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[PR middle-end/71373] Document missing OMP_CLAUSE_* in gcc/tree-nested.c
- From: Thomas Schwinge <thomas at codesourcery dot com>
- To: Jakub Jelinek <jakub at redhat dot com>, <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 13 Jun 2016 16:43:25 +0200
- Subject: [PR middle-end/71373] Document missing OMP_CLAUSE_* in gcc/tree-nested.c
- Authentication-results: sourceware.org; auth=none
- References: <87h9ddrlrx dot fsf at hertz dot schwinge dot homeip dot net>
Hi!
On Wed, 01 Jun 2016 17:06:42 +0200, Thomas Schwinge <thomas@codesourcery.com> wrote:
> Here are the OpenACC bits of <http://gcc.gnu.org/PR71373>.
In the PR, Jakub clarified that all the missing other OMP_CLAUSE_* are in
fact all unreachable here. OK to document this as follows, in trunk?
The "anything else" default case in fact now is just the non-clause
OMP_CLAUSE_ERROR, so when adding a case for that one, we could then
remove the default case, and thus get a compiler warning when new clauses
are added in the future, without handling them here. That makes sense to
me (would have made apparent much earlier the original problem of missing
handling for certain OMP_CLAUSE_*), but based on feedback received, it
feels as if I'm the only supporter of such "defensive" programming
paradigms?
commit c6b10a9bc1437395c4931d43f30e778152a28cb2
Author: Thomas Schwinge <thomas@codesourcery.com>
Date: Mon Jun 13 16:29:37 2016 +0200
[PR middle-end/71373] Document missing OMP_CLAUSE_* in gcc/tree-nested.c
gcc/
* tree-nested.c (convert_nonlocal_omp_clauses):
(convert_local_omp_clauses): Document missing OMP_CLAUSE_*.
---
gcc/tree-nested.c | 60 ++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 42 insertions(+), 18 deletions(-)
diff --git gcc/tree-nested.c gcc/tree-nested.c
index 812f619..62cb01f 100644
--- gcc/tree-nested.c
+++ gcc/tree-nested.c
@@ -1203,17 +1203,29 @@ convert_nonlocal_omp_clauses (tree *pclauses, struct walk_stmt_info *wi)
case OMP_CLAUSE_AUTO:
break;
+ /* OpenACC tile clauses are discarded during gimplification. */
case OMP_CLAUSE_TILE:
- /* OpenACC tile clauses are discarded during gimplification, so we
- don't expect to see anything here. */
- gcc_unreachable ();
-
+ /* The following clause belongs to the OpenACC cache directive, which
+ is discarded during gimplification. */
case OMP_CLAUSE__CACHE_:
- /* These clauses belong to the OpenACC cache directive, which is
- discarded during gimplification, so we don't expect to see
- anything here. */
- gcc_unreachable ();
-
+ /* The following clauses are only allowed in the OpenMP declare simd
+ directive, so not seen here. */
+ case OMP_CLAUSE_UNIFORM:
+ case OMP_CLAUSE_INBRANCH:
+ case OMP_CLAUSE_NOTINBRANCH:
+ /* The following clauses are only allowed on OpenMP cancel and
+ cancellation point directives, which at this point have already
+ been lowered into a function call. */
+ case OMP_CLAUSE_FOR:
+ case OMP_CLAUSE_PARALLEL:
+ case OMP_CLAUSE_SECTIONS:
+ case OMP_CLAUSE_TASKGROUP:
+ /* The following clauses are only added during OMP lowering; nested
+ function decomposition happens before that. */
+ case OMP_CLAUSE__LOOPTEMP_:
+ case OMP_CLAUSE__SIMDUID_:
+ case OMP_CLAUSE__GRIDDIM_:
+ /* Anything else. */
default:
gcc_unreachable ();
}
@@ -1899,17 +1911,29 @@ convert_local_omp_clauses (tree *pclauses, struct walk_stmt_info *wi)
case OMP_CLAUSE_AUTO:
break;
+ /* OpenACC tile clauses are discarded during gimplification. */
case OMP_CLAUSE_TILE:
- /* OpenACC tile clauses are discarded during gimplification, so we
- don't expect to see anything here. */
- gcc_unreachable ();
-
+ /* The following clause belongs to the OpenACC cache directive, which
+ is discarded during gimplification. */
case OMP_CLAUSE__CACHE_:
- /* These clauses belong to the OpenACC cache directive, which is
- discarded during gimplification, so we don't expect to see
- anything here. */
- gcc_unreachable ();
-
+ /* The following clauses are only allowed in the OpenMP declare simd
+ directive, so not seen here. */
+ case OMP_CLAUSE_UNIFORM:
+ case OMP_CLAUSE_INBRANCH:
+ case OMP_CLAUSE_NOTINBRANCH:
+ /* The following clauses are only allowed on OpenMP cancel and
+ cancellation point directives, which at this point have already
+ been lowered into a function call. */
+ case OMP_CLAUSE_FOR:
+ case OMP_CLAUSE_PARALLEL:
+ case OMP_CLAUSE_SECTIONS:
+ case OMP_CLAUSE_TASKGROUP:
+ /* The following clauses are only added during OMP lowering; nested
+ function decomposition happens before that. */
+ case OMP_CLAUSE__LOOPTEMP_:
+ case OMP_CLAUSE__SIMDUID_:
+ case OMP_CLAUSE__GRIDDIM_:
+ /* Anything else. */
default:
gcc_unreachable ();
}
GrÃÃe
Thomas