[LLVMdev] Uniform data dependence info?

[Victor Leikehman]

> What specific information do you need?

All my experiments eventually analyze or transform
the data dependence graph, which takes into account both
registers and aliasing information.  Because there is already
a built-in support for graphs, I hoped there is also built-in
support for data dependence graphs. That would allow, for example,
to display them naturally with dot utility.

      Victor


                                                                                                                                     
                      Chris Lattner                                                                                                  
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                      >                        cc:       Victor Leikehman/Haifa/IBM at IBMIL                                            
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                      02/23/05 06:02 PM                                                                                              
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> Is there some uniform way to find data dependence between two (sets of)
> instructions?  There is use/def data, and there is AliasAnalysis
> information, but I am looking for something more high-level and uniform.
> I guess I am missing then was abandoned. Any ideas?

Nope, there currently isn't a uniform interface for doing so, at least not
at the LLVM level.  As you said, use/def information will tell you about
dependence between non-side-effecting instructions, and AliasAnalysis will
tell you what dependences exist between side-effecting ones.

What are you trying to do here?  It would be really easy to add a helper
method to the AliasAnalysis interface that took into consideration
dependencies between scalar instructions.  What specific information do
you need?

-Chris

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