[LLVMdev] Invalid comparison instruction generation

Eli Friedman eli.friedman at gmail.com
Mon Nov 10 16:37:42 PST 2008


On Mon, Nov 10, 2008 at 3:06 PM, Villmow, Micah <Micah.Villmow at amd.com> wrote:
> With the above kernel run through llc with -march=x86
> -view-dag-combine1-dags I still see the ogt as the comparison operation, but
> when I run it with llc -march=x86 -view-legalize-dags the ogt node has been
> transformed into a ule.

Okay... I can see that in the attached graph.

> So, my question is, how do I get llvm to stop doing invalid translation of
> comparison instructions? This problem affects my custom backend and I have
> reproduced it with the x86 backend.

It seems valid to me... what makes you think it's invalid?

-Eli



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