Add -m8bit-idiv for x86.

[pf3gnuchains/gcc-fork.git] / gcc / varpool.c

diff --git a/gcc/varpool.c b/gcc/varpool.c
index a3be262..2b08094 100644 (file)
--- a/gcc/varpool.c
+++ b/gcc/varpool.c
@@ -111,7 +111,8 @@ varpool_get_node (tree decl)
 {
   struct varpool_node key, **slot;
 
-  gcc_assert (DECL_P (decl) && TREE_CODE (decl) != FUNCTION_DECL);
+  gcc_assert (TREE_CODE (decl) == VAR_DECL
+             && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)));
 
   if (!varpool_hash)
     return NULL;
@@ -129,7 +130,8 @@ varpool_node (tree decl)
 {
   struct varpool_node key, *node, **slot;
 
-  gcc_assert (DECL_P (decl) && TREE_CODE (decl) != FUNCTION_DECL);
+  gcc_assert (TREE_CODE (decl) == VAR_DECL
+             && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)));
 
   if (!varpool_hash)
     varpool_hash = htab_create_ggc (10, hash_varpool_node,
@@ -139,7 +141,7 @@ varpool_node (tree decl)
     htab_find_slot (varpool_hash, &key, INSERT);
   if (*slot)
     return *slot;
-  node = GGC_CNEW (struct varpool_node);
+  node = ggc_alloc_cleared_varpool_node ();
   node->decl = decl;
   node->order = cgraph_order++;
   node->next = varpool_nodes;
@@ -346,17 +348,6 @@ decide_is_variable_needed (struct varpool_node *node, tree decl)
       && !DECL_EXTERNAL (decl))
     return true;
 
-  /* When emulating tls, we actually see references to the control
-     variable, rather than the user-level variable.  */
-  if (!targetm.have_tls
-      && TREE_CODE (decl) == VAR_DECL
-      && DECL_THREAD_LOCAL_P (decl))
-    {
-      tree control = emutls_decl (decl);
-      if (decide_is_variable_needed (varpool_node (control), control))
-       return true;
-    }
-
   /* When not reordering top level variables, we have to assume that
      we are going to keep everything.  */
   if (flag_toplevel_reorder)
@@ -368,6 +359,37 @@ decide_is_variable_needed (struct varpool_node *node, tree decl)
   return true;
 }
 
+/* Return if NODE is constant and its initial value is known (so we can do
+   constant folding).  The decision depends on whole program decisions
+   and can not be recomputed at ltrans stage for variables from other
+   partitions.  For this reason the new value should be always combined
+   with the previous knowledge.  */
+
+bool
+varpool_decide_const_value_known (struct varpool_node *node)
+{
+  tree decl = node->decl;
+
+  gcc_assert (TREE_STATIC (decl) || DECL_EXTERNAL (decl));
+  gcc_assert (TREE_CODE (decl) == VAR_DECL);
+  if (!TREE_READONLY (decl))
+    return false;
+  /* Variables declared 'const' without an initializer
+     have zero as the initializer if they may not be
+     overridden at link or run time.  */
+  if (!DECL_INITIAL (decl)
+      && (DECL_EXTERNAL (decl)
+         || DECL_REPLACEABLE_P (decl)))
+    return false;
+
+  /* Variables declared `const' with an initializer are considered
+     to not be overwritable with different initializer by default. 
+
+     ??? Previously we behaved so for scalar variables but not for array
+     accesses.  */
+  return true;
+}
+
 /* Mark DECL as finalized.  By finalizing the declaration, frontend instruct the
    middle end to output the variable to asm file, if needed or externally
    visible.  */
@@ -376,6 +398,8 @@ varpool_finalize_decl (tree decl)
 {
   struct varpool_node *node = varpool_node (decl);
 
+  gcc_assert (TREE_STATIC (decl));
+
   /* The first declaration of a variable that comes through this function
      decides whether it is global (in C, has external linkage)
      or local (in C, has internal linkage).  So do nothing more
@@ -399,6 +423,7 @@ varpool_finalize_decl (tree decl)
      there.  */
   else if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl))
     varpool_mark_needed_node (node);
+  node->const_value_known |= varpool_decide_const_value_known (node);
   if (cgraph_global_info_ready)
     varpool_assemble_pending_decls ();
 }
@@ -651,7 +676,7 @@ varpool_extra_name_alias (tree alias, tree decl)
   if (*slot)
     return false;
 
-  alias_node = GGC_CNEW (struct varpool_node);
+  alias_node = ggc_alloc_cleared_varpool_node ();
   alias_node->decl = alias;
   alias_node->alias = 1;
   alias_node->extra_name = decl_node;