[LLVMdev] Creating DAGs

[Gergö Barany]

On Wed, Aug 08, 2012 at 11:24:27 -0600, Ben Bergen wrote:
> I apologize if this is an inappropriate question for this mailing
> list.

This is the correct list.

> My question is: Is it possible to create a DAG from an llvm::Module?
> I would like to do this independent of a specific architecture using
> LLVM IR.  In particular, I am interested in using a DAG to compute the
> Strahler number (http://en.wikipedia.org/wiki/Strahler_number) of the
> graph to determine the minimum number of register needed to evaluate
> an expression tree.

If you are actually interested in processor registers, I don't think it
makes sense to perform this computation at the LLVM IR level. The backend
changes the code too much to map such results from the IR to the generated
machine code, regardless of the platform. Are you after processor registers?
Then the ScheduleDAG you found is the one to use.

-- 
Gergö Barany, research assistant                 gergo at complang.tuwien.ac.at
Institute of Computer Languages      http://www.complang.tuwien.ac.at/gergo/
Vienna University of Technology                       Tel: +43-1-58801-58522
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