Optimisation Problem

[vikramsp]

hello there... i am trying my hands on gcc optimisations options.
i tried e.g. -finline-functions, -funroll-loops and the likes but none
worked for me
for ex. i tried -funroll-loops for code
for (int i = 0; i < 3; ++i)
  a[i] = i;

which should unroll like
a[0] = 0
a[1] = 1
a[2] = 2
but it didn't seem to happen. Is this a bug or something?
please help me write good test case or suggest some. i am using gcc
4.1.2. tried 5.4.2 also on rhel5

Best Regards
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Re: Optimisation Problem

[vikramsp]

Thanks Eric.
But i wanted to try them indivisually. Is there any method to do so?
Regards - vikramsp

Eric Botcazou-3 wrote:
> 
>> hello there... i am trying my hands on gcc optimisations options.
>> i tried e.g. -finline-functions, -funroll-loops and the likes but none
>> worked for me
>> for ex. i tried -funroll-loops for code
>> for (int i = 0; i < 3; ++i)
>>   a[i] = i;
> 
> Try -O -funroll-loops.
> 
> -- 
> Eric Botcazou
> 
> 

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Re: Optimisation Problem

[vikramsp]

Thanks Eric

Eric Botcazou-3 wrote:
> 
>> But i wanted to try them indivisually. Is there any method to do so?
> 
> The compiler doesn't optimize anything if you don't pass at least -O.
> 
> -- 
> Eric Botcazou
> 
> 

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