pt.c (maybe_fold_nontype_arg): Use TREE_TYPE of ARG as the criterion to avoid rebuilding expression tree...

* pt.c (maybe_fold_nontype_arg): Use TREE_TYPE of ARG as the
	criterion to avoid rebuilding expression tree instead of
	processing_template_decl.

	* g++.dg/template/unify1.C: New test.

From-SVN: r44793

gcc/cp/ChangeLog

@@ -1,3 +1,9 @@
+2001-08-11  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>
+
+	* pt.c (maybe_fold_nontype_arg): Use TREE_TYPE of ARG as the
+	criterion to avoid rebuilding expression tree instead of
+	processing_template_decl.
+
 2001-08-07  Jason Merrill  <jason_merrill@redhat.com>
 
 	Support named return value optimization for inlines, too.

gcc/cp/pt.c

@@ -5280,12 +5280,7 @@ static tree
 maybe_fold_nontype_arg (arg)
      tree arg;
 {
-  /* If we're not in a template, ARG is already as simple as it's going to
-     get, and trying to reprocess the trees will break.  */
-  if (! processing_template_decl)
-    return arg;
-
-  if (!TYPE_P (arg) && !uses_template_parms (arg))
+  if (arg && !TYPE_P (arg) && !uses_template_parms (arg))
     {
       /* Sometimes, one of the args was an expression involving a
 	 template constant parameter, like N - 1.  Now that we've
@@ -5295,10 +5290,18 @@ maybe_fold_nontype_arg (arg)
 	 fool build_expr_from_tree() into building an actual
 	 tree.  */
 
-      int saved_processing_template_decl = processing_template_decl; 
-      processing_template_decl = 0;
-      arg = fold (build_expr_from_tree (arg));
-      processing_template_decl = saved_processing_template_decl; 
+      /* If the TREE_TYPE of ARG is not NULL_TREE, ARG is already
+	 as simple as it's going to get, and trying to reprocess
+	 the trees will break.  */
+      if (!TREE_TYPE (arg))
+	{
+	  int saved_processing_template_decl = processing_template_decl; 
+	  processing_template_decl = 0;
+	  arg = build_expr_from_tree (arg);
+	  processing_template_decl = saved_processing_template_decl; 
+	}
+
+      arg = fold (arg);
     }
   return arg;
 }

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2001-08-11  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>
+
+	* g++.dg/template/unify1.C: New test.
+
 2001-08-07  Nathan Sidwell  <nathan@codesourcery.com>
 
 	* g++.dg/abi/empty4.C: New test.

gcc/testsuite/g++.dg/template/unify1.C

@@ -0,0 +1,26 @@
+// Test non-type template argument folding.
+// Origin: smacdonald@seimac.com
+
+// { dg-do compile }
+
+template < int I1, int I2 >
+class unit
+{
+public:
+  unit() {}
+  unit( const unit<I1,I2>& ) {}
+ 
+  template< int Q1, int Q2 >
+  unit< I1 - Q1, I2 - Q2 > operator / ( const unit< Q1, Q2 >& rhs ) const {
+    return unit< I1 - Q1, I2 - Q2 >();
+  }
+ 
+};
+ 
+int main()
+{
+  const unit<1,0> u1;
+  const unit<2,0> u2;
+ 
+  unit<-1,0> u3( u1 / u2 );
+}