RE: [avr-gcc-list] Stack usage under heavy inlining

[Weddington, Eric]

> -----Original Message-----
> From: John Regehr [mailto:address@hidden 
> Sent: Monday, September 08, 2008 11:11 AM
> To: Weddington, Eric
> Cc: Tristan Gingold; Paulo Marques; address@hidden
> Subject: RE: [avr-gcc-list] Stack usage under heavy inlining
> 
> Couple responses:
> 
> I have a student who has hacked gcc so that stack slots are 
> reused, when 
> possible, eliminating the "stack bloat under inlining" 
> problem.  He has 
> also increased the precision of the live range analysis.  All 
> of this is 
> towards the goal of greatly reducing stack memory usage (we 
> can already 
> substantially reduce stack usage vs. default avr-gcc, at 
> least for some 
> applications).  He's integrating with IRA now, not sure when 
> this'll all 
> be ready to share.  We hope to publish something in the Fall 
> but there's a 
> big gap between publishability and usability.

Have him contact me. I have patches from Andy Hutchinson that gets the latest 
AVR toolchain working again after IRA. These patches have been tested but have 
not yet been committed to the FSF tree.

I would also be interested in the work that he is doing.


> To see why this is hard, consider that 
> there may be 
> threads, there may be coroutines, there may be reentrant 
> and/or nested 
> interrupts, etc.

True. I still say that you could make some basic assumptions about a typical 
AVR application that removes some of those complexities. The probablity is next 
to nil that a typical AVR application will have threads, coroutines, and 
reentrant/nested interrupts. There is a greater probability for the latter when 
you start going into the xmega series.

Eric