diff --git a/src/Expr.cc b/src/Expr.cc
index 23a0863678..7827f50713 100644
--- a/src/Expr.cc
+++ b/src/Expr.cc
@@ -1403,7 +1403,7 @@ void AddExpr::Canonicalize() {
         SwapOps();
 }
 
-AggrAddExpr::AggrAddExpr(ExprPtr _op) : UnaryExpr(EXPR_AGGR_ADD, std::move(_op)) {
+AggrAddExpr::AggrAddExpr(ExprPtr _op) : AggrAddDelExpr(EXPR_AGGR_ADD, std::move(_op)) {
     if ( ! op->IsError() && ! op->CanAdd() )
         ExprError("illegal add expression");
 
@@ -1412,7 +1412,7 @@ AggrAddExpr::AggrAddExpr(ExprPtr _op) : UnaryExpr(EXPR_AGGR_ADD, std::move(_op))
 
 ValPtr AggrAddExpr::Eval(Frame* f) const { return op->Add(f); }
 
-AggrDelExpr::AggrDelExpr(ExprPtr _op) : UnaryExpr(EXPR_AGGR_DEL, std::move(_op)) {
+AggrDelExpr::AggrDelExpr(ExprPtr _op) : AggrAddDelExpr(EXPR_AGGR_DEL, std::move(_op)) {
     if ( ! op->IsError() && ! op->CanDel() )
         Error("illegal delete expression");
 
diff --git a/src/Expr.h b/src/Expr.h
index 9ca5434c10..d937870e79 100644
--- a/src/Expr.h
+++ b/src/Expr.h
@@ -707,31 +707,36 @@ protected:
     ExprPtr BuildSub(const ExprPtr& op1, const ExprPtr& op2);
 };
 
-class AggrAddExpr final : public UnaryExpr {
+// A helper class that enables us to factor some common code.
+class AggrAddDelExpr : public UnaryExpr {
 public:
-    explicit AggrAddExpr(ExprPtr e);
+    explicit AggrAddDelExpr(ExprTag _tag, ExprPtr _e) : UnaryExpr(_tag, std::move(_e)) {}
 
     bool IsPure() const override { return false; }
 
     // Optimization-related:
-    ExprPtr Duplicate() override;
     bool IsReduced(Reducer* c) const override { return HasReducedOps(c); }
+    bool HasReducedOps(Reducer* c) const override { return op->HasReducedOps(c); }
     ExprPtr Reduce(Reducer* c, StmtPtr& red_stmt) override;
+};
+
+class AggrAddExpr final : public AggrAddDelExpr {
+public:
+    explicit AggrAddExpr(ExprPtr e);
+
+    // Optimization-related:
+    ExprPtr Duplicate() override;
 
 protected:
     ValPtr Eval(Frame* f) const override;
 };
 
-class AggrDelExpr final : public UnaryExpr {
+class AggrDelExpr final : public AggrAddDelExpr {
 public:
     explicit AggrDelExpr(ExprPtr e);
 
-    bool IsPure() const override { return false; }
-
     // Optimization-related:
     ExprPtr Duplicate() override;
-    bool IsReduced(Reducer* c) const override { return HasReducedOps(c); }
-    ExprPtr Reduce(Reducer* c, StmtPtr& red_stmt) override;
 
 protected:
     ValPtr Eval(Frame* f) const override;
diff --git a/src/script_opt/CPP/Compile.h b/src/script_opt/CPP/Compile.h
index 5b05cc07e9..fb7889e6f4 100644
--- a/src/script_opt/CPP/Compile.h
+++ b/src/script_opt/CPP/Compile.h
@@ -757,6 +757,8 @@ private:
 
     std::string GenNameExpr(const NameExpr* ne, GenType gt);
     std::string GenConstExpr(const ConstExpr* c, GenType gt);
+    std::string GenAggrAdd(const Expr* e);
+    std::string GenAggrDel(const Expr* e);
     std::string GenIncrExpr(const Expr* e, GenType gt, bool is_incr, bool top_level);
     std::string GenCondExpr(const Expr* e, GenType gt);
     std::string GenCallExpr(const CallExpr* c, GenType gt, bool top_level);
diff --git a/src/script_opt/CPP/Exprs.cc b/src/script_opt/CPP/Exprs.cc
index 24ab36f4b4..40eba322b6 100644
--- a/src/script_opt/CPP/Exprs.cc
+++ b/src/script_opt/CPP/Exprs.cc
@@ -52,6 +52,9 @@ string CPPCompile::GenExpr(const Expr* e, GenType gt, bool top_level) {
             gen = GenExpr(e->GetOp1(), GEN_VAL_PTR) + "->Clone()";
             return GenericValPtrToGT(gen, e->GetType(), gt);
 
+        case EXPR_AGGR_ADD: return GenAggrAdd(e);
+        case EXPR_AGGR_DEL: return GenAggrDel(e);
+
         case EXPR_INCR:
         case EXPR_DECR: return GenIncrExpr(e, gt, e->Tag() == EXPR_INCR, top_level);
 
@@ -183,6 +186,39 @@ string CPPCompile::GenConstExpr(const ConstExpr* c, GenType gt) {
     return NativeToGT(GenVal(c->ValuePtr()), t, gt);
 }
 
+string CPPCompile::GenAggrAdd(const Expr* e) {
+    auto op = e->GetOp1();
+    auto aggr = GenExpr(op->GetOp1(), GEN_DONT_CARE);
+    auto indices = GenExpr(op->GetOp2(), GEN_VAL_PTR);
+
+    return "add_element__CPP(" + aggr + ", index_val__CPP({" + indices + "}))";
+}
+
+string CPPCompile::GenAggrDel(const Expr* e) {
+    auto op = e->GetOp1();
+
+    if ( op->Tag() == EXPR_NAME ) {
+        auto aggr_gen = GenExpr(op, GEN_VAL_PTR);
+
+        if ( op->GetType()->Tag() == TYPE_TABLE )
+            return aggr_gen + "->RemoveAll()";
+        else
+            return aggr_gen + "->Resize(0)";
+    }
+
+    auto aggr = op->GetOp1();
+    auto aggr_gen = GenExpr(aggr, GEN_VAL_PTR);
+
+    if ( op->Tag() == EXPR_INDEX ) {
+        auto indices = GenExpr(op->GetOp2(), GEN_VAL_PTR);
+        return "remove_element__CPP(" + aggr_gen + ", index_val__CPP({" + indices + "}))";
+    }
+
+    ASSERT(op->Tag() == EXPR_FIELD);
+    auto field = GenField(aggr, op->AsFieldExpr()->Field());
+    return aggr_gen + "->Remove(" + field + ")";
+}
+
 string CPPCompile::GenIncrExpr(const Expr* e, GenType gt, bool is_incr, bool top_level) {
     // For compound operands (table indexing, record fields),
     // Zeek's interpreter will actually evaluate the operand
diff --git a/src/script_opt/CPP/maint/do-CPP-btest.sh b/src/script_opt/CPP/maint/do-CPP-btest.sh
index 5c3aff7c62..b7a7e47489 100755
--- a/src/script_opt/CPP/maint/do-CPP-btest.sh
+++ b/src/script_opt/CPP/maint/do-CPP-btest.sh
@@ -34,7 +34,9 @@ export ZEEK_OPT_FILES="testing/btest"
 # export -n ZEEK_GEN_CPP ZEEK_CPP_DIR ZEEK_OPT_FUNCS ZEEK_OPT_FILES
 unset ZEEK_GEN_CPP ZEEK_REPORT_UNCOMPILABLE ZEEK_CPP_DIR ZEEK_OPT_FILES
 
+ls -l CPP-gen.cc
 ninja
+ls -l src/zeek
 
 (
     cd ../testing/btest
diff --git a/src/script_opt/CSE.cc b/src/script_opt/CSE.cc
index 2d97038670..3e217ee322 100644
--- a/src/script_opt/CSE.cc
+++ b/src/script_opt/CSE.cc
@@ -38,16 +38,6 @@ TraversalCode CSE_ValidityChecker::PreStmt(const Stmt* s) {
         return TC_ABORTALL;
     }
 
-    if ( t == STMT_ADD || t == STMT_DELETE )
-        in_aggr_mod_stmt = true;
-
-    return TC_CONTINUE;
-}
-
-TraversalCode CSE_ValidityChecker::PostStmt(const Stmt* s) {
-    if ( s->Tag() == STMT_ADD || s->Tag() == STMT_DELETE )
-        in_aggr_mod_stmt = false;
-
     return TC_CONTINUE;
 }
 
@@ -120,6 +110,9 @@ TraversalCode CSE_ValidityChecker::PreExpr(const Expr* e) {
             }
         } break;
 
+        case EXPR_AGGR_ADD:
+        case EXPR_AGGR_DEL: ++in_aggr_mod_expr; break;
+
         case EXPR_APPEND_TO:
             // This doesn't directly change any identifiers, but does
             // alter an aggregate.
@@ -155,7 +148,7 @@ TraversalCode CSE_ValidityChecker::PreExpr(const Expr* e) {
             auto aggr = e->GetOp1();
             auto aggr_t = aggr->GetType();
 
-            if ( in_aggr_mod_stmt ) {
+            if ( in_aggr_mod_expr ) {
                 auto aggr_id = aggr->AsNameExpr()->Id();
 
                 if ( CheckID(aggr_id, true) || CheckAggrMod(aggr_t) )
@@ -174,6 +167,13 @@ TraversalCode CSE_ValidityChecker::PreExpr(const Expr* e) {
     return TC_CONTINUE;
 }
 
+TraversalCode CSE_ValidityChecker::PostExpr(const Expr* e) {
+    if ( e->Tag() == EXPR_AGGR_ADD || e->Tag() == EXPR_AGGR_DEL )
+        --in_aggr_mod_expr;
+
+    return TC_CONTINUE;
+}
+
 bool CSE_ValidityChecker::CheckID(const ID* id, bool ignore_orig) {
     for ( auto i : ids ) {
         if ( ignore_orig && i == ids.front() )
diff --git a/src/script_opt/CSE.h b/src/script_opt/CSE.h
index 9507cd493e..56d6572d9a 100644
--- a/src/script_opt/CSE.h
+++ b/src/script_opt/CSE.h
@@ -21,8 +21,8 @@ public:
                         const Expr* end_e);
 
     TraversalCode PreStmt(const Stmt*) override;
-    TraversalCode PostStmt(const Stmt*) override;
     TraversalCode PreExpr(const Expr*) override;
+    TraversalCode PostExpr(const Expr*) override;
 
     // Returns the ultimate verdict re safety.
     bool IsValid() const {
@@ -99,10 +99,12 @@ protected:
     bool have_start_e = false;
     bool have_end_e = false;
 
-    // Whether analyzed expressions occur in the context of a statement
+    // Whether analyzed expressions occur in the context of an expression
     // that modifies an aggregate ("add" or "delete"), which changes the
     // interpretation of the expressions.
-    bool in_aggr_mod_stmt = false;
+    //
+    // A count to allow for nesting.
+    int in_aggr_mod_expr = 0;
 };
 
 // Used for debugging, to communicate which expression wasn't
diff --git a/src/script_opt/Expr.cc b/src/script_opt/Expr.cc
index f597d4e969..9985448cd6 100644
--- a/src/script_opt/Expr.cc
+++ b/src/script_opt/Expr.cc
@@ -723,30 +723,20 @@ ExprPtr AddExpr::BuildSub(const ExprPtr& op1, const ExprPtr& op2) {
     return with_location_of(make_intrusive<SubExpr>(op1, rhs), this);
 }
 
+ExprPtr AggrAddDelExpr::Reduce(Reducer* c, StmtPtr& red_stmt) {
+    if ( c->Optimizing() ) {
+        op = c->OptExpr(op);
+        return ThisPtr();
+    }
+
+    red_stmt = op->ReduceToSingletons(c);
+    return ThisPtr();
+}
+
 ExprPtr AggrAddExpr::Duplicate() { return SetSucc(new AggrAddExpr(op->Duplicate())); }
 
-ExprPtr AggrAddExpr::Reduce(Reducer* c, StmtPtr& red_stmt) {
-    if ( c->Optimizing() ) {
-        op = c->OptExpr(op);
-        return ThisPtr();
-    }
-
-    red_stmt = op->ReduceToSingletons(c);
-    return ThisPtr();
-}
-
 ExprPtr AggrDelExpr::Duplicate() { return SetSucc(new AggrDelExpr(op->Duplicate())); }
 
-ExprPtr AggrDelExpr::Reduce(Reducer* c, StmtPtr& red_stmt) {
-    if ( c->Optimizing() ) {
-        op = c->OptExpr(op);
-        return ThisPtr();
-    }
-
-    red_stmt = op->ReduceToSingletons(c);
-    return ThisPtr();
-}
-
 ExprPtr AddToExpr::Duplicate() {
     auto op1_d = op1->Duplicate();
     auto op2_d = op2->Duplicate();
diff --git a/src/script_opt/ProfileFunc.cc b/src/script_opt/ProfileFunc.cc
index 29a0b02005..b10fbda940 100644
--- a/src/script_opt/ProfileFunc.cc
+++ b/src/script_opt/ProfileFunc.cc
@@ -157,17 +157,6 @@ TraversalCode ProfileFunc::PreStmt(const Stmt* s) {
                 expr_switches.insert(sw);
         } break;
 
-        case STMT_ADD:
-        case STMT_DELETE: {
-            auto ad_stmt = static_cast<const AddDelStmt*>(s);
-            auto ad_e = ad_stmt->StmtExpr();
-            auto lhs = ad_e->GetOp1();
-            if ( lhs )
-                aggr_mods.insert(lhs->GetType().get());
-            else
-                aggr_mods.insert(ad_e->GetType().get());
-        } break;
-
         default: break;
     }
 
@@ -339,6 +328,15 @@ TraversalCode ProfileFunc::PreExpr(const Expr* e) {
             }
         } break;
 
+        case EXPR_AGGR_ADD:
+        case EXPR_AGGR_DEL: {
+            auto lhs = e->GetOp1();
+            if ( lhs )
+                aggr_mods.insert(lhs->GetType().get());
+            else
+                aggr_mods.insert(e->GetType().get());
+        } break;
+
         case EXPR_CALL: {
             auto c = e->AsCallExpr();
             auto args = c->Args();
diff --git a/src/script_opt/UseDefs.cc b/src/script_opt/UseDefs.cc
index 1e786c9403..c9d17a3038 100644
--- a/src/script_opt/UseDefs.cc
+++ b/src/script_opt/UseDefs.cc
@@ -436,6 +436,19 @@ UDs UseDefs::ExprUDs(const Expr* e) {
             break;
         }
 
+        case EXPR_AGGR_ADD:
+        case EXPR_AGGR_DEL: {
+            auto op = e->GetOp1();
+            if ( op->Tag() == EXPR_INDEX ) {
+                AddInExprUDs(uds, op->GetOp1().get());
+                auto rhs_UDs = ExprUDs(op->GetOp2().get());
+                uds = UD_Union(uds, rhs_UDs);
+            }
+            else
+                AddInExprUDs(uds, op.get());
+            break;
+        }
+
         case EXPR_INCR:
         case EXPR_DECR: AddInExprUDs(uds, e->GetOp1()->AsRefExprPtr()->GetOp1().get()); break;
 
diff --git a/src/script_opt/ZAM/Compile.h b/src/script_opt/ZAM/Compile.h
index 2ee365e64c..dbe50dc2d9 100644
--- a/src/script_opt/ZAM/Compile.h
+++ b/src/script_opt/ZAM/Compile.h
@@ -186,6 +186,8 @@ private:
 
     const ZAMStmt CompileIncrExpr(const IncrExpr* e);
     const ZAMStmt CompileAppendToExpr(const AppendToExpr* e);
+    const ZAMStmt CompileAdd(const AggrAddExpr* e);
+    const ZAMStmt CompileDel(const AggrDelExpr* e);
     const ZAMStmt CompileAddToExpr(const AddToExpr* e);
     const ZAMStmt CompileRemoveFromExpr(const RemoveFromExpr* e);
     const ZAMStmt CompileAssignExpr(const AssignExpr* e);
diff --git a/src/script_opt/ZAM/Expr.cc b/src/script_opt/ZAM/Expr.cc
index facc6952ff..02eefb9939 100644
--- a/src/script_opt/ZAM/Expr.cc
+++ b/src/script_opt/ZAM/Expr.cc
@@ -16,6 +16,10 @@ const ZAMStmt ZAMCompiler::CompileExpr(const Expr* e) {
 
         case EXPR_APPEND_TO: return CompileAppendToExpr(static_cast<const AppendToExpr*>(e));
 
+        case EXPR_AGGR_ADD: return CompileAdd(static_cast<const AggrAddExpr*>(e));
+
+        case EXPR_AGGR_DEL: return CompileDel(static_cast<const AggrDelExpr*>(e));
+
         case EXPR_ADD_TO: return CompileAddToExpr(static_cast<const AddToExpr*>(e));
 
         case EXPR_REMOVE_FROM: return CompileRemoveFromExpr(static_cast<const RemoveFromExpr*>(e));
@@ -78,6 +82,56 @@ const ZAMStmt ZAMCompiler::CompileAppendToExpr(const AppendToExpr* e) {
     return n2 ? AppendToVV(n1, n2) : AppendToVC(n1, cc);
 }
 
+const ZAMStmt ZAMCompiler::CompileAdd(const AggrAddExpr* e) {
+    auto op = e->GetOp1();
+    auto aggr = op->GetOp1()->AsNameExpr();
+    auto index_list = op->GetOp2();
+
+    if ( index_list->Tag() != EXPR_LIST )
+        reporter->InternalError("non-list in \"add\"");
+
+    auto indices = index_list->AsListExprPtr();
+    auto& exprs = indices->Exprs();
+
+    if ( exprs.length() == 1 ) {
+        auto e1 = exprs[0];
+        if ( e1->Tag() == EXPR_NAME )
+            return AddStmt1VV(aggr, e1->AsNameExpr());
+        else
+            return AddStmt1VC(aggr, e1->AsConstExpr());
+    }
+
+    return AddStmtVO(aggr, BuildVals(indices));
+}
+
+const ZAMStmt ZAMCompiler::CompileDel(const AggrDelExpr* e) {
+    auto op = e->GetOp1();
+
+    if ( op->Tag() == EXPR_NAME ) {
+        auto n = op->AsNameExpr();
+
+        if ( n->GetType()->Tag() == TYPE_TABLE )
+            return ClearTableV(n);
+        else
+            return ClearVectorV(n);
+    }
+
+    auto aggr = op->GetOp1()->AsNameExpr();
+
+    if ( op->Tag() == EXPR_FIELD ) {
+        int field = op->AsFieldExpr()->Field();
+        return DelFieldVi(aggr, field);
+    }
+
+    auto index_list = op->GetOp2();
+
+    if ( index_list->Tag() != EXPR_LIST )
+        reporter->InternalError("non-list in \"delete\"");
+
+    auto internal_ind = std::unique_ptr<OpaqueVals>(BuildVals(index_list->AsListExprPtr()));
+    return DelTableVO(aggr, internal_ind.get());
+}
+
 const ZAMStmt ZAMCompiler::CompileAddToExpr(const AddToExpr* e) {
     auto op1 = e->GetOp1();
     auto t1 = op1->GetType()->Tag();