind of wrapper called "intrinsics" that looks and feels like a function call but are translated directly to assembly. A description is given in this article. For a recent example with AVX2, you might be interested in my blog.