better codegen for getfield on type objects (#3938)

base/inference.jl

@@ -1671,6 +1671,11 @@ function inlineable(f, e::Expr, sv, enclosing_ast)
         # remove redundant unbox
         return (e.args[3],())
     end
+    if isdefined(Main.Base,:isbits) && is(f,Main.Base.isbits) &&
+        length(atypes)==1 && isType(atypes[1]) && effect_free(argexprs[1]) &&
+        isleaftype(atypes[1].parameters[1])
+        return (isbits(atypes[1].parameters[1]),())
+    end
     # special-case inliners for known pure functions that compute types
     if isType(e.typ)
         if (is(f,apply_type) || is(f,fieldtype) ||
@@ -1679,10 +1684,6 @@ function inlineable(f, e::Expr, sv, enclosing_ast)
             isleaftype(e.typ.parameters[1])
             return (e.typ.parameters[1],())
         end
-        if isdefined(Main.Base,:isbits) && is(f,Main.Base.isbits) &&
-            isleaftype(e.typ.parameters[1])
-            return (isbits(e.typ.parameters[1]),())
-        end
         if is(f,Union)
             union = e.typ.parameters[1]
             if isa(union,UnionType) && all(isleaftype, (union::UnionType).types)

src/codegen.cpp

@@ -957,6 +957,8 @@ static Value *emit_getfield(jl_value_t *expr, jl_sym_t *name, jl_codectx_t *ctx)
     }
 
     jl_datatype_t *sty = (jl_datatype_t*)expr_type(expr, ctx);
+    if (jl_is_type_type((jl_value_t*)sty) && jl_is_leaf_type(jl_tparam0(sty)))
+        sty = (jl_datatype_t*)jl_typeof(jl_tparam0(sty));
     JL_GC_PUSH1(&sty);
     if (jl_is_structtype(sty) && sty != jl_module_type && sty->uid != 0) {
         unsigned idx = jl_field_index(sty, name, 0);