llvm dev - May 2011 - [LLVMdev] How to determine if a variable has been discarded

Hi all,

When I check the ll code, I found sometimes an operation has one or  
more "undef" operands. Does that means this operations has been  
discarded? What I want to check is how to determine which variables  
have been discarded. If I decide to discard everything that is  
transitively related to an undef then is that correct? If I implement  
that algorithm, is there a discard I'll be missing? Thanks.

Best,

Kecheng

Hi Kecheng,

Undef means that there hasn't been a value assigned to a variable.  If
you're expecting to have initialized values for your variables, you have to
specify that.

--Sam

>________________________________
>From: "kecheng at cecs.pdx.edu" <kecheng at cecs.pdx.edu>
>To: llvmdev at cs.uiuc.edu
>Sent: Saturday, May 21, 2011 12:37 AM
>Subject: [LLVMdev] How to determine if a variable has been discarded
>
>Hi all,
>
>When I check the ll code, I found sometimes an operation has one or  
>more "undef" operands. Does that means this operations has been  
>discarded? What I want to check is how to determine which variables  
>have been discarded. If I decide to discard everything that is  
>transitively related to an undef then is that correct? If I implement  
>that algorithm, is there a discard I'll be missing? Thanks.
>
>Best,
>
>Kecheng
>
>
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>
>