Fix PR49493

Index: gcc/tree-ssa-structalias.c
===================================================================
--- gcc/tree-ssa-structalias.c	(revision 175294)
+++ gcc/tree-ssa-structalias.c	(working copy)
@@ -2746,6 +2746,18 @@  get_constraint_for_ssa_var (tree t, VEC(
       return;
     }
 
+  /* For global variables resort to the alias target.  */
+  if (TREE_CODE (t) == VAR_DECL
+      && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
+    {
+      struct varpool_node *node = varpool_get_node (t);
+      if (node && node->alias)
+	{
+	  node = varpool_variable_node (node, NULL);
+	  t = node->decl;
+	}
+    }
+
   vi = get_vi_for_tree (t);
   cexpr.var = vi->id;
   cexpr.type = SCALAR;
@@ -6703,16 +6751,6 @@  associate_varinfo_to_alias (struct cgrap
   return false;
 }
 
-/* Associate node with varinfo DATA. Worker for
-   varpool_for_node_and_aliases.  */
-static bool
-associate_varinfo_to_alias_1 (struct varpool_node *node, void *data)
-{
-  if (node->alias)
-    insert_vi_for_tree (node->decl, (varinfo_t)data);
-  return false;
-}
-
 /* Execute the driver for IPA PTA.  */
 static unsigned int
 ipa_pta_execute (void)
@@ -6744,12 +6788,10 @@  ipa_pta_execute (void)
   /* Create constraints for global variables and their initializers.  */
   for (var = varpool_nodes; var; var = var->next)
     {
-      varinfo_t vi;
       if (var->alias)
 	continue;
 
-      vi = get_vi_for_tree (var->decl);
-      varpool_for_node_and_aliases (var, associate_varinfo_to_alias_1, vi, true);
+      get_vi_for_tree (var->decl);
     }
 
   if (dump_file)
Index: gcc/cgraph.h
===================================================================
--- gcc/cgraph.h	(revision 175294)
+++ gcc/cgraph.h	(working copy)
@@ -981,7 +981,7 @@  varpool_alias_aliased_node (struct varpo
 
   ipa_ref_list_reference_iterate (&n->ref_list, 0, ref);
   gcc_checking_assert (ref->use == IPA_REF_ALIAS);
-  if (ref->refered_type == IPA_REF_CGRAPH)
+  if (ref->refered_type == IPA_REF_VARPOOL)
     return ipa_ref_varpool_node (ref);
   return NULL;
 }
@@ -1011,7 +1011,7 @@  cgraph_function_node (struct cgraph_node
 	    *availability = a;
 	}
     }
-  if (*availability)
+  if (availability)
     *availability = AVAIL_NOT_AVAILABLE;
   return NULL;
 }
@@ -1039,7 +1039,7 @@  cgraph_function_or_thunk_node (struct cg
 	    *availability = a;
 	}
     }
-  if (*availability)
+  if (availability)
     *availability = AVAIL_NOT_AVAILABLE;
   return NULL;
 }
@@ -1067,7 +1067,7 @@  varpool_variable_node (struct varpool_no
 	    *availability = a;
 	}
     }
-  if (*availability)
+  if (availability)
     *availability = AVAIL_NOT_AVAILABLE;
   return NULL;
 }
Index: gcc/testsuite/gcc.dg/ipa/ipa-pta-17.c
===================================================================
--- gcc/testsuite/gcc.dg/ipa/ipa-pta-17.c	(revision 0)
+++ gcc/testsuite/gcc.dg/ipa/ipa-pta-17.c	(revision 0)
@@ -0,0 +1,6 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O -fipa-pta" } */
+
+static int i;
+extern int j __attribute__ ((alias ("i")));
+int *p = &j;