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Re: [PATCH 1/3] Fix logic bug in Cilk Plus array expansion


On Mon, Jan 4, 2016 at 1:35 PM, Jeff Law <law@redhat.com> wrote:
> On 01/02/2016 04:26 PM, Patrick Palka wrote:
>>
>> On Sat, Jan 2, 2016 at 3:21 AM, Jakub Jelinek <jakub@redhat.com> wrote:
>>>
>>> On Fri, Jan 01, 2016 at 10:06:34PM -0700, Jeff Law wrote:
>>>>>
>>>>> gcc/cp/ChangeLog:
>>>>>
>>>>>      * cp-array-notation.c (cp_expand_cond_array_notations): Return
>>>>>      error_mark_node only if find_rank failed, not if it was
>>>>>      successful.
>>>>
>>>> Can you use -fdump-tree-original in the testcase and verify there's no
>>>> <<<
>>>> error >>> expressions in the resulting dump file?
>>>>
>>>> With that change, this is OK.
>>>
>>>
>>> I think the patch is incomplete.  Because, find_rank does not always emit
>>> an error if it returns false, so we again have cases where we can get
>>> error_mark_node in the code without error being emitted.
>>>        else if (*rank != current_rank)
>>>          {
>>>            /* In this case, find rank is being recursed through a set of
>>>               expression of the form A <OPERATION> B, where A and B both
>>> have
>>>               array notations in them and the rank of A is not equal to
>>> rank of B.
>>>               A simple example of such case is the following: X[:] +
>>> Y[:][:] */
>>>            *rank = current_rank;
>>>            return false;
>>>          }
>>> and other spots.  E.g.
>>>                    if (prev_arg && EXPR_HAS_LOCATION (prev_arg))
>>>                      error_at (EXPR_LOCATION (prev_arg),
>>>                                "rank mismatch between %qE and %qE",
>>> prev_arg,
>>>                                TREE_OPERAND (expr, ii));
>>> looks very suspicious.
>>
>>
>> Hmm, good point. Here's a contrived test case that causes find_rank to
>> return false without emitting an error message thus we again end up
>> with an error_mark_node in the gimplifier:
>>
>> /* { dg-do compile } */
>> /* { dg-options "-fcilkplus" } */
>>
>> void foo() {}
>>
>> #define ALEN 1024
>>
>> int main(int argc, char* argv[])
>> {
>>    typedef void (*f) (void *);
>>    f b[ALEN], c[ALEN][ALEN];
>>    (b[:]) ((void *)c[:][:]);
>>    _Cilk_spawn foo();
>>    return 0;
>> }
>>
>> But this patch was intended to only fix the testsuite fallout that
>> patch 3 would have otherwise caused, and not to e.g. fix all the bugs
>> with find_rank.
>>
>> (BTW patch 3 also makes this test case trigger an ICE, instead of
>> being silently miscompiled.)
>
> Can you please include this test (xfailed) when you commit patch #1.  I
> think you want the test to scan for error_mark_node in the gimplified dump.

There are four subdirectories under
gcc/testsuite/c-c++-common/cilk-plus -- AN, CK, PS and SE. Into which
directory should this new xfailed test go?

>
> Jeff
>


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