some inlining cost model updates

base/compiler/optimize.jl

@@ -355,20 +355,22 @@ function statement_cost(ex::Expr, line::Int, src::Union{CodeInfo, IRCode}, sptyp
                 # tuple iteration/destructuring makes that impossible
                 # return plus_saturate(argcost, isknowntype(extyp) ? 1 : params.inline_nonleaf_penalty)
                 return 0
+            elseif (f === Core.arrayref || f === Core.const_arrayref || f === Core.arrayset) && length(ex.args) >= 3
+                atyp = argextype(ex.args[3], src, sptypes, slottypes)
+                return isknowntype(atyp) ? 4 : error_path ? params.inline_error_path_cost : params.inline_nonleaf_penalty
+            elseif f === typeassert && isconstType(widenconst(argextype(ex.args[3], src, sptypes, slottypes)))
+                return 1
             elseif f === Core.isa
                 # If we're in a union context, we penalize type computations
                 # on union types. In such cases, it is usually better to perform
                 # union splitting on the outside.
                 if union_penalties && isa(argextype(ex.args[2],  src, sptypes, slottypes), Union)
                     return params.inline_nonleaf_penalty
                 end
-            elseif (f === Core.arrayref || f === Core.const_arrayref) && length(ex.args) >= 3
-                atyp = argextype(ex.args[3], src, sptypes, slottypes)
-                return isknowntype(atyp) ? 4 : error_path ? params.inline_error_path_cost : params.inline_nonleaf_penalty
             end
             fidx = find_tfunc(f)
             if fidx === nothing
-                # unknown/unhandled builtin or anonymous function
+                # unknown/unhandled builtin
                 # Use the generic cost of a direct function call
                 return 20
             end

base/compiler/tfuncs.jl

@@ -545,7 +545,7 @@ function typeof_tfunc(@nospecialize(t))
     end
     return DataType # typeof(anything)::DataType
 end
-add_tfunc(typeof, 1, 1, typeof_tfunc, 0)
+add_tfunc(typeof, 1, 1, typeof_tfunc, 1)
 
 function typeassert_tfunc(@nospecialize(v), @nospecialize(t))
     t = instanceof_tfunc(t)[1]