[LLVMdev] Problem with LoopDependenceAnalysis

shanmuk rao shanmuk.rao008 at gmail.com
Wed Mar 14 22:58:14 PDT 2012


Hi,
I am using LLVM for implementing LoopFission pass.
I am using LoopPass.
I know that for checking circular dependency in loop I have to use
LoopDependenceAnalysis

This is what i want to do.
        for(int i = 0; i< n ; i++){

s1 :                 a[i] = a[i] + x[i];
s2 :                 x[i] = x[i+1] + i*2 ;
        }

/**there is no dependence from s2 to s1/
so after distribution(it should be) :

        for(int i = 0; i< n ; i++)
s1:                a[i] = a[i] + x[i];

        for(int i = 0; i< n ; i++)
s2:                x[i] = x[i+1] + i*2 ;


but in llvm i couldn't able to find there is no dependency from s2 to s1.

LoopDependenceAnalyis always gives there is a dependency from every
load instructions to every store instructions.


is there any other alternative to LoopDependencyAnalysis ?
thank you

......
Regards,
Shanmukha Rao
Compilers lab,
Indian Institute of Science, Bangalore.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20120315/94716630/attachment.html>


More information about the llvm-dev mailing list