llvm dev - Jan 2013 - [LLVMdev] Value* to Instruction*/LoadInst* casting

Hello everyone,

Can you please tell me if it is possible in LLVM to cast a `Value*` to an
`Instruction*/LoadInst*` if for example `isa<LoadInst>(MyValue)` is true?
In my particular piece of code:

    Value* V1 = icmpInstrArray[i]->getOperand(0);
    Value* V2 = icmpInstrArray[i]->getOperand(1);
    if (isa<LoadInst>(V1) || isa<LoadInst>(V2)){
    ...
    if(isa<LoadInst>(icmpInstrArray[i]->getOperand(0)))
        LoadInst *LD100 =
cast<LoadInst>(icmpInstrArray[i]->getOperand(0));
            Value *C100 = LD100->getPointerOperand(); //HERE COMPILATION
ERROR
Further, I just need to make `C100->getName()` and I will get the loaded
variable.

I don't think that I can use cast like that. Can you tell me a method to
obtain the loaded variable from a Load instruction correspondent to my ICMP
instructions? Or better how I can extract the Load instruction from
`icmpInstrArray[i]->getOperand(0)`?

Thank you a lot !
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20130128/b7e75875/attachment.html>

The compilation error is : `error: ‘LD100’ was not declared in this scope.`


On Mon, Jan 28, 2013 at 11:31 AM, Alexandru Ionut Diaconescu <
alexandruionutdiaconescu at gmail.com> wrote:
> Hello everyone,
>
> Can you please tell me if it is possible in LLVM to cast a `Value*` to an
> `Instruction*/LoadInst*` if for example `isa<LoadInst>(MyValue)` is
true?
> In my particular piece of code:
>
>     Value* V1 = icmpInstrArray[i]->getOperand(0);
>     Value* V2 = icmpInstrArray[i]->getOperand(1);
>     if (isa<LoadInst>(V1) || isa<LoadInst>(V2)){
>     ...
>     if(isa<LoadInst>(icmpInstrArray[i]->getOperand(0)))
>         LoadInst *LD100 =
cast<LoadInst>(icmpInstrArray[i]->getOperand(0));
>             Value *C100 = LD100->getPointerOperand(); //HERE COMPILATION
> ERROR
> Further, I just need to make `C100->getName()` and I will get the loaded
> variable.
>
> I don't think that I can use cast like that. Can you tell me a method
to
> obtain the loaded variable from a Load instruction correspondent to my ICMP
> instructions? Or better how I can extract the Load instruction from
> `icmpInstrArray[i]->getOperand(0)`?
>
> Thank you a lot !



-- 
Best regards,
Alexandru Ionut Diaconescu
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20130128/6dee2e5c/attachment.html>

Hi Alexandru,
> The compilation error is : `error: ‘LD100’ was not declared in this scope.`
> 
> On Mon, Jan 28, 2013 at 11:31 AM, Alexandru Ionut Diaconescu <
> alexandruionutdiaconescu at gmail.com> wrote:
> 
>> Hello everyone,
>>
>> Can you please tell me if it is possible in LLVM to cast a `Value*` to
an
>> `Instruction*/LoadInst*` if for example `isa<LoadInst>(MyValue)`
is true?
>> In my particular piece of code:
>>
>>     Value* V1 = icmpInstrArray[i]->getOperand(0);
>>     Value* V2 = icmpInstrArray[i]->getOperand(1);
>>     if (isa<LoadInst>(V1) || isa<LoadInst>(V2)){
>>     ...
>>     if(isa<LoadInst>(icmpInstrArray[i]->getOperand(0)))
>>         LoadInst *LD100 =
cast<LoadInst>(icmpInstrArray[i]->getOperand(0));
>>             Value *C100 = LD100->getPointerOperand(); //HERE
COMPILATION
>> ERROR
>> Further, I just need to make `C100->getName()` and I will get the
loaded
>> variable.
Looks like you meant to write

if (isa<LoadInst>(icmpInstrArray[i]->getOperand(0))) {
  LoadInst *LD100 = cast<LoadInst>(icmpInstrArray[i]->getOperand(0));
  Value *C100 = LD100->getPointerOperand(); //HERE COMPILATION ERROR
  ...
}

(i.e., you were missing "{...}" after the "if").
>> I don't think that I can use cast like that. Can you tell me a
method to
>> obtain the loaded variable from a Load instruction correspondent to my
ICMP
>> instructions? Or better how I can extract the Load instruction from
>> `icmpInstrArray[i]->getOperand(0)`?
>>
>> Thank you a lot !
Hope this helps,
Stephan

Hello,

Thank you for answering. I copy paste-it not precisely (I had the bracket),
but the array was not ok. Not it is solved.

Thank you a lot !

On Mon, Jan 28, 2013 at 11:54 AM, Nick Lewycky <nicholas at mxc.ca> wrote:
> Alexandru Ionut Diaconescu wrote:
>
>> Hello everyone,
>>
>> Can you please tell me if it is possible in LLVM to cast a `Value*` to
>> an `Instruction*/LoadInst*` if for example
`isa<LoadInst>(MyValue)` is
>> true?
>>
>
> http://llvm.org/docs/**ProgrammersManual.html#the-**isa-cast-and-dyn-cast-
>
**templates<http://llvm.org/docs/ProgrammersManual.html#the-isa-cast-and-dyn-cast-templates>
>
>
>  In my particular piece of code:
>
>>
>>      Value* V1 = icmpInstrArray[i]->getOperand(**0);
>>      Value* V2 = icmpInstrArray[i]->getOperand(**1);
>>      if (isa<LoadInst>(V1) || isa<LoadInst>(V2)){
>>      ...
>>      if(isa<LoadInst>(**icmpInstrArray[i]->getOperand(**0)))
>>          LoadInst *LD100 = cast<LoadInst>(icmpInstrArray[**
>> i]->getOperand(0));
>>              Value *C100 = LD100->getPointerOperand(); //HERE
>> COMPILATION ERROR
>>
>
> You're missing braces after the if-statement.
>
> Nick
>
>  Further, I just need to make `C100->getName()` and I will get the
loaded
>> variable.
>>
>> I don't think that I can use cast like that. Can you tell me a
method to
>> obtain the loaded variable from a Load instruction correspondent to my
>> ICMP instructions? Or better how I can extract the Load instruction
from
>> `icmpInstrArray[i]->**getOperand(0)`?
>>
>> Thank you a lot !
>>
>>
>> ______________________________**_________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>
http://lists.cs.uiuc.edu/**mailman/listinfo/llvmdev<http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev>
>>
>
>

-- 
Best regards,
Alexandru Ionut Diaconescu
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20130128/b0b0fefb/attachment.html>

Alexandru Ionut Diaconescu wrote:
> Hello everyone,
>
> Can you please tell me if it is possible in LLVM to cast a `Value*` to
> an `Instruction*/LoadInst*` if for example `isa<LoadInst>(MyValue)`
is
> true?
http://llvm.org/docs/ProgrammersManual.html#the-isa-cast-and-dyn-cast-templates

  In my particular piece of code:
>
>      Value* V1 = icmpInstrArray[i]->getOperand(0);
>      Value* V2 = icmpInstrArray[i]->getOperand(1);
>      if (isa<LoadInst>(V1) || isa<LoadInst>(V2)){
>      ...
>      if(isa<LoadInst>(icmpInstrArray[i]->getOperand(0)))
>          LoadInst *LD100 =
cast<LoadInst>(icmpInstrArray[i]->getOperand(0));
>              Value *C100 = LD100->getPointerOperand(); //HERE
> COMPILATION ERROR
You're missing braces after the if-statement.

Nick
> Further, I just need to make `C100->getName()` and I will get the loaded
> variable.
>
> I don't think that I can use cast like that. Can you tell me a method
to
> obtain the loaded variable from a Load instruction correspondent to my
> ICMP instructions? Or better how I can extract the Load instruction from
> `icmpInstrArray[i]->getOperand(0)`?
>
> Thank you a lot !
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

Hi,

   
if(isa<LoadInst>(icmpInstrArray[i]->getOperand(0)))
>>         LoadInst *LD100 >>
cast<LoadInst>(icmpInstrArray[i]->getOperand(0));
>>             Value *C100 = LD100->getPointerOperand(); //HERE
COMPILATION
>> ERROR
>>
>
Could it be that you simply forgot the braces around the if() body?

Best,
Jonas
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20130128/aaeeee3f/attachment.html>