`[4, 5].max` is slower than `[a, b].max` with ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin16]

benchmark.rb

require 'benchmark'

n = 100000000

Benchmark.bmbm do |x|
  x.report('[4, 5].max') { n.times { [4, 5].max } }
  a, b = 4, 5
  x.report('[a, b].max') { n.times { [a, b].max } }
end

disasm.rb

puts RubyVM::InstructionSequence.compile('[4, 5].max').disasm
# == disasm: #<ISeq:<compiled>@<compiled>>================================
# 0000 trace            1                                               (   1)
# 0002 duparray         [4, 5]
# 0004 opt_send_without_block <callinfo!mid:max, argc:0, ARGS_SIMPLE>, <callcache>
# 0007 leave

puts RubyVM::InstructionSequence.compile('x, y = 4, 5; [x, y].max').disasm
# == disasm: #<ISeq:<compiled>@<compiled>>================================
# local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
# [ 2] x          [ 1] y
# 0000 trace            1                                               (   1)
# 0002 putobject        4
# 0004 putobject        5
# 0006 setlocal_OP__WC__0 3
# 0008 setlocal_OP__WC__0 4
# 0010 getlocal_OP__WC__0 4
# 0012 getlocal_OP__WC__0 3
# 0014 opt_newarray_max 2
# 0016 leave

output

Rehearsal ----------------------------------------------
[4, 5].max   9.600000   0.030000   9.630000 (  9.688531)
[a, b].max   4.720000   0.020000   4.740000 (  4.794517)
------------------------------------ total: 14.370000sec

                 user     system      total        real
[4, 5].max   9.730000   0.030000   9.760000 (  9.792203)
[a, b].max   4.410000   0.000000   4.410000 (  4.413312)