toplev.c (check_global_declarations): Suppress not-used warning for volatile variables.

2003-05-05  Geoffrey Keating  <geoffk@apple.com>

	* toplev.c (check_global_declarations): Suppress not-used warning
	for volatile variables.

Index: testsuite/ChangeLog
2003-05-05  Geoffrey Keating  <geoffk@apple.com>

	* gcc.dg/unused-5.c: New test.

From-SVN: r66493

gcc/ChangeLog

+2003-05-05  Geoffrey Keating  <geoffk@apple.com>
+
+	* toplev.c (check_global_declarations): Suppress not-used warning
+	for volatile variables.
+
 2003-05-05  Olivier Hainque  <hainque@act-europe.fr>
 
         * expr.c (expand_expr, case BIT_FIELD_REF): Refine the test forcing

gcc/testsuite/ChangeLog

+2003-05-05  Geoffrey Keating  <geoffk@apple.com>
+
+	* gcc.dg/unused-5.c: New test.
+
 2003-05-05  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>
 
 	PR c++/10496

gcc/testsuite/gcc.dg/unused-5.c

+/* { dg-do compile } */
+/* { dg-options "-Wunused" } */
+/* { dg-final { scan-assembler "string_to_look_for" } } */
+
+/* 'volatile' variables get output and don't produce a warning about being
+   unused.  */
+static volatile char string[] 
+  = "string_to_look_for";  /* { dg-bogus "not used" } */

gcc/toplev.c

@@ -2132,6 +2132,8 @@ check_global_declarations (vec, len)
 	  && ! TREE_USED (DECL_NAME (decl))
 	  && ! DECL_EXTERNAL (decl)
 	  && ! TREE_PUBLIC (decl)
+	  /* A volatile variable might be used in some non-obvious way.  */
+	  && ! TREE_THIS_VOLATILE (decl)
 	  /* Global register variables must be declared to reserve them.  */
 	  && ! (TREE_CODE (decl) == VAR_DECL && DECL_REGISTER (decl))
 	  /* Otherwise, ask the language.  */