[LLVMdev] How to know if an instruction is "usable"

[Krzysztof Parzyszek]

On 4/25/2013 11:52 AM, Giacomo Tagliabue wrote:
> Is there an easy way to know if, at a certain instruction, a certain
> value is usable or not? i.e., I am sure that if i use that value i don't
> to get the error "Instruction does not dominate all uses!"

Check if the block containing the definition dominates the block where 
you want to use the value.  If this is the same block, the definition 
has to appear before the use.  This follows directly from the error 
message, so I'm not sure if this answers your question.  Use the 
dominator tree analysis to check the dominance.

-Krzysztof

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