Hi!
As reported, the newly added testcase ICEs with --param ggc-min-heapsize=0.
The problem is that while the remove type is not referenced by anything
else, it is a distinct type created to hold the attributes, there is another
type with TYPE_NAME equal to the newdecl we want to tree. That one is
created in common_handle_aligned_attribute:
{
if ((flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
/* OK, modify the type in place. */;
/* If we have a TYPE_DECL, then copy the type, so that we
don't accidentally modify a builtin type. See pushdecl. */
else if (decl && TREE_TYPE (decl) != error_mark_node
&& DECL_ORIGINAL_TYPE (decl) == NULL_TREE)
{
tree tt = TREE_TYPE (decl);
*type = build_variant_type_copy (*type);
DECL_ORIGINAL_TYPE (decl) = tt;
TYPE_NAME (*type) = decl;
TREE_USED (*type) = TREE_USED (decl);
TREE_TYPE (decl) = *type;
}
else
*type = build_variant_type_copy (*type);
where we create a variant type and set the TYPE_NAME too. I've tried to
remove that else if ... and just do *type = build_variant_type_copy (*type);
but that regressed some DWARF DW_AT_alignment tests.
So, the following patch instead removes the remove type from the variants
list if it is not a main variant (as before), otherwise tries to find in
TYPE_MAIN_VARIANT (DECL_ORIGINAL_TYPE (newdecl)) variant list a type
with TYPE_NAME equal to newdecl and remove that one.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2019-04-18 Jakub Jelinek <ja...@redhat.com>
PR c++/90108
* c-decl.c (merge_decls): If remove is main variant and
DECL_ORIGINAL_TYPE is some other type, remove a DECL_ORIGINAL_TYPE
variant that has newdecl as TYPE_NAME if any.
* decl.c (duplicate_decls): If remove is main variant and
DECL_ORIGINAL_TYPE is some other type, remove a DECL_ORIGINAL_TYPE
variant that has newdecl as TYPE_NAME if any.
* c-c++-common/pr90108.c: New test.
--- gcc/c/c-decl.c.jj 2019-04-17 21:21:39.936133112 +0200
+++ gcc/c/c-decl.c 2019-04-17 23:25:08.098936888 +0200
@@ -2513,7 +2513,24 @@ merge_decls (tree newdecl, tree olddecl,
{
tree remove = TREE_TYPE (newdecl);
if (TYPE_MAIN_VARIANT (remove) == remove)
- gcc_assert (TYPE_NEXT_VARIANT (remove) == NULL_TREE);
+ {
+ gcc_assert (TYPE_NEXT_VARIANT (remove) == NULL_TREE);
+ /* If remove is the main variant, no need to remove that
+ from the list. One of the DECL_ORIGINAL_TYPE
+ variants, e.g. created for aligned attribute, might still
+ refer to the newdecl TYPE_DECL though, so remove that one
+ in that case. */
+ if (DECL_ORIGINAL_TYPE (newdecl)
+ && DECL_ORIGINAL_TYPE (newdecl) != remove)
+ for (tree t = TYPE_MAIN_VARIANT (DECL_ORIGINAL_TYPE (newdecl));
+ t; t = TYPE_MAIN_VARIANT (t))
+ if (TYPE_NAME (TYPE_NEXT_VARIANT (t)) == newdecl)
+ {
+ TYPE_NEXT_VARIANT (t)
+ = TYPE_NEXT_VARIANT (TYPE_NEXT_VARIANT (t));
+ break;
+ }
+ }
else
for (tree t = TYPE_MAIN_VARIANT (remove); ;
t = TYPE_NEXT_VARIANT (t))
--- gcc/cp/decl.c.jj 2019-04-17 21:21:39.753136091 +0200
+++ gcc/cp/decl.c 2019-04-17 23:27:13.995875527 +0200
@@ -2133,7 +2133,24 @@ next_arg:;
{
tree remove = TREE_TYPE (newdecl);
if (TYPE_MAIN_VARIANT (remove) == remove)
- gcc_assert (TYPE_NEXT_VARIANT (remove) == NULL_TREE);
+ {
+ gcc_assert (TYPE_NEXT_VARIANT (remove) == NULL_TREE);
+ /* If remove is the main variant, no need to remove that
+ from the list. One of the DECL_ORIGINAL_TYPE
+ variants, e.g. created for aligned attribute, might still
+ refer to the newdecl TYPE_DECL though, so remove that one
+ in that case. */
+ if (tree orig = DECL_ORIGINAL_TYPE (newdecl))
+ if (orig != remove)
+ for (tree t = TYPE_MAIN_VARIANT (orig); t;
+ t = TYPE_MAIN_VARIANT (t))
+ if (TYPE_NAME (TYPE_NEXT_VARIANT (t)) == newdecl)
+ {
+ TYPE_NEXT_VARIANT (t)
+ = TYPE_NEXT_VARIANT (TYPE_NEXT_VARIANT (t));
+ break;
+ }
+ }
else
for (tree t = TYPE_MAIN_VARIANT (remove); ;
t = TYPE_NEXT_VARIANT (t))
--- gcc/testsuite/c-c++-common/pr90108.c.jj 2019-04-17 23:18:23.466566296
+0200
+++ gcc/testsuite/c-c++-common/pr90108.c 2019-04-17 23:18:23.466566296
+0200
@@ -0,0 +1,6 @@
+/* PR c++/90108 */
+/* { dg-do compile } */
+/* { dg-options "--param ggc-min-heapsize=0" } */
+
+typedef unsigned int a __attribute__ ((__aligned__(8), __may_alias__));
+typedef unsigned int a __attribute__ ((__aligned__(8), __may_alias__));
Jakub
