typeck.c (build_compound_expr): If RHS is a TARGET_EXPR, put the compound expr…

typeck.c (build_compound_expr): If RHS is a TARGET_EXPR, put the compound expr inside the target's initializer.

cp:
	* typeck.c (build_compound_expr): If RHS is a TARGET_EXPR, put the
	compound expr inside the target's initializer.
testsuite:
	* g++.dg/opt/tmp1.C: New test.

From-SVN: r70042

gcc/cp/ChangeLog

 2003-08-01  Nathan Sidwell  <nathan@codesourcery.com>
 
+	* typeck.c (build_compound_expr): If RHS is a TARGET_EXPR, put the
+	compound expr inside the target's initializer.
+	
 	PR c++/11525
 	* parser.c (cp_parser_primary_expression): Do not set
 	non-constant-p merely because it is a dependent scope.

gcc/cp/typeck.c

@@ -4322,6 +4322,19 @@ build_compound_expr (tree lhs, tree rhs)
   lhs = convert_to_void (lhs, "left-hand operand of comma");
   if (lhs == error_mark_node || rhs == error_mark_node)
     return error_mark_node;
+
+  if (TREE_CODE (rhs) == TARGET_EXPR)
+    {
+      /* If the rhs is a TARGET_EXPR, then build the compound
+         expression inside the target_expr's initializer. This
+	 helps the compiler to eliminate unncessary temporaries.  */
+      tree init = TREE_OPERAND (rhs, 1);
+
+      init = build (COMPOUND_EXPR, TREE_TYPE (init), lhs, init);
+      TREE_OPERAND (rhs, 1) = init;
+      
+      return rhs;
+    }
   
   return build (COMPOUND_EXPR, TREE_TYPE (rhs), lhs, rhs);
 }

gcc/testsuite/ChangeLog

 2003-08-01  Nathan Sidwell  <nathan@codesourcery.com>
 
+	* g++.dg/opt/tmp1.C: New test.
+
 	PR c++/11525
 	* g++.dg/parse/constant4.C: New test.
 

gcc/testsuite/g++.dg/opt/tmp1.C

+// { dg-do run }
+
+
+// Copyright (C) 2003 Free Software Foundation, Inc.
+// Contributed by Nathan Sidwell 30 Jul 2003 <nathan@codesourcery.com>
+
+// compound exprs were causing additional temporaries.
+
+extern "C" int printf (char const *, ...);
+extern "C" void abort ();
+
+
+static unsigned order[] = 
+{
+  1, 2, 502, 102, 101,
+  0
+};
+
+static unsigned point;
+
+static void Check (unsigned t, unsigned i, void const *ptr, char const *name)
+{
+  printf ("%d %d %p %s\n", t, i, ptr, name);
+  
+  if (order[point++] != i + t)
+    abort ();
+  
+}
+
+template <int I> struct A 
+{
+  A () { Check (0, I, this, __PRETTY_FUNCTION__); }
+  ~A () { Check (100, I, this, __PRETTY_FUNCTION__); }
+  A (A const &) { Check (200, I, this, __PRETTY_FUNCTION__); }
+  A &operator= (A const &) { Check (300, I, this, __PRETTY_FUNCTION__); }
+  void Foo () const { Check (400, I, this, __PRETTY_FUNCTION__); }
+};
+
+template <int I> void Foo (A<I> a)
+{
+  Check (500, I, &a, __PRETTY_FUNCTION__);
+}
+
+int main ()
+{
+  Foo ((A<1> (), A<2> ()));
+  Check (0, 0, 0, "end");
+}