Summary:
This pass detangles induction variables from functions, which take variables by
reference. Most fortran functions compiled with gfortran pass variables by
reference. Unfortunately a common pattern, printf calls of induction variables,
prevent in this situation the promotion of the induction variable to a register,
which again inhibits any kind of loop analysis. To work around this issue
we developed a specialized pass which introduces separate alloca slots for
known-read-only references, which indicate the mem2reg pass that the induction
variables can be promoted to registers and consquently enable SCEV to work.
We currently hardcode the information that a function
_gfortran_transfer_integer_write does not read its second parameter, as
dragonegg does not add the right annotations and we cannot change old dragonegg
releases. Hopefully flang will produce the right annotations.
Reviewers: Meinersbur, bollu, singam-sanjay
Reviewed By: bollu
Subscribers: mgorny, pollydev, llvm-commits
Tags: #polly
Differential Revision: https://reviews.llvm.org/D36800
llvm-svn: 311066
Summary:
Before, if we fail to parse a jscop file, this will be reported as an
error and importing is aborted. However, this isn't actually strong
enough, since although the import is aborted, the scop has already been
modified and is very likely broken. Instead, make this a hard failure
and throw an LLVM error. This new behaviour requires small changes to
the tests for the legacy pass, namely using `not` to verify the error.
Further, fixed the jscop file for the
base_pointer_load_is_inst_inside_invariant_1 testcase.
Reviewed By: Meinersbur
Split out of D36578.
llvm-svn: 310599
Summary:
I pulled out all functionality into static functions, and use those both
in the legacy passes and in the new ones.
Reviewers: grosser, Meinersbur, bollu
Reviewed By: Meinersbur
Subscribers: llvm-commits, pollydev
Differential Revision: https://reviews.llvm.org/D36578
llvm-svn: 310597
Summary:
During code generation for a Scop we modify the IR of a function.
While this shouldn't affect a Scop in the formal sense, the implementation
caches various information about the IR such as SCEV expressions for bounds or
parameters. This cached information needs to be updated or invalidated. To this
end, SPMUpdater allows passes to report when they've invalidated a Scop to the
PassManager, which will then flush and recompute all Scops. This in turn
invalidates all iterators, so references to Scops shouldn't be held.
Reviewers: grosser, Meinersbur, bollu
Reviewed By: grosser
Subscribers: llvm-commits, pollydev
Differential Revision: https://reviews.llvm.org/D36524
llvm-svn: 310551
We are working towards removing uses of Scop::getStmtFor(BB). In this
patch, we remove dependency of Scop::getStmtFor(Inst) on getStmtFor(BB).
To do so, we introduce a map of instructions to their corresponding scop
statements and use it to get the instructions' statement.
Contributed-by: Nandini Singhal <cs15mtech01004@iith.ac.in>
Differential Revision: https://reviews.llvm.org/D35663
llvm-svn: 310494
This pass is useful to automatically convert a codebase that uses malloc/free
to use their managed memory counterparts.
Currently, rewrite malloc and free to the `polly_{malloc,free}Managed` variants.
A future patch will teach ManagedMemoryRewrite to rewrite global arrays
as pointers to globally allocated managed memory.
Differential Revision: https://reviews.llvm.org/D36513
llvm-svn: 310471
Codegen with -polly-parallel queried the unmapped MemoryAccess, but only
the MemoryKind after mapping is relevant for codegen.
This should fix various fails of the
perf-x86_64-penryn-O3-polly-parallel-fast buildbot.
llvm-svn: 310466
The previous value of "polly-delicm" was forgotten to to be changed when
ForwardOpTree was split from DeLICM.
Thanks to Tobias for noticing!
llvm-svn: 310465
distributeDomain() and filterKnownValInst() are used in a scop
of ForwardOpTree that limits the number of isl operations.
Therefore some isl functions may return null after any operation.
Remove assertion that assume non-null results and handle
isl_*_foreach returning isl::stat::error.
I hope this fixes the crash of the asop buildbot at ihevc_recon.c.
llvm-svn: 310461
Previously, we used to compute this with `elementSizeInBits / 8`. This
would yield an element size of 0 when the array had element size < 8 in
bits.
To fix this, ask data layout what the size in bytes should be.
Differential Revision: https://reviews.llvm.org/D36459
llvm-svn: 310448
We introduce another level of alias metadata to distinguish the individual
non-aliasing accesses that have inter iteration alias-free base pointers
marked with "Inter iteration alias-free" mark nodes. To distinguish two
accesses, the comparison of raw pointers representing base pointers is used.
In case of, for example, ublas's prod function that implements GEMM, and
DeLiCM we can get accesses to same location represented by different raw
pointers. Consequently, we create different alias sets that can prevent
accesses from, for example, being sinked or hoisted.
To avoid the issue, we compare the corresponding SCEV information instead
of the corresponding raw pointers.
Reviewed-by: Tobias Grosser <tobias@grosser.es>
Differential Revision: https://reviews.llvm.org/D35761
llvm-svn: 310380
Currently, only convex isolation sets can be efficiently processed by isl.
Consequently, as a temporary solution, we use a different algorithm for partial
tile isolation that helps to build convex isolation sets in some cases.
Reviewed-by: Tobias Grosser <tobias@grosser.es>
Differential Revision: https://reviews.llvm.org/D36278
llvm-svn: 310374
This allows us to get rid of stores that are overwritten within the very same
basic block, without ever being read beforehand. This simplification is
necessary for delicm to run on pb4's correlation.
llvm-svn: 310369
To do this, we replicate what `CodeGeneration` does. We expose
`markNodeUnreachable` from `CodeGeneration` to `PPCGCodeGeneration`.
Differential Revision: https://reviews.llvm.org/D36457
llvm-svn: 310350
It is possible that partial writes are empty (write is never executed).
In this case, when in PHINode's incoming edge is never taken such that
the incoming write becomes an empty partial write, if enabled. The
issue is that when converting the union_map to an map, it's space
cannot be derived from the union_map itself. Rather, we need to
determine its space independently.
This fixes test-suite's MultiSource/Benchmarks/ASC_Sequoia/CrystalMk.
llvm-svn: 310348
In certain cases delicm might decide to not leave the original array write in
the loop body, but to remove it and instead leave a transformed phi node as
write access. This commit teached the matmul pattern detection to order the
memory accesses according to when the access actually happens and use this
information to detect the new pattern. This makes pattern based matmul
optimization work for 2mm and 3mm in polybench 4 after
polly-position=before-vectorizer has been enabled.
llvm-svn: 310338
Polly has traditionally always been executed at the beginning of the pass
pipeline as LLVM's inliner and DeLICM passes introduced plenty of scalar
dependences which prevented any kind of useful high-level loop optimizations
later in the pass pipeline. With DeLICM now being available, Polly can also
run optimizations when folded into the pass pipeline. This has the benefit
that Polly should now be more effective on C++ code and as an additional bonus,
no additional early canonicalization phase must be run. As a result, Polly
touches the code only if it applies a transformation. Code that does not
benefit from Polly is not touched and consequently will have the very same
execution time as without Polly enabled. Random performance changes, as could
sometimes be observed with polly-position=early are consequently not possible
any more. If performance is changed, this is due to Polly is choosing to
perform a transformation. If this choice is wrong, it can be fixed directly
in Polly.
http://polly.llvm.org/docs/Architecture.html#polly-in-the-llvm-pass-pipeline
llvm-svn: 310319
This allows us to remove more scalar dependences. While this feature is still
rather experimental, we want to give it sufficient test coverage.
llvm-svn: 310314
Two write statements which write into the very same array slot generally are
conflicting. However, in case the value that is written is identical, this
does not cause any problem. Hence, allow such write pairs in this specific
situation.
llvm-svn: 310311
This commit implements the initial version of fully-indexed static
expansion.
```
for(int i = 0; i<Ni; i++)
for(int j = 0; j<Ni; j++)
S: B[j] = j;
T: A[i] = B[i]
```
After the pass, we want this :
```
for(int i = 0; i<Ni; i++)
for(int j = 0; j<Ni; j++)
S: B[i][j] = j;
T: A[i] = B[i][i]
```
For now we bail (fail) in the following cases:
- Scalar access
- Multiple writes per SAI
- MayWrite Access
- Expansion that leads to an access to the original array
Furthermore: We still miss checks for escaping references to the array
base pointers. A future commit will add the missing escape-checks to
stay correct in those cases. The expansion is still locked behind a
CLI-Option and should not yet be used.
Patch contributed by: Nicholas Bonfante <bonfante.nicolas@gmail.com>
Reviewers: simbuerg, Meinersbur, bollu
Reviewed By: Meinersbur
Subscribers: mgorny, llvm-commits, pollydev
Differential Revision: https://reviews.llvm.org/D34982
llvm-svn: 310304
This is an addition to the -polly-optree pass that reuses the array
content analysis from DeLICM to find array elements that contain the
same value as the value loaded when the target statement instance
is executed.
The analysis is now enabled by default.
The known content analysis could also be used to rematerialize any
llvm::Value that was written to some array element, but currently
only loads are forwarded.
Differential Revision: https://reviews.llvm.org/D36380
llvm-svn: 310279
This update is mostly a maintenance update, but also exposes a couple of new
functions that will be needed for the next version of the isl++ bindings.
llvm-svn: 310205
Summary:
Small patch to fix the JSON exporter.
Currently, using "opt -polly-export-jscop" does not generate jscop files, but gives an error:
*** Error in `opt': corrupted double-linked list: 0x0000000000bc4bb0 ***
Updated the function getAccessRelationStr() to work with the current version of getAccessRelation(), fixing the JSON exporter
Reviewers: bollu, grosser
Reviewed By: grosser
Subscribers: grosser, llvm-commits, pollydev
Tags: #polly
Differential Revision: https://reviews.llvm.org/D36370
llvm-svn: 310199
Summary:
This resolves some "instruction does not dominate use" errors, as we used to
prepare the arrays at the location of the first kernel, which not necessarily
dominated all other kernel calls.
Reviewers: Meinersbur, bollu, singam-sanjay
Subscribers: nemanjai, pollydev, llvm-commits, kbarton
Differential Revision: https://reviews.llvm.org/D36372
llvm-svn: 310196
A Scop with a loop outside it is not handled currently by
PPCGCodeGeneration. The test case is such that the Scop has only one inner loop
that is detected. This currently breaks codegen.
The fix is to reuse the existing mechanism in `IslNodeBuilder` within
`GPUNodeBuilder.
Differential Revision: https://reviews.llvm.org/D36290
llvm-svn: 310193
This logic is duplicated, so we refactor it into a separate function.
This will be used in a later patch to teach PPCGCodeGen code generation
for loops that are outside the scop.
Differential Revision: https://reviews.llvm.org/D36310
llvm-svn: 310192
In https://reviews.llvm.org/D36278 it was pointed out that the behavior of
getPartialTilePrefixes is not very well understood. To allow for a better
understanding, we first provide some basic unittests.
llvm-svn: 310175
The method forwardSpeculatable forwards speculatively executable
instructions and is currently the only way to forward an
instruction.
In the future we intend to add more methods.
llvm-svn: 310056
Summary:
Testing the new-pm passes becomes much easier once they behave more like the
old passes in terms of the order in which Scops are processed and printed. This
requires three changes:
- ScopInfo: Use an ordered map to store scops
- ScopInfo: Iterate and print Scops in reverse order to match legacy PM behaviour
- ScopDetection: print function name in ScopAnalysisPrinter
Reviewers: grosser, Meinersbur, bollu
Reviewed By: grosser
Subscribers: pollydev, llvm-commits
Differential Revision: https://reviews.llvm.org/D36303
llvm-svn: 310052
The complication of bspatch.cc of the AOSP buildbot currently fails
presumably because the occurance of a MetadataAsValue in an operand.
This kind of value can occur as operands of intrinsics, the typical
example being the debug intrinsics.
Polly currently ignores the debug intrinsics and it is not yet clear
which other intrinic might occur. For such cases, and to unbreak the
AOSP buildbot, treat a MetadataAsValue as a constant because it can be
referenced without modification in generated code.
llvm-svn: 309992
With this patch, we get rid of the last use of getStmtFor(BB). Here
this is done by getting the last statement of the incoming block in
case the user is a phi node; otherwise just fetching the statement
comprising the instruction for which the virtual use is being created.
Differential Revision: https://reviews.llvm.org/D36268
llvm-svn: 309947
Summary:
In case the option -polly-ignore-parameter-bounds is set, not all parameters
will be added to context and domains. This is useful to keep the size of the
sets and maps we work with small. Unfortunately, for AST generation it is
necessary to ensure all parameters are part of the schedule tree. Hence,
we modify the GPGPU code generation to make sure this is the case.
To obtain the necessary information we expose a new function
Scop::getFullParamSpace(). We also make a couple of functions const to be
able to make SCoP::getFullParamSpace() const.
Reviewers: Meinersbur, bollu, gareevroman, efriedma, huihuiz, sebpop, simbuerg
Subscribers: nemanjai, kbarton, pollydev, llvm-commits
Tags: #polly
Differential Revision: https://reviews.llvm.org/D36243
llvm-svn: 309939
When we have `-polly-ignore-parameter-bounds`, `Scop::Context` does not contain
all the paramters present in the program.
The construction of the `isl_multi_pw_aff` requires all the indivisual `pw_aff`
to have the same parameter dimensions. To achieve this, we used to realign
every `pw_aff` with `Scop::Context`. However, in conjunction with
`-polly-ignore-parameter-bounds`, this is now incorrect, since `Scop::Context`
does not contain all parameters.
We set this up correctly by creating a space that has all the parameters
used by all the `isl_pw_aff`. Then, we realign all `isl_pw_aff` to this space.
llvm-svn: 309934
These passes have been tested over the last month and should generally help
to remove scalar data dependences in Polly. We enable them to give them even
wider test coverage. Large performance regressions and any kind of correctness
regressions are not expected.
llvm-svn: 309878
When compiling with clang, explicit instantiation of the
OwningScopAnalysisManagerFunctionProxy needs to happen within the polly
namespace. Same goes with the specialization of its run method.
llvm-svn: 309835
Summary:
This patch is a first attempt at registering Polly passes with the LLVM tools. Tool plugins are still unsupported, but this registration is usable from the tools if Polly is linked into them (albeit requiring minimal patches to those tools). Registration requires a small amount of machinery (the owning analysis proxies), necessary for injecting ScopAnalysisManager objects into the calling tools.
This patch is marked WIP because the registration is incomplete. Parsing manual pipelines is fully supported, but default pass injection into the O3 pipeline is lacking, mostly because there is opportunity for some redesign here, I believe. The first point of order would be insertion points. I think it makes sense to run before the vectorizers. Running Polly Early, however, is weird. Mostly because it actually is the default (which to me is unexpected), and because Polly runs it's own O1 pipeline. Why not instead insert it at an appropriate place somewhere after simplification happend? Running after the loop optimizers seems intuitive, but it also seems wasteful, since multiple consecutive loops might well be a single scop, and we don't need to run for all of them.
My second request for comments would be regarding all those smallish helper passes we have, like PollyViewer, PollyPrinter, PollyImportJScop. Right now these are controlled by command line options, deciding whether they should be part of the Polly pipeline. What is your opinion on treating them like real passes, and have the user write an appropriate pipeline if they want to use any of them?
Reviewers: grosser, Meinersbur, bollu
Reviewed By: grosser
Subscribers: llvm-commits, pollydev
Tags: #polly
Differential Revision: https://reviews.llvm.org/D35458
llvm-svn: 309826
Summary:
**Remove debug metadata from instruction to be copied to prevent the source file's debug metadata being copied into GPUModule and eventually failing Module verification and ASM string codegeneration.**
When copying the instruction onto the Module meant for the GPU, debug metadata attached to an instruction causes all related metadata to be pulled into the Module, including the DICompileUnit, which is not listed in llvm.dbg.cu of the Module. This fails the verification of the Module and generation of the ASM string.
The only debug metadata of the instruction, the DebugLoc, is unset by this patch.
This patch reattempts https://reviews.llvm.org/D35630 by targeting only those instructions that are to end up in a Module meant for the GPU.
Reviewers: grosser, bollu
Reviewed By: grosser
Subscribers: pollydev
Tags: #polly
Differential Revision: https://reviews.llvm.org/D36161
llvm-svn: 309822
Summary: I made a mistake in handling transitive invalidation of analysis results. I've updated the list of preserved analyses as well as the correct result dependences.
The Invalidator passed through the invalidate() path can be used to
transitively invalidate analyses. It frequently happens that analysis
results depend on other analyses, and thus store references to their
results. When the dependee now gets invalidated, the depender needs to
be invalidated as well. This is the purpose of the Invalidator object,
which can be used to check whether some dependee analysis is in the
process of being invalidated. I originally was checking the wrong
dependee analyses, which is an actual error, you can only check analysis
results that are in the cache (which they are if you've captured their
reference). The invalidation I'm handling inside the proxy deals with
the standard analyses the proxy passes into the Scop pipeline, since I'm
capturing their reference.
This checking allows us to actually preserve a couple of results outside
of the proxy, since the Scop pipeline shouldn't break those, or
otherwise should update them accordingly.
Reviewers: grosser, Meinersbur, bollu
Reviewed By: grosser
Subscribers: pollydev, llvm-commits
Differential Revision: https://reviews.llvm.org/D36216
llvm-svn: 309811
Commit r309730 moved the call to canForwardTree into an assert(), even
though this function has side-effects if its DoIt parameter is true. To
avoid a warning in release builds, do an (void)Execution of its result
instead.
To avoid such confusion in the future, rename
canForwardTree() to forwardTree().
llvm-svn: 309753
The previous algorithm was to search a writes and the sours of its value
operand, and see whether the write just stores the same read value back,
which includes a search whether there is another write access between
them. This is O(n^2) in the max number of accesses in a statement
(+ the complexity of isl comparing the access functions).
The new algorithm is more similar to the one used for searching for
overwrites and coalescable writes. It scans over all accesses in order
of execution while tracking which array elements still have the same
value since it was read. This is O(n), not counting the complexity
within isl. It should be more reliable than trying to catch all
non-conforming cases in the previous approach. It is also less code.
We now also support if the write is a partial write of the read's
domain, and to some extent non-affine subregions.
Differential Revision: https://reviews.llvm.org/D36137
llvm-svn: 309734
With a lot of reads and writes to the same array in a statement,
some isl sets that capture the state between access can become
complex such that isl takes more considerable time and memory
for operations on them.
The problems identified were:
- is_subset() takes considerable time with many disjoints in the
arguments. We limit the number of disjoints to 4, any additional
information is thrown away.
- subtract() can lead to many disjoints. We instead assume that any
array element is possibly accessed, which removes all disjoints.
- subtract_domain() may lead to considerable processing, even if all
elements are are to be removed. Instead, we remove determine and
remove the affected spaces manually. No behaviour is changed.
llvm-svn: 309728
It is possible that the `HostPtr` that coresponds to an array could be
invariant load hoisted. Make sure we use the invariant load hoisted
value by using `IslNodeBuilder::getLatestValue`.
Differential Revision: https://reviews.llvm.org/D36001
llvm-svn: 309681
We populate `IslNodeBuilder::ValueMap` which contains replacements for
`llvm::Value`s. There was no simple method to pick up a replacement if
it exists, otherwise fall back to the original.
Create a method `IslNodeBuilder::getLatestValue` which provides this
functionality.
This will be used in a later patch to fix bugs in `PPCGCodeGeneration`
where the latest value is not being used.
Differential Revision: https://reviews.llvm.org/D36000
llvm-svn: 309674
This allows -polly-optree to move instructions that depend on
synthesizable values.
The difficulty for synthesizable values is that their value depends on
the location. When it is moved over a loop header, and the SCEV
expression depends on the loop induction variable (SCEVAddRecExpr), it
would use the current induction variable instead of the last one.
At the moment we cannot forward PHI nodes such that crossing the header
of loops referenced by SCEVAddRecExpr is not possible (assuming the loop
header has at least two incoming blocks: for entering the loop and the
backedge, such any instruction to be forwarded must have a phi between
use and definition).
A remaining issue is when the forwarded value is used after the loop,
but is only synthesizable inside the loop. This happens e.g. if
ScalarEvolution is unable to determine the number of loop iterations or
the initial loop value. We do not forward in this situation.
Differential Revision: https://reviews.llvm.org/D36102
llvm-svn: 309609
In addition to array and PHI writes, also allow scalar value writes.
The only kind of write not allowed are writes by functions
(including memcpy/memmove/memset).
llvm-svn: 309582
Summary:
This allows us to map functions such as exp, expf, expl, for which no
LLVM intrinsics exist. Instead, we link to NVIDIA's libdevice which provides
high-performance implementations of a wide range of (math) functions. We
currently link only a small subset, the exp, cos and copysign functions. Other
functions will be enabled as needed.
Reviewers: bollu, singam-sanjay
Reviewed By: bollu
Subscribers: tstellar, tra, nemanjai, pollydev, mgorny, llvm-commits, kbarton
Tags: #polly
Differential Revision: https://reviews.llvm.org/D35703
llvm-svn: 309560
This reverts commit r309490 as it triggers on our AOSP buildbut error messages
of the form:
inlinable function call in a function with debug info must have a !dbg location
llvm-svn: 309556
Summary:
**Remove debug metadata from instruction to be copied to prevent the source file's debug metadata being copied into GPUModule and eventually failing Module verification and ASM string codegeneration.**
When copying the instruction onto the Module meant for the GPU, debug metadata attached to an instruction causes all related metadata to be pulled into the Module, including the DICompileUnit, which is not listed in llvm.dbg.cu of the Module. This fails the verification of the Module and generation of the ASM string.
The only debug metadata of the instruction, the DebugLoc, is unset by this patch.
Reviewers: grosser, bollu, Meinersbur
Reviewed By: grosser, bollu
Subscribers: pollydev
Tags: #polly
Differential Revision: https://reviews.llvm.org/D35630
llvm-svn: 309490
Tobias Grosser