Re: Function Inlining for FORTRAN

[Canqun Yang <canqun at nudt dot edu dot cn>]

Paul Brook <paul@codesourcery.com>:

> On Wednesday 20 July 2005 15:35, Canqun Yang wrote:
> > Hi, all
> >
> > Function inlining for FORTRAN programs always fails. 
> 
> Not entirely true. Inlining of contained procedures works fine (or it did la
> st 
> time I checked). This should include inlining of siblings within a module.
> 
> > If no one engages in it, I will give a try. Would you please give me
> > some clues? 
> 
> The problem is that each top level program unit (PU)[1] is compiled 
> separately. Each PU has it's own "external" decls for all function calls, 
> even if the function happens to be in the same function. Thus each PU is an 
> 
> isolated self-contained tree structure, and the callgraph doesn't know the 
> definition and declaration are actually the same thing.
> 
> Basically what you need to do is parse the whole file, then start generating
>  
> code.
> 
> Unfortunately this isn't simple (or it would have been fixed already!).
> Unlike C Fortran doesn't have file-level scope. It makes absolutely no 
> difference whether two procedures are in the same file, or in different 
> files.  You get all the problems that multifile IPA in C experiences within 
> a 
> single Fortran file. 
> 
> The biggest problem is type consistency and aliasing. Consider the following
>  

I have several FORTRAN 77 programs. After inlining the small functions in them by hand, they 
made a great performance improvements. So I need a trial implementation of function inlining to 
verify the effectiveness of it.

Now, my question is: If we just take the FORTRAN 77 syntax into account (no derived types, no 
complex aliasing), may it be simpler to implement function inlining for FORTRAN 77.

> 
> Paul
> 


Canqun Yang
Creative Compiler Research Group.
National University of Defense Technology, China.