[LLVMdev] Folding an insertelt chain

[Duncan Sands]

Hi Ivan,

> I've added a little combining operation in DAGCombiner to fold a chain of
> insertelt nodes if that chain is proved to fully overwrite the very first source
> vector. In which case, I supposed a build_vector is better. It seems to be safe
> but I don't know if it is correctly implemented or if it is already done
> somewhere else. Please find attached the patch.

please also provide some testcases.

Thanks, Duncan.