[LLVMdev] ScheduleDAG Question

[Eli Friedman]

On Thu, Sep 3, 2009 at 7:24 PM, David Greene<dag at cray.com> wrote:
> 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
> LLVM.
>
> Fun times, indeed.

You might want to try the -debug dumps; it might be a bit easier to follow.

-Eli