re PR c++/60955 (Erroneous warning about taking address of register with std=c++1y)

/cp
2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/60955
	* pt.c (struct warning_sentinel): Move it...
	* cp-tree.h: ... here.
	* semantics.c (force_paren_expr): Use it.

/testsuite
2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/60955
	* g++.dg/warn/register-parm-1.C: New.

From-SVN: r218871

gcc/cp/ChangeLog

+2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/60955
+	* pt.c (struct warning_sentinel): Move it...
+	* cp-tree.h: ... here.
+	* semantics.c (force_paren_expr): Use it.
+
 2014-12-17  Jason Merrill  <jason@redhat.com>
 
 	PR c++/64333

gcc/cp/cp-tree.h

@@ -1149,6 +1149,18 @@ struct processing_template_decl_sentinel
   }
 };
 
+/* RAII sentinel to disable certain warnings during template substitution
+   and elsewhere.  */
+
+struct warning_sentinel
+{
+  int &flag;
+  int val;
+  warning_sentinel(int& flag, bool suppress=true)
+    : flag(flag), val(flag) { if (suppress) flag = 0; }
+  ~warning_sentinel() { flag = val; }
+};
+
 /* The cached class binding level, from the most recently exited
    class, or NULL if none.  */
 

gcc/cp/pt.c

@@ -14438,16 +14438,6 @@ tsubst_non_call_postfix_expression (tree t, tree args,
   return t;
 }
 
-/* Sentinel to disable certain warnings during template substitution.  */
-
-struct warning_sentinel {
-  int &flag;
-  int val;
-  warning_sentinel(int& flag, bool suppress=true)
-    : flag(flag), val(flag) { if (suppress) flag = 0; }
-  ~warning_sentinel() { flag = val; }
-};
-
 /* Like tsubst but deals with expressions and performs semantic
    analysis.  FUNCTION_P is true if T is the "F" in "F (ARGS)".  */
 

gcc/cp/semantics.c

@@ -1660,6 +1660,9 @@ force_paren_expr (tree expr)
 	  tree type = unlowered_expr_type (expr);
 	  bool rval = !!(kind & clk_rvalueref);
 	  type = cp_build_reference_type (type, rval);
+	  /* This inhibits warnings in, eg, cxx_mark_addressable
+	     (c++/60955).  */
+	  warning_sentinel s (extra_warnings);
 	  expr = build_static_cast (type, expr, tf_error);
 	  if (expr != error_mark_node)
 	    REF_PARENTHESIZED_P (expr) = true;

gcc/testsuite/ChangeLog

+2014-12-18  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/60955
+	* g++.dg/warn/register-parm-1.C: New.
+
 2014-12-18  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gcc.target/i386/amd64-abi-7.c: New tests.

gcc/testsuite/g++.dg/warn/register-parm-1.C

+// PR c++/60955
+// { dg-options "-Wextra" }
+
+unsigned int erroneous_warning(register int a) {
+    if ((a) & 0xff) return 1; else return 0;
+}
+unsigned int no_erroneous_warning(register int a) {
+    if (a & 0xff) return 1; else return 0;
+}