llvm dev - Jan 2016 - Pattern doesn't match error

I made a small change to my target and them tried to recompile it. The
following error showed up:

error: Pattern doesn't match mayLoad = 0

A little bit of searched revealed that it came from here:
https://github.com/llvm-mirror/llvm/blob/master/utils/TableGen/CodeGenDAGPatterns.cpp#L2861

Unfortunately I can't understand what it means. Can someone help me out?

-- 
Rail Shafigulin
Software Engineer
Esencia Technologies
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This happens when the mayLoad field inferred from the instruction 
pattern is different from the mayLoad field that is explicitly set in 
the instruction definition.

TableGen will try to infer certain properties from the pattern used to 
match an instruction.  If, at the same time, the property is specified 
explicitly, it must match what TableGen inferred.  If there is a 
conflict between the two, this kind of an error shows up.

Not sure if this helps.

-Krzysztof


On 1/5/2016 7:59 PM, Rail Shafigulin via llvm-dev wrote:
> I made a small change to my target and them tried to recompile it. The
> following error showed up:
>
> error: Pattern doesn't match mayLoad = 0
>
> A little bit of searched revealed that it came from here:
>
https://github.com/llvm-mirror/llvm/blob/master/utils/TableGen/CodeGenDAGPatterns.cpp#L2861
>
> Unfortunately I can't understand what it means. Can someone help me
out?
>
> --
> Rail Shafigulin
> Software Engineer
> Esencia Technologies
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, 
hosted by The Linux Foundation

On Wed, Jan 6, 2016 at 6:45 AM, Krzysztof Parzyszek via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> This happens when the mayLoad field inferred from the instruction pattern
> is different from the mayLoad field that is explicitly set in the
> instruction definition.
>
> TableGen will try to infer certain properties from the pattern used to
> match an instruction.  If, at the same time, the property is specified
> explicitly, it must match what TableGen inferred.  If there is a conflict
> between the two, this kind of an error shows up.
>
> Not sure if this helps.
>
> -Krzysztof

I'm not sure I understand it. Here is the change that I made for my target

class InstEscala<dag outs, dag ins, string asmstr, list<dag>
pattern>
  : Instruction {
....
....
  let mayLoad = 0;
....
....
 }

All I have done is set mayLoad to 0. Would you mind using your explanation
in the context of my change? I think once there is a specific case it is
easier to understand what is the problem.

Thanks,

-- 
Rail Shafigulin
Software Engineer
Esencia Technologies
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