Induction variable
[1] For example, in the following loop, i and j are induction variables: A common compiler optimization is to recognize the existence of induction variables and replace them with simpler computations; for example, the code above could be rewritten by the compiler as follows, on the assumption that the addition of a constant will be cheaper than a multiplication.This optimization is a special case of strength reduction.In some cases, it is possible to reverse this optimization in order to remove an induction variable from the code entirely.Either one can be rewritten as a linear function of the other; therefore, the compiler may optimize this code as if it had been written Induction variable substitution is a compiler transformation to recognize variables which can be expressed as functions of the indices of enclosing loops and replace them with expressions involving loop indices.Example: Input code: Output code The same optimizations can be applied to induction variables that are not necessarily linear functions of the loop counter; for example, the loop may be converted to