what is function cloning?

[Ian Lance Taylor]

ranjith kumar <ranjithproxy@gmail.com> writes:

> What is function cloning?

In the context of a compiler, it's when the compiler makes a second
copy of a function with some modification.  For example, if the
compiler discovers that a function is called many different times with
the same initial parameter, it may clone the function to produce a
version which takes one less parameter, and then change all the
callers to call the clone.

Another example is that a compiler may make several clones of a
function and compile them tuned for different microarchitectures, and
then arrange for the appropriate one to be used at runtime based on
some sort of CPU test.

Ian