[RFH] negate_expr_p bug?

[Richard Guenther <rguenther at suse dot de>]

negate_expr_p currently contains

  switch (TREE_CODE (t))
    {
    case INTEGER_CST:
      if (TYPE_UNSIGNED (type) || ! flag_trapv) 
        return true;

      /* Check that -CST will not overflow type.  */
      return may_negate_without_overflow_p (t);

where it looks bogus to simply return true for signed types but
unset flag_trapv.  This was introduced by Roger

@@ -822,8 +853,8 @@ negate_expr_p (tree t)
   switch (TREE_CODE (t))
     {
     case INTEGER_CST:
-      if (TREE_UNSIGNED (type))
-       return false;
+      if (TREE_UNSIGNED (type) || ! flag_trapv)
+       return true;
 
       /* Check that -CST will not overflow type.  */
       prec = TYPE_PRECISION (type);

with r72381

 2003-10-11  Roger Sayle  <roger@eyesopen.com>
 
+       (negate_expr_p):  We can always negate integer constants unless
+       we honor -ftrapv and the signed type would overflow.

which is bogus as it should read || (!flag_trapv && flag_wrapv) - no?
I hit this with a patch to fold A +- CST to A -+ CST for negative CST,
which tells me it is ok to negate -INT_MAX.

Fix outlined above ok for mainline?

Thanks,
Richard.