c++: Improve build_template_decl

I discovered all the users of build_template_decl were explicitly
setting the RESULT and TYPE fields of the built decl.  Let's just have
build_template_decl do that in the first place.

	* pt.c (build_template_decl): Init DECL_TEMPLATE_RESULT &
	TREE_TYPE here ...
	(process_partial_specialization): ... not here ...
	(push_template_decl_real, add_inherited_template_parms)
	(build_deduction_guide): ... or here.

2 files changed, 11 insertions, 10 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 5f5b31b..45b60de 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2020-05-14  Nathan Sidwell  <nathan@acm.org>
+
+	* pt.c (build_template_decl): Init DECL_TEMPLATE_RESULT &
+	TREE_TYPE here ...
+	(process_partial_specialization): ... not here ...
+	(push_template_decl_real, add_inherited_template_parms)
+	(build_deduction_guide): ... or here.
+
 2020-05-14  Jakub Jelinek  <jakub@redhat.com>
 
 	* cp-gimplify.c (cp_genericize_r): Set cfun->has_omp_target.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index a36f603..837644f 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -4883,7 +4883,9 @@ build_template_decl (tree decl, tree parms, bool member_template_p)
   tree tmpl = build_lang_decl (TEMPLATE_DECL, DECL_NAME (decl), NULL_TREE);
   SET_DECL_LANGUAGE (tmpl, DECL_LANGUAGE (decl));
   DECL_TEMPLATE_PARMS (tmpl) = parms;
+  DECL_TEMPLATE_RESULT (tmpl) = decl;
   DECL_CONTEXT (tmpl) = DECL_CONTEXT (decl);
+  TREE_TYPE (tmpl) = TREE_TYPE (decl);
   DECL_SOURCE_LOCATION (tmpl) = DECL_SOURCE_LOCATION (decl);
   DECL_MEMBER_TEMPLATE_P (tmpl) = member_template_p;
 
@@ -5233,8 +5235,6 @@ process_partial_specialization (tree decl)
   // Build the template decl.
   tree tmpl = build_template_decl (decl, current_template_parms,
 				   DECL_MEMBER_TEMPLATE_P (maintmpl));
-  TREE_TYPE (tmpl) = type;
-  DECL_TEMPLATE_RESULT (tmpl) = decl;
   SET_DECL_TEMPLATE_SPECIALIZATION (tmpl);
   DECL_TEMPLATE_INFO (tmpl) = build_template_info (maintmpl, specargs);
   DECL_PRIMARY_TEMPLATE (tmpl) = maintmpl;
@@ -5908,8 +5908,6 @@ push_template_decl_real (tree decl, bool is_friend)
 	  new_tmpl
 	    = build_template_decl (decl, current_template_parms,
 				   member_template_p);
-	  DECL_TEMPLATE_RESULT (new_tmpl) = decl;
-	  TREE_TYPE (new_tmpl) = TREE_TYPE (decl);
 	  DECL_TI_TEMPLATE (decl) = new_tmpl;
 	  SET_DECL_TEMPLATE_SPECIALIZATION (new_tmpl);
 	  DECL_TEMPLATE_INFO (new_tmpl)
@@ -5979,8 +5977,7 @@ push_template_decl_real (tree decl, bool is_friend)
 	}
     }
 
-  DECL_TEMPLATE_RESULT (tmpl) = decl;
-  TREE_TYPE (tmpl) = TREE_TYPE (decl);
+  gcc_checking_assert (DECL_TEMPLATE_RESULT (tmpl) == decl);
 
   /* Push template declarations for global functions and types.  Note
      that we do not try to push a global template friend declared in a
@@ -6085,8 +6082,6 @@ add_inherited_template_parms (tree fn, tree inherited)
   tree tmpl = build_template_decl (fn, parms, /*member*/true);
   tree args = template_parms_to_args (parms);
   DECL_TEMPLATE_INFO (fn) = build_template_info (tmpl, args);
-  TREE_TYPE (tmpl) = TREE_TYPE (fn);
-  DECL_TEMPLATE_RESULT (tmpl) = fn;
   DECL_ARTIFICIAL (tmpl) = true;
   DECL_PRIMARY_TEMPLATE (tmpl) = tmpl;
   return tmpl;
@@ -28314,8 +28309,6 @@ build_deduction_guide (tree type, tree ctor, tree outer_args, tsubst_flags_t com
   DECL_NONCONVERTING_P (ded_fn) = explicit_p;
   tree ded_tmpl = build_template_decl (ded_fn, tparms, /*member*/false);
   DECL_ARTIFICIAL (ded_tmpl) = true;
-  DECL_TEMPLATE_RESULT (ded_tmpl) = ded_fn;
-  TREE_TYPE (ded_tmpl) = TREE_TYPE (ded_fn);
   DECL_TEMPLATE_INFO (ded_fn) = build_template_info (ded_tmpl, targs);
   DECL_PRIMARY_TEMPLATE (ded_tmpl) = ded_tmpl;
   if (DECL_P (ctor))