llvm dev - Jul 2014 - [LLVMdev] extract a specific element from a vector in LLVM IR

Hello everybody,

I am creating a vector in llvm IR and I am able to insert and extract 
elements.
However, I want to take a specific index from the vector but I am not 
able to do that. I found in the doxygen the getIndexOperand(), but I 
have an error during the compilation.
The code I use is the following:

Instruction *extract = ExtractElementInst::Create(emptyVec, ch,
"extract");
b->getInstList().insertAfter(Insert3, extract);

Value *index_val = extract->getIndexOperand();

The error I get is:
error: ‘class llvm::Instruction’ has no member named ‘getIndexOperand’
Value *index_val = extract->getIndexOperand();

I see that I cannot use the getIndexOperand() in an Instruction Type, 
but only through an ExtractElementInst Type.

Do you have any suggestions to get the elements?

Best Regards,
Vasilis

Use the casting operators documented here to convert your Instruction
to ExtractElementInst:
http://llvm.org/docs/ProgrammersManual.html#the-isa-cast-and-dyn-cast-templates

Amara

On 21 July 2014 15:56, Vasileios Koutsoumpos
<bill_koutsoumpos at hotmail.com> wrote:
> Hello everybody,
>
> I am creating a vector in llvm IR and I am able to insert and extract
> elements.
> However, I want to take a specific index from the vector but I am not able
> to do that. I found in the doxygen the getIndexOperand(), but I have an
> error during the compilation.
> The code I use is the following:
>
> Instruction *extract = ExtractElementInst::Create(emptyVec, ch,
"extract");
> b->getInstList().insertAfter(Insert3, extract);
>
> Value *index_val = extract->getIndexOperand();
>
> The error I get is:
> error: ‘class llvm::Instruction’ has no member named ‘getIndexOperand’
> Value *index_val = extract->getIndexOperand();
>
> I see that I cannot use the getIndexOperand() in an Instruction Type, but
> only through an ExtractElementInst Type.
>
> Do you have any suggestions to get the elements?
>
> Best Regards,
> Vasilis
>
>
>
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