On 11/27/2013 04:14 PM, Iyer, Balaji V wrote:
I completely agree with you that there are certain parts of Cilk Plus
that is similar to OMP4, namely #pragma simd and SIMD-enabled functions
(formerly called elemental functions). But, the Cilk keywords is almost
completely orthogonal to OpenMP. They are semantically different and one
cannot be transformed to another. Cilk uses automatically load-balanced
work-stealing using the Cilk runtime, whereas OMP uses work sharing via OMP
runtime. There are a number of other semantic differences but this is the
core-issue. #pragma simd and #pragma omp have converged in several places but
the Cilk part has always been different from OpenMP.
Yes, Cilk for loops will use the Cilk runtime and OMP for loops will use
the OMP runtime, but that doesn't mean they can't share a lot of the
middle end code along the way.
We already have several different varieties of parallel/simd loops all
represented by GIMPLE_OMP_FOR, and I think this could be another
GP_OMP_FOR_KIND_.
...
As you can tell, this is not how openmp handles a #pragma omp for loop.
It's different in detail, but #pragma omp parallel for works very
similarly: it creates a separate function for the body of the loop and
then passes that to GOMP_parallel along with any shared data.
Jason
