The OpenMP device runtime needs to support the OpenMP standard. However
constructs like nested parallelism are very uncommon in real application
yet lead to complexity in the runtime that is sometimes difficult to
optimize out. As a stop-gap for performance we should supply an argument
that selectively disables this feature. This patch adds the
`-fopenmp-assume-no-nested-parallelism` argument which explicitly
disables the usee of nested parallelism in OpenMP.
Reviewed By: carlo.bertolli
Differential Revision: https://reviews.llvm.org/D132074
We use globals to configure debugging at compile-time for the device
runtime. Because these are only used by the OpenMP runtime we shouldn't
define them if we aren't using the device runtime. When a user passes in
'-nogpulib' this indicates that we are not using the device runtime, so
we should check for the precense of this flag and not emit these globals
if used.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D125314
The runtime uses thread state values to indicate when we use an ICV or
are in nested parallelism. This is done for OpenMP correctness, but it
not needed in the majority of cases. The new flag added is
`-fopenmp-assume-no-thread-state`.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D120106
This patch completely removes the old OpenMP device runtime. Previously,
the old runtime had the prefix `libomptarget-new-` and the old runtime
was simply called `libomptarget-`. This patch makes the formerly new
runtime the only runtime available. The entire project has been deleted,
and all references to the `libomptarget-new` runtime has been replaced
with `libomptarget-`.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D118934
This patch changes the code generation of runtime flags to only occur if
a host bitcode file was passed in. This is a cheap way to determine if
we are compiling the OpenMP device runtime itself or user code. This is
needed because the global flags we generate for the device runtime e.g.
__omp_rtl_debug_kind were being generated with default values when we
compiled the runtime library. This would then invalidate the ones we
want to be able to add in when the user defines it.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D118399
This patch changes the visibility of the `__omp_rtl_debug_kind` variable
to be hidden. These variables are only used by the plugin so they do not
need to be read externally. Previously the default visibility prevented
these variables from being completely eliminated in the module.
Reviewed By: tianshilei1992
Differential Revision: https://reviews.llvm.org/D117320
This patch adds two flags to be supported for the new runtime. The flags
are `-fopenmp-assume-threads-oversubscription` and
-fopenmp-assume-teams-oversubscription`. These add global values that
can be checked by the work sharing runtime functions to make better
judgements about how to distribute work between the threads.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D111348
Joseph Huber