[LLVMdev] ScheduleDAG Question

David Greene dag at cray.com
Thu Sep 3 19:24:56 PDT 2009

On Thursday 03 September 2009 21:13, David Greene wrote:

> Hmm...except there's a little dashed blue line from the call to the chain
> (I think) field of the load.  Is that the dependence I want?  I don't know
> how to read these graphs.

Interesting.  So with -view-legalize-dags, that little dashed blue line has
moved from the load to the store that feeds the load.  That's wrong.

But it's still there with -view-legalize-types-dags, so legalize types must
be buggy.  But -disable-legalize-types doesn't fix the problem.  So the 
general legalize code seems to have the same issue.

LLVM 2.5 compiles this fine, so it's something we've altered in the codebase.
I did a diff of all of our changes to lib/CodeGen and include/llvm/CodeGen
but nothing jumpoed out as obviously wrong.  I suppose it's possible we
present slightly different code to the legalize passes than the unmodified

Fun times, indeed.


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