kifejezéshelyettesítést

Kifejezéshelyettesítés is a Hungarian term that translates to "expression substitution" or "sub-expression elimination" in English. It refers to a compiler optimization technique aimed at improving code efficiency by replacing repeated computations of the same expression with a single computation.

The core idea behind kifejezéshelyettesítés is to identify instances where an identical expression, such as a calculation or a function call, appears multiple times within a program's code. Instead of re-evaluating this expression each time it is encountered, the compiler calculates it once and stores the result in a temporary variable. Subsequent occurrences of the same expression then simply retrieve the value from this temporary variable, thereby reducing redundant computations.

This optimization is particularly beneficial for complex or computationally intensive expressions. By avoiding repeated calculations, kifejezéshelyettesítés can lead to significant performance gains, especially in loops or frequently called functions. It also contributes to reducing the overall execution time of the program. The effectiveness of this technique depends on the compiler's ability to accurately identify identical expressions and the overhead associated with managing temporary variables.