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Re: [gomp] OpenMP IL design notes
On Tue, May 03, 2005 at 02:16:35PM -0700, Richard Henderson wrote:
> On Tue, May 03, 2005 at 04:42:47PM -0400, Diego Novillo wrote:
> > GENERIC
> > GIMPLE
> > GOMP_ATOMIC <expression-statement>
>
> Do we gain anything over expanding this to the approprate __sync_foo
> builtin in the front end.?
>
Can the optimizers tell that this is an atomic builtin? If so,
then no, they're not necessary.
> My intention is to use TLS for this, and to NOT support this feature
> on any system that doesn't support TLS. Thus this bit is synonymous
> with DECL_THREAD_LOCAL.
>
OK, good.
> These shouldn't need gimplification. We should only have decls in
> this list.
>
That's what I thought at first, but the standard threw me into a
loop when it mentioned "id-expression" instead of just
"identifier" in the C++ case. If they're essentially the same,
then great.
> > * CLAUSE default (shared | none)
> >
> > GENERIC This is a boolean field in the GOMP_PARALLEL
> > expression.
> >
> > GIMPLE Same.
>
> IMO this shouldn't escape the front end. We have different requirements
> for Fortran and C. We should require that front ends do all symbol
> resolution and provide GENERIC with a complete list of decls. What
> reaches GENERIC should be equivalent to default(none) -- that is, all
> variables are either (1) declared inside BIND_EXPRs inside the body of
> the block, or (2) mentioned in one of the relevant variable lists.
>
OK, that's certainly simpler.
> #pragma omp for reduction(+: a, b) reduction(*: c, d)
>
> I assume the best option would be a list or vector of operator/variable
> pairs.
>
Yes. I was only referring to a single instance of reduction.
We'd have to have a vector of those.
> Also note that reduction is also legal on for constructs, and that the
> firstprivate, lastprivate, and copyprivate clauses are legal on other
> work sharing constructs.
>
Yes, I tried to express that by putting common clauses in
data_clauses and have the various constructs reference it.
Diego.