c-typeck.c (build_compound_expr): Correct logic in last change.

	* c-typeck.c (build_compound_expr): Correct logic in last change.

testsuite:
	* gcc.dg/void-cast-2.c: New test.

From-SVN: r98901

gcc/ChangeLog

+2005-04-28  Joseph S. Myers  <joseph@codesourcery.com>
+
+	* c-typeck.c (build_compound_expr): Correct logic in last change.
+
 2005-04-27  James E. Wilson  <wilson@specifixinc.com>
 
 	* config/ia64/ia64.c (update_set_flags): Delete ppred and pcond

gcc/c-typeck.c

@@ -3108,12 +3108,13 @@ build_compound_expr (tree expr1, tree expr2)
       /* The left-hand operand of a comma expression is like an expression
          statement: with -Wextra or -Wunused, we should warn if it doesn't have
 	 any side-effects, unless it was explicitly cast to (void).  */
-      if (warn_unused_value
-	  && !VOID_TYPE_P (TREE_TYPE (expr1)))
+      if (warn_unused_value)
 	{
-	  if (TREE_CODE (expr1) == CONVERT_EXPR)
+	  if (VOID_TYPE_P (TREE_TYPE (expr1))
+	      && TREE_CODE (expr1) == CONVERT_EXPR)
 	    ; /* (void) a, b */
-	  else if (TREE_CODE (expr1) == COMPOUND_EXPR
+	  else if (VOID_TYPE_P (TREE_TYPE (expr1))
+		   && TREE_CODE (expr1) == COMPOUND_EXPR
 		   && TREE_CODE (TREE_OPERAND (expr1, 1)) == CONVERT_EXPR)
 	    ; /* (void) a, (void) b, c */
 	  else

gcc/testsuite/ChangeLog

+2005-04-28  Joseph S. Myers  <joseph@codesourcery.com>
+
+	* gcc.dg/void-cast-2.c: New test.
+
 2005-04-27  Joseph S. Myers  <joseph@codesourcery.com>
 
 	PR c/21159

gcc/testsuite/gcc.dg/void-cast-2.c

+/* Test further cases of warnings for comma expressions, with and
+   without casts to void.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-Wall" } */
+int a, b, c, d;
+int e(void) { return (char)a, b; } /* { dg-warning "warning: left-hand operand of comma expression has no effect" } */
+int f(void) { return (a ? (void)b : (void)c), d; } /* { dg-warning "warning: left-hand operand of comma expression has no effect" } */