lattice overhaul step 3: simplify tmerge

base/compiler/abstractinterpretation.jl

@@ -94,7 +94,7 @@ function abstract_call_gf_by_type(interp::AbstractInterpreter, @nospecialize(f),
                 if const_result !== nothing
                     any_const_result = true
                 end
-                this_rt = tmerge(this_rt, rt)
+                this_rt = this_rt ⊔ rt
                 if bail_out_call(interp, this_rt, sv)
                     break
                 end
@@ -139,16 +139,16 @@ function abstract_call_gf_by_type(interp::AbstractInterpreter, @nospecialize(f),
         this_rt = widenconditional(this_rt)
         @assert !isConditional(this_conditional) "invalid lattice element returned from inter-procedural context"
         seen += 1
-        rettype = tmerge(rettype, this_rt)
+        rettype = rettype ⊔ this_rt
         if this_conditional !== ⊥ && is_lattice_bool(rettype) && fargs !== nothing
             if conditionals === nothing
                 conditionals = LatticeElement[⊥ for _ in 1:length(argtypes)],
                                LatticeElement[⊥ for _ in 1:length(argtypes)]
             end
             for i = 1:length(argtypes)
                 cnd = conditional_argtype(this_conditional, sig, argtypes, i)
-                conditionals[1][i] = tmerge(conditionals[1][i], cnd.vtype)
-                conditionals[2][i] = tmerge(conditionals[2][i], cnd.elsetype)
+                conditionals[1][i] = conditionals[1][i] ⊔ cnd.vtype
+                conditionals[2][i] = conditionals[2][i] ⊔ cnd.elsetype
             end
         end
         if bail_out_call(interp, rettype, sv)
@@ -290,7 +290,7 @@ In such cases `maybecondinfo` should be either of:
 - `maybecondinfo::Tuple{Vector{Any},Vector{Any}}`: precomputed argument type refinement information
 - method call signature tuple type
 When we deal with multiple `MethodMatch`es, it's better to precompute `maybecondinfo` by
-`tmerge`ing argument signature type of each method call.
+`⊔`-joining argument signature type of each method call.
 """
 function from_interprocedural!(rt::LatticeElement, sv::InferenceState, arginfo::ArgInfo, @nospecialize(maybecondinfo))
     rt = collect_limitations!(rt, sv)
@@ -916,7 +916,7 @@ function precise_container_type(interp::AbstractInterpreter, itft::LatticeElemen
             tps = (t::DataType).parameters
             _all(valid_as_lattice, tps) || continue
             for j in 1:ltp
-                result[j] = tmerge(result[j], rewrap_unionall(tps[j], tti0))
+                result[j] = result[j] ⊔ NativeType(rewrap_unionall(tps[j], tti0))
             end
         end
         return result, nothing
@@ -1019,9 +1019,9 @@ function abstract_iteration(interp::AbstractInterpreter, itft::LatticeElement, i
             end
             break
         end
-        valtype0 = tmerge(valtype0, nounion.parameters[1])
+        valtype0 = valtype0 ⊔ NativeType(nounion.parameters[1])
         valtype = widenconst(valtype0)
-        statetype0 = tmerge(statetype0, nounion.parameters[2])
+        statetype0 = statetype0 ⊔ NativeType(nounion.parameters[2])
         statetype = widenconst(statetype0)
         stateordonet = abstract_call_known(interp, iteratef, ArgInfo(nothing, LatticeElement[Const(iteratef), itertype, statetype0]), sv).rt
         stateordonet_widened = widenconst(stateordonet)
@@ -1067,14 +1067,14 @@ function abstract_apply(interp::AbstractInterpreter, argtypes::Argtypes, sv::Inf
                 cti = cti_info[1]::Argtypes
                 info = cti_info[2]::MaybeAbstractIterationInfo
                 # We can't represent a repeating sequence of the same types,
-                # so tmerge everything together to get one type that represents
+                # so ⊔-join everything together to get one type that represents
                 # everything.
                 argt = cti[end]
                 if isVararg(argt)
                     argt = NativeType(unwrapva(vararg(argt)))
                 end
                 for i in 1:(length(cti)-1)
-                    argt = tmerge(argt, cti[i])
+                    argt = argt ⊔ cti[i]
                 end
                 cti = LatticeElement[NativeType(Vararg{widenconst(argt)})]
             end
@@ -1083,12 +1083,13 @@ function abstract_apply(interp::AbstractInterpreter, argtypes::Argtypes, sv::Inf
             end
             for j = 1:length(ctypes)
                 ct = ctypes[j]::Vector{LatticeElement}
-                if isVararg(ct[end])
+                ctend = ct[end]
+                if isVararg(ctend)
                     # This is vararg, we're not gonna be able to do any inling,
                     # drop the info
                     info = nothing
-                    tail = tuple_tail_elem(ct[end], cti)
-                    push!(ctypes´, push!(ct[1:(end - 1)], tail))
+                    tail = tuple_tail_elem(unwrapva(vararg(ctend)), anymap(vawidenconst, cti))
+                    push!(ctypes´, push!(ct[1:(end - 1)], NativeType(tail)))
                 else
                     push!(ctypes´, append!(ct[:], cti))
                 end
@@ -1106,15 +1107,17 @@ function abstract_apply(interp::AbstractInterpreter, argtypes::Argtypes, sv::Inf
         lct = length(ct)
         # truncate argument list at the first Vararg
         for i = 1:lct-1
-            if isVararg(ct[i])
-                ct[i] = tuple_tail_elem(ct[i], ct[(i+1):lct])
+            cti = ct[i]
+            if isVararg(cti)
+                tail = tuple_tail_elem(vararg(cti), Any[vawidenconst(ct[j]) for j = (i+1):lct]) # TODO (lattice overhaul) we want to unwrapva(vararg(cti)) ?
+                ct[i] = NativeType(tail)
                 resize!(ct, i)
                 break
             end
         end
         call = abstract_call(interp, ArgInfo(nothing, ct), sv, max_methods)
         push!(retinfos, ApplyCallInfo(call.info, arginfo))
-        res = tmerge(res, call.rt)
+        res = res ⊔ call.rt
         if bail_out_apply(interp, res, sv)
             if i != length(ctypes)
                 # No point carrying forward the info, we're not gonna inline it anyway
@@ -1128,6 +1131,8 @@ function abstract_apply(interp::AbstractInterpreter, argtypes::Argtypes, sv::Inf
     return CallMeta(res, retinfo)
 end
 
+vawidenconst(t::LatticeElement) = isVararg(t) ? vararg(t) : widenconst(t)
+
 function is_method_pure(method::Method, @nospecialize(sig), sparams::SimpleVector)
     if isdefined(method, :generator)
         method.generator.expand_early || return false
@@ -1201,7 +1206,7 @@ function abstract_call_builtin(
                 if isa(b, SlotNumber) && cnd.slot_id == slot_id(b)
                     ty = (cnd.elsetype ⊑ ty ? cnd.elsetype : (ty ⊓ widenconst(cnd.elsetype)))
                 end
-                return tmerge(tx, ty)
+                return tx ⊔ ty
             end
         end
     end
@@ -1288,13 +1293,13 @@ function abstract_call_builtin(
                     cnd = isdefined_tfunc(ty, fld)
                     if isConst(cnd)
                         if constant(cnd)::Bool
-                            vtype = tmerge(vtype, ty)
+                            vtype = vtype ⊔ ty
                         else
-                            elsetype = tmerge(elsetype, ty)
+                            elsetype = elsetype ⊔ ty
                         end
                     else
-                        vtype = tmerge(vtype, ty)
-                        elsetype = tmerge(elsetype, ty)
+                        vtype = vtype ⊔ ty
+                        elsetype = elsetype ⊔ ty
                     end
                 end
                 return Conditional(a.id, vtype, elsetype)
@@ -1653,7 +1658,7 @@ function abstract_eval_statement(interp::AbstractInterpreter, @nospecialize(e),
         if isa(e, PhiNode)
             rt = ⊥
             for val in e.values
-                rt = tmerge(rt, abstract_eval_special_value(interp, val, vtypes, sv))
+                rt = rt ⊔ abstract_eval_special_value(interp, val, vtypes, sv)
             end
             return rt
         end
@@ -1691,7 +1696,7 @@ function abstract_eval_statement(interp::AbstractInterpreter, @nospecialize(e),
                 end
                 if !anyrefine
                     anyrefine = has_nontrivial_const_info(at) || # constant information
-                                at ⋤ ft                          # just a type-level information, but more precise than the declared type
+                                at ⋤ₜ ft                         # just a type-level information, but more precise than the declared type
                 end
                 ats[i-1] = at
             end
@@ -1830,7 +1835,7 @@ end
 function widenreturn(rt::LatticeElement, bestguess::LatticeElement, nslots::Int, slottypes::Argtypes, changes::VarTable)
     if !(bestguess ⊑ Bool) || unwraptype(bestguess) === Bool
         # give up inter-procedural constraint back-propagation
-        # when tmerge would widen the result anyways (as an optimization)
+        # when ⊔ would widen the result anyways (as an optimization)
         rt = widenconditional(rt)
     else
         if isConditional(rt)
@@ -1988,7 +1993,7 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
                 bestguess = frame.bestguess
                 rt = abstract_eval_value(interp, stmt.val, changes, frame)
                 rt = widenreturn(rt, bestguess, nslots, slottypes, changes)
-                # narrow representation of bestguess slightly to prepare for tmerge with rt
+                # narrow representation of bestguess slightly to prepare for ⊔ with rt
                 if isInterConditional(rt) && isConst(bestguess)
                     let cnd = interconditional(rt)
                         slot_id = cnd.slot_id
@@ -2008,9 +2013,9 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
                 if !isempty(frame.limitations)
                     rt = LimitedAccuracy(rt, copy(frame.limitations))
                 end
-                if tchanged(rt, bestguess)
+                if bestguess ⋤ rt
                     # new (wider) return type for frame
-                    bestguess = tmerge(bestguess, rt)
+                    bestguess = bestguess ⊔ rt
                     # TODO: if isInterConditional(bestguess) && !interesting(bestguess); bestguess = widenconditional(bestguess); end
                     frame.bestguess = bestguess
                     for (caller, caller_pc) in frame.cycle_backedges

base/compiler/inferencestate.jl

@@ -322,8 +322,8 @@ function record_ssa_assign(ssa_id::Int, new::LatticeElement, frame::InferenceSta
     if old === NOT_FOUND || !(new ⊑ old)
         # typically, we expect that old ⊑ new (that output information only
         # gets less precise with worse input information), but to actually
-        # guarantee convergence we need to use tmerge here to ensure that is true
-        ssavaluetypes[ssa_id] = old === NOT_FOUND ? new : tmerge(old, new)
+        # guarantee convergence we need to use ⊔ here to ensure that is true
+        ssavaluetypes[ssa_id] = old === NOT_FOUND ? new : old ⊔ new
         W = frame.ip
         s = frame.stmt_types
         for r in frame.ssavalue_uses[ssa_id]

base/compiler/ssair/inlining.jl

@@ -1042,9 +1042,9 @@ function narrow_opaque_closure!(ir::IRCode, stmt::Expr, @nospecialize(info), sta
         ub, exact = instanceof_tfunc(ubt)
         exact || return
         # Narrow opaque closure type
-        newT = widenconst(tmerge(lb, info.unspec.rt) ⊓ ub)
+        newT = typeintersect(typemerge(lb, widenconst(info.unspec.rt)), ub)
         if newT !== ub
-            # N.B.: Narrowing the ub requires a backdge on the mi whose type
+            # N.B.: Narrowing the ub requires a backedge on the mi whose type
             # information we're using, since a change in that function may
             # invalidate ub result.
             stmt.args[4] = newT

base/compiler/ssair/passes.jl

@@ -271,7 +271,7 @@ function walk_to_defs(compact::IncrementalCompact, @nospecialize(defssa), @nospe
                             # path, with a different type constraint. We may have
                             # to redo some work here with the wider typeconstraint
                             push!(worklist_defs, new_def)
-                            push!(worklist_constraints, unwraptype(tmerge(new_constraint, visited_constraints[new_def])))
+                            push!(worklist_constraints, typemerge(new_constraint, visited_constraints[new_def]))
                         end
                         continue
                     end
@@ -468,8 +468,6 @@ function walk_to_def(compact::IncrementalCompact, @nospecialize(leaf))
     return Pair{Any, Any}(def, leaf)
 end
 
-make_MaybeUndef(@nospecialize(typ)) = isa(typ, MaybeUndef) ? typ : MaybeUndef(typ)
-
 """
     lift_comparison!(compact::IncrementalCompact, idx::Int, stmt::Expr)
 

base/compiler/ssair/slot2ssa.jl

@@ -592,7 +592,7 @@ function recompute_type(node::Union{PhiNode, PhiCNode}, ci::CodeInfo, ir::IRCode
         while isDelayedTyp(typ)
             typ = types(ir)[getDelayedTyp(typ).phi::NewSSAValue]
         end
-        new_typ = tmerge(new_typ, was_maybe_undef ? MaybeUndef(typ) : typ)
+        new_typ = new_typ ⊔ (was_maybe_undef ? MaybeUndef(typ) : typ)
     end
     return new_typ
 end
@@ -735,7 +735,7 @@ function construct_ssa!(ci::CodeInfo, ir::IRCode, domtree::DomTree,
             if isDelayedTyp(typ)
                 push!(type_refine_phi, ssaval.id)
             end
-            new_typ = isDelayedTyp(typ) ? ⊥ : tmerge(old_entry[:type], typ)
+            new_typ = isDelayedTyp(typ) ? ⊥ : (old_entry[:type] ⊔ typ)
             old_entry[:type] = new_typ
             old_entry[:inst] = node
             incoming_vals[slot] = ssaval
@@ -869,7 +869,7 @@ function construct_ssa!(ci::CodeInfo, ir::IRCode, domtree::DomTree,
                 while isDelayedTyp(typ)
                     typ = types(ir)[getDelayedTyp(typ).phi::NewSSAValue]
                 end
-                new_typ = tmerge(new_typ, typ)
+                new_typ = new_typ ⊔ typ
             end
             node[:type] = new_typ
         end

base/compiler/tfuncs.jl

@@ -233,7 +233,7 @@ function ifelse_tfunc(cnd::LatticeElement, x::LatticeElement, y::LatticeElement)
     elseif !(Bool ⊑ cnd)
         return ⊥
     end
-    return tmerge(x, y)
+    return x ⊔ y
 end
 add_tfunc(Core.ifelse, 3, 3, ifelse_tfunc, 1)
 
@@ -318,8 +318,7 @@ function isdefined_tfunc(arg1::LatticeElement, sym::LatticeElement)
             end
         end
     elseif isa(a1, Union)
-        return tmerge(isdefined_tfunc(NativeType(a1.a), sym),
-                      isdefined_tfunc(NativeType(a1.b), sym))
+        return isdefined_tfunc(NativeType(a1.a), sym) ⊔ isdefined_tfunc(NativeType(a1.b), sym)
     end
     return LBool
 end
@@ -391,8 +390,7 @@ function _sizeof_tfunc(@nospecialize x#=::Type=#)
     isconstType(x) && return _const_sizeof(x.parameters[1])
     xu = unwrap_unionall(x)
     if isa(xu, Union)
-        return tmerge(_sizeof_tfunc(rewrap_unionall(xu.a, x)),
-                      _sizeof_tfunc(rewrap_unionall(xu.b, x)))
+        return _sizeof_tfunc(rewrap_unionall(xu.a, x)) ⊔ _sizeof_tfunc(rewrap_unionall(xu.b, x))
     end
     # Core.sizeof operates on either a type or a value. First check which
     # case we're in.
@@ -433,7 +431,7 @@ function _nfields_tfunc(@nospecialize(x#=::Type=#))
         na === LInt && return na
         nb = _nfields_tfunc(x.b)
         nb === LInt && return nb
-        return tmerge(na, nb)
+        return na ⊔ nb
     end
     return LInt
 end
@@ -874,8 +872,8 @@ end
 function __getfield_tfunc(@nospecialize(s0#=::Type=#), name::LatticeElement, setfield::Bool)
     s = unwrap_unionall(s0)
     if isa(s, Union)
-        return tmerge(__getfield_tfunc(rewrap_unionall(s.a, s0), name, setfield),
-                      __getfield_tfunc(rewrap_unionall(s.b, s0), name, setfield))
+        return __getfield_tfunc(rewrap_unionall(s.a, s0), name, setfield) ⊔
+               __getfield_tfunc(rewrap_unionall(s.b, s0), name, setfield)
     end
     isa(s, DataType) || return ⊤
     isabstracttype(s) && return ⊤
@@ -924,7 +922,7 @@ function __getfield_tfunc(@nospecialize(s0#=::Type=#), name::LatticeElement, set
         for i in 1:nf
             _ft = ftypes[i]
             setfield && isconst(s, i) && continue
-            t = tmerge(t, NativeType(rewrap_unionall(unwrapva(_ft), s0)))
+            t = t ⊔ NativeType(rewrap_unionall(unwrapva(_ft), s0))
             t === ⊤ && break
         end
         return t
@@ -1150,8 +1148,8 @@ function fieldtype_tfunc(s0::LatticeElement, name::LatticeElement)
 
     su = unwrap_unionall(s)
     if isa(su, Union)
-        return tmerge(fieldtype_tfunc(NativeType(rewrap_unionall(su.a, s)), name),
-                      fieldtype_tfunc(NativeType(rewrap_unionall(su.b, s)), name))
+        return fieldtype_tfunc(NativeType(rewrap_unionall(su.a, s)), name) ⊔
+               fieldtype_tfunc(NativeType(rewrap_unionall(su.b, s)), name)
     end
 
     s, exact = instanceof_tfunc(s0)
@@ -1221,7 +1219,7 @@ function _fieldtype_tfunc(@nospecialize(s#=::Type=#), exact::Bool, name::Lattice
             else
                 ft1 = Const(ft1)
             end
-            t = tmerge(t, ft1)
+            t = t ⊔ ft1
             t === ⊤ && break
         end
         return t