re PR c/44322 (Bogus warning when assigning pointer-to-array with both "const" and "restrict")

	PR c/44322
	* c-typeck.c (build_unary_op): Merge qualifiers into pointer
	target type for ADDR_EXPR; require no changes to qualifiers except
	for function types.
	* c-tree.h (c_build_type_variant): Remove.

testsuite:
	* gcc.dg/c99-restrict-4.c: New test.

From-SVN: r160312

gcc/ChangeLog

+2010-06-05  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/44322
+	* c-typeck.c (build_unary_op): Merge qualifiers into pointer
+	target type for ADDR_EXPR; require no changes to qualifiers except
+	for function types.
+	* c-tree.h (c_build_type_variant): Remove.
+
 2010-06-05  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	genautomata.c (get_excl_set): Do work per element, not per char.

gcc/c-tree.h

@@ -490,11 +490,6 @@ extern bool c_warn_unused_global_decl (const_tree);
 extern void c_initialize_diagnostics (diagnostic_context *);
 extern bool c_vla_unspec_p (tree x, tree fn);
 
-#define c_build_type_variant(TYPE, CONST_P, VOLATILE_P)		  \
-  c_build_qualified_type ((TYPE),				  \
-			  ((CONST_P) ? TYPE_QUAL_CONST : 0) |	  \
-			  ((VOLATILE_P) ? TYPE_QUAL_VOLATILE : 0))
-
 /* in c-typeck.c */
 extern bool in_late_binary_op;
 extern int in_alignof;

gcc/c-typeck.c

@@ -3744,14 +3744,24 @@ build_unary_op (location_t location,
       argtype = TREE_TYPE (arg);
 
       /* If the lvalue is const or volatile, merge that into the type
-	 to which the address will point.  Note that you can't get a
-	 restricted pointer by taking the address of something, so we
-	 only have to deal with `const' and `volatile' here.  */
+	 to which the address will point.  This should only be needed
+	 for function types.  */
       if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
 	  && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
-	  argtype = c_build_type_variant (argtype,
-					  TREE_READONLY (arg),
-					  TREE_THIS_VOLATILE (arg));
+	{
+	  int orig_quals = TYPE_QUALS (strip_array_types (argtype));
+	  int quals = orig_quals;
+
+	  if (TREE_READONLY (arg))
+	    quals |= TYPE_QUAL_CONST;
+	  if (TREE_THIS_VOLATILE (arg))
+	    quals |= TYPE_QUAL_VOLATILE;
+
+	  gcc_assert (quals == orig_quals
+		      || TREE_CODE (argtype) == FUNCTION_TYPE);
+
+	  argtype = c_build_qualified_type (argtype, quals);
+	}
 
       if (!c_mark_addressable (arg))
 	return error_mark_node;

gcc/testsuite/ChangeLog

+2010-06-05  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/44322
+	* gcc.dg/c99-restrict-4.c: New test.
+
 2010-06-04  Magnus Fromreide  <magfr@lysator.liu.se>
 
 	* g++.dg/cpp0x/nullptr01.C: Test nullptr_t variable.

gcc/testsuite/gcc.dg/c99-restrict-4.c

+/* Qualifiers lost when taking the address of a const restrict object.
+   PR 44322.  */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
+void * restrict const a[2];
+void * restrict const (*p2)[2];
+
+void foo(void) {
+   p2 = &a;
+}
+
+void * restrict volatile b[2];
+void * restrict volatile (*q2)[2];
+
+void bar(void) {
+   q2 = &b;
+}