[PING] [PATCH] _Cilk_for for C and C++

[Jakub Jelinek]

On Mon, Feb 10, 2014 at 10:07:18PM +0000, Iyer, Balaji V wrote:
> I looked at both but forgot to test them with my implementation. Sorry
> about this.  I have fixed the ICE issue.  To make sure this does not
> happen further, I have added your test cf3.C into test suite (renamed to
> cf3.cc).  I hope that is OK with you.

The testcase is GPL as the original libgomp.c++/for-1.C testcase, so sure.
Perhaps it would be much better though if instead of having a compile time
testcase you'd just do what libgomp.c++/for-1.C does, just replace all the
#pragma omp parallel for in there with _Cilk_for and turn it into a runtime
testcase.

> I have attached a fixed patch and Changelogs. Is this OK?

Looks better (note, still looking just at the dumps), but not completely ok
yet.  On cf3.cc, I see in *.gimple:

        D.2883 = J<int>::begin (j);
        I<int>::I (&i, D.2883);
        D.2885 = J<int>::end (j);
        retval.0 = operator-<int> (D.2885, &i);
        D.2886 = retval.0 / 2;
        #pragma omp parallel firstprivate(i) if(D.2886) shared(D.2865) shared(j)
          {
            difference_type retval.1;
            const struct I & D.2888;
            const difference_type D.2866;
            long int D.2889;
            struct I & D.2890;

            try
              {

                _Cilk_for (D.2864 = 0; D.2864 < retval.1; D.2864 = D.2864 + 2) private(D.2864)
                  {
                    D.2889 = D.2864 - D.2865;
                    D.2866 = D.2889;
                    try
                      {
                        D.2890 = I<int>::operator+= (&i, &D.2866);

First a minor nit, there is extra newline before _Cilk_for:
          newline_and_indent (buffer, spc);
          if (flag_cilkplus
              && gimple_omp_for_kind (gs) == GF_OMP_FOR_KIND_CILKFOR)
            pp_string (buffer, "_Cilk_for (");
          else
            pp_string (buffer, "for (");
I guess for _Cilk_for collapse is never > 1, right?  If that is the case,
then perhaps you should move the newline_and_indent (buffer, spc); call
into the else block.

More importantly, what is retval.1?  I'd expect you should be using retval.0
there and have it also as firstprivate(retval.0) on the parallel.
In *.omplower dump I actually see:
        retval.0 = operator-<int> (D.2885, &i);
...
                            retval.1 = operator-<int> (D.2888, &i);
i.e. operator-<int> is called twice.

	Jakub