7 Commits

Author SHA1 Message Date
Tobias Grosser
b9fc860a57 GPGPU: collect array references
Initialize the list of references to a GPU array to ensure that the arrays that
need to be passed to kernel calls are computed correctly.  Furthermore, the very
same information is also necessary to compute synchronization correctly. As the
functionality to compute these references is already available, what is left for
us to do is only to connect the necessary functionality to compute array
reference information.

llvm-svn: 275798
2016-07-18 15:44:32 +00:00
Tobias Grosser
60f63b49f2 GPGPU: Model array access information
This allows us to derive host-device and device-host data-transfers.

llvm-svn: 275535
2016-07-15 07:05:54 +00:00
Tobias Grosser
69b4675180 GPGPU: Generate an AST for the GPU-mapped schedule
For this we need to provide an explicit list of statements as they occur in
the polly::Scop to ppcg.

We also setup basic AST printing facilities to facilitate debugging. To allow
code reuse some (minor) changes in ppcg are have been necessary.

llvm-svn: 275436
2016-07-14 15:51:37 +00:00
Tobias Grosser
60c6002570 GPGPU: Add dummy implementation for ast expression construction
Instead of calling to a pet function that does not return anything, we pass
our own dummy implementation to ppcg that always returns a nullptr. This
ensures that the list of ast expressions always contains a nullptr and we do
not accidentally free a random (uninitalized) pointer. This resolves the
last valgrind warning we see.

We provide an implementation for this function, when the generated AST
expressions can be used and consequently can be tested.

llvm-svn: 275435
2016-07-14 15:51:32 +00:00
Tobias Grosser
aef5196f75 GPGPU: Map initial schedule to GPU schedule
This change now applies ppcg's GPU mapping on our initial schedule. For this
to work, we need to also initialize the set of all names (isl_ids) used in
the scop as well as the program context.

llvm-svn: 275396
2016-07-14 10:51:52 +00:00
Tobias Grosser
f384594d5e GPGPU: compute new schedule from polly scop
To do so we copy the necessary information to compute an initial schedule from
polly::Scop to ppcg's scop. Most of the necessary information is directly
available and only needs to be passed on to ppcg, with the exception of 'tagged'
access relations, access relations that additionally carry information about
which memory access an access relation originates from.

We could possibly perform the construction of tagged accesses as part of
ScopInfo, but as this format is currently specific to ppcg we do not do this
yet, but keep this functionality local to our GPU code generation.

After the scop has been initialized, we compute data dependences and ask ppcg to
compute an initial schedule. Some of this functionality is already available in
polly::DependenceInfo and polly::ScheduleOptimizer, but to keep differences
to ppcg small we use ppcg's functionality here. We may later investiage if
a closer integration of these tools makes sense.

llvm-svn: 275390
2016-07-14 10:22:25 +00:00
Tobias Grosser
a041239bb7 Add ppcg-0.04 to lib/External
ppcg will be used to provide mapping decisions for GPU code generation.

As we do not use C as input language, we do not include pet. However, we include
pet.h from pet 82cacb71 plus a set of dummy functions to ensure ppcg links
without problems.

The version of ppcg committed is unmodified ppcg-0.04 which has been well tested
in the context of LLVM. It does not provide an official library interface yet,
which means that in upcoming commits we will add minor modifications to make
necessary functionality accessible. We will aim to upstream these modifications
after we gained enough experience with GPU generation support in Polly to
propose a stable interface.

Reviewers: Meinersbur

Subscribers: pollydev, llvm-commits

Differential Revision: http://reviews.llvm.org/D22033

llvm-svn: 275274
2016-07-13 15:54:47 +00:00