Automatic inference of const/pure function attributes

[Yang Zhang]

Can gcc automatically determine that a function is const/pure (on a 
best-effort basis), instead of requiring the user to explicitly specify 
the attribute always?  (I realize determining this may be difficult for 
certain functions, or the user may simply wish to specify this anyway 
regardless of the true nature of the function.)
-- 
Yang Zhang
http://www.mit.edu/~y_z/