C PATCH to fix missing -Wlogical-op warning (PR c/80525)

[Jeff Law]

On 05/04/2017 06:23 AM, Marek Polacek wrote:
> On Thu, May 04, 2017 at 02:13:24PM +0200, Richard Biener wrote:
>> On Thu, May 4, 2017 at 2:11 PM, Marek Polacek <polacek@redhat.com> wrote:
>>> On Thu, May 04, 2017 at 12:42:03PM +0200, Richard Biener wrote:
>>>>> +static tree
>>>>> +unwrap_c_maybe_const (tree *tp, int *walk_subtrees, void *)
>>>>> +{
>>>>> +  if (TREE_CODE (*tp) == C_MAYBE_CONST_EXPR)
>>>>> +    {
>>>>> +      *tp = C_MAYBE_CONST_EXPR_EXPR (*tp);
>>>>> +      /* C_MAYBE_CONST_EXPRs don't nest.  */
>>>>> +      *walk_subtrees = false;
>>>>
>>>> This changes trees in-place -- do you need to operate on a copy?
>>>
>>> Ugh, yes.  But I can't simply copy_node, because that creates new VAR_DECLs,
>>> and operand_equal_p would consider them unequal.  Hmm...  We need something
>>> else.
>>
>> unshare_expr?
> 
> Yeah, so:
> 
> 2017-05-04  Marek Polacek  <polacek@redhat.com>
> 
> 	PR c/80525
> 	* c-warn.c (unwrap_c_maybe_const): New.
> 	(warn_logical_operator): Call it.
> 
> 	* c-c++-common/Wlogical-op-1.c: Don't use -fwrapv anymore.
> 	* c-c++-common/Wlogical-op-2.c: New test.
OK.
jeff