PATCH PR 43061: check DECL_PRESERVE_P in the midend

[Mike Stump]

This fixes 245 failures in the objective-c testsuite for me.  The  
interesting question is, should we also remove the || lookup_attribute  
("used", DECL_ATTRIBUTES (decl) part?  My first guess, would be no,  
other frontends might only set the attribute and not DECL_PRESERVE_P.

Ok?

$ cat ~/diffs/ipa.diffs
2010-02-18  Mike Stump  <mikestump@comcast.net>

	PR objc/43061
	* cgraphunit.c (process_function_and_variable_attributes): Check
	DECL_PRESERVE_P as well.
	* ipa-pure-const.c (check_decl): Likewise.
	* ipa-reference.c (has_proper_scope_for_analysis): Likewise.
	* ipa-type-escape.c (has_proper_scope_for_analysis): Likewise.

Doing diffs in .:
--- cgraphunit.c.~1~	2010-02-15 17:16:39.000000000 -0800
+++ cgraphunit.c	2010-02-18 12:32:35.000000000 -0800
@@ -885,7 +885,8 @@ process_function_and_variable_attributes
    for (node = cgraph_nodes; node != first; node = node->next)
      {
        tree decl = node->decl;
-      if (lookup_attribute ("used", DECL_ATTRIBUTES (decl)))
+      if (DECL_PRESERVE_P (decl)
+	  || lookup_attribute ("used", DECL_ATTRIBUTES (decl)))
  	{
  	  mark_decl_referenced (decl);
  	  if (node->local.finalized)
@@ -904,7 +905,8 @@ process_function_and_variable_attributes
    for (vnode = varpool_nodes; vnode != first_var; vnode = vnode->next)
      {
        tree decl = vnode->decl;
-      if (lookup_attribute ("used", DECL_ATTRIBUTES (decl)))
+      if (DECL_PRESERVE_P (decl)
+	  || lookup_attribute ("used", DECL_ATTRIBUTES (decl)))
  	{
  	  mark_decl_referenced (decl);
  	  vnode->force_output = true;
--- ipa-pure-const.c.~1~	2010-01-27 07:39:41.000000000 -0800
+++ ipa-pure-const.c	2010-02-18 12:33:03.000000000 -0800
@@ -159,7 +159,7 @@ check_decl (funct_state local,

    /* If the variable has the "used" attribute, treat it as if it had a
       been touched by the devil.  */
-  if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
+  if (DECL_PRESERVE_P (t) || lookup_attribute ("used",  
DECL_ATTRIBUTES (t)))
      {
        local->pure_const_state = IPA_NEITHER;
        if (dump_file)
--- ipa-reference.c.~1~	2010-01-27 07:33:40.000000000 -0800
+++ ipa-reference.c	2010-02-18 12:33:58.000000000 -0800
@@ -306,7 +306,7 @@ has_proper_scope_for_analysis (tree t)
  {
    /* If the variable has the "used" attribute, treat it as if it had a
       been touched by the devil.  */
-  if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
+  if (DECL_PRESERVE_P (t) || lookup_attribute ("used",  
DECL_ATTRIBUTES (t)))
      return false;

    /* Do not want to do anything with volatile except mark any
--- ipa-type-escape.c.~1~	2010-01-27 07:39:44.000000000 -0800
+++ ipa-type-escape.c	2010-02-18 12:36:49.000000000 -0800
@@ -1072,7 +1072,7 @@ has_proper_scope_for_analysis (tree t)
    tree type = get_canon_type (TREE_TYPE (t), false, false);
    if (!type) return;

-  if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
+  if (DECL_PRESERVE_P (t) || lookup_attribute ("used",  
DECL_ATTRIBUTES (t)))
      {
        mark_interesting_type (type, FULL_ESCAPE);
        return;
--------------