Hi!
This testcase got fixed in G++ 3.2, where we used for decision if inline
function body should be kept TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (...)),
but we now use cgraph and the testcase fails again; the particular problem
is that we set TREE_USED only on the local extern decl and don't propagate
it to the decl that extern_decl_map maps it into.
Fixed by the following patch, which propagates it at genericization time.
Bootstrapped/regtested on x86_64-linux and i686-linux.
Another option is:
+ /* If decl is local extern, recurse into corresponding decl. */
+ if (cfun
+ && cp_function_chain
+ && cp_function_chain->extern_decl_map
+ && VAR_OR_FUNCTION_DECL_P (decl)
+ && DECL_EXTERNAL (decl))
+ {
+ struct cxx_int_tree_map *h, in;
+ in.uid = DECL_UID (decl);
+ h = cp_function_chain->extern_decl_map->find_with_hash (&in, in.uid);
+ if (h)
+ TREE_USED (h->to) = 1;
+ }
+
in mark_used, another one:
+ /* If decl is local extern, recurse into corresponding decl. */
+ if (cfun
+ && cp_function_chain
+ && cp_function_chain->extern_decl_map
+ && VAR_OR_FUNCTION_DECL_P (decl)
+ && DECL_EXTERNAL (decl))
+ {
+ struct cxx_int_tree_map *h, in;
+ in.uid = DECL_UID (decl);
+ h = cp_function_chain->extern_decl_map->find_with_hash (&in, in.uid);
+ if (h && !mark_used (h->to))
+ return false;
+ }
+
in the same spot.
None of these fix the PR82204 though.
2018-07-02 Jakub Jelinek <ja...@redhat.com>
PR c++/3698
PR c++/86208
* cp-gimplify.c (cp_genericize_r): When using extern_decl_map, or
in TREE_USED flag from stmt to h->to.
* g++.dg/opt/pr3698.C: New test.
--- gcc/cp/cp-gimplify.c.jj 2018-06-20 08:15:28.980857357 +0200
+++ gcc/cp/cp-gimplify.c 2018-07-02 18:03:00.714313555 +0200
@@ -1085,6 +1085,7 @@ cp_genericize_r (tree *stmt_p, int *walk
if (h)
{
*stmt_p = h->to;
+ TREE_USED (h->to) |= TREE_USED (stmt);
*walk_subtrees = 0;
return NULL;
}
--- gcc/testsuite/g++.dg/opt/pr3698.C.jj 2018-07-02 18:05:52.535479087
+0200
+++ gcc/testsuite/g++.dg/opt/pr3698.C 2018-07-02 18:05:44.507471531 +0200
@@ -0,0 +1,21 @@
+// PR c++/3698
+// { dg-do link }
+// { dg-options "-O0" }
+
+struct X {
+ int i;
+};
+
+inline const int&
+OHashKey (const X& x)
+{
+ return x.i;
+}
+
+int
+main ()
+{
+ extern const int& OHashKey (const X& x);
+ X x;
+ return OHashKey (x);
+}
Jakub
