Re: [PATCH] Fix PR ipa/113996

[Eric Botcazou]

> Patch is still OK, but ipa-ICF will only identify the functions if
> static chain is unused. Perhaps just picking the winning candidate to be
> version without static chain and making ipa-inline to not ICE when calls
> with static chain lands to function with no static chain would help us
> to optimize better.

I see, thanks for the explanation.  The attached patch appears to work.


        PR ipa/113996
        * ipa-icf.h (sem_function): Add static_chain_p member.
        * ipa-icf.cc (sem_function::init): Initialize it.
        (sem_item_optimizer::merge_classes): If the class is made of
        functions, pick one without static chain as the target.

-- 
Eric Botcazou
diff --git a/gcc/ipa-icf.cc b/gcc/ipa-icf.cc
index 5d5a42f9c6c..4fc02831798 100644
--- a/gcc/ipa-icf.cc
+++ b/gcc/ipa-icf.cc
@@ -1368,6 +1368,8 @@ sem_function::init (ipa_icf_gimple::func_checker *checker)
   /* iterating all function arguments.  */
   arg_count = count_formal_params (fndecl);
 
+  static_chain_p = func->static_chain_decl != NULL_TREE;
+
   edge_count = n_edges_for_fn (func);
   cgraph_node *cnode = dyn_cast <cgraph_node *> (node);
   if (!cnode->thunk)
@@ -3399,11 +3401,22 @@ sem_item_optimizer::merge_classes (unsigned int prev_class_count,
 
 	sem_item *source = c->members[0];
 
-	if (DECL_NAME (source->decl)
-	    && MAIN_NAME_P (DECL_NAME (source->decl)))
-	  /* If merge via wrappers, picking main as the target can be
-	     problematic.  */
-	  source = c->members[1];
+	if (source->type == FUNC)
+	  {
+	    /* Pick a member without static chain, if any.  */
+	    for (unsigned int j = 0; j < c->members.length (); j++)
+	      if (!static_cast<sem_function *> (c->members[j])->static_chain_p)
+		{
+		  source = c->members[j];
+		  break;
+		}
+
+	    /* If merge via wrappers, picking main as the target can be
+	       problematic.  */
+	    if (DECL_NAME (source->decl)
+		&& MAIN_NAME_P (DECL_NAME (source->decl)))
+	      source = c->members[source == c->members[0] ? 1 : 0];
+	  }
 
 	for (unsigned int j = 0; j < c->members.length (); j++)
 	  {
diff --git a/gcc/ipa-icf.h b/gcc/ipa-icf.h
index ef7e41bfa88..da20862c306 100644
--- a/gcc/ipa-icf.h
+++ b/gcc/ipa-icf.h
@@ -355,6 +355,9 @@ public:
      parameters.  */
   bool compatible_parm_types_p (tree, tree);
 
+  /* Return true if parameter I may be used.  */
+  bool param_used_p (unsigned int i);
+
   /* Exception handling region tree.  */
   eh_region region_tree;
 
@@ -379,6 +382,9 @@ public:
   /* Total number of SSA names used in the function.  */
   unsigned ssa_names_size;
 
+  /* Whether the special PARM_DECL for the static chain is present.  */
+  bool static_chain_p;
+
   /* Array of structures for all basic blocks.  */
   vec <ipa_icf_gimple::sem_bb *> bb_sorted;
 
@@ -386,9 +392,6 @@ public:
      function.  */
   hashval_t m_alias_sets_hash;
 
-  /* Return true if parameter I may be used.  */
-  bool param_used_p (unsigned int i);
-
 private:
   /* Calculates hash value based on a BASIC_BLOCK.  */
   hashval_t get_bb_hash (const ipa_icf_gimple::sem_bb *basic_block);