CODEWITHSUNDEEP
llvmllvm-ircontrol-flowcontrol-flow-graphllvm-3.0
mikasa
mikasa

Reputation: 900

llvm - get the first instruction of the basic block referred to in the label field of instruction of type br

I'm trying to write a pass that will check the control flow of a code. Given a br instruction, I need to access the basic blocks referred to in the label fields.

For example, for the code:

 for(i = 0; i < count; i++){
    sum = add(sum, array[i]);
  }

I get the IR representation 

br i1 %cmp, label %for.body, label %for.end

Now when I come across this instruction in the pass, I need to know exactly where these labels are pointing to. Can anybody please tell me how I can do that?

Upvotes: 4

Views: 2062

Answers (1)

arrowd
arrowd

Reputation: 34401

Call ->getOperand(1) and ->getOperand(2) methods for that instruction. This would give you 1st and 2nd BB respectively. See http://llvm.org/doxygen/classllvm_1_1User.html#abe1de1520a21f77ac57cc210bf0fb0b4

Upvotes: 1

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