[PATCH] Fix ICF sem_function::merge (PR target/63892)

[Jakub Jelinek]

Hi!

As written in the PR, the sibcall-3.c testcase fails on Darwin, because
!sem_item::target_supports_symbol_aliases_p () and we don't really try
redirect_callers, even when that is the best way to perform ICF (both
original and alias are local).

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2015-02-20  Jakub Jelinek  <ja...@redhat.com>
            Martin Liska  <mli...@suse.cz>

        PR target/63892
        * ipa-icf.c (sem_function::merge): If DECL_COMDAT_GROUP (alias->decl),
        don't try to create_thunk if stdarg_p.  If
        !sem_item::target_supports_symbol_aliases_p (), similarly, and try to
        redirect_callers if possible.
        (sem_item_optimizer::execute): Call unregister_hooks here...
        (ipa_icf_driver): ... instead of here.

--- gcc/ipa-icf.c
+++ gcc/ipa-icf.c
@@ -651,7 +651,9 @@ sem_function::merge (sem_item *alias_item)
      section (or we risk link failures when section is discarded).  */
   if ((original_address_matters
        && alias_address_matters)
-      || original_discardable)
+      || original_discardable
+      || DECL_COMDAT_GROUP (alias->decl)
+      || !sem_item::target_supports_symbol_aliases_p ())
     {
       create_thunk = !stdarg_p (TREE_TYPE (alias->decl));
       create_alias = false;
@@ -659,6 +661,7 @@ sem_function::merge (sem_item *alias_item)
          the extra thunk wrapper for direct calls.  */
       redirect_callers
        = (!original_discardable
+          && !DECL_COMDAT_GROUP (alias->decl)
           && alias->get_availability () > AVAIL_INTERPOSABLE
           && original->get_availability () > AVAIL_INTERPOSABLE
           && !alias->instrumented_version);
@@ -670,13 +673,6 @@ sem_function::merge (sem_item *alias_item)
       redirect_callers = false;
     }
 
-  if (create_alias && (DECL_COMDAT_GROUP (alias->decl)
-                      || !sem_item::target_supports_symbol_aliases_p ()))
-    {
-      create_alias = false;
-      create_thunk = true;
-    }
-
   /* We want thunk to always jump to the local function body
      unless the body is comdat and may be optimized out.  */
   if ((create_thunk || redirect_callers)
@@ -1717,6 +1713,8 @@ void
 sem_item_optimizer::execute (void)
 {
   filter_removed_items ();
+  unregister_hooks ();
+
   build_hash_based_classes ();
 
   if (dump_file)
@@ -2578,7 +2576,6 @@ ipa_icf_driver (void)
   gcc_assert (optimizer);
 
   optimizer->execute ();
-  optimizer->unregister_hooks ();
 
   delete optimizer;
   optimizer = NULL;

        Jakub