Get non-constant operands in LLVM

Question

Say I have an instruction like %res = add i32 4, %var and I want to extract only the operand %var because it's a variable. My question is how I can determine whether an operand is a constant number or rvalue so that I can exclude them in my pass.

Thanks in advance.

Answer 1

使用Instruction::value_op_begin() ， Instruction::value_op_end()或Instruction::operand_values()循环指令的操作数，并使用isa<Constant>()测试给定的操作数是否为常数1。