[LLVMdev] ScheduleDAG Question

Eli Friedman eli.friedman at gmail.com
Thu Sep 3 14:04:54 PDT 2009


On Thu, Sep 3, 2009 at 9:48 AM, David Greene<dag at cray.com> wrote:
> I'm debugging a ScheduleDAG problem.  Somehow a load appearing
> before a call in the source gets scheduled after the call.
> Since the callee modifies the location loaded from, wrong answers result.
>
> Looking at the dag with -view-sched-dags, I don't see an edge from the
> load to depend on the call.
>
> How is this supposed to be handled by ScheduleDAG?

My first step would be to make sure there's an appropriate edge in the
selection DAG... there's a possibility something could get messed up
by legalization or the dagcombiner.

Since scheduling and selection is mostly within a block, hopefully it
wouldn't be too hard to come up with a testcase?

-Eli




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