script optimization support for clearing tables/vectors using "delete"

src/script_opt/CPP/Stmts.cc

@@ -159,6 +159,15 @@ void CPPCompile::GenAddStmt(const ExprStmt* es) {
 
 void CPPCompile::GenDeleteStmt(const ExprStmt* es) {
     auto op = es->StmtExpr();
+
+    if ( op->Tag() == EXPR_NAME ) {
+        if ( op->GetType()->Tag() == TYPE_TABLE )
+            Emit("%s->RemoveAll();", GenExpr(op, GEN_VAL_PTR));
+        else
+            Emit("%s->Resize(0);", GenExpr(op, GEN_VAL_PTR));
+        return;
+    }
+
     auto aggr = op->GetOp1();
     auto aggr_gen = GenExpr(aggr, GEN_VAL_PTR);
 

src/script_opt/ProfileFunc.cc

@@ -161,8 +161,11 @@ TraversalCode ProfileFunc::PreStmt(const Stmt* s) {
         case STMT_DELETE: {
             auto ad_stmt = static_cast<const AddDelStmt*>(s);
             auto ad_e = ad_stmt->StmtExpr();
-            auto& lhs_t = ad_e->GetOp1()->GetType();
-            aggr_mods.insert(lhs_t.get());
+            auto lhs = ad_e->GetOp1();
+            if ( lhs )
+                aggr_mods.insert(lhs->GetType().get());
+            else
+                aggr_mods.insert(ad_e->GetType().get());
         } break;
 
         default: break;

src/script_opt/Stmt.cc

@@ -255,7 +255,7 @@ StmtPtr IfStmt::DoReduce(Reducer* c) {
         sl = make_intrusive<StmtList>(red_e_stmt, ThisPtr());
 
     if ( sl )
-        return TransformMe(sl, c);
+        return TransformMe(std::move(sl), c);
 
     return ThisPtr();
 }
@@ -418,14 +418,10 @@ StmtPtr AddDelStmt::DoReduce(Reducer* c) {
         return ThisPtr();
     }
 
-    if ( e->Tag() != EXPR_INDEX && e->Tag() != EXPR_FIELD )
-        Internal("bad \"add\"/\"delete\"");
-
     auto red_e_stmt = e->ReduceToSingletons(c);
 
     if ( red_e_stmt )
         return TransformMe(make_intrusive<StmtList>(red_e_stmt, ThisPtr()), c);
-
     else
         return ThisPtr();
 }

src/script_opt/ZAM/Expr.cc

@@ -874,7 +874,7 @@ const ZAMStmt ZAMCompiler::Call(const ExprStmt* e) {
 
     if ( IsZAM_BuiltIn(c.get()) ) {
         auto ret = LastInst();
-        insts1.back()->call_expr = c;
+        insts1.back()->call_expr = std::move(c);
         return ret;
     }
 

src/script_opt/ZAM/Ops.in

@@ -2087,6 +2087,17 @@ type VC
 eval	EvalAddStmt(z.c.ToVal(z.t))
 
 
+op ClearTable
+op1-read
+type V
+eval	frame[z.v1].table_val->RemoveAll();
+
+op ClearVector
+op1-read
+type V
+eval	frame[z.v1].vector_val->Resize(0);
+
+
 op DelTable
 op1-read
 type VO

src/script_opt/ZAM/Stmt.cc

@@ -591,6 +591,16 @@ const ZAMStmt ZAMCompiler::CompileAdd(const AddStmt* as) {
 
 const ZAMStmt ZAMCompiler::CompileDel(const DelStmt* ds) {
     auto e = ds->StmtExprPtr();
+
+    if ( e->Tag() == EXPR_NAME ) {
+        auto n = e->AsNameExpr();
+
+        if ( n->GetType()->Tag() == TYPE_TABLE )
+            return ClearTableV(n);
+        else
+            return ClearVectorV(n);
+    }
+
     auto aggr = e->GetOp1()->AsNameExpr();
 
     if ( e->Tag() == EXPR_FIELD ) {