Function Versioning

[Revital Eres]

Hello,

We would like to implement function versioning in tree level 
for the use of IPA constant propagation.
(http://gcc.gnu.org/ml/gcc/2004-06/msg00518.html)

We intend to work on the tree-profiling branch.

As for the implementation - we intend to create a new call-graph 
node for the new version of the function (using the current cloning
interface). 
The copy of the new version tree body will be done using copy_body_r () 
function (tree-inline.c). Since it is now completely specified to 
inlining I will adjust it to handle also simple coping of trees.

We would like to thank Steven Bosscher, Jan Hubicka and Stuart Hastings 
for their feedback.

Revital