[LLVMdev] Landing my new development on the trunk ...

[Brian West]

Here is the patch for the new Operator Strength Reduction optimization
pass that I have written.  The bulk of the code is in

lib/Transforms/Scalar/OperatorStrengthReduce.cpp

The optimization is based on the algorithm described within the paper
that can be found here:

http://portal.acm.org/citation.cfm?id=504709.504710

Keith D. Cooper , L. Taylor Simpson , Christopher A. Vick, Operator
strength reduction, ACM Transactions on Programming Languages and
Systems (TOPLAS), v.23 n.5, p.603-625, September 2001.

I have embedded the paper's pseudo code into comment blocks within the code.

The algorithm finds reduction opportunities in both array accesses and
explicit multiplications within loops.

Next, I plan on writing the regression tests.

thanks,
Brian


Brian West <bnwest <at> rice.edu> writes:
> I am currently writing a new optimization pass for LLVM, based on the
> paper Operator Strength Reduction (Taylor Simpson et al, 2001).  I
> noticed from the Developer Policy page that my code will need to be
> reviewed before it is committed to the trunk.
>
> The Policy page also indicated that all "major" changes should to be
> announced before coding and should be done as a series of incremental
> changes.  I am not sure a new stand alone optimization pass counts as a
> major change or not.
>
> I have run my pass against the test suite (as described here: "How to
> test my pass"
> http://comments.gmane.org/gmane.comp.compilers.llvm.devel/32875).  I
> have fixed all of the compilation errors and all but one of the
> execution errors.
>
> I have made a pass over my code to conform to the LLVM coding standards.
>
> I have not written the regressions tests yet.
>
> I also still need to work on the performance, but as is it is faster
> than the existing -loop-reduce pass.
>
> My question is how to proceed.  What steps do I need to take to get my
> code reviewed and committed to the trunk?
>
> thanks,
> Brian West


Duncan Sands <baldrick <at> free.fr> writes:
> Hi Brian,
>
> > My question is how to proceed.  What steps do I need to take to get my
> > code reviewed and committed to the trunk?
>
> the first step is to send a patch adding your pass (and hopefully the
> associated documentation!) to LLVM to the mailing list, so that others
> can test and study your code.
>
> Ciao,
>
> Duncan.
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