more fix

base/compiler/optimize.jl

@@ -1108,8 +1108,9 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
                 new_edges = Int32[]
                 new_vals = Any[]
                 for j = 1:length(expr.edges)
-                    (expr.edges[j] in sv.unreachable) && continue
-                    push!(new_edges, expr.edges[j])
+                    edge = expr.edges[j]
+                    (edge in sv.unreachable || ssavaluetypes[edge] === Union{}) && continue
+                    push!(new_edges, edge)
                     if isassigned(expr.values, j)
                         push!(new_vals, expr.values[j])
                     else

test/compiler/ssair.jl

@@ -755,6 +755,7 @@ end
 end
 
 # Test that things don't break if one branch of the frontend PhiNode becomes unreachable
+global global_error_switch::Bool = true
 function gen_unreachable_phinode_edge(world::UInt, source, _)
     ci = make_codeinfo(Any[
         # block 1
@@ -774,7 +775,9 @@ end
     $(Expr(:meta, :generated_only))
     #= no body =#
 end
-global global_error_switch = true
+let ir = first(only(Base.code_ircode(f_unreachable_phinode_edge)))
+    @test !any(@nospecialize(x)->isa(x,PhiNode), ir.stmts.stmt)
+end
 @test_throws ErrorException f_unreachable_phinode_edge()
 global global_error_switch = false
 @test f_unreachable_phinode_edge() == 1