This code is analyzed . Typically, the flow of control and the liveness of variables are analyzed. The code is again optimized . The final code is emitted . If you do not understand the syntax vs. semantics distinction made earlier, let's consider it in terms of English.
Syntax gives the structure of a sentence.
Semantics assigns a meaning . Given that weak definition, the following might all be sentences. John threw the ball. The books are pretty colors. John are a book.