re PR tree-optimization/19217 (ICE: verify_stmts failed: address taken, but…

re PR tree-optimization/19217 (ICE: verify_stmts failed: address taken, but ADDRESSABLE bit not set)

	PR tree-optimization/19217
	* tree-cfg.c (verify_expr): Use the data field to see if TP was
	seen inside a PHI node.  Do not do the ADDR_EXPR check if it was.
	(verify_stmts): Pass (void*)1 as data to verify_expr to signal
	that it is walking a PHI node.

From-SVN: r94570

gcc/ChangeLog

+2005-02-01  Steven Bosscher  <stevenb@suse.de>
+
+	PR tree-optimization/19217
+	* tree-cfg.c (verify_expr): Use the data field to see if TP was
+	seen inside a PHI node.  Do not do the ADDR_EXPR check if it was.
+	(verify_stmts): Pass (void*)1 as data to verify_expr to signal
+	that it is walking a PHI node.
+
 2005-02-01  Joseph S. Myers  <joseph@codesourcery.com>
 
 	* doc/extend.texi (Nested Functions): Update.

gcc/tree-cfg.c

@@ -3231,12 +3231,14 @@ has_label_p (basic_block bb, tree label)
 
 
 /* Callback for walk_tree, check that all elements with address taken are
-   properly noticed as such.  */
+   properly noticed as such.  The DATA is an int* that is 1 if TP was seen
+   inside a PHI node.  */
 
 static tree
 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
 {
   tree t = *tp, x;
+  bool in_phi = (data != NULL);
 
   if (TYPE_P (t))
     *walk_subtrees = 0;
@@ -3270,6 +3272,16 @@ verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
       break;
 
     case ADDR_EXPR:
+      /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
+	 dead PHIs that take the address of something.  But if the PHI
+	 result is dead, the fact that it takes the address of anything
+	 is irrelevant.  Because we can not tell from here if a PHI result
+	 is dead, we just skip this check for PHIs altogether.  This means
+	 we may be missing "valid" checks, but what can you do?
+	 This was PR19217.  */
+      if (in_phi)
+	break;
+
       /* Skip any references (they will be checked when we recurse down the
 	 tree) and ensure that any variable used as a prefix is marked
 	 addressable.  */
@@ -3546,7 +3558,7 @@ verify_stmts (void)
 		  err |= true;
 		}
 
-	      addr = walk_tree (&t, verify_expr, NULL, NULL);
+	      addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
 	      if (addr)
 		{
 		  debug_generic_stmt (addr);