re PR c++/23691 (`mpl_::bool_<false>::value' is not a valid template argument…

re PR c++/23691 (`mpl_::bool_<false>::value' is not a valid template argument for type `bool' because it is a non-constant expression)

	PR c++/23691
	* decl2.c (mark_used): Instantiate static data members initialized
	by constants, even in a template.

	PR c++/23691
	* g++.dg/template/static16.C: New test.

From-SVN: r104041

gcc/cp/ChangeLog

+2005-09-08  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23691
+	* decl2.c (mark_used): Instantiate static data members initialized
+	by constants, even in a template.
+
 2005-09-08  Andrew Pinski  <pinskia@physics.uc.edu>
 
 	PR obj-c++/16816

gcc/cp/decl2.c

@@ -3217,12 +3217,38 @@ check_default_args (tree x)
     }
 }
 
+/* Mark DECL as "used" in the program.  If DECL is a specialization or
+   implicitly declared class member, generate the actual definition.  */
+
 void
 mark_used (tree decl)
 {
+  HOST_WIDE_INT saved_processing_template_decl = 0;
+
   TREE_USED (decl) = 1;
-  if (processing_template_decl || skip_evaluation)
+  /* If we don't need a value, then we don't need to synthesize DECL.  */ 
+  if (skip_evaluation)
     return;
+  /* Normally, we can wait until instantiation-time to synthesize
+     DECL.  However, if DECL is a static data member initialized with
+     a constant, we need the value right now because a reference to
+     such a data member is not value-dependent.  */
+  if (processing_template_decl)
+    {
+      if (TREE_CODE (decl) == VAR_DECL
+	  && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl)
+	  && DECL_CLASS_SCOPE_P (decl)
+	  && !dependent_type_p (DECL_CONTEXT (decl)))
+	{
+	  /* Pretend that we are not in a template so that the
+	     initializer for the static data member will be full
+	     simplified.  */
+	  saved_processing_template_decl = processing_template_decl;
+	  processing_template_decl = 0;
+	}
+      else
+	return;  
+    }
 
   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl)
       && !TREE_ASM_WRITTEN (decl))
@@ -3282,6 +3308,8 @@ mark_used (tree decl)
        need.  */
     instantiate_decl (decl, /*defer_ok=*/true, 
 		      /*expl_inst_class_mem_p=*/false);
+
+  processing_template_decl = saved_processing_template_decl;
 }
 
 #include "gt-cp-decl2.h"

gcc/testsuite/ChangeLog

+2005-09-08  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23691
+	* g++.dg/template/static16.C: New test.
+
 2005-09-08  Richard Sandiford  <richard@codesourcery.com>
 
 	PR fortran/15326