re PR c++/23789 (compilation error when template parameters have certain complexity)

PR c++/23789
	* cvt.c (perform_qualification_conversions): Don't create
	unnecessary NOP_EXPRs.
	* pt.c (tsubst_template_arg): Use fold_non_dependent_expr.

	PR c++/23789
	* g++.dg/template/nontype14.C: New test.

From-SVN: r104193

gcc/cp/ChangeLog

@@ -1,3 +1,10 @@
+2005-09-12  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23789
+	* cvt.c (perform_qualification_conversions): Don't create
+	unnecessary NOP_EXPRs.
+	* pt.c (tsubst_template_arg): Use fold_non_dependent_expr.
+
 2005-09-12  Ian Lance Taylor  <ian@airs.com>
 
 	PR g++/7874

gcc/cp/cvt.c

@@ -1209,8 +1209,10 @@ perform_qualification_conversions (tree type, tree expr)
 
   expr_type = TREE_TYPE (expr);
 
-  if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type)
-      && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type)))
+  if (same_type_p (type, expr_type))
+    return expr;
+  else if (TYPE_PTR_P (type) && TYPE_PTR_P (expr_type)
+	   && comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (expr_type)))
     return build_nop (type, expr);
   else if (TYPE_PTR_TO_MEMBER_P (type)
 	   && TYPE_PTR_TO_MEMBER_P (expr_type)

gcc/cp/pt.c

@@ -5919,32 +5919,7 @@ tsubst_template_arg (tree t, tree args, tsubst_flags_t complain, tree in_decl)
   else
     {
       r = tsubst_expr (t, args, complain, in_decl);
-
-      if (!uses_template_parms (r))
-	{
-	  /* Sometimes, one of the args was an expression involving a
-	     template constant parameter, like N - 1.  Now that we've
-	     tsubst'd, we might have something like 2 - 1.  This will
-	     confuse lookup_template_class, so we do constant folding
-	     here.  We have to unset processing_template_decl, to fool
-	     tsubst_copy_and_build() into building an actual tree.  */
-
-	 /* 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.  Once tsubst_expr et al DTRT for
-	    non-dependent exprs, this code can go away, as the type
-	    will always be set.  */
-	  if (!TREE_TYPE (r))
-	    {
-	      int saved_processing_template_decl = processing_template_decl;
-	      processing_template_decl = 0;
-	      r = tsubst_copy_and_build (r, /*args=*/NULL_TREE,
-					 tf_error, /*in_decl=*/NULL_TREE,
-					 /*function_p=*/false);
-	      processing_template_decl = saved_processing_template_decl;
-	      r = fold (r);
-	    }
-	}
+      r = fold_non_dependent_expr (r);
     }
   return r;
 }

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2005-09-12  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23789
+	* g++.dg/template/nontype14.C: New test.
+
 2005-09-12  Ian Lance Taylor  <ian@airs.com>
 
 	PR g++/7874

gcc/testsuite/g++.dg/template/nontype14.C

@@ -0,0 +1,13 @@
+// PR c++/23789
+
+template <int W> struct X { 
+  template <int W2> 
+  X< (W+(W&&W) > 1 ? W+(W&&W) : 1)+1> 
+  operator + (const X<W2>&) const; 
+}; 
+ 
+template <int dummy> void foo() 
+{ 
+  X<6> A,B; 
+  A + B; 
+}