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

[Jeff Law]

On 12/31/2015 08:40 AM, Patrick Palka wrote:
> The Cilk Plus code may sometimes turn a COND_EXPR into an
> error_mark_node for no good reason.  This can be seen by compiling the
> test case c-c++-common/cilk-plus/CK/pr60469.c with both gcc and g++ and
> observing the differences of the -fdump-tree-original dumps:
>
> With gcc, we get the following code in the GENERIC dump:
>
> finally
>    {
>      _Cilk_sync;
>      D.1897.worker->current_stack_frame = D.1897.call_parent;
>      __cilkrts_pop_frame (&D.1897);
>      if (D.1897.flags != 16777216)
>        {
>          __cilkrts_leave_frame (&D.1897);
>        }
>    }
>
> Whereas with g++ we get
>
> finally
>    {
>      _Cilk_sync;
>      D.2387.worker->current_stack_frame = D.2387.call_parent;
>      __cilkrts_pop_frame (&D.2387);
>      <<< error >>>
>    }
>
> Notice that the COND_EXPR is replaced with an << error >> in the g++
> dump.
>
> This patch fixes the COND_EXPR handling within Cilk Plus.  I think the
> cause is a simple typo/logic bug.
>
> 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.

jeff