A Study and Analysis of Function Inlining

Function inlining is a widely known technique which has been used to improve program performance. Inlining replaces a function call by the body of the function. In this report, we study the effects of inline function expansion by observing the empirical behavior of a set of C and C++ programs. Our results indicate that for the average C program improvements in timings due to inlining are not much (2-3%). However, C++ programs benefit much more (up to 46%) from inlining due to smaller average function size and a larger call stack depth. 1 Introduction Almost all programs are typically written as a collection of smaller computing units (procedures or functions) to aid program development. However, function invocation in a program has an associated overhead which might affect the execution time of the program. It also affects compile time optimizations like register allocation, dead code elimination, common subexpression elimination, constant propagation etc. Besides, conservative assump..