Want an example about simple intrinsic in X86

Hi,every one.
I am here again for your help.
Writing a simple intrinsic in X86 is what I wanted to do from the beginning. For this , I read almost all posts on online forums and emails on llvm-dev. There are different
methods about how to add an intrinsic. But none was effective*,* even I even pasted into my own repo .

Combining various methods, I also carried out my own attempt. The attempt ended with an error “error: use of unknown builtin” and I can’t find how to change.

I am very disappointed and crazy !!
So, here, I hope you can give me an example about simple intrinsic in X86.
Thanks you.