[LLVMdev] Loop-Unroll optimization

[Arushi Aggarwal]

Hi,

You might want to try running -loops -loop-simplify before loop unroll.

>From loop simplify.cpp

This pass performs several transformations to transform natural loops
into a00011 // simpler form, which makes subsequent analyses and
transformations simpler and00012 // more effective.


Arushi

On Tue, May 3, 2011 at 2:17 PM, Manish Gupta <mgupta.iitr at gmail.com> wrote:

> You mean like
>
> *llvm-gcc-4.2 -O2 -emit-llvm Hello.c -c -o Hello.bc*
>
> But still i am not able to observe any effect on bit code by running
>
> *opt-2.8 -loop-unroll Hello.bc -o Hello_unroll.bc*
>
> On Tue, May 3, 2011 at 3:58 AM, Zakk <zakk0610 at gmail.com> wrote:
>
>> Hi, you need to run some optimization passes first. (like -O2)
>>
>> 2011/5/3 Manish Gupta <mgupta.iitr at gmail.com>
>>
>>> I just want to try loop-unroll and see corresponding changes in the
>>> bitcode file. For that any loop will do. Have you been able to test llvm
>>> loop-unroll successfully?
>>>
>>>
>>> On Mon, May 2, 2011 at 10:04 PM, Yuan Pengfei <coolypf at qq.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> > The loop that I am trying it on is:
>>>> > for(i=0; i< 1000; i++)
>>>> > {
>>>> > c[i] = a[i] + b[i];
>>>> > }
>>>>
>>>> I can't find any benefit unrolling this loop.
>>>>
>>>> ------------------
>>>> Yuan Pengfei
>>>> Peking Unversity, China
>>>
>>>
>>>
>>> _______________________________________________
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>>>
>>>
>>
>>
>> --
>> Best regards,
>> Kuan-Hsu
>>
>>
>>
>
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