Commit Graph

610 Commits

Author SHA1 Message Date
Tobias Grosser
296fe2e2ad [ScopInfo] Use original base address when building ScopArrayInfo [NFC]
This change clarfies that we want to indeed use the original base address
when creating the ScopArrayInfo that corresponds to a given memory access.

This change prepares for https://reviews.llvm.org/D28518.

llvm-svn: 294734
2017-02-10 10:09:46 +00:00
Tobias Grosser
5db171a9da [ScopInfo] Use getAccessValue to obtain the accessed value
This replaces the use of getOriginalAddrPtr, a value that is stored in
ScopArrayInfo and might at some point not be unique any more. However, the
access value is defined to be unique.

This change is an update on r294576, which only clarified that we need the
original memory access, but where we still remained dependent to have one base
pointer per scop.

This change removes unnecessary uses of MemoryAddress::getOriginalBaseAddr() in
preparation for https://reviews.llvm.org/D28518.

llvm-svn: 294733
2017-02-10 10:09:44 +00:00
Tobias Grosser
e24b7b929d [ScopInfo] Use MemoryAccess::getScopArrayInfo() interface to access Array [NFC]
By using the public interface MemoryAccess::getScopArrayInfo() we avoid the
direct access to the ScopArrayInfoMap and as a result also do not need to
use the BasePtr as key. This change makes the code cleaner.

The const-cast we introduce is a little ugly. We may consider to drop const
correctness for getScopArrayInfo() at some point.

This change removes unnecessary uses of MemoryAddress::getBaseAddr() in
preparation for https://reviews.llvm.org/D28518.

llvm-svn: 294655
2017-02-09 23:24:57 +00:00
Tobias Grosser
9c7d181c92 [ScopInfo] Use types instead of 'auto' and use more descriptive variable names [NFC]
LLVM's coding conventions suggest to use auto only in obvious cases. Hence,
we move this code to actually declare the types used. We also replace the
variable name 'SAI', with the name 'Array', as this improves readability.

llvm-svn: 294654
2017-02-09 23:24:54 +00:00
Tobias Grosser
889830b1c5 [ScopInfo] Use ScopArrayInfo instead of base address
When building alias groups, we sort different ScopArrays into unrelated groups.
Historically we identified arrays through their base pointer, as no
ScopArrayInfo class was yet available. This change changes the alias group
construction to reference arrays through their ScopArrayInfo object.

This change removes unnecessary uses of MemoryAddress::getBaseAddr() in
preparation for https://reviews.llvm.org/D28518.

llvm-svn: 294649
2017-02-09 23:12:22 +00:00
Tobias Grosser
be372d5a04 [ScopInfo] Expect the OriginalBaseAddr when looking at underlying instructions [NFC]
During SCoP construction we sometimes inspect the underlying IR by looking at
the base address of a MemoryAccess. In such cases, we always want the original
base address. Make this clear by calling getOriginalBaseAddr().

This is a non-functional change as getBaseAddr maps to getOriginalBaseAddr
at the moment.

This change removes unnecessary uses of MemoryAddress::getBaseAddr() in
preparation for https://reviews.llvm.org/D28518.

llvm-svn: 294576
2017-02-09 10:11:58 +00:00
Tobias Grosser
e0e0e4d4f6 [ScopInfo] Remove unnecessary indirection through SCEV [NFC]
The base address of a memory access is already an llvm::Value. Hence, there is
no need to go through SCEV, but we can directly work with the llvm::Value.

Also use 'Value *' instead of 'auto' for cases where the type is not obvious.

llvm-svn: 294575
2017-02-09 09:34:46 +00:00
Tobias Grosser
ff40087a6a Update to recent formatting changes
llvm-svn: 293756
2017-02-01 10:12:09 +00:00
Tobias Grosser
e1ff0cf2eb Relax assert when setting access functions with invariant base pointers
Summary:
Instead of forbidding such access functions completely, we verify that their
base pointer has been hoisted and only assert in case the base pointer was
not hoisted.

I was trying for a little while to get a test case that ensures the assert is
correctly fired in case of invariant load hoisting being disabled, but I could
not find a good way to do so, as llvm-lit immediately aborts if a command
yields a non-zero return value. As we do not generally test our asserts,
not having a test case here seems OK.

This resolves http://llvm.org/PR31494

Suggested-by: Michael Kruse <llvm@meinersbur.de>

Reviewers: efriedma, jdoerfert, Meinersbur, gareevroman, sebpop, zinob, huihuiz, pollydev

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D28798

llvm-svn: 292213
2017-01-17 12:00:42 +00:00
Eli Friedman
71329901ea Tidy up getFirstNonBoxedLoopFor [NFC]
Move the function getFirstNonBoxedLoopFor which is used in ScopBuilder
and in ScopInfo to Support/ScopHelpers to make it reusable in other
locations. No functionality change.

Patch by Sameer Abu Asal.

Differential Revision: https://reviews.llvm.org/D28754

llvm-svn: 292168
2017-01-16 22:54:29 +00:00
Tobias Grosser
0032d87337 ScopInfo: document base pointers in alias-checks must be invariant [NFC]
Before this change, this code has been mixed with a check for non-affine
loops (and when originally introduce was also duplicated). By creating
a separate loop and explicitly documenting this property, the current
behavior becomes a lot more clear.

llvm-svn: 292140
2017-01-16 15:49:14 +00:00
Tobias Grosser
f3c145f2ab ScopInfo: Improve comments in buildAliasGroup [NFC]
llvm-svn: 292139
2017-01-16 15:49:09 +00:00
Tobias Grosser
77f3257b41 ScopInfo: split out construction of a single alias group [NFC]
The loop body in buildAliasGroups is still too large to easily scan it. Hence,
we split the loop body out into a separate function to improve readability.

llvm-svn: 292138
2017-01-16 15:49:07 +00:00
Tobias Grosser
e95222343c ScopInfo: Do not modify the original alias group [NFC]
Instead of modifying the original alias group and repurposing it as read-write
access group when splitting accesses in read-only and read-write accesses, we
just keep all three groups: the original alias group, the set of read-only
accesses and the set of read-write accesses.  This allows us to remove some
complicated iterator handling and also allows for more code-reuse in
calculateMinMaxAccess.

llvm-svn: 292137
2017-01-16 15:49:04 +00:00
Tobias Grosser
457eb579dd ScopInfo: No need to keep ReadOnlyAccesses in an additional map [NFC]
It seems over time we added an additional map that maps from the base address
of a read-only access to the actual access. However this map is never used.
Drop the creation and use of this map to simplify our alias check generation
code.

llvm-svn: 292126
2017-01-16 14:24:48 +00:00
Tobias Grosser
dba2206b65 ScopInfo: no need to clear alias group explicitly
The alias group will anyhow be cleared at the end of this function and is not
used afterwards. We avoid an explicit clear() call at multiple places to
improve readability of this code.

llvm-svn: 292125
2017-01-16 14:13:01 +00:00
Tobias Grosser
21a059af09 Adjust formatting to commit r292110 [NFC]
llvm-svn: 292123
2017-01-16 14:08:10 +00:00
Tobias Grosser
92fd612c84 ScopInfo: Fold SmallVectors used in alias check generation back into loop [NFC]
Hoisting small vectors out of a loop seems to be a pure performance
optimization, which is unlikely to have great impact in practice. As this
hoisting just increases code-complexity, we fold the SmallVectors back into
the loop.

In subsequent commits, we will further simplify and structure this code, but
we committed this change separately to provide an explanation to make clear
that we purposefully reverted this optimization.

llvm-svn: 292122
2017-01-16 14:08:02 +00:00
Tobias Grosser
e39f9127f9 ScopInfo: Extract out splitAliasGroupsByDomain [NFC]
The function buildAliasGroups got very large. We extract out the splitting
of alias groups to reduce its size and to better document the current behavior.

llvm-svn: 292121
2017-01-16 14:08:00 +00:00
Tobias Grosser
9edcf07e83 ScopInfo: Extract out buildAliasGroupsForAccesses [NFC]
The function buildAliasGroups got very large. We extract out the actual
construction of alias groups to reduce its size and to better document the
current behavior.

llvm-svn: 292120
2017-01-16 14:07:57 +00:00
Hongbin Zheng
6aded2a0e4 Fix compilation on MSVC, NFC
Differential Revision: https://reviews.llvm.org/D28739

llvm-svn: 292067
2017-01-15 16:47:26 +00:00
Tobias Grosser
4d5a917287 Use typed enums to model MemoryKind and move MemoryKind out of ScopArrayInfo
To benefit of the type safety guarantees of C++11 typed enums, which would have
caught the type mismatch fixed in r291960, we make MemoryKind a typed enum.
This change also allows us to drop the 'MK_' prefix and to instead use the more
descriptive full name of the enum as prefix. To reduce the amount of typing
needed, we use this opportunity to move MemoryKind from ScopArrayInfo to a
global scope, which means the ScopArrayInfo:: prefix is not needed. This move
also makes historically sense. In the beginning of Polly we had different
MemoryKind enums in both MemoryAccess and ScopArrayInfo, which were later
canonicalized to one. During this canonicalization we just choose the enum in
ScopArrayInfo, but did not consider to move this shared enum to global scope.

Reviewed-by: Michael Kruse <llvm@meinersbur.de>
Differential Revision: https://reviews.llvm.org/D28090

llvm-svn: 292030
2017-01-14 20:25:44 +00:00
Eli Friedman
c6e3b6f156 Delete stray isl_map_dump call.
llvm-svn: 291521
2017-01-10 01:08:11 +00:00
Tobias Grosser
cdbe5c9d6c Fix some typos in comments
llvm-svn: 291247
2017-01-06 17:30:34 +00:00
Michael Kruse
7037fde427 Remove references to AssumptionCache. NFC.
The AssumptionCache was removed in r289756 after being replaced by the an
addtional operand list of affected values in r289755. The absence of that cache
means that we have now have to manually search for llvm.assume intrinsics as
now done by other passes (LazyValueInfo, CodeMetrics) do not take into
account an llvm::Instruction's user lists (ScalarEvolution).

llvm-svn: 289791
2016-12-15 09:25:14 +00:00
Tobias Grosser
bedef00e2c [ScopInfo] Fold constant coefficients in array dimensions to the right
This allows us to delinearize code such as the one below, where the array
sizes are A[][2 * n] as there are n times two elements in the innermost
dimension. Alternatively, we could try to generate another dimension for the
struct in the innermost dimension, but as the struct has constant size,
recovering this dimension is easy.

   struct com {
     double Real;
     double Img;
   };

   void foo(long n, struct com A[][n]) {
     for (long i = 0; i < 100; i++)
       for (long j = 0; j < 1000; j++)
         A[i][j].Real += A[i][j].Img;
   }

   int main() {
     struct com A[100][1000];
     foo(1000, A);

llvm-svn: 288489
2016-12-02 08:10:56 +00:00
Tobias Grosser
491b799a4d [ScopInfo] Separate construction and finalization of memory accesses [NFC]
After having built memory accesses we perform some additional transformations
on them to increase the chances that our delinearization guesses the right
shape. Only after these transformations, we take the assumptions that the
array shape we predict is such that no out-of-bounds memory accesses arise.

Before this change, the construction of the memory access, the access folding
that improves the represenation for certain parametric subscripts, and taking
the assumption was all done right after a memory access was created. In this
change we split this now into three separate iterations over all memory
accesses. This means only after all memory accesses have been built, we start
to canonicalize accesses, and to take assumptions. This split prepares for
future canonicalizations that must consider all memory accesses for deriving
additional beneficial transformations.

llvm-svn: 288479
2016-12-02 05:21:22 +00:00
Johannes Doerfert
b1d6608430 [NFC] Check for feasibility prior to the profitability check
Feasibility is checked late on its own but early it is hidden behind
the "PollyProcessUnprofitable" guard. This change will make sure we opt
out early if the runtime context is infeasible anyway.

llvm-svn: 288329
2016-12-01 11:12:14 +00:00
Tobias Grosser
278f9e7d27 [ScopInfo] Use SCEVRewriteVisitor to simplify SCEVSensitiveParameterRewriter [NFC]
llvm-svn: 287984
2016-11-26 17:58:40 +00:00
Hongbin Zheng
a8fb73fc0b Split ScopInfo::addScopStmt into two versions. NFC
One for adding statement for region, another one for BB

llvm-svn: 287566
2016-11-21 20:09:40 +00:00
Johannes Doerfert
81aa6e882f [NFC] Adjust naming scheme of statistic variables
Suggested-by: Tobias Grosser <tobias@grosser.es>
llvm-svn: 287347
2016-11-18 14:37:08 +00:00
Johannes Doerfert
c97654681e [FIX] Do not try to hoist memory intrinsic
Since we do not necessarily treat memory intrinsics as non-affine
anymore, we have to check for them explicitly before we try to hoist an
access.

llvm-svn: 287270
2016-11-17 22:11:56 +00:00
Johannes Doerfert
b3265a3612 [NFC] Skip over trivial assumptions
Filter trivial assumptions, thus assume { : } or restrict { : 0 = 1 },
as they clutter the user output as well as the statistics.

llvm-svn: 287269
2016-11-17 22:08:40 +00:00
Johannes Doerfert
cd195326bf [DBG] Collect statistics about taken assumptions
llvm-svn: 287261
2016-11-17 21:41:08 +00:00
Tobias Grosser
f67433abd9 SCEVAffinator: pass parameter-only set to addRestriction if BB=nullptr
Assumptions can either be added for a given basic block, in which case the set
describing the assumptions is expected to match the dimensions of its domain.
In case no basic block is provided a parameter-only set is expected to describe
the assumption.

The piecewise expressions that are generated by the SCEVAffinator sometimes
have a zero-dimensional domain (e.g., [p] -> { [] : p <= -129 or p >= 128 }),
which looks similar to a parameter-only domain, but is still a set domain.

This change adds an assert that checks that we always pass parameter domains to
addAssumptions if BB is empty to make mismatches here fail early.

We also change visitTruncExpr to always convert to parameter sets, if BB is
null. This change resolves http://llvm.org/PR30941

Another alternative to this change would have been to inspect all code to make
sure we directly generate in the SCEV affinator parameter sets in case of empty
domains. However, this would likely complicate the code which combines parameter
and non-parameter domains when constructing a statement domain. We might still
consider doing this at some point, but as this likely requires several non-local
changes this should probably be done as a separate refactoring.

Reported-by: Eli Friedman <efriedma@codeaurora.org>
llvm-svn: 286444
2016-11-10 11:44:10 +00:00
Tobias Grosser
bbaeda3fe5 Do not allow switch statements in loop latches
In r248701 "Allow switch instructions in SCoPs" support for switch statements
has been introduced, but support for switch statements in loop latches was
incomplete. This change completely disables switch statements in loop latches.

The original commit changed addLoopBoundsToHeaderDomain to support non-branch
terminator instructions, but this change was incorrect: it added a check for
BI != null to the if-branch of a condition, but BI was used in the else branch
es well. As a result, when a non-branch terminator instruction is encounted a
nullptr dereference is triggered. Due to missing test coverage, this bug was
overlooked.

r249273 "[FIX] Approximate non-affine loops correctly" added code to disallow
switch statements for non-affine loops, if they appear in either a loop latch
or a loop exit. We adapt this code to now prohibit switch statements in
loop latches even if the control condition is affine.

We could possibly add support for switch statements in loop latches, but such
support should be evaluated and tested separately.

This fixes llvm.org/PR30952

Reported-by: Eli Friedman <efriedma@codeaurora.org>
llvm-svn: 286426
2016-11-10 05:20:29 +00:00
Tobias Grosser
eba86a1208 ScopInfo: only run code needed for ASSERT in DEBUG mode
Suggested-by: Johannes Doerfert
llvm-svn: 286338
2016-11-09 04:24:49 +00:00
Tobias Grosser
744740ad91 ScopInfo: Ensure copy statement memory accesses are correct
Add asserts that verify that the memory accesses of a new copy statement
are defined for all domain instances the copy statement is defined for.

llvm-svn: 286047
2016-11-05 21:02:43 +00:00
Michael Kruse
e1dc387731 [ScopInfo] Fix isl object leak.
Fix return from function without releasing isl objects, which was introduced
in r269055.

llvm-svn: 285924
2016-11-03 15:19:41 +00:00
Eli Friedman
b9c6f01a81 [ScopInfo] Make memset etc. affine where possible.
We don't actually check whether a MemoryAccess is affine in very many
places, but one important one is in checks for aliasing.

Differential Revision: https://reviews.llvm.org/D25706

llvm-svn: 285746
2016-11-01 20:53:11 +00:00
Michael Kruse
426e6f71f8 [ScopInfo] Fix: use raw source pointer.
When adding an llvm.memcpy instruction to AliasSetTracker, it uses the raw
source and target pointers which preserve bitcasts.
MemAccInst::getPointerOperand() also returns the raw target pointers, but
Scop::buildAliasGroups() did not for the source pointer. This lead to mismatches
between AliasSetTracker and ScopInfo on which pointer to use.

Fixed by also using raw pointers in Scop::buildAliasGroups().

llvm-svn: 285071
2016-10-25 13:37:43 +00:00
Mandeep Singh Grang
48e7add80f [polly] Change SmallPtrSet which are being iterated into SmallSetVector
Summary: Otherwise the lack of an iteration order results in non-determinism in codegen.

Reviewers: _jdoerfert, zinob, grosser

Tags: #polly

Differential Revision: https://reviews.llvm.org/D25863

llvm-svn: 284845
2016-10-21 17:29:10 +00:00
Michael Kruse
6ab4476835 [ScopInfo] Add -polly-unprofitable-scalar-accs option.
With this option one can disable the heuristic that assumes that statements with
a scalar write access cannot be profitably optimized. Such a statement instances
necessarily have WAW-dependences to itself. With DeLICM scalar accesses can be
changed to array accesses, which can avoid these WAW-dependence.

llvm-svn: 283233
2016-10-04 17:33:39 +00:00
Michael Kruse
ca7cbcca37 [ScopInfo] Scalar access do not have indirect base pointers.
ScopArrayInfo used to determine base pointer origins by looking up whether the
base pointer is a load. The "base pointer" for scalar accesses is the
llvm::Value being accessed. This is only a symbolic base pointer, it
represents the alloca variable (.s2a or .phiops) generated for it at code
generation.

This patch disables determining base pointer origin for scalars.
A test case where this caused a crash will be added in the next commit. In that
test SAI tried to get the origin base pointer that was only declared later,
therefore not existing. This is probably only possible for scalars used in
PHINode incoming blocks.

llvm-svn: 283232
2016-10-04 17:33:34 +00:00
Tobias Grosser
fe74a7a1f5 GPGPU: Detect read-only scalar arrays ...
and pass these by value rather than by reference.

llvm-svn: 281837
2016-09-17 19:22:18 +00:00
Roman Gareev
b3224adfb6 Perform copying to created arrays according to the packing transformation
This is the fourth 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 copying to created
arrays, which is the last step to implement the packing transformation.

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

Differential Revision: https://reviews.llvm.org/D23260

llvm-svn: 281441
2016-09-14 06:26:09 +00:00
Michael Kruse
19c9d99f45 Use value directly instead of reference. NFC.
The alias to the array element is read-only and a primitive type (pointer),
therefore use the value directly instead of a reference to it.

llvm-svn: 281311
2016-09-13 09:56:05 +00:00
Roman Gareev
f5aff70405 Store the size of the outermost dimension in case of newly created arrays that require memory allocation.
We do not need the size of the outermost dimension in most cases, but if we
allocate memory for newly created arrays, that size is needed.

Reviewed-by: Michael Kruse <llvm@meinersbur.de>

Differential Revision: https://reviews.llvm.org/D23991

llvm-svn: 281234
2016-09-12 17:08:31 +00:00
Tobias Grosser
55a7af7da5 ScopInfo: Make clear that no double-free problem exists
When running the clang static analyser to check for memory issues, this code
originally showed a double free, as the analyser was unable to understand that
isl_set_free always returns NULL and consequently later uses of the isl object
we just freed will never be reached. Without this knowledge, the analyser has
to issue a warning.

We refactor the code to make it clear that for empty maps the current loop
iteration is aborted.

llvm-svn: 280940
2016-09-08 14:08:07 +00:00
Tobias Grosser
2a526feec9 ScopInfo: Add missing __isl_take annotation
llvm-svn: 280923
2016-09-08 11:18:56 +00:00