[pushed] c++: Fix deferred noexcept on constructor [PR93901].

[Jason Merrill]

My change in r10-4394 to only update clones when we actually instantiate a
deferred noexcept-spec broke this because deferred parsing updates the
primary function but not the clones.  For GCC 10 I just reverted that
change; this patch adjusts maybe_instantiate_noexcept to update only the
clone passed as the argument.

Tested x86_64-pc-linux-gnu, applying to trunk.

gcc/cp/ChangeLog
2020-05-14  Jason Merrill  <jason@redhat.com>

	PR c++/93901
	* pt.c (maybe_instantiate_noexcept): Change clone handling.
---
 gcc/cp/pt.c | 55 ++++++++++++++++++++++++++---------------------------
 1 file changed, 27 insertions(+), 28 deletions(-)

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 61e6fa7484d..2a0b18f5517 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -25174,7 +25174,7 @@ always_instantiate_p (tree decl)
 bool
 maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 {
-  tree fntype, spec, noex, clone;
+  tree fntype, spec, noex;
 
   /* Don't instantiate a noexcept-specification from template context.  */
   if (processing_template_decl
@@ -25193,8 +25193,16 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
       return !DECL_MAYBE_DELETED (fn);
     }
 
-  if (DECL_CLONED_FUNCTION_P (fn))
-    fn = DECL_CLONED_FUNCTION (fn);
+  fntype = TREE_TYPE (fn);
+  spec = TYPE_RAISES_EXCEPTIONS (fntype);
+
+  if (!spec || !TREE_PURPOSE (spec))
+    return true;
+
+  noex = TREE_PURPOSE (spec);
+  if (TREE_CODE (noex) != DEFERRED_NOEXCEPT
+      && TREE_CODE (noex) != DEFERRED_PARSE)
+    return true;
 
   tree orig_fn = NULL_TREE;
   /* For a member friend template we can get a TEMPLATE_DECL.  Let's use
@@ -25206,15 +25214,14 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
       fn = DECL_TEMPLATE_RESULT (fn);
     }
 
-  fntype = TREE_TYPE (fn);
-  spec = TYPE_RAISES_EXCEPTIONS (fntype);
-
-  if (!spec || !TREE_PURPOSE (spec))
-    return true;
-
-  noex = TREE_PURPOSE (spec);
-
-  if (TREE_CODE (noex) == DEFERRED_NOEXCEPT)
+  if (DECL_CLONED_FUNCTION_P (fn))
+    {
+      tree prime = DECL_CLONED_FUNCTION (fn);
+      if (!maybe_instantiate_noexcept (prime, complain))
+	return false;
+      spec = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (prime));
+    }
+  else if (TREE_CODE (noex) == DEFERRED_NOEXCEPT)
     {
       static hash_set<tree>* fns = new hash_set<tree>;
       bool added = false;
@@ -25284,27 +25291,19 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 
       if (added)
 	fns->remove (fn);
-
-      if (spec == error_mark_node)
-	{
-	  /* This failed with a hard error, so let's go with false.  */
-	  gcc_assert (seen_error ());
-	  spec = noexcept_false_spec;
-	}
-
-      TREE_TYPE (fn) = build_exception_variant (fntype, spec);
-      if (orig_fn)
-	TREE_TYPE (orig_fn) = TREE_TYPE (fn);
     }
 
-  FOR_EACH_CLONE (clone, fn)
+  if (spec == error_mark_node)
     {
-      if (TREE_TYPE (clone) == fntype)
-	TREE_TYPE (clone) = TREE_TYPE (fn);
-      else
-	TREE_TYPE (clone) = build_exception_variant (TREE_TYPE (clone), spec);
+      /* This failed with a hard error, so let's go with false.  */
+      gcc_assert (seen_error ());
+      spec = noexcept_false_spec;
     }
 
+  TREE_TYPE (fn) = build_exception_variant (fntype, spec);
+  if (orig_fn)
+    TREE_TYPE (orig_fn) = TREE_TYPE (fn);
+
   return true;
 }
 

base-commit: 3a36428b5fbc825e2d3455f5770b5d6e71c63413
-- 
2.18.1