Re: [PATCH] openmp: Add OMPT variant of GOMP_has_masked_thread_num

[Tobias Burnus]

Paul-Antoine Arras wrote:

Add GOMP_has_masked_thread_num_with_end, which is semantically identically but
meant for -fopenmp-ompt.

Which solves the issue I mentioned in my other email
- sorry for the belated review due to vaccation - namely:

For OMPT, libgomp needs to know whether to pass ompt_scope_beginend
or ompt_scope_begin followed by a later ompt_scope_end to the
registered tool.

gcc/ChangeLog:
        * omp-builtins.def (BUILT_IN_GOMP_HAS_MASKED_THREAD_NUM_WITH_END):
        New builtin.
        * omp-low.cc (lower_omp_master): Use it when -fopenmp-ompt.

libgomp/ChangeLog:
        * libgomp.map: Add GOMP_has_masked_thread_num_with_end.
        * libgomp.texi: Document it.
        * libgomp_g.h (GOMP_has_masked_thread_num_with_end): Declare.
        * parallel.c (GOMP_has_masked_thread_num_with_end): New function.

gcc/testsuite/ChangeLog:
        * c-c++-common/gomp/masked-1.c: Check new builtin is not emitted.
        * c-c++-common/gomp/masked-3.c: Check new builtin is emitted with
        -fopenmp-ompt.

...

@@ -9098,7 +9098,11 @@ lower_omp_master (gimple_stmt_iterator *gsi_p, 
omp_context *ctx)
    gsi_replace (gsi_p, bind, true);
-  bfn_decl = builtin_decl_explicit (BUILT_IN_GOMP_HAS_MASKED_THREAD_NUM);
+  if (flag_openmp_ompt)
+    bfn_decl
+      = builtin_decl_explicit (BUILT_IN_GOMP_HAS_MASKED_THREAD_NUM_WITH_END);
+  else
+    bfn_decl = builtin_decl_explicit (BUILT_IN_GOMP_HAS_MASKED_THREAD_NUM);

Elsewhere, you use such version:

  bfn_decl = builtin_decl_explicit (
               flag_openmp_ompt ? BUILT_IN_GOMP_HAS_MASKED_THREAD_NUM
                                : BUILT_IN_GOMP_HAS_MASKED_THREAD_NUM_WITH_END);

which seems to be tad more readable - however, not that it really
matters.

--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi

-@code{GOMP_has_masked_thread_num} encapsulates the following check, so that OMPT

-can distinguish the compiler-generated code from user-level thread-number
-queries:
+@code{GOMP_has_masked_thread_num} (or its variant
+@code{GOMP_has_masked_thread_num_with_end} enabled by @option{-fopenmp-ompt})
+encapsulates the following check, so that OMPT can distinguish the
+compiler-generated code from user-level thread-number queries:

I think it is more readable and clearer (+ more details) to keep the
current wording and add a sentence, i.e.

@code{GOMP_has_masked_thread_num} encapsulates the following check, so that OMPT
can distinguish the compiler-generated code from user-level thread-number
queries; with @option{-fopenmp-ompt}, a paired call to
@code{GOMP_has_masked_thread_num_with_end} and @code{GOMP_masked_end} is
generated instead.

Otherwise, LGTM.

Thanks,

Tobias