Disassembled YARV versions of various nil checks in Ruby 2

nil_check_bytecode.rb

[
  "true unless nil.nil?",
  "true if nil != nil",
  "true if !!nil",
  "true unless nil"

].each do |source|
  puts "====="
  puts source
  puts

  puts RubyVM::InstructionSequence.compile(source).disasm
  puts "====="
end

out.txt

=====
true unless nil.nil?

== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
0000 trace            1                                               (   1)
0002 putnil           
0003 opt_send_simple  <callinfo!mid:nil?, argc:0, ARGS_SKIP>
0005 branchunless     10
0007 putnil           
0008 leave            
0009 pop              
0010 putobject        true
0012 leave            
=====
=====
true if nil != nil

== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
0000 trace            1                                               (   1)
0002 putnil           
0003 putnil           
0004 opt_neq          <callinfo!mid:!=, argc:1, ARGS_SKIP>, <callinfo!mid:==, argc:1, ARGS_SKIP>
0007 branchunless     13
0009 putobject        true
0011 leave            
0012 pop              
0013 putnil           
0014 leave            
=====
=====
true if !!nil

== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
0000 trace            1                                               (   1)
0002 putnil           
0003 opt_not          <callinfo!mid:!, argc:0, ARGS_SKIP>
0005 opt_not          <callinfo!mid:!, argc:0, ARGS_SKIP>
0007 branchunless     13
0009 putobject        true
0011 leave            
0012 pop              
0013 putnil           
0014 leave            
=====
=====
true unless nil

== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
0000 trace            1                                               (   1)
0002 jump             7
0004 putnil           
0005 leave            
0006 pop              
0007 putobject        true
0009 leave            
=====