llvm dev - Apr 2008 - [LLVMdev] llvm-ld optimization options

I have been wondering why llvm-ld generates the same code with or
without the option "-O5" so I looked at its source (llvm 2.2). And
apparently, the options "-On" are accepted but never used! The program
runs a fixed set of optimization passes, unless "-disable-opt" is
specified. What is the reason for this? If this is intended, then the
documentation should say something about this IMHO.


Regards,
Kevin André

On Thu, 17 Apr 2008, HyperQuantum wrote:
> I have been wondering why llvm-ld generates the same code with or
without the option "-O5" so I looked at its source (llvm 2.2). And
apparently, the options "-On" are accepted but never used! The program
runs a fixed set of optimization passes, unless "-disable-opt" is
specified. What is the reason for this? If this is intended, then the
documentation should say something about this IMHO.

Probably the standard answer: "because noone has done it yet" :)

-Chris

-- 
http://nondot.org/sabre/
http://llvm.org/

On 17 Apr 2008, at 20:39, Chris Lattner wrote:
> On Thu, 17 Apr 2008, HyperQuantum wrote:
>> I have been wondering why llvm-ld generates the same code with or
> without the option "-O5" so I looked at its source (llvm 2.2).
And
> apparently, the options "-On" are accepted but never used! The
program
> runs a fixed set of optimization passes, unless "-disable-opt" is
> specified. What is the reason for this? If this is intended, then the
> documentation should say something about this IMHO.
>
> Probably the standard answer: "because noone has done it yet" :)
I don't want to sound too much like advertising our work, but COLE  
(see the CGO paper at http://www.elis.ugent.be/~kehoste) seems to be  
extremely well suited to figure out which passes should go where for  
llvm-ld... Same goes for llvm-gcc and opt btw :-)

I hope I can find the time sometime soon to work on this...

greetings,

Kenneth

-- 

Computer Science is no more about computers than astronomy is about  
telescopes. (E. W. Dijkstra)

Kenneth Hoste
ELIS - Ghent University
email: kenneth.hoste at elis.ugent.be
blog: http://www.elis.ugent.be/~kehoste/blog
website: http://www.elis.ugent.be/~kehoste