Those tests set nvptx64 in IR but doesn't require the target. The optimization
now needs TTI such that if nvptx is not registered, it just uses whatever
default target is, which will cause the check lines mismatch.

If the underlying object already has a non-flat address space, we simply
use
that before calling `getAssumedAddrSpace`.

Partially fixes SWDEV-536263.

Specifying a kernel with the `ptx_kernel` or `amdgpu_kernel` calling
convention is a more idiomatic and compile-time performant than using
the `nvvm.annoation !"kernel"` metadata.

Transition OMPIRBuilder to use calling conventions for PTX kernels and
no longer emit `nvvm.annoation`. Update OpenMPOpt to work with kernels
specified via calling convention as well as metadata. Update OpenMP
tests to use the calling conventions.

This reverts commit e592c2dcf5b7d2da6c2564f5d9990aa34079bad4.

We can finally reland the PR since the issue that caused the PR to be
reverted has been resolved in
https://github.com/llvm/llvm-project/pull/104051.

Before we tracked the size of the teams reduction buffer in order to
allocate it at runtime per kernel launch. This patch splits the number
into two parts, the size of the reduction data (=all reduction
variables) and the (maximal) length of the buffer. This will allow us to
allocate less if we need less, e.g., if we have less teams than the
maximal length. It also allows us to move code from clangs codegen into
the runtime as we now know how large the reduction data is.

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

This reverts commit ddbaa11e9f43a38d50d62a9b9b07c3653b6bf8ab.

Reapply the original commit, the broken test was repaired in 5e51363f38d083ab326736c0d4d1b5f9fe0de080 in the meantime.

This reverts commit c2a1249a8257ed033a98e32e425539c6da6700ec.

The MLIR bots are broken with an omp test failure.

The runtime needs to know about the acceptable launch bounds, especially
if the compiler (middle- or backend) assumed those bounds. While this
patch does not yet inform the runtime, it stores the bounds in a place
that can/will be accessed and is associated with the kernel.