The KernelEnvironment is for compile time information about a kernel. It
allows the compiler to feed information to the runtime. The
KernelLaunchEnvironment is for dynamic information *per* kernel launch.
It allows the rutime to feed information to the kernel that is not
shared with other invocations of the kernel. The first use case is to
replace the globals that synchronize teams reductions with per-launch
versions. This allows concurrent teams reductions. More uses cases will
follow, e.g., per launch memory pools.
Fixes: https://github.com/llvm/llvm-project/issues/70249
We now provide the information about the min/max thread and team count
from to the OMPIRBuilder, no matter what the source was. That means we
unify `thread_limit`, `num_teams`, `num_threads` handling with the
target specific attriutes (`__launch_bounds__` and
`amdgpu_flat_work_group_size`). This is in preparation to pass the
values to the runtime, and to allow the middle-end (OpenMP-opt) to
tighten the values if it seems appropriate. There is no "real" change
after this commit.
This reverts commit 0d12683046ca75fb08e285f4622f2af5c82609dc and
reapplies ef9ec4bbcca2fa4f64df47bc426f1d1c59ea47e2 with an extension to
fix the Flang build.
Differential Revision: https://reviews.llvm.org/D156184
CUDA and HIP have kernel attributes to tune the code generation (in the
backend). To reuse this functionality for OpenMP target regions we
introduce the `ompx_attribute` clause that takes these kernel
attributes and emits code as if they had been attached to the kernel
fuction (which is implicitly generated).
To limit the impact, we only support three kernel attributes:
`amdgpu_waves_per_eu`, for AMDGPU
`amdgpu_flat_work_group_size`, for AMDGPU
`launch_bounds`, for NVPTX
The existing implementations of those attributes are used for error
checking and code generation. `ompx_attribute` can be attached to any
executable target region and it can hold more than one kernel attribute.
Differential Revision: https://reviews.llvm.org/D156184
