Changes in src/Tuples/TupleExpansion.cc [f240484:aee472e]

File:

• src/Tuples/TupleExpansion.cc (modified) (3 diffs)

src/Tuples/TupleExpansion.cc

@@ -30 +30 @@
 #include "SynTree/Type.h"         // for Type, Type::Qualifiers, TupleType
 #include "SynTree/Visitor.h"      // for Visitor
+#include "Tuples.h"
 
 class CompoundStmt;
@@ -128 +129 @@
                         Expression * aggr = memberExpr->aggregate->clone()->acceptMutator( *visitor );
                         // aggregate expressions which might be impure must be wrapped in unique expressions
-                        // xxx - if there's a member-tuple expression nested in the aggregate, this currently generates the wrong code if a UniqueExpr is not used, and it's purely an optimization to remove the UniqueExpr
-                        // if ( Tuples::maybeImpureIgnoreUnique( memberExpr->get_aggregate() ) ) aggr = new UniqueExpr( aggr );
-                        aggr = new UniqueExpr( aggr );
+                        if ( Tuples::maybeImpureIgnoreUnique( memberExpr->aggregate ) ) aggr = new UniqueExpr( aggr );
                         for ( Expression *& expr : tupleExpr->exprs ) {
                                 expr = reconstructMemberExpr( expr, aggr, memberExpr->location );
@@ -227 +226 @@
 
         Expression * TupleIndexExpander::postmutate( TupleIndexExpr * tupleExpr ) {
-                Expression * tuple = tupleExpr->get_tuple();
+                Expression * tuple = tupleExpr->tuple;
                 assert( tuple );
-                tupleExpr->set_tuple( nullptr );
-                unsigned int idx = tupleExpr->get_index();
-                TypeSubstitution * env = tupleExpr->get_env();
-                tupleExpr->set_env( nullptr );
+                tupleExpr->tuple = nullptr;
+                unsigned int idx = tupleExpr->index;
+                TypeSubstitution * env = tupleExpr->env;
+                tupleExpr->env = nullptr;
                 delete tupleExpr;
 
-                StructInstType * type = strict_dynamic_cast< StructInstType * >( tuple->get_result() );
-                StructDecl * structDecl = type->get_baseStruct();
-                assert( structDecl->get_members().size() > idx );
-                Declaration * member = *std::next(structDecl->get_members().begin(), idx);
+                if ( TupleExpr * tupleExpr = dynamic_cast< TupleExpr * > ( tuple ) ) {
+                        if ( ! maybeImpureIgnoreUnique( tupleExpr ) ) {
+                                // optimization: definitely pure tuple expr => can reduce to the only relevant component.
+                                assert( tupleExpr->exprs.size() > idx );
+                                Expression *& expr = *std::next(tupleExpr->exprs.begin(), idx);
+                                Expression * ret = expr;
+                                ret->env = env;
+                                expr = nullptr; // remove from list so it can safely be deleted
+                                delete tupleExpr;
+                                return ret;
+                        }
+                }
+
+                StructInstType * type = strict_dynamic_cast< StructInstType * >( tuple->result );
+                StructDecl * structDecl = type->baseStruct;
+                assert( structDecl->members.size() > idx );
+                Declaration * member = *std::next(structDecl->members.begin(), idx);
                 MemberExpr * memExpr = new MemberExpr( strict_dynamic_cast< DeclarationWithType * >( member ), tuple );
-                memExpr->set_env( env );
+                memExpr->env = env;
                 return memExpr;
         }