Commit Graph

2752 Commits

Author SHA1 Message Date
Michael Kruse 349779cc99 Disable MSVC warnings on ISL.
Disable some Visual C++ warnings on ISL. These are not reported by GCC/Clang in
the ISL build system. We do not intend to fix them in the Polly in-tree copy,
hence disable these warnings.

llvm-svn: 280811
2016-09-07 14:11:20 +00:00
Michael Kruse 564579726a Add check-polly-tests build target.
The check-polly-tests target runs regression/unit tests but without checking
formatting. This is useful to not having to reload a file in an open editor
(which eg. clears the undo buffer, moves cursor/window position) when running
polly-update-format.

After this change, the following test targets exist:
 - check-polly-unittests to run unittests only
 - check-polly-tests to run unit and regression tests
 - polly-check-format to check formatting using clang-format
 - check-polly to run them all

As a side-effect, when running check-polly, polly-check-format and run in
parallel (instead of polly-check-format first).

Differential Revision: https://reviews.llvm.org/D24191

llvm-svn: 280654
2016-09-05 10:54:16 +00:00
Tobias Grosser 8d4cb1a060 ScopInfo: Do not derive assumptions from all GEP pointer instructions
... but instead rely on the assumptions that we derive for load/store
instructions.

Before we were able to delinearize arrays, we used GEP pointer instructions
to derive information about the likely range of induction variables, which
gave us more freedom during loop scheduling. Today, this is not needed
any more as we delinearize multi-dimensional memory accesses and as part
of this process also "assume" that all accesses to these arrays remain
inbounds. The old derive-assumptions-from-GEP code has consequently become
mostly redundant. We drop it both to clean up our code, but also to improve
compile time. This change reduces the scop construction time for 3mm in
no-asserts mode on my machine from 48 to 37 ms.

llvm-svn: 280601
2016-09-03 21:55:25 +00:00
Tobias Grosser 66c6506aac Dependences: Only create flat StmtSchedule in presence of reductions
Without reductions we do not need a flat union_map schedule describing
the computation we want to perform, but can work purely on the schedule
tree. This reduces the dependence computation and scheduling time from 33ms
to 25ms. Another 30% reduction.

llvm-svn: 280558
2016-09-02 23:40:15 +00:00
Tobias Grosser dff5de2e44 Dependences: Exit early, if no reduction dependences are needed.
In case we do not compute reduction dependences or dependences that are more
fine-grained than statement level dependences, we can avoid the corresponding
part of the dependence analysis all together. For the 3mm benchmark, this
reduces scheduling + dependence analysis time from 62ms to 33ms for a no-asserts
build.  The majority of the compile time is anyhow spent in the LLVM backends,
when doing code generation. Nevertheless, there is no need to waste compile time
either.

llvm-svn: 280557
2016-09-02 23:29:38 +00:00
Tobias Grosser b1000c39a0 Introduce option to run isl AST generation, but no IR generation.
We replace the options

  -polly-code-generator=none
                       =isl

with the options

  -polly-code-generation=none
                        =ast
                        =full

This allows us to measure the overhead of Polly itself, versus the compile
time increases due to us generating more IR and consequently the LLVM backends
spending more time on this IR.

We also use this opportunity to rename the option. The original name was
introduced at a point where we still had two code generators. CLooG and the
isl AST generator. Since we only have one AST generator left, there is no need
to distinguish between 'isl' and something else. However, being able to disable
code generation all together has been shown useful for debugging. Hence, we
rename and extend this option to make it a good fit for its new use case.

llvm-svn: 280554
2016-09-02 23:05:42 +00:00
Tobias Grosser c80d6979bd Drop '@brief' from doxygen comments
LLVM's coding guideline suggests to not use @brief for one-sentence doxygen
comments to improve readability. Switch this once and for all to ensure people
do not copy @brief comments from other parts of Polly, when writing new code.

llvm-svn: 280468
2016-09-02 06:33:33 +00:00
Michael Kruse 2fa3519463 Allow mapping scalar MemoryAccesses to array elements.
Change the code around setNewAccessRelation to allow to use a an existing array
element for memory instead of an ad-hoc alloca. This facility will be used for
DeLICM/DeGVN to convert scalar dependencies into regular ones.

The changes necessary include:
- Make the code generator use the implicit locations instead of the alloca ones.
- A test case
- Make the JScop importer accept changes of scalar accesses for that test case.
- Adapt the MemoryAccess interface to the fact that the MemoryKind can change.
  They are named (get|is)OriginalXXX() to get the status of the memory access
  before any change by setNewAccessRelation() (some properties such as
  getIncoming() do not change even if the kind is changed and are still
  required). To get the modified properties, there is (get|is)LatestXXX(). The
  old accessors without Original|Latest become synonyms of the
  (get|is)OriginalXXX() to not make functional changes in unrelated code.

Differential Revision: https://reviews.llvm.org/D23962

llvm-svn: 280408
2016-09-01 19:53:31 +00:00
Michael Kruse 772ce72000 Check validity of new access relations. NFC.
There are some constraints on maps that can be access relations. In builds with assertions enabled, verify

  - The access domain is the same space as the statement's domain (modulo parameters).
  - Whether an access is defined for every instance of the statement. (codegen does not yet support partial access relations)
  - Whether the access range links to an array, represented by a ScopArrayInfo.
  - The number of access dimensions equals the dimensions of the array.
  - The array is not an indirect access. (also not supported by codegen)

Differential Revision: https://reviews.llvm.org/D23916

llvm-svn: 280404
2016-09-01 19:16:58 +00:00
Michael Kruse d56b90a967 [ScopInfo] Add missing ISL annotations NFC.
llvm-svn: 280343
2016-09-01 09:03:27 +00:00
Michael Kruse 77564f92e8 Update ISL to isl-0.17.1-203-g3fef898.
This version has isl_space_has_equal_tuples added to the public API.

llvm-svn: 280341
2016-09-01 08:26:22 +00:00
Tobias Grosser 90a3c0ba99 Add forgotten image
llvm-svn: 280083
2016-08-30 12:41:29 +00:00
Tobias Grosser cb8f813254 www: homepage "Overview and News"
llvm-svn: 280082
2016-08-30 12:41:08 +00:00
Tobias Grosser 0bb9c4b09a www: shorten links in menu
llvm-svn: 280081
2016-08-30 12:41:04 +00:00
Tobias Grosser e1889f186d www: link to github source mirror, drop the other old source viewers
llvm-svn: 280080
2016-08-30 12:41:02 +00:00
Tobias Grosser 027d2f7bfd www: improve formatting of external links
llvm-svn: 280079
2016-08-30 12:40:59 +00:00
Tobias Grosser e5721d659c www: Add links to Polly Labs and Polyhedral.info
llvm-svn: 280076
2016-08-30 12:08:25 +00:00
Tobias Grosser 80a9579db9 www: Add IMPACT 2017 announcement to news page
llvm-svn: 280060
2016-08-30 06:35:17 +00:00
Michael Kruse d262feff80 Add space between access string and follow-up.
llvm-svn: 279826
2016-08-26 15:43:52 +00:00
Michael Kruse 6b6e38d9b1 Add "New access function" to update_check.py classifier.
Lines with this prefix are printed by JSONImporter.

llvm-svn: 279825
2016-08-26 15:43:43 +00:00
Tobias Grosser 9d61e4a980 Avoid the use of large unsigned values in isl unit test
isl_val_int_from_ui takes an 'unsigned long' which has on 32-bit and LLP64
windows systems only 32 bit. Hence, make sure we do not use it with constants
that are larger than 32 bit.

Reported-by: Michael Kruse <llvm@meinersbur.de>
llvm-svn: 279824
2016-08-26 15:42:38 +00:00
Roman Gareev 44aeef7ecf [FIX] Access dimensions should correspond to number of dimensions of the accesses array.
llvm-svn: 279821
2016-08-26 13:41:53 +00:00
Tobias Grosser aa6eb5cd80 unittests: Make the expected value the first argument in EXPECT_EQ [NFC]
This improves the readability of failing test results, as gtest prints always
the first argument as the 'expected value'.

In the previous commit we already changed the tests for isl_valFromAPInt. In
this commit, the tests for IslValToAPInt follow.

Suggested-by: Michael Kruse <llvm@meinersbur.de>
llvm-svn: 279817
2016-08-26 12:25:08 +00:00
Tobias Grosser 437200089d Improve documentation and testing for isl_valFromAPInt
The recent unit tests we gained made clear that the semantics of
isl_valFromAPInt are not clear, due to missing documentation. In this change we
document both the calling interface as well as the implementation of
isl_valFromAPInt.

We also make the implementation easier to read by removing integer wrappig in
abs() when passing in the minimal integer value for a given bitwidth. Even
though wrapping and subsequently interpreting the result as unsigned value gives
the correct result, this is far from obvious.  Instead, we explicitly add one
more bit to the input type to ensure that abs will never wrap. This change did
not uncover a bug in the old implementation, but was introduced to increase
readability.

We update the tests to add a test case for this special case and use this
opportunity to also test a number larger than 64 bit. Finally, we order the
arguments of the test cases to make sure the expected output is first. This
helps readability in case of failing test cases as gtest assumes the first value
to be the exected value.

Reviewed-by: Michael Kruse <llvm@meinersbur.de>
Differential Revision: https://reviews.llvm.org/D23917

llvm-svn: 279815
2016-08-26 12:01:07 +00:00
Tobias Grosser 76f8279e44 Improve documentation and testing of APIntFromVal
The recent unit tests we gained made clear that the semantics of APIntFromVal
are not clear, due to missing documentation. In this change we document both
the calling interface as well as the implementation of APIntFromVal. We also
make the implementation easier to read by removing the use of magic numbers.
Finally, we add tests to check the bitwidth of the created values as well as
the correct modeling of very large numbers.

Reviewed-by: Michael Kruse <llvm@meinersbur.de>
Differential Revision: https://reviews.llvm.org/D23910

llvm-svn: 279813
2016-08-26 10:43:28 +00:00
Michael Kruse b41b990e05 Query llvm-config to get system libs required for linking.
Remove the unused function get_system_libs. Instead, run
'llvm-config --system-libs' to determine which libraries are required in
addition LLVM's for linking an executable. At the moment these are the unittests
that link to gtest and transitively depend on these system libs.

llvm-svn: 279743
2016-08-25 14:58:29 +00:00
Michael Kruse 606b06a156 Add comment for querying --libdir. NFC.
llvm-svn: 279742
2016-08-25 14:43:04 +00:00
Michael Kruse fd4a332a3a Do not build unittests by default.
Only build them for check-polly and check-polly-unittests in out-of-tree builds.

In LLVM, this behaviour is controlled with LLVM_BUILD_TESTS. Polly out-of-tree
does not have such a flag.

llvm-svn: 279740
2016-08-25 14:33:44 +00:00
Michael Kruse b6eadcc5cc Add missing words to wanrning.
llvm-svn: 279738
2016-08-25 13:29:26 +00:00
Michael Kruse 225d583825 Add warning for FORCE_STATIC libraries when using BUILD_SHARED_LIBS.
We cannot built ISL as shared object because we build it with
-fvisibility=hidden; The created shared object would have no accessible symbols.

The reason it is built with -fvisibility=hidden is because opt/clang might load
other libraries that have ISL embedded and whose' symbols would conflict with
Polly's private ISL. This could happend with Draggonegg.

In the future we might instead statically link PollyISL into the Polly shared
object to avoid installing the static library.

Requested-by: Vedran Miletic <vedran@miletic.net>

See-also: llvm.org/PR27306
llvm-svn: 279737
2016-08-25 13:21:53 +00:00
Michael Kruse 05cf9c22f1 Introduce unittests.
Add the infrastructure for unittests to Polly and two simple tests for
conversion between isl_val and APInt. In addition, a build target
check-polly-unittests is added to run only the unittests but not the regression
tests.

Clang's unittest mechanism served as as a blueprint which then was adapted to
Polly.

Differential Revision: https://reviews.llvm.org/D23833

llvm-svn: 279734
2016-08-25 12:36:15 +00:00
Michael Kruse 0e63ab4243 Use configure_lit_site_cfg instead of configure_file.
configure_lit_site_cfg defines some more parameters that are used in
lit.site.cfg.in. configure_file would leave those empty. These additional
definitions seem to be unimportant for regression tests, but unittests do not
work without them.

In case of out-of-tree builds, define the additional parameters with default
values. These may not take all configuration parameters into account, as
configure_lit_site_cfg would.

llvm-svn: 279733
2016-08-25 12:03:33 +00:00
Michael Kruse 17a8b791ae Add LLVM libdir to library search path in out-of-tree builds.
This previously was not required because in an out-of-tree build Polly would
only build libraries (LLVMPolly, libPolly, libPollyISL, libPollyPPCG), but no
executables where the libraries would be linked to. This will change when adding
unittests in a follow-up commit.

llvm-svn: 279730
2016-08-25 11:28:52 +00:00
Michael Kruse 941a692690 Also warn if llvm-lit is not available.
The program 'llvm-lit', like 'not' and 'FileCheck' are necessary for running
check-polly. Warn of any of the three is not in LLVM_INSTALL_ROOT/bin directory.

llvm-svn: 279728
2016-08-25 10:35:22 +00:00
Michael Kruse 4a080de057 Add %loadPolly to test command line.
Required for out-of-tree builds of Polly.

llvm-svn: 279657
2016-08-24 19:12:48 +00:00
Tim Shen 12921aaa7b Migrate from NodeType * to NodeRef.
llvm-svn: 279488
2016-08-22 22:30:27 +00:00
Roman Gareev 5f99f8656e Add a flag to dump SCoP optimized with the IslScheduleOptimizer pass
Dump polyhedral descriptions of Scops optimized with the isl scheduling
optimizer and the set of post-scheduling transformations applied
on the schedule tree to be able to check the work of the IslScheduleOptimizer
pass at the polyhedral level.

Reviewed-by: Tobias Grosser <tobias@grosser.es>

Differential Revision: https://reviews.llvm.org/D23740

llvm-svn: 279395
2016-08-21 11:20:39 +00:00
Roman Gareev e2ee79afde Simplify AccFuncMap to vector<> AccessFunctions
getAccessFunctions() is dead code and the 'BB' argument
of getOrCreateAccessFunctions() is not used. This patch deletes
getAccessFunctions and transforms AccFuncMap into
a std::vector<std::unique_ptr<MemoryAccess>> AccessFunctions.

Reviewed-by: Tobias Grosser <tobias@grosser.es>

Differential Revision: https://reviews.llvm.org/D23759

llvm-svn: 279394
2016-08-21 11:09:19 +00:00
Eli Friedman 28671c83d6 [SCEVValidator] Don't reorder multiplies in extractConstantFactor.
The existing code would add the operands in the wrong order, and eventually
crash because the SCEV expression doesn't exactly match the parameter SCEV
expression in SCEVAffinator::visit. (SCEV doesn't sort the operands to
getMulExpr in general.)

Differential Revision: https://reviews.llvm.org/D23592

llvm-svn: 279087
2016-08-18 16:30:42 +00:00
Tobias Grosser 1c18440958 [BlockGenerator] Invalidate SCEV values for instructions in scop
We already invalidated a couple of critical values earlier on, but we now
invalidate all instructions contained in a scop after the scop has been code
generated. This is necessary as later scops may otherwise obtain SCEV
expressions that reference values in the earlier scop that before dominated
the later scop, but which had been moved into the conditional branch and
consequently do not dominate the later scop any more. If these very values are
then used during code generation of the later scop, we generate used that are
dominated by the values they use.

This fixes: http://llvm.org/PR28984

llvm-svn: 279047
2016-08-18 10:45:57 +00:00
Michael Kruse ffb3278e27 Update ISL to isl-0.17.1-200-gd8de4ea.
This version fixes a bug in set coalescing.

llvm-svn: 278936
2016-08-17 15:24:45 +00:00
Tobias Grosser b143e31164 [ScopInfo] Make scalars used by PHIs in non-affine regions available
Normally this is ensured when adding PHI nodes, but as PHI node dependences
do not need to be added in case all incoming blocks are within the same
non-affine region, this was missed.

This corrects an issue visible in LNT's sqlite3, in case invariant load hoisting
was disabled.

llvm-svn: 278792
2016-08-16 11:44:48 +00:00
Tobias Grosser c80c15bd50 [ScopDetect] Do not assert in case of AddRecs with non-constant start expression
llvm-svn: 278738
2016-08-15 20:59:30 +00:00
Tobias Grosser 74814e1a07 Disable invariant load hoisting temporarily
With invariant load hoisting enabled the LLVM buildbots currently show some
miscompiles, which are possibly caused by invariant load hosting itself.
Confirming and fixing this requires a more in-depth analysis. To meanwhile get
back green buildbots that allow us to observe other regressions, we disable
invariant code hoisting temporarily. The relevant bug is tracked at:

http://llvm.org/PR28985

llvm-svn: 278681
2016-08-15 16:43:36 +00:00
Tobias Grosser 13e55a32fd [test] Force invariant load hoisting one last time
Without invariant load hoisting an (unrelated) bug is exposed in this test
case: http://llvm.org/PR28984

llvm-svn: 278680
2016-08-15 16:43:33 +00:00
Tobias Grosser 7cb809983d [tests] Force invariant load hoisting for test cases that need it -- III
llvm-svn: 278673
2016-08-15 15:56:24 +00:00
Tobias Grosser ad61c170d5 [tests] Force invariant load hoisting for test cases that need it II
llvm-svn: 278669
2016-08-15 13:58:16 +00:00
Tobias Grosser 75b9c7df4d [test] Correct spelling in test case
and explicitly enable invariant load hoisting for this test case.

llvm-svn: 278668
2016-08-15 13:58:04 +00:00
Tobias Grosser 6e6264c142 [tests] Force invariant load hoisting for test cases that need it
This will make it easier to switch the default of Polly's invariant load
hoisting strategy and also makes it very clear that these test cases
indeed require invariant code hoisting to work.

llvm-svn: 278667
2016-08-15 13:27:49 +00:00
Roman Gareev 1c892e91e3 Perform replacement of access relations and creation of new arrays according to the packing transformation
This is the third patch to apply the BLIS matmul optimization pattern on matmul
kernels (http://www.cs.utexas.edu/users/flame/pubs/TOMS-BLIS-Analytical.pdf).
BLIS implements gemm as three nested loops around a macro-kernel, plus two
packing routines. The macro-kernel is implemented in terms of two additional
loops around a micro-kernel. The micro-kernel is a loop around a rank-1
(i.e., outer product) update. In this change we perform replacement of
the access relations and create empty arrays, which are steps to implement
the packing transformation. In subsequent changes we will implement copying
to created arrays.

Reviewed-by: Tobias Grosser <tobias@grosser.es>

Differential Revision: http://reviews.llvm.org/D22187

llvm-svn: 278666
2016-08-15 12:22:54 +00:00
Tobias Grosser d58acf866a [GPGPU] Ensure arrays where only parts are modified are copied to GPU
To do so we change the way array exents are computed. Instead of the precise
set of memory locations accessed, we now compute the extent as the range between
minimal and maximal address in the first dimension and the full extent defined
by the sizes of the inner array dimensions.

We also move the computation of the may_persist region after the construction
of the arrays, as it relies on array information. Without arrays being
constructed no useful information is computed at all.

llvm-svn: 278212
2016-08-10 10:58:19 +00:00
Mandeep Singh Grang 8c5314479e Fix spacing around variable initializations and for-loops. NFC.
Reviewers: grosser, _jdoerfert, zinob

Projects: #polly

Differential Revision: https://reviews.llvm.org/D23285

llvm-svn: 278143
2016-08-09 17:49:24 +00:00
Tobias Grosser b06ff4574e [GPGPU] Support PHI nodes used in GPU kernel
Ensure the right scalar allocations are used as the host location of data
transfers. For the device code, we clear the allocation cache before device
code generation to be able to generate new device-specific allocation and
we need to make sure to add back the old host allocations as soon as the
device code generation is finished.

llvm-svn: 278126
2016-08-09 15:35:06 +00:00
Tobias Grosser 750160e260 [GPGPU] Use separate basic block for GPU initialization code
This increases the readability of the IR and also clarifies that the GPU
inititialization is executed _after_ the scalar initialization which needs
to before the code of the transformed scop is executed.

Besides increased readability, the IR should not change. Specifically, I
do not expect any changes in program semantics due to this patch.

llvm-svn: 278125
2016-08-09 15:35:03 +00:00
Tobias Grosser 776700d0b7 [BlockGenerator] Insert initializations at beginning of start block
In case some code -- not guarded by control flow -- would be emitted directly in
the start block, it may happen that this code would use uninitalized scalar
values if the scalar initialization is only emitted at the end of the start
block. This is not a problem today in normal Polly, as all statements are
emitted in their own basic blocks, but Polly-ACC emits host-to-device copy
statements into the start block.

Additional Polly-ACC test coverage will be added in subsequent changes that
improve the handling of PHI nodes in Polly-ACC.

llvm-svn: 278124
2016-08-09 15:34:59 +00:00
Tobias Grosser 77f76788dc [tests] Add two missing 'REQUIRES' lines
llvm-svn: 278104
2016-08-09 09:11:39 +00:00
Tobias Grosser c59b3ce044 [BlockGenerator] Also eliminate dead code not originating from BB
After having generated the code for a ScopStmt, we run a simple dead-code
elimination that drops all instructions that are known to be and remain unused.
Until this change, we only considered instructions for dead-code elimination, if
they have a corresponding instruction in the original BB that belongs to
ScopStmt. However, when generating code we do not only copy code from the BB
belonging to a ScopStmt, but also generate code for operands referenced from BB.
After this change, we now also considers code for dead code elimination, which
does not have a corresponding instruction in BB.

This fixes a bug in Polly-ACC where such dead-code referenced CPU code from
within a GPU kernel, which is possible as we do not guarantee that all variables
that are used in known-dead-code are moved to the GPU.

llvm-svn: 278103
2016-08-09 08:59:05 +00:00
Tobias Grosser cf66ef26f3 [GPGPU] Pass parameters always by using their own type
llvm-svn: 278100
2016-08-09 07:22:08 +00:00
Michael Kruse a6cc0d3a2d [ScopDetection] Remove unused DetectionContexts during expansion.
The function expandRegion() frees Region* objects again when it determines that
these are not valid SCoPs. However, the DetectionContext added to the
DetectionContextMap still holds a reference. The validity is checked using the
ValidRegions lookup table. When a new Region is added to that list, it might
share the same address, such that the DetectionContext contains two
Region* associations that are in ValidRegions, but that are unrelated and of
which one has already been free.

Also remove the DetectionContext when not a valid expansion.

llvm-svn: 278062
2016-08-08 22:39:32 +00:00
Tobias Grosser 124534038a [GPGPU] Support Values referenced from both isl expr and llvm instructions
When adding code that avoids to pass values used in isl expressions and
LLVM instructions twice, we forgot to make single variable passed to the
kernel available in the ValueMap that makes it usable for instructions that
are not replaced with isl ast expressions. This change adds the variable
that is passed to the kernel to the ValueMap to ensure it is available
for such use cases as well.

llvm-svn: 278039
2016-08-08 19:22:19 +00:00
Tobias Grosser cb1aef8de4 [GPGPU] Create code to verify run-time conditions
llvm-svn: 278026
2016-08-08 17:35:55 +00:00
Tobias Grosser fa9abd1f03 Fix compilation in 'asserts' mode
llvm-svn: 278025
2016-08-08 17:35:52 +00:00
Tobias Grosser 0aa29532b7 [IslNodeBuilder] Move run-time check generation to NodeBuilder [NFC]
This improves the structure of the code and allows us to reuse the runtime
code generation in the PPCGCodeGeneration.

llvm-svn: 278017
2016-08-08 15:41:52 +00:00
Tobias Grosser 219feac456 [CodeGeneration] Do not set insert position redundantly
There is no need to reset the position of the builder, as we can just continue
to insert code at the current position of the IRBuilder, which happens to
be precisely the location we reset the builder to.

llvm-svn: 278014
2016-08-08 15:25:50 +00:00
Tobias Grosser 000db70754 [IslNodeBuilder] Directly use the insert location of our Builder
... instead of adding instructions at the end of the basic block the builder
is currently at. This makes it easier to reason about where IR is generated,
as with the IRBuilder there is just a single location that specificies where
IR is generated.

llvm-svn: 278013
2016-08-08 15:25:46 +00:00
Michael Kruse fbde435517 [CodeGen] Use MapVector instead of DenseMap.
The map is iterated over when generating the values escaping the SCoP. The
indeterministic iteration order of DenseMap causes the output IR to change at
every compilation, adding noise to comparisons.

Replace DenseMap by a MapVector to ensure the same iteration order at every
compilation.

llvm-svn: 277832
2016-08-05 16:45:51 +00:00
Michael Kruse d82222fc1b [DependenceInfo] Reset operations counter when setting limit.
When entering the dependence computation and the max_operations is set, the
operations counter may have already exceeded the counter, thus aborting any ISL
computation from the start. The counter is reset at the end of the dependence
calculation such that a follow-up recomputation might succeed, ie. the success
of the first dependence calculation depends on unrelated ISL operations that
happened before, giving it a disadvantage to the following calculations.

This patch resets the operations counter at the beginning of the dependence
recalculation to not depend on previous actions. Otherwise additional
preprocessing of the Scop that aims to improve its schedulability (eg. DeLICM)
do have the effect that DependenceInfo and hence the scheduling fail more
likely, contraproductive to the goal of said preprocessing.

llvm-svn: 277810
2016-08-05 11:31:02 +00:00
Tobias Grosser 928d7573dd GPGPU: Sort dimension sizes of multi-dimensional shared memory arrays correctly
Before this commit we generated the array type in reverse order and we also
added the outermost dimension size to the new array declaration, which is
incorrect as Polly additionally assumed an additional unsized outermost
dimension, such that we had an off-by-one error in the linearization of access
expressions.

llvm-svn: 277802
2016-08-05 08:27:24 +00:00
Tobias Grosser 470608e3e4 Add missing 'REQUIRES' line
llvm-svn: 277800
2016-08-05 07:08:45 +00:00
Tobias Grosser c1c6a2a61b GPGPU: Add cuda annotations to specify maximal number of threads per block
These annotations ensure that the NVIDIA PTX assembler limits the number of
registers used such that we can be certain the resulting kernel can be executed
for the number of threads in a thread block that we are planning to use.

llvm-svn: 277799
2016-08-05 06:47:43 +00:00
Tobias Grosser f919d8b360 GPGPU: Support scalars that are mapped to shared memory
llvm-svn: 277726
2016-08-04 13:57:29 +00:00
Tobias Grosser 8950cead7f GPGPU: Disable verbose debug output
llvm-svn: 277724
2016-08-04 12:44:03 +00:00
Tobias Grosser b0dd95bcd2 Remove leftover debug output
llvm-svn: 277723
2016-08-04 12:41:28 +00:00
Tobias Grosser 130ca30f92 GPGPU: Add private memory support
llvm-svn: 277722
2016-08-04 12:39:03 +00:00
Tobias Grosser b513b4916b GPGPU: Add support for shared memory
llvm-svn: 277721
2016-08-04 12:18:14 +00:00
Tobias Grosser b187515784 GPGPU: Cache PTX kernels
We always keep a number of already compiled kernels available to ensure to avoid
costly recompilation.

llvm-svn: 277707
2016-08-04 09:15:58 +00:00
Tobias Grosser 00bb5a99f5 GPGPU: Handle scalar array references
Pass the content of scalar array references to the alloca on the kernel side
and do not pass them additional as normal LLVM scalar value.

llvm-svn: 277699
2016-08-04 06:55:59 +00:00
Tobias Grosser 3216f8546c BlockGenerator: Assert that we do not get alloca of array access
llvm-svn: 277698
2016-08-04 06:55:53 +00:00
Tobias Grosser 576932728d GPGPU: Pass subtree values correctly to the kernel
llvm-svn: 277697
2016-08-04 06:55:49 +00:00
Tobias Grosser 629109b633 GPGPU: Mark kernel functions as polly.skip
Otherwise, we would try to re-optimize them with Polly-ACC and possibly even
generate kernels that try to offload themselves, which does not work as the
GPURuntime is not available on the accelerator and also does not make any
sense.

llvm-svn: 277589
2016-08-03 12:00:07 +00:00
Tobias Grosser 2219d15748 Fix a couple of spelling mistakes
llvm-svn: 277569
2016-08-03 05:28:09 +00:00
Roman Gareev 0c09a3af00 Add missing prefixes.
llvm-svn: 277264
2016-07-30 11:15:00 +00:00
Roman Gareev d7754a1245 Extend the jscop interface to allow the user to declare new arrays and to reference these arrays from access expressions
Extend the jscop interface to allow the user to export arrays. It is required
that already existing arrays of the list of arrays correspond to arrays
of the SCoP. Each array that is appended to the list will be newly created.
Furthermore, we allow the user to modify access expressions to reference
any array in case it has the same element type.

Reviewed-by: Tobias Grosser <tobias@grosser.es>

Differential Revision: https://reviews.llvm.org/D22828

llvm-svn: 277263
2016-07-30 09:25:51 +00:00
Tobias Grosser 8af38ecaa3 Add missing REQUIRES line
llvm-svn: 276964
2016-07-28 07:08:34 +00:00
Tobias Grosser d8b94bcac1 GPGPU: Pass context parameters to GPU kernel
llvm-svn: 276963
2016-07-28 06:47:59 +00:00
Tobias Grosser a490147c90 GPGPU: Pass host iterators to kernel
llvm-svn: 276962
2016-07-28 06:47:56 +00:00
Tobias Grosser 44143bb927 GPGPU: use current 'Index' to find slot in parameter array
Before this change we used the array index, which would result in us accessing
the parameter array out-of-bounds. This bug was visible for test cases where not
all arrays in a scop are passed to a given kernel.

llvm-svn: 276961
2016-07-28 06:47:53 +00:00
Tobias Grosser 4e18d71c71 GPGPU: Generate kernel parameter allocation with right size
Before this change we miscounted the number of function parameters.

llvm-svn: 276960
2016-07-28 06:47:50 +00:00
Tobias Grosser 79a947c233 GPGPU: Add basic support for kernel launches
llvm-svn: 276863
2016-07-27 13:20:16 +00:00
Tobias Grosser 5779359624 GPGPU: Load GPU kernels
We embed the PTX code into the host IR as a global variable and compile it
at run-time into a GPU kernel.

llvm-svn: 276645
2016-07-25 16:31:21 +00:00
Johannes Doerfert 8031238017 [GSoC] Add PolyhedralInfo pass - new interface to polly analysis
Adding a new pass PolyhedralInfo. This pass will be the interface to Polly.
  Initially, we will provide the following interface:
    - #IsParallel(Loop *L) - return a bool depending on whether the loop is
                             parallel or not for the given program order.

Patch by Utpal Bora <cs14mtech11017@iith.ac.in>

Differential Revision: https://reviews.llvm.org/D21486

llvm-svn: 276637
2016-07-25 12:48:45 +00:00
Tobias Grosser 13c78e4d51 GPGPU: Emit data-transfer code
Also factor out getArraySize() to avoid code dupliciation and reorder some
function arguments to indicate the direction into which data is transferred.

llvm-svn: 276636
2016-07-25 12:47:39 +00:00
Tobias Grosser 7287aeddf1 GPGPU: Complete code to allocate and free device arrays
At the beginning of each SCoP, we allocate device arrays for all arrays
used on the GPU and we free such arrays after the SCoP has been executed.

llvm-svn: 276635
2016-07-25 12:47:33 +00:00
Tobias Grosser 19b8a0bbfb GPURuntime: Add missing debug output
llvm-svn: 276634
2016-07-25 12:47:28 +00:00
Tobias Grosser 9855e8bd80 GPURuntime: Fix typo in docu
llvm-svn: 276633
2016-07-25 12:47:25 +00:00
Tobias Grosser a71eedd4c5 GPURuntime: Drop polly_cleanupGPGPUResources
This function is currently unused and won't be used in this form again. Instead
of freeing many unrelated items at the same time, we will instead explicitly
call free function from the host-IR we generate for each object we want to free.
These specific free functions will be added together with the corresponding
host-IR generation code.

llvm-svn: 276632
2016-07-25 12:47:22 +00:00
Johannes Doerfert 3b7ac0a691 [GSoC] Do not process SCoPs with infeasible runtime context
Do not process SCoPs with infeasible runtime context in the new
  ScopInfoWrapperPass. Do not compute dependences for such SCoPs in the new
  DependenceInfoWrapperPass.

Patch by Utpal Bora <cs14mtech11017@iith.ac.in>

Differential Revision: https://reviews.llvm.org/D22402

llvm-svn: 276631
2016-07-25 12:40:59 +00:00
Roman Gareev 3a18a931a8 Apply all necessary tilings and interchangings to get a macro-kernel
This is the second patch to apply the BLIS matmul optimization pattern
on matmul kernels
(http://www.cs.utexas.edu/users/flame/pubs/TOMS-BLIS-Analytical.pdf).
BLIS implements gemm as three nested loops around a macro-kernel, plus
two packing routines. The macro-kernel is implemented in terms
of two additional loops around a micro-kernel. The micro-kernel
is a loop around a rank-1 (i.e., outer product) update. In this change
we create the BLIS macro-kernel by applying a combination of tiling
and interchanging. In subsequent changes we will implement the packing
transformation.

Reviewed-by: Tobias Grosser <tobias@grosser.es>

Differential Revision: http://reviews.llvm.org/D21491

llvm-svn: 276627
2016-07-25 09:42:53 +00:00
Tobias Grosser fa7b080218 GPGPU: initialize GPU context and simplify the corresponding GPURuntime interface.
There is no need to expose the selected device at the moment. We also pass back
pointers as return values, as this simplifies the interface.

llvm-svn: 276623
2016-07-25 09:16:01 +00:00
Tobias Grosser 8ed5e5999f IslNodeBuilder: Make finalize() virtual
This allows the finalization routine of the IslNodeBuilder to be overwritten
by derived classes. Being here, we also drop the unnecessary 'Scop' postfix
and the unnecessary 'Scop' parameter.

llvm-svn: 276622
2016-07-25 09:15:57 +00:00
Tobias Grosser 0a1a2720c8 GPURuntime: Check for debug-mode early on
Before this change, the debug statements in polly_initDevice would all be
skipped, as debug-mode would only be enabled _after_ they have already been run.

llvm-svn: 276621
2016-07-25 09:15:53 +00:00
Tobias Grosser dc816da455 GPURuntime: Drop timing functionality (some leftover II)
llvm-svn: 276617
2016-07-25 08:03:08 +00:00
Roman Gareev 2cb4d133f5 [NFC] Refactor creation of the BLIS mirco-kernel and improve documentation
Reviewed-by: Tobias Grosser <tobias@grosser.es>
llvm-svn: 276616
2016-07-25 07:27:59 +00:00
Tobias Grosser 97aa23519e GPURuntime: Drop timing functionality (some leftover)
llvm-svn: 276612
2016-07-25 07:11:49 +00:00
Tobias Grosser 92713bea42 GPURuntime: Drop timing functionality
This functionality won't be used in the current iteration. Drop it for now to
reduce the surface of the library. We can always add it back in when we need
it again.

llvm-svn: 276611
2016-07-25 07:10:45 +00:00
Tobias Grosser 9a18d55947 GPGPU: Optimize kernel IR before generating assembly code
We optimize the kernel _after_ dumping the IR we generate to make the IR we
dump easier readable and independent of possible changes in the general
purpose LLVM optimizers.

llvm-svn: 276551
2016-07-24 06:43:21 +00:00
Tobias Grosser e1a98343a1 GPGPU: Verify kernel IR before generating assembly
llvm-svn: 276550
2016-07-24 06:43:17 +00:00
Michael Kruse 977d38bd87 Remove unused parameters from simplifySCoP(). NFC.
llvm-svn: 276444
2016-07-22 17:31:17 +00:00
Tobias Grosser 74dc3cb431 GPGPU: Generate PTX assembly code for the kernel modules
Run the NVPTX backend over the GPUModule IR and write the resulting assembly
code in a string.

To work correctly, it is important to invalidate analysis results that still
reference the IR in the kernel module. Hence, this change clears all references
to dominators, loop info, and scalar evolution.

Finally, the NVPTX backend has troubles to generate code for various special
floating point types (not surprising), but also for uncommon integer types. This
commit does not resolve these issues, but pulls out problematic test cases into
separate files to XFAIL them individually and resolve them in future (not
immediate) changes one by one.

llvm-svn: 276396
2016-07-22 07:11:12 +00:00
Tobias Grosser edb885cb12 GPGPU: generate code for ScopStatements
This change introduces the actual compute code in the GPU kernels. To ensure
all values referenced from the statements in the GPU kernel are indeed available
we scan all ScopStmts in the GPU kernel for references to llvm::Values that
are not yet covered by already modeled outer loop iterators, parameters, or
array base pointers and also pass these additional llvm::Values to the
GPU kernel.

For arrays used in the GPU kernel we introduce a new ScopArrayInfo object, which
is referenced by the newly generated access functions within the GPU kernel and
which is used to help with code generation.

llvm-svn: 276270
2016-07-21 13:15:59 +00:00
Tobias Grosser 86083da0ec IslNodeBuilder: expose addReferencesFromStmt [NFC]
This will be used by Polly GPGPU to determine the values that need to be
passed to GPU kernels.

llvm-svn: 276269
2016-07-21 13:15:55 +00:00
Tobias Grosser 04b909fcca IslExprBuilder: allow to specify an external isl_id to ScopArrayInfo mapping
This is useful for external users using IslExprBuilder, in case they cannot
embed ScopArrayInfo data into their isl_ids, because the isl_ids either already
carry other information or the isl_ids have been created and their user pointers
cannot be updated any more.

llvm-svn: 276268
2016-07-21 13:15:51 +00:00
Tobias Grosser 9d12d8ade3 BlockGenerator: remove dead instructions in normal statements
This ensures that no trivially dead code is generated. This is not only cleaner,
but also avoids troubles in case code is generated in a separate function and
some of this dead code contains references to values that are not available.
This issue may happen, in case the memory access functions have been updated
and old getelementptr instructions remain in the code. With normal Polly,
a test case is difficult to draft, but the upcoming GPU code generation can
possibly trigger such problems. We will later extend this dead-code elimination
to region and vector statements.

llvm-svn: 276263
2016-07-21 11:48:36 +00:00
Tobias Grosser 212469e0ed tests: make test cases more robust using regexp
llvm-svn: 276262
2016-07-21 11:48:31 +00:00
Tobias Grosser 903eefd1f2 tests: fix order of memory accesses to ensure import succeeds
It seems the order in which we generated memory accesses changed such that
the import of these updated memory accesses failed for the 'loop3' statement
in this test case. Unfortunately, the existing CHECK lines were not strict
enough to catch this. Hence, besides fixing the order of the memory access
lines we also ensure that the memory access changes are both clearly visibly
and well checked.

llvm-svn: 276247
2016-07-21 07:12:17 +00:00
Tobias Grosser 9ea152714a JScop: Factor out importContext [NFC]
This makes the structure of the code clearer and reduces the size of runOnScop.

We also adjust the coding style to the latest LLVM style guide.

llvm-svn: 276246
2016-07-21 06:56:33 +00:00
Tobias Grosser dbe34f7c58 JScop: Factor out importContext [NFC]
This makes the structure of the code clearer and reduces the size of runOnScop.

We also adjust the coding style to the latest LLVM style guide.

llvm-svn: 276245
2016-07-21 06:56:31 +00:00
Tobias Grosser c602d3bc84 JScop: Factor out importSchedule [NFC]
This makes the structure of the code clearer and reduces the size of runOnScop.

We also adjust the coding style to the latest LLVM style guide.

llvm-svn: 276244
2016-07-21 06:56:28 +00:00
Tobias Grosser 9ec4f95234 Update isl to isl-0.17.1-191-g540b2fd
This update resolves a bug in computing lexicographic minima/maxima.

llvm-svn: 276138
2016-07-20 16:53:07 +00:00
Tobias Grosser f533571fd2 Update isl to isl-0.17.1-171-g233f589
This fixes an issue with equality detection that resulted in an assertion
being triggered during coalescing.

llvm-svn: 276094
2016-07-20 07:52:42 +00:00
Tobias Grosser 2d58a64e7f GPGPU: Bail out of scops with hoisted invariant loads
This is currently not supported and will only be added later. Also update the
test cases to ensure no invariant code hoisting is applied.

llvm-svn: 275987
2016-07-19 15:56:25 +00:00
Tobias Grosser 22117a8913 GPGPU: Disable invariant load hoisting for GPU code generation
This simplifies the upcoming patches to add code generation for ScopStmts. Load
hoisting support will later be added in a separate commit. This commit will
be implicitly tested by the subsequent GPGPU changes.

llvm-svn: 275969
2016-07-19 11:13:58 +00:00
Tobias Grosser f95c5cd06a test: Add missing 'REQUIRES' line
llvm-svn: 275962
2016-07-19 07:47:27 +00:00
Tobias Grosser 92852dbe78 test: Add missing 'REQUIRES' line
llvm-svn: 275960
2016-07-19 07:39:54 +00:00
Tobias Grosser 5260c041ea GPGPU: Emit in-kernel synchronization statements
We use this opportunity to further classify the different user statements that
can arise and add TODOs for the ones not yet implemented.

llvm-svn: 275957
2016-07-19 07:33:16 +00:00
Tobias Grosser 59ab070523 GPGPU: generate control flow within the kernel
llvm-svn: 275956
2016-07-19 07:33:11 +00:00
Tobias Grosser c84a1995fe GPGPU: add scop parameters to kernel arguments
llvm-svn: 275955
2016-07-19 07:33:06 +00:00
Tobias Grosser f6044bd0ef GPGPU: add host iterators to kernel arguments
llvm-svn: 275954
2016-07-19 07:32:55 +00:00
Tobias Grosser 472f9654c8 GPGPU: add intrinsic functions to obtain a kernels thread and block ids
llvm-svn: 275953
2016-07-19 07:32:44 +00:00
Tobias Grosser 32837fe313 GPGPU: create kernel function skeleton
Create for each kernel a separate LLVM-IR module containing a single function
marked as kernel function and taking one pointer for each array referenced
by this kernel. Add debugging output to verify the kernels are generated
correctly.

llvm-svn: 275952
2016-07-19 07:32:38 +00:00
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 1fb9b64dc0 GPGPU: Pull implementation out of class definition
This will allow us to see the full class definition even after we add
non-trivial implementations of the different member functions.

llvm-svn: 275797
2016-07-18 15:44:25 +00:00
Tobias Grosser 05aad8dbcd test: Add missing 'REQUIRES' line
llvm-svn: 275784
2016-07-18 12:02:44 +00:00
Tobias Grosser 38fc0aed08 GPGPU: Create host control flow
Create LLVM-IR for all host-side control flow of a given GPU AST. We implement
this by introducing a new GPUNodeBuilder class derived from IslNodeBuilder.  The
IslNodeBuilder will take care of generating all general-purpose ast nodes, but
we provide our own createUser implementation to handle the different GPU
specific user statements. For now, we just skip any user statement and only
generate a host-code sceleton, but in subsequent commits we will add handling of
normal ScopStmt's performing computations, kernel calls, as well as host-device
data transfers. We will also introduce run-time check generation and LICM in
subsequent commits.

llvm-svn: 275783
2016-07-18 11:56:39 +00:00
Tobias Grosser cda19c230c GPGPU: Abort if any dummy function is called
This ensures that accidental calls to these functions will break loadly instead
of corrupting the stack with invalid return values.

These functions have been introduced earlier as replacement of pet and parts of
ppcg which we will never use and consequently have not been imported or compiled
into Polly.

llvm-svn: 275680
2016-07-16 07:30:27 +00:00
Tobias Grosser 2025173494 GPGPU: Format statements scheduled on the host ourselves
Otherwise ppcg would try to call into pet functionality that this not available,
which obviously will cause trouble. As we can easily print these statements
ourselves, we just do so.

llvm-svn: 275579
2016-07-15 17:12:41 +00:00
Tobias Grosser 2341fe9e76 GPGPU: Use schedule whole components for scheduler
This option increases the scalability of the scheduler and allows us to remove
the 'gisting' workaround we introduced in r275565 to handle a more complicated
test case. Another benefit of using this option is also that the generated
code looks a lot more streamlined.

Thanks to Sven Verdoolaege for reminding me of this option.

llvm-svn: 275573
2016-07-15 16:15:47 +00:00
Tobias Grosser e4725437e8 GPGPU: Drop domain constraints from flow dependences
This works around a shortcoming of the isl scheduler, which even for some
smaller test cases does not terminate in case domain constraints are part
of the flow dependences.

llvm-svn: 275565
2016-07-15 14:43:04 +00:00
Tobias Grosser 6293ba6973 GPGPU: Add memory reference tag ids to tagged accesses
It seems we forgot to actually add the memory access ids to the tagged accesses,
but instead just tagged the accesses with empty isl_ids. This issue was found
by inspection and without code generation it is difficult to test just by
itself. We fix it for now without test case and expect our code generation
tests to cover this later on.

llvm-svn: 275557
2016-07-15 12:44:27 +00:00
Tobias Grosser cfa0361d35 GPGPU: Do not check for hidden declarations
We do not have them in Polly and the code to check for them is directly
referring to pet data structures which we do not have available.

This commit avoids undefined behavior. As such issues are difficult to
reproduce, this commit comes without a test case.

llvm-svn: 275553
2016-07-15 11:42:53 +00:00
Tobias Grosser 225dca7838 GPGPU: Test scalar/array types i1/i3/i8/i32/i60/i64/i80/i120/i128/i3000
Arrays with integer base type are similar to arrays with floating point types,
with the exception that LLVM's integer types can take some odd values. We
add a selection of different values to make sure we correctly round these
types when necessary.

References to scalar integer types are special, as we currently do not model
these types as array accesses as they are considered 'synthesizable' by Polly.
As a result, we do not generate explicit data-transfers for them, but instead
will need to keep track of all references to 'synthesizable' values separately.

At the current stage, this is only visible by missing host-to-device
data-transfer calls. In the future, we will also require special code generation
strategies.

llvm-svn: 275551
2016-07-15 11:33:47 +00:00
Tobias Grosser 8d9dcfc592 GPGPU: Test scalar parameters of type half/float/double/fp128/x86_fp80/ppc_fp128
We currently only test that the code structure we generate for these scalar
parameters is correct and we add these types to make sure later code generation
additions have sufficient test coverage.

In case some of these types cannot be mapped due to missing hardware support
on the GPU some of these test cases may need to be updated later on.

llvm-svn: 275548
2016-07-15 11:12:29 +00:00
Tobias Grosser 2d010daf85 GPGPU: Make sure scops with more than one array work
We use this opportunity to add a test case containing a scalar parameter.

llvm-svn: 275547
2016-07-15 10:51:14 +00:00
Tobias Grosser b307ed4d08 GPGPU: Free options to avoid memory leak
ppcg does not free the option structs for us. To avoid a memory leak we do this
ourselves.

llvm-svn: 275546
2016-07-15 10:32:22 +00:00
Tobias Grosser a56f8f8e58 GPGPU: Shorten ppcg include paths to avoid conflict with cuda.h
Instead of directly linking to ppcg's main source directory, we link to the
parent director. This allows us to access ppcg's include files with
'ppcg/cuda.h' and avoids a conflict with NVIDIA's cuda.h header.

Also drop an include directory that is currently not used.

llvm-svn: 275536
2016-07-15 07:50:36 +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 eeb8a95ac5 GPGPU: Use CHECK-NEXT to harden test cases
A sequence of CHECK lines allows additional statements to appear in the
output of the tested program without any test failures appearing. As we do
not want this to happen, switch this test case to use CHECK-NEXT.

llvm-svn: 275534
2016-07-15 07:05:49 +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 4eaedde530 GPGPU: Use a tile size of 32 by default
The tile size was previously uninitialized. As a result, it was often zero (aka.
no tiling), which is not what we want in general. More importantly, there was
the risk for arbitrary tile sizes to be choosen, which we did not observe, but
which still is highly problematic.

llvm-svn: 275418
2016-07-14 14:14:02 +00:00