Unreachable Code Elimination

1. How does the compiler can identify unreachable code?

In order to check if the program contains sections of code that will never be reached, compiler checks the flow of the program. In order to check for such code compiler makes use of static analysis techniques.

2. Mention some of the conditions where Unreachable Code occurs.

Unreachable Code Elimination mostly arises in the code where the conditions are always true or they are always false after the returns or unconditional jumps or due to some conflicting conditions that occur.

3. Does Unreachable Code Elimination work under runtime conditions?

No, Unreachable Code Elimination does not consider runtime conditions rather it is based only on static analysis. It then eliminates the code under static analysis without considering the input or runtime behavior.

4. What are the limitations of Unreachable Code Elimination?

The limitation of Unreachable Code Elimination is that it can mistakenly identify a code section as unreachable, even if it can be reached under certain conditions.

5. Can Unreachable Code Elimination work for dynamically typed languages?

Yes, Unreachable Code Elimination can be used for dynamically typed languages also. It can be used until the compiler or interpreter is able to perform all the required static analyses in order to determine the code’s reachability.

Unreachable Code is also known as dead code in Compiler Design that points to the portion of a program that is never executed under any condition or scenario. This dead code doesn’t do any functionality in the program but unnecessarily occupies the space in the application memory, and also due to this there are different problems of unnecessary computation, that describe the program’s performance. So, to avoid this issue in Compiler Design, we can use the technique of Unreachable Code Elimination. In this Compiler Design article, we will see Unreachable Code Elimination with its techniques, practical examples, and advantages.