Inlineoptimointi

Inlineoptimointi, known in English as inline optimization or inlining, is a compiler optimization technique. Its primary goal is to reduce the overhead associated with function calls. When a compiler decides to perform inline optimization on a function, it replaces the function call site with the actual body of the function itself. This means that instead of executing a separate jump to the function's code, performing the function's operations, and then jumping back, the code for the function is directly embedded where it was called.

The main benefit of inline optimization is performance improvement. By eliminating function call overhead, such as stack frame management and parameter passing, the program can execute faster. Furthermore, inlining can enable further optimizations. Once the function's code is directly within the caller, the compiler has a larger block of code to analyze, which can lead to better register allocation, loop unrolling, and other optimizations that might not be possible if the code remained in a separate function.

However, inline optimization is not without its drawbacks. Excessive inlining can lead to code bloat, where the overall size of the executable program increases significantly. This can negatively impact cache performance, as larger code segments might not fit into the CPU's instruction cache as effectively, potentially slowing down execution. Compilers typically employ heuristics and analysis to decide which functions are good candidates for inlining, balancing the potential performance gains against the risk of code bloat. Many modern compilers also allow developers to provide hints to guide the inlining process.