re PR c/4697 (Warning 'value computed is not used' missing)

	PR c/4697:
	* stmt.c (warn_if_unused_value): Move side effects test once more.

	* gcc.dg/20020220-2.c: New test.

From-SVN: r49937

gcc/ChangeLog

+2002-02-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/4697:
+	* stmt.c (warn_if_unused_value): Move side effects test once more.
+
 2002-02-20  Torbjorn Granlund  <tege@swox.com>
 
 	* config/avr/avr.md: Add more patterns for mized-mode add and subtract

gcc/stmt.c

@@ -2303,10 +2303,6 @@ warn_if_unused_value (exp)
   if (VOID_TYPE_P (TREE_TYPE (exp)))
     return 0;
 
-  /* If this is an expression with side effects, don't warn.  */
-  if (TREE_SIDE_EFFECTS (exp))
-    return 0;
-
   switch (TREE_CODE (exp))
     {
     case PREINCREMENT_EXPR:
@@ -2366,7 +2362,7 @@ warn_if_unused_value (exp)
 	    || TREE_CODE (tem) == CALL_EXPR)
 	  return 0;
       }
-      goto warn;
+      goto maybe_warn;
 
     case INDIRECT_REF:
       /* Don't warn about automatic dereferencing of references, since
@@ -2389,7 +2385,11 @@ warn_if_unused_value (exp)
 	  && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
 	return 0;
 
-    warn:
+    maybe_warn:
+      /* If this is an expression with side effects, don't warn.  */
+      if (TREE_SIDE_EFFECTS (exp))
+	return 0;
+
       warning_with_file_and_line (emit_filename, emit_lineno,
 				  "value computed is not used");
       return 1;

gcc/testsuite/ChangeLog

+2002-02-21  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.dg/20020220-2.c: New test.
+
 2002-02-20  Alexandre Oliva  <aoliva@redhat.com>
 
 	* gcc.c-torture/compile/20020110.c: New test.

gcc/testsuite/gcc.dg/20020220-2.c

+/* PR c/4697
+   Test whether value computed not used warning is given for compound
+   expression.  */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wunused" } */
+
+int b;
+int foo (int a)
+{
+  a = a + 1, 5 * b;	/* { dg-warning "value computed is not used" } */
+  return a;
+}