C++ PATCH for c++/65509 (constexpr address comparison)

C++ PATCH for c++/65509 (constexpr address comparison)

[Jason Merrill]

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This was breaking because ancient code in the front end to avoid 
emitting unreferenced static const variables was preventing the 
vdefinition flag from being set on the varpool node for the variables. 
Now that we have cgraph controlling what gets emitted, there is no point 
in keeping this code around.

Tested x86_64-pc-linux-gnu, applying to trunk.

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commit 3fac157f5884e88d15a42b9c3136fd0e7024595a
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Mar 27 12:01:44 2015 -0400

    	PR c++/65509
    	* decl.c (make_rtl_for_nonlocal_decl): Don't defer static
    	constants.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index cb0f11f..f05aefa 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -6061,7 +6061,6 @@ make_rtl_for_nonlocal_decl (tree decl, tree init, const char* asmspec)
 {
   int toplev = toplevel_bindings_p ();
   int defer_p;
-  const char *filename;
 
   /* Set the DECL_ASSEMBLER_NAME for the object.  */
   if (asmspec)
@@ -6109,32 +6108,9 @@ make_rtl_for_nonlocal_decl (tree decl, tree init, const char* asmspec)
      DECL_EXPR is expanded.  */
   defer_p = DECL_FUNCTION_SCOPE_P (decl) || DECL_VIRTUAL_P (decl);
 
-  /* We try to defer namespace-scope static constants so that they are
-     not emitted into the object file unnecessarily.  */
-  filename = LOCATION_FILE (input_location);
-  if (!DECL_VIRTUAL_P (decl)
-      && TREE_READONLY (decl)
-      && DECL_INITIAL (decl) != NULL_TREE
-      && DECL_INITIAL (decl) != error_mark_node
-      && filename != NULL
-      && ! EMPTY_CONSTRUCTOR_P (DECL_INITIAL (decl))
-      && toplev
-      && !TREE_PUBLIC (decl))
-    {
-      /* Fool with the linkage of static consts according to #pragma
-	 interface.  */
-      struct c_fileinfo *finfo = get_fileinfo (filename);
-      if (!finfo->interface_unknown && !TREE_PUBLIC (decl))
-	{
-	  TREE_PUBLIC (decl) = 1;
-	  DECL_EXTERNAL (decl) = finfo->interface_only;
-	}
-
-      defer_p = 1;
-    }
-  /* Likewise for template instantiations.  */
-  else if (DECL_LANG_SPECIFIC (decl)
-	   && DECL_IMPLICIT_INSTANTIATION (decl))
+  /* Defer template instantiations.  */
+  if (DECL_LANG_SPECIFIC (decl)
+      && DECL_IMPLICIT_INSTANTIATION (decl))
     defer_p = 1;
 
   /* If we're not deferring, go ahead and assemble the variable.  */
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-ptrcomp1.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-ptrcomp1.C
new file mode 100644
index 0000000..2eee1b0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-ptrcomp1.C
@@ -0,0 +1,8 @@
+// PR c++/65509
+// { dg-do compile { target c++11 } }
+
+const int i1 = 1;
+const int i2 = 2;
+
+#define SA(X) static_assert (X,#X)
+SA(&i1 != &i2);