> has to dump the pipeline Modern Intel processors have a "stack engine" (similar to the return stack buffer) that speeds up access through RSP. But regardless

> has to dump the pipeline Modern Intel processors have a "stack engine" (similar to the return stack buffer) that speeds up access through RSP. But regardless, there's no need to dump any pipeline; a call just has an implicit store to memory and the RSP gets updated (register-renamed, really). Calls are very, very fast these days.