RE: Compilation time in gcc-4.4.0

[BLUE 3TOO <blue_3too at hotmail dot com>]

33 minutes to 39 second? that sounds a drastic improvement. 
The performance improvement is also amazing.
 
You can try to divide your program into subphases and measure 
the biggest change in time and then focus on parts that contribute
to the most improvement. Sometimes it is can be done quickly through
comparing the optimization log/IR dumpings/assembly.
 
if everything is right, your paper probably is a good story to tell.
But before that, I guess the compiler is quite noisey. :)

 

----------------------------------------
> From: iant@google.com
> To: maxiwell@gmail.com
> CC: gcc@gcc.gnu.org
> Subject: Re: Compilation time in gcc-4.4.0
> Date: Sat, 10 Jul 2010 15:04:02 -0700
>
> Maxiwell Garcia writes:
>
>> I am writing a paper about instruction-set architecture simulators. In
>> first time, I used gcc-4.4.0 and the compilation time reached 33
>> minutes (with -O3) for my simulator and the performance reached 270
>> MIPS (Million instruction per second). When I used the gcc-4.4.4, in
>> the same code, the compilation time reached 39 seconds and the
>> performance reached 600 MIPS. My code have many "switchs" with 512
>> "cases" and the library is in use.
>> How to explain this behavior in the compilation and performance in my paper?
>
> If I'm reading this correctly, it sounds like a useful optimization fix
> in gcc 4.4.4. The compiler runs faster and generates better code.
>
> So I'm not sure what your question is. Are you asking us why gcc has
> gotten better?
>
> Ian 		 	   		  
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