Perhaps not a major loss but eqq calls in case/when do not do any caching currently, in either the interpreter or the JIT.

case foo; when Bar; end

    %v_3 = call_0o(%self ;n:foo, t:VA, cl:false)
    %v_6 = search_const(scope<0> ;name: Bar, no_priv: false)
    %v_5 = eqq(%v_6, %v_3)
    b_true(LBL_2:11, %v_5)

EqqInstr and its equivalent code in the JIT do not do any caching, and just call IRRuntimeHelpers.isEQQ.