ncremental compilation is a compiler optimization technique designed to improve the efficiency of the build process by recompiling only the portions of a program that have been modified, rather than recompiling the entire codebase from scratch. This method is particularly advantageous in large-scale projects where full recompilation could be time-consuming and resource-intensive. By focusing only on the changed code and its dependencies, incremental compilation significantly reduces build times, leading to faster development cycles.

When a developer makes changes to a small section of the codebase, the incremental compiler evaluates those changes to identify which parts of the project are affected. It then recompiles only the modified portions and any associated dependencies, leaving the unaffected parts of the program untouched. This targeted recompilation saves both time and computing resources, making it especially beneficial in environments where developers need quick feedback on their changes.

Incremental compilation plays a crucial role in continuous integration (CI) and continuous delivery (CD) environments, where code is frequently modified, and rapid builds are essential. In CI workflows, developers often commit changes multiple times a day, and waiting for full compilations to complete with every change would drastically slow down the process. With incremental compilation, feedback is delivered much faster, enabling teams to identify and resolve issues more quickly, thereby maintaining a high development velocity.

The technique is widely used in development environments for languages such as Java, C++, Scala, and Swift, where the build processes for large projects can otherwise be very slow. Modern integrated development environments (IDEs) like IntelliJ IDEA, Eclipse, and Visual Studio often incorporate incremental compilation to offer faster builds, improved productivity, and a smoother development experience.

However, incremental compilation can introduce complexity, as the compiler must correctly track and manage dependencies to ensure that all necessary parts of the program are recompiled when changes occur. Despite this, the efficiency gains it provides make incremental compilation a key feature in modern software development.