[gcc r13-515] attribs: fix typedefs in generic code [PR105492]

[gcc r13-515] attribs: fix typedefs in generic code [PR105492]

[Jason Merrill]

https://gcc.gnu.org/g:ed12749a3c9d9569a2c23df2e0db2136dcd3512d

commit r13-515-ged12749a3c9d9569a2c23df2e0db2136dcd3512d
Author: Jason Merrill <jason@redhat.com>
Date:   Thu May 5 11:03:44 2022 -0400

    attribs: fix typedefs in generic code [PR105492]
    
    In my patch for PR100545 I added an assert to check for broken typedefs in
    set_underlying_type, and it found one in this case:
    rs6000_handle_altivec_attribute had the same problem as
    handle_mode_attribute.  So let's move the fixup into decl_attributes.
    
            PR c/105492
    
    gcc/ChangeLog:
    
            * attribs.cc (decl_attributes): Fix broken typedefs here.
    
    gcc/c-family/ChangeLog:
    
            * c-attribs.cc (handle_mode_attribute): Don't fix broken typedefs
            here.

Diff:
---
 gcc/attribs.cc            | 15 +++++++++++++++
 gcc/c-family/c-attribs.cc | 10 ----------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/gcc/attribs.cc b/gcc/attribs.cc
index 6d4a30dc412..fb89616ff29 100644
--- a/gcc/attribs.cc
+++ b/gcc/attribs.cc
@@ -872,6 +872,21 @@ decl_attributes (tree *node, tree attributes, int flags,
 	  tree ret = (spec->handler) (cur_and_last_decl, name, args,
 				      flags|cxx11_flag, &no_add_attrs);
 
+	  /* Fix up typedefs clobbered by attribute handlers.  */
+	  if (TREE_CODE (*node) == TYPE_DECL
+	      && anode == &TREE_TYPE (*node)
+	      && DECL_ORIGINAL_TYPE (*node)
+	      && TYPE_NAME (*anode) == *node
+	      && TYPE_NAME (cur_and_last_decl[0]) != *node)
+	    {
+	      tree t = cur_and_last_decl[0];
+	      DECL_ORIGINAL_TYPE (*node) = t;
+	      tree tt = build_variant_type_copy (t);
+	      cur_and_last_decl[0] = tt;
+	      TREE_TYPE (*node) = tt;
+	      TYPE_NAME (tt) = *node;
+	    }
+
 	  *anode = cur_and_last_decl[0];
 	  if (ret == error_mark_node)
 	    {
diff --git a/gcc/c-family/c-attribs.cc b/gcc/c-family/c-attribs.cc
index e50e79e0cd1..4dc68dbe82a 100644
--- a/gcc/c-family/c-attribs.cc
+++ b/gcc/c-family/c-attribs.cc
@@ -2215,16 +2215,6 @@ handle_mode_attribute (tree *node, tree name, tree args,
 						 TYPE_QUALS (type));
       if (TYPE_USER_ALIGN (type))
 	*node = build_aligned_type (*node, TYPE_ALIGN (type));
-
-      tree decl = node[2];
-      if (decl && TYPE_NAME (type) == decl)
-	{
-	  /* Set up the typedef all over again.  */
-	  DECL_ORIGINAL_TYPE (decl) = NULL_TREE;
-	  TREE_TYPE (decl) = *node;
-	  set_underlying_type (decl);
-	  *node = TREE_TYPE (decl);
-	}
     }
 
   return NULL_TREE;