[llvm-dev] [GlobalISel] [X86] unable to legalize instruction (original) (raw)

Friedman, Eli via llvm-dev llvm-dev at lists.llvm.org
Fri Nov 10 12:16:31 PST 2017

On 11/10/2017 12:00 PM, S. Bharadwaj Yadavalli via llvm-dev wrote:

Thank you very much for your reply. That helped.

I spent a little bit of time debugging the failure. It appears that X86LegalizerInfo does not (yet?) set up the required actions and tables for the opcode GSDIV. I have not looked at GlobalISel phase earlier, but am curious to learn of the reasons for GSDIV not being supported, yet. Are there any pointers that give some background? Of course, I hope to continue to dig irrespectively (albeit slowly :-)).

The x86 IDIV instruction is a bit unusual; it actually has three register inputs.  DAG ISel custom-lowers it; GlobalISel probably needs to do the same.

-Eli

-- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

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