Don't bail out of inference early if effects could still be refined (#48263)

We have an early out in inference that bails if the inferred return
type of the method being called is `Any`. This makes sense in the
absence of effects, because once the rt has hit `Any`, there is
nothing new we can learn by looking at any subsequent calls.
However, in the presence of effects, we likely want to keep
going if we can prove all methods of the callsite `:foldable` as
being `:foldable` can save significant inference time down the
line if it enables concrete evaluation of the containing function.

Author: Keno

base/compiler/abstractinterpretation.jl

@@ -194,7 +194,8 @@ function abstract_call_gf_by_type(interp::AbstractInterpreter, @nospecialize(f),
                 conditionals[2][i] = tmerge(conditionals[2][i], cnd.elsetype)
             end
         end
-        if bail_out_call(interp, rettype, sv)
+        if bail_out_call(interp, rettype, sv, effects)
+            add_remark!(interp, sv, "One of the matched returned maximally imprecise information. Bailing on call.")
             break
         end
     end
@@ -838,6 +839,7 @@ function concrete_eval_eligible(interp::AbstractInterpreter,
     elseif !result.effects.noinbounds && stmt_taints_inbounds_consistency(sv)
         # If the current statement is @inbounds or we propagate inbounds, the call's consistency
         # is tainted and not consteval eligible.
+        add_remark!(interp, sv, "[constprop] Concrete evel disabled for inbounds")
         return nothing
     end
     isoverlayed(method_table(interp)) && !is_nonoverlayed(result.effects) && return nothing

base/compiler/inferencestate.jl

@@ -224,8 +224,8 @@ add_remark!(::AbstractInterpreter, sv::Union{InferenceState, IRCode}, remark) =
 function bail_out_toplevel_call(::AbstractInterpreter, @nospecialize(callsig), sv::Union{InferenceState, IRCode})
     return isa(sv, InferenceState) && sv.restrict_abstract_call_sites && !isdispatchtuple(callsig)
 end
-function bail_out_call(::AbstractInterpreter, @nospecialize(rt), sv::Union{InferenceState, IRCode})
-    return rt === Any
+function bail_out_call(::AbstractInterpreter, @nospecialize(rt), sv::Union{InferenceState, IRCode}, effects::Effects)
+    return rt === Any && !is_foldable(effects)
 end
 function bail_out_apply(::AbstractInterpreter, @nospecialize(rt), sv::Union{InferenceState, IRCode})
     return rt === Any

test/compiler/inference.jl

@@ -4697,3 +4697,10 @@ Base.@constprop :aggressive type_level_recurse1(x...) = x[1] == 2 ? 1 : (length(
 Base.@constprop :aggressive type_level_recurse2(x...) = type_level_recurse1(x...)
 type_level_recurse_entry() = Val{type_level_recurse1(1)}()
 @test Base.return_types(type_level_recurse_entry, ()) |> only == Val{1}
+
+# Test that inference doesn't give up if it can potentially refine effects,
+# even if the return type is Any.
+f_no_bail_effects_any(x::Any) = x
+f_no_bail_effects_any(x::NamedTuple{(:x,), Tuple{Any}}) = getfield(x, 1)
+g_no_bail_effects_any(x::Any) = f_no_bail_effects_any(x)
+@test Core.Compiler.is_total(Base.infer_effects(g_no_bail_effects_any, Tuple{Any}))