diff --git a/base/compiler/optimize.jl b/base/compiler/optimize.jl
index 3a8de06811cc26..7c8413ceaf9af5 100644
--- a/base/compiler/optimize.jl
+++ b/base/compiler/optimize.jl
@@ -561,7 +561,7 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
             idx += 1
             prevloc = codeloc
         end
-        if code[idx] isa Expr && ssavaluetypes[idx] === Union{}
+        if ssavaluetypes[idx] === Union{} && code[idx] !== nothing && !(code[idx] isa Core.Const)
             if !(idx < length(code) && isa(code[idx + 1], ReturnNode) && !isdefined((code[idx + 1]::ReturnNode), :val))
                 # insert unreachable in the same basic block after the current instruction (splitting it)
                 insert!(code, idx + 1, ReturnNode())