Re: [gomp4] remove kernel-specific launch

[Tom de Vries <Tom_deVries at mentor dot com>]

On 21/07/15 12:19, Thomas Schwinge wrote:
> Hi!
>
> Thanks for the cleanup!
>
> On Mon, 20 Jul 2015 11:54:48 +0200, Tom de Vries <Tom_deVries@mentor.com> wrote:
> > On 19/07/15 23:08, Nathan Sidwell wrote:
> > > On 07/19/15 16:30, Thomas Schwinge wrote:
> > > > Does it make sense then to rename GOACC_kernels_internal to
> > > > GOACC_kernels?
>
> > > [...] perhaps it should be an internal fn? IIUC those
> > > are for pseudo-funcs that should be converted to something else before
> > > the end of compilation.
> >
> > Turning it into an internal fn will make it harder to convert a
> > GOACC_kernels_internal call into a GOACC_parallel call, which we're
> > doing here in omp-low.c:
> > ...
> >             tree fndecl = builtin_decl_explicit (BUILT_IN_GOACC_PARALLEL);
> >             gimple_call_set_fndecl (call, fndecl);
> >             gimple_call_set_fntype (call, TREE_TYPE (fndecl));
> >             gimple_call_reset_alias_info (call);
> >    ...
>
> ..., and also a similar transformation in gcc/tree-parloops.c, I think,

That's not a similar transformation. The GOACC_kernels_internal call is 
removed.

> which I've not been too fond of ;-) anyway, because of:
>
> > --- a/gcc/tree-parloops.c
> > +++ b/gcc/tree-parloops.c
> > @@ -2045,11 +2045,12 @@ create_parallel_loop (struct loop *loop, tree loop_fn, tree data,
> >       }
> >     else
> >       {
> > -      /* Create oacc parallel pragma based on oacc kernels pragma.  */
> > +      /* Create oacc parallel pragma based on oacc kernels pragma and
> > +	 GOAC_kernels_internal call.  */
> >         gomp_target *kernels = as_a <gomp_target *> (gsi_stmt (gsi));
> >
> >         gsi_prev (&gsi);
> > -      gcall *goacc_kernels = as_a <gcall *> (gsi_stmt (gsi));
> > +      gcall *goacc_kernels_internal = as_a <gcall *> (gsi_stmt (gsi));
> >
> >         tree clauses = gimple_omp_target_clauses (kernels);
> >         /* FIXME: We need a more intelligent mapping onto vector, gangs,
> > @@ -2070,7 +2071,8 @@ create_parallel_loop (struct loop *loop, tree loop_fn, tree data,
> >         gimple_omp_target_set_child_fn (stmt, child_fn);
> >         tree data_arg = gimple_omp_target_data_arg (kernels);
> >         gimple_omp_target_set_data_arg (stmt, data_arg);
> > -      tree ganglocal_size = gimple_call_arg (goacc_kernels, /* TODO */ 9);
> > +      tree ganglocal_size
> > +	= gimple_call_arg (goacc_kernels_internal, /* TODO */ 9);
> >         gimple_omp_target_set_ganglocal_size (stmt, ganglocal_size);
>
> ... this "clumsy" argument copying.
>
> As I understand it, there is an implicit/non-obvious requirement that the
> GOACC_kernels_internal and GOACC_parallel function/built-in signatures
> match?

It's not a hard requirement, but it's probably a good idea.

Thanks,
- Tom