llvm dev - May 2019 - Problem of getNumOperands() for CallInst

Hi all,

    I got a interesting problem when calling getNumOperands() of CallInst.
    For example,
             call void @_Z2f2PA100_i([100 x i32]* nonnull %arraydecay)
    If I use getNumOperands(), it will return 2.
    However, if I use getCalledFunction()->getNumParams(), it will return 1.
    According to the IR, I think the number of operands of the call instruction
should be 1.
    I wonder what is going on for this situation.
    Thanks in advance for your time and suggestion!

Best regards,

Tingyuan LIANG
MPhil Student
HKUST
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Hi Tingyuan,

    For example,
             call void @_Z2f2PA100_i([100 x i32]* nonnull %arraydecay)
    If I use getNumOperands(), it will return 2.
    However, if I use getCalledFunction()->getNumParams(), it will return 1.
    According to the IR, I think the number of operands of the call instruction
should be 1.

I think you'll find that the first operand of the 'call' instruction
is the callee (the function being called) itself. So two operands makes sense in
your case: one callee and one parameter.

/ Bevin
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There's a getNumArgOperands() that counts just arguments to the function
and not the callee itself.

~Craig


On Wed, May 29, 2019 at 3:53 AM Bevin Hansson via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi Tingyuan,
>
>     For example,
>              call void @_Z2f2PA100_i([100 x i32]* nonnull %arraydecay)
>     If I use getNumOperands(), it will return 2.
>     However, if I use getCalledFunction()->getNumParams(), it will
return
> 1.
>     According to the IR, I think the number of operands of the call
> instruction should be 1.
>
> I think you'll find that the first operand of the 'call'
instruction is
> the callee (the function being called) itself. So two operands makes sense
> in your case: one callee and one parameter.
>
> / Bevin
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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