Commit Graph

1619 Commits

Author SHA1 Message Date
Michael Kruse 82a1c7de09 Make TempScopInfo a RegionPass
This modifies the order in which Polly passes are executed.

Assuming a function has two scops (A and B), the order before was:

FunctionPassManager
  ScopDetection
  IndependentBlocks
  TempScopInfo for A and B
  RegionPassManager
    ScopInfo for A
    DependenceInfo for A
    IslScheduleOptimizer for A
    IslAstInfo for A
    CodeGeneration for A
    ScopInfo for B
    DependenceInfo for B
    IslScheduleOptimizer for B
    IslAstInfo for B
    CodeGeneration for B

After this patch:

FunctionPassManager
  ScopDetection
  IndependentBlocks
  RegionPassManager
    TempScopInfo for A
    ScopInfo for A
    DependenceInfo for A
    IslScheduleOptimizer for A
    IslAstInfo for A
    CodeGeneration for A
    TempScopInfo for B
    ScopInfo for B
    DependenceInfo for B
    IslScheduleOptimizer for B
    IslAstInfo for B
    CodeGeneration for B

TempScopInfo for B might store information and references to the IR
that CodeGeneration for A might modify. Changing the order ensures that
the IR is not modified from the analysis of a region until code
generation.

Reviewers: grosser

Differential Revision: http://reviews.llvm.org/D12014

llvm-svn: 245091
2015-08-14 20:10:27 +00:00
Tobias Grosser bccd1b0af0 Fix test case after recent LLVM changes
llvm-svn: 244954
2015-08-13 21:08:15 +00:00
Tobias Grosser 7e584168ab Manuallt simplify test case
llvm-svn: 244907
2015-08-13 16:33:32 +00:00
Michael Kruse 5a8ddd74a5 Remove unimplemented private method getTempScop
llvm-svn: 244906
2015-08-13 16:28:04 +00:00
Michael Kruse 2da3872a99 Add test case for SCEV synthesizing
CodeGenerator currently tries to generate code for a parameter using
values values that are computed later.

llvm-svn: 244903
2015-08-13 15:53:53 +00:00
Tobias Grosser 0164b8ff70 Enable code generation of scalar dependences from function arguments
This change extends the BlockGenerator to not only allow Instructions as
base elements of scalar dependences, but any llvm::Value. This allows
us to code-generate scalar dependences which reference function arguments, as
they arise when moddeling read-only scalar dependences.

llvm-svn: 244874
2015-08-13 08:07:39 +00:00
Tobias Grosser 72e8f5999e Make sure we increment the reference counter when passing out the isl_pw_aff
llvm-svn: 244758
2015-08-12 15:45:41 +00:00
Tobias Grosser d46fd5ed95 Make the dimension sizes of in ScopArrayInfo available as isl_pw_affs
This makes it easier to reason about the size of an array dimension with isl.

llvm-svn: 244757
2015-08-12 15:27:16 +00:00
Johannes Doerfert 5451544a17 Remove identity operation from SCEVAffinator
llvm-svn: 244736
2015-08-12 10:58:01 +00:00
Johannes Doerfert 33d98a3f45 Revert r244459 'Make StmtSet a list'
llvm-svn: 244735
2015-08-12 10:55:52 +00:00
Johannes Doerfert 3f0a2a325f Add caching to the SCEVAffinator
While the compile time is not affected by this patch much it will
  allow us to look at all translated expressions after the SCoP is build
  in a convenient way. Additionally, bigger SCoPs or SCoPs with
  repeating complicated expressions might benefit from the cache later
  on.

Reviewers: grosser, Meinersbur

Subscribers: #polly

Differential Revision: http://reviews.llvm.org/D11975

llvm-svn: 244734
2015-08-12 10:46:33 +00:00
Johannes Doerfert f363bfb730 [FIX] Typo
llvm-svn: 244733
2015-08-12 10:45:20 +00:00
Johannes Doerfert 916736ef73 Expose the SCEVAffinator and make it a member of a SCoP (cont'd)
Added missing documentation and linked to the correct revision.

Differential Revision: http://reviews.llvm.org/D11974

llvm-svn: 244731
2015-08-12 10:28:45 +00:00
Johannes Doerfert 574182d394 Expose the SCEVAffinator and make it a member of a SCoP.
This change has three major advantages:
    - The ScopInfo becomes smaller.
    - It allows to use the SCEVAffinator from outside the ScopInfo.
    - A member object allows state which in turn allows e.g., caching.

Differential Revision: http://reviews.llvm.org/D9099

llvm-svn: 244730
2015-08-12 10:19:50 +00:00
Johannes Doerfert 9e0daff91e Make arc unit work with ninja builds
In order to find the llvm-obj directory it has to be (or a soft link
  to it) at one of the following locations:

    ${POLLY_SRC_DIR}/build
    ${POLLY_SRC_DIR}.build
    ${POLLY_SRC_DIR}-build
    s/${POLLY_SRC_DIR}/src/build

  Alternatively, the environment variable $POLLY_BIN_DIR can point to it.

llvm-svn: 244727
2015-08-12 09:02:20 +00:00
Johannes Doerfert a7ba98caa2 Adjusted arc linter config for modern version of arcanist
llvm-svn: 244726
2015-08-12 09:01:16 +00:00
Tobias Grosser a77cea49d1 Always model PHI nodes in scop (if not in same nonaffine subregion)
Before we only modeled PHI nodes if at least one incoming basic block was itself
part of the region, now we always model them except if all of their operands are
part of a single non-affine subregion which we model as a black-box.

This change only affects PHI nodes in the entry block, that have exactly one
incoming edge. Before this change, we did not model them and as a result code
generation would not know how to code generate them. With this change, code
generation can code generate them like any other PHI node.

This issue was exposed by r244606. Before this change simplifyRegion would have
moved these PHI nodes out of the SCoP, so we would never have tried to code
generate them. We could implement this behavior again, but changing the IR
after the scop has been modeled and transformed always adds a risk of us
invalidating earlier analysis results. It seems more save and overall also more
consistent to just model and handle this one-entry-edge PHI nodes like any
other PHI node in the scop.

Solution proposed by:  Michael Kruse  <llvm@meinersbur.de>

llvm-svn: 244721
2015-08-12 07:48:54 +00:00
Michael Kruse fba24b3775 Add another test case with trival PHI in entry BB
This one was extracted from the test-suite's pifft and caused a
miscompilation because a scalar was not written to its alloca address.

llvm-svn: 244720
2015-08-12 07:34:55 +00:00
Michael Kruse 4f9caf2b28 Add test case for entry node with trivial PHI
This is a break-down from the test-suite's oggenc where Polly currently
crashes. 

llvm-svn: 244692
2015-08-11 23:09:19 +00:00
Michael Kruse 9c483c5834 Assign regions to all BBs from CodeGeneration
In order to have a valid region analysis, we assign all newly created blocks to the parent of the scop's region. This is correct for any pre-existing regions (including the scop's region and its parent), but does not discover any region inside the generated code. For Polly this is not necessary because we do not want to re-run Polly on its own generated code anyway.

Reviewers: grosser

Part of Differential Revision: http://reviews.llvm.org/D11867

llvm-svn: 244608
2015-08-11 14:47:37 +00:00
Michael Kruse 22370884c4 Revise the simplification of regions
The previous code had several problems:

For newly created BasicBlocks it did not (always) call RegionInfo::setRegionFor in order to update its analysis. At the moment RegionInfo does not verify its BBMap, but will in the future. This is fixed by determining the region new BBs belong to and set it accordingly. The new executeScopConditionally() requires accurate getRegionFor information. 

Which block is created by SplitEdge depends on the incoming and outgoing edges of the blocks it connects, which makes handling its output more difficult than it needs to be. Especially for finding which block has been created an to assign a region to it for the setRegionFor problem above. This patch uses an implementation for splitEdge that always creates a block between the predecessor and successor. simplifyRegion has also been simplified by using SplitBlockPredecessors instead of SplitEdge. Isolating the entries and exits have been refectored into individual functions.

Previously simplifyRegion did more than just ensuring that there is only one entering and one exiting edge. It ensured that the entering block had no other outgoing edge which was necessary for executeScopConditionally(). Now the latter uses the alternative splitEdge implementation which can handle this situation so simplifyRegion really only needs to simplify the region.

Also, executeScopConditionally assumed that there can be no PHI nodes in blocks with one incoming edge. This is wrong and LCSSA deliberately produces such edges. However, previous passes ensured that there can be no such PHIs in exit nodes, but which will no longer hold in the future.

The new code that the property that it preserves the identity of region block (the property that the memory address of the BasicBlock containing the instructions remains the same; new blocks only contain PHI nodes and a terminator), especially the entry block. As a result, there is no need to update the reference to the BasicBlock of ScopStmt that contain its instructions because they have been moved to other basic blocks.

Reviewers: grosser

Part of Differential Revision: http://reviews.llvm.org/D11867 

llvm-svn: 244606
2015-08-11 14:39:21 +00:00
Michael Kruse 23d0e83aa3 Introduce splitBlock and use it in splitEntryBlockForAlloca
RegionInfo::splitBlock did not update RegionInfo correctly. Specifically, it tried to make the new block the entry block if possible. This breaks for nested regions that have edges to the old block. 

We simply do not change the entry block. Updating RegionInfo becomes trivial as both block will always be in the same region.

splitEntryBlockForAlloca makes use of the new splitBlock.

Reviewers: grosser

Part of Differential Revision: http://reviews.llvm.org/D11867

llvm-svn: 244600
2015-08-11 14:04:06 +00:00
Tobias Grosser 6e3ba33b07 Update isl to isl-0.15-117-ge42acfe
Besides other changes this version of isl contains a fundamental fix to memory
corruption issues we have seen with imath-32 backed isl_ints.

This update also contains a fix that ensures that the schedule-tree based
version of isl's dependence analysis takes the domain of the schedule into
account.

llvm-svn: 244585
2015-08-11 11:31:18 +00:00
Tobias Grosser c186ac7aea BlockGenerator: Do not store 'store' statements in BBMap
A store statement has no return value and can consequently not be referenced
from another statement.

llvm-svn: 244576
2015-08-11 08:13:15 +00:00
Michael Kruse 874b5c2197 Correct non-existing past participle of split in filename
llvm-svn: 244478
2015-08-10 18:37:34 +00:00
Johannes Doerfert d6c30160e7 Make StmtSet a list.
With a deque (or any other sequential container) it is not sound to
  take the address of the elements when the container is still under
  construction. With a pointer based container this is save.

llvm-svn: 244459
2015-08-10 16:47:20 +00:00
Michael Kruse 4adb0279a8 Add test case with PHI node in exit block
The PHI node with multiple incoming edges from inside the region.

Thanks Tobias for coming up with the example. 

llvm-svn: 244456
2015-08-10 16:17:59 +00:00
Michael Kruse 1d3c9b54fb Remove leftover comment
The function to which this commit applies has been removed in a
previous commit.

llvm-svn: 244450
2015-08-10 15:07:16 +00:00
Michael Kruse 046dde40c5 [Polly] Refactor buildScop
Summary: The extracted function buildBBScopStmt will be needed later to be invoked individually on the region's exit block.

Reviewers: grosser, jdoerfert

Subscribers: jdoerfert, llvm-commits, pollydev

Projects: #polly

Differential Revision: http://reviews.llvm.org/D11878

llvm-svn: 244443
2015-08-10 13:01:57 +00:00
Michael Kruse fd613545cb [Polly] Remove dead code in IndependentBlocks
Summary: The splitExitBlock function is never called. Going to replace its functionality in successive patches that do not modify the IR.

Reviewers: grosser

Subscribers: pollydev

Projects: #polly

Differential Revision: http://reviews.llvm.org/D11865

llvm-svn: 244404
2015-08-08 20:31:20 +00:00
Michael Kruse 9bb8ef03a2 Add an assertion
Check whether a block is a direct predecessor.

llvm-svn: 244401
2015-08-08 18:10:54 +00:00
Michael Kruse 27aae88d76 Do not use -fvisibility option with Visual C
It doesn't know the option and prints a warning. 

llvm-svn: 244363
2015-08-07 22:16:44 +00:00
Tanya Lattner 62dba3b7b6 Update links to lists.llvm.org.
llvm-svn: 244009
2015-08-05 04:19:04 +00:00
Tobias Grosser dcc3b435ab Optionally model read-only scalars
Even though read-only accesses to scalars outside of a scop do not need to be
modeled to derive valid transformations or to generate valid sequential code,
but information about them is useful when we considering memory footprint
analysis and/or kernel offloading.

llvm-svn: 243981
2015-08-04 13:54:20 +00:00
Tobias Grosser fbe7a2e841 Run ScopInfo after the ScopViewers
This change is required to see the detected scops even in cases where there is
no other ScopInfo user after the ScopViewers. Before this change, when
running with -polly-optimizer=none -polly-code-generator=none detected scops
have not been shown.

llvm-svn: 243971
2015-08-04 11:49:39 +00:00
Tobias Grosser ac3a95f347 Do not add spaces into memory-access identifiers
llvm-svn: 243889
2015-08-03 17:53:21 +00:00
Duncan P. N. Exon Smith 20b50f2b2a Update testcases after LLVM r243885
llvm-svn: 243887
2015-08-03 17:28:43 +00:00
Tobias Grosser 14e67e43a7 Add option -polly-view-only
If set, this option instructs -view-scops and -polly-show to only print
functions that contain the specified string in their name. This allows to
look at the scops of a specific function in a large .ll file, without flooding
the screen with .dot graphs.

llvm-svn: 243882
2015-08-03 16:39:56 +00:00
Tobias Grosser 6213913244 Use the branch instruction to define the location of a PHI-node write
We use the branch instruction as the location at which a PHI-node write takes
place, instead of the PHI-node itself. This allows us to identify the
basic-block in a region statement which is on the incoming edge of the PHI-node
and for which the write access was originally introduced. As a result we can,
during code generation, avoid generating PHI-node write accesses for basic
blocks that do not preceed the PHI node without having to look at the IR
again.

This change fixes a bug which was introduced in r243420, when we started to
explicitly model PHI-node reads and writes, but dropped some additional checks
that where still necessary during code generation to not emit PHI-node writes
for basic-blocks that are not on incoming edges of the original PHI node.
Compared to the code before r243420 the new code does not need to inspect the IR
any more and we also do not generate multiple redundant writes.

llvm-svn: 243852
2015-08-02 16:17:41 +00:00
Tobias Grosser d2d15a8c65 Dependences: Zero pad the schedule map
The schedule map we derive from a schedule tree map may map statements into
schedule spaces of different dimensionality. This change adds zero padding
to ensure just a single schedule space is used and the translation from
a union_map to an isl_multi_union_pw_aff does not fail.

llvm-svn: 243849
2015-08-02 13:30:33 +00:00
Tobias Grosser 45e7944bcf Only use instructions as insert locations for SCEVExpander
SCEVExpander, which we are using during code generation, only allows
instructions as insert locations, but breaks in case BasicBlock->end() iterators
are passed to it due to it trying to obtain the basic block in which code should
be generated by calling Instruction->getParent(), which is not defined for
->end() iterators.

This change adds an assert to Polly that ensures we only pass valid instructions
to SCEVExpander and it fixes one case, where we used IRBuilder->SetInsertBlock()
to set an ->end() insert location which was later passed to SCEVExpander.

In general, Polly is always trying to build up the CFG first, before we actually
insert instructions into the CFG sceleton. As a result, each basic block should
already have at least one branch instruction before we start adding code. Hence,
always requiring the IRBuilder insert location to be set to a real instruction
should always be possible.

Thanks Utpal Bora <cs14mtech11017@iith.ac.in> for his help with test case
reduction.

llvm-svn: 243830
2015-08-01 09:07:57 +00:00
Tobias Grosser d3f21833b9 Fix typo
llvm-svn: 243829
2015-08-01 06:26:51 +00:00
Duncan P. N. Exon Smith c51714a0c6 Fix polly tests after LLVM IR change in r243774
llvm-svn: 243801
2015-07-31 23:58:50 +00:00
Michael Kruse 471a5e3388 Move computations out of constructors
It is common practice to keep constructors lightweight. The reasons
include:

- The vtable during the constructor's execution is set to the static
type of the object, not to the vtable of the derived class. That is,
method calls behave differently in constructors and ordinary methods.
This way it is possible to call unimplemented methods of abstract
classes, which usually results in a segmentation fault.

- If an exception is thrown in the constructor, the destructor is not
called, potentially leaking memory.

- Code in constructors cannot be called in a regular way, e.g. from
non-constructor methods of derived classes.

- Because it is common practice, people may not expect the constructor
to do more than initializing data and skip them when looking for bugs.

Not all of these are applicable to LLVM (e.g. exceptions are disabled).

This patch refactors out the computational work in the constructors of
Scop and IslAst into regular init functions and introduces static
create-functions as replacement. 

Differential revision: http://reviews.llvm.org/D11491

Reviewers: grosser, jdoerfert
llvm-svn: 243677
2015-07-30 19:27:04 +00:00
Tobias Grosser 80e237bd53 Do not detect scops that are delinearized to arrays with "undef" size
Such codes are not interesting to optimize and most likely never appear in the
normal compilation flow. However, they show up during test case reduction with
bugpoint and trigger -- without this change -- an assert in
polly::MemoryAccess::foldAccess(). It is better to detect them in
ScopDetection itself and just bail out.

Contributed-by:  Utpal Bora  <cs14mtech11017@iith.ac.in>

Reviewers: grosser

Subscribers: pollydev, llvm-commits

Differential Revision: http://reviews.llvm.org/D11425

llvm-svn: 243515
2015-07-29 13:52:05 +00:00
Tobias Grosser d20aba7047 Remove some dead code
llvm-svn: 243465
2015-07-28 19:16:46 +00:00
Tobias Grosser 2be13913bb Do not end lines with '\'
This fixes 'warning: multi-line comment [-Wcomment]'

llvm-svn: 243464
2015-07-28 19:16:42 +00:00
Tobias Grosser b241d928bd Rewrite getPrevectorMap using schedule trees operations
Schedule trees are a lot easier to work with, for both humans and machines. For
humans the more structured schedule representation is easier to reason about.
Together with the more abstract isl programming interface this can result in a
lot cleaner code (see this changeset). For machines, the structured schedule and
the fact that we now use explicit piecewise affine expressions instead of
integer maps makes it easier to generate code from this schedule tree. As a
result, we can already see a slight compile-time improvement -- for 3mm from
0m0.593s to 0m0.551s seconds (-7 %). More importantly, future optimizations such
as full-partial tile separation will most likely result in more streamlined code
to be generated.

Contributed-by: Roman Gareev <gareevroman@gmail.com>
llvm-svn: 243458
2015-07-28 18:03:36 +00:00
Tobias Grosser 922452285a Keep track of ScopArrayInfo objects that model PHI node storage
Summary:
When translating PHI nodes into memory dependences during code generation we
require two kinds of memory. 'Normal memory' as for all scalar dependences and
'PHI node memory' to store the incoming values of the PHI node. With this
patch we now mark and track these two kinds of memories, which we previously
incorrectly marked as a single memory object.

Being aware of PHI node storage makes code generation easier, as we do not need
to guess what kind of storage a scalar reference requires. This simplifies the
code nicely.

Reviewers: jdoerfert

Subscribers: pollydev, llvm-commits

Differential Revision: http://reviews.llvm.org/D11554

llvm-svn: 243420
2015-07-28 14:53:44 +00:00
Tobias Grosser 9696a3f903 Do not compile GPU library with sanitizers
llvm-svn: 243411
2015-07-28 12:51:23 +00:00