Summary:
This initiates a discussion on changing Polly accordingly while re-applying r335197 (D48338).
I have never worked on Polly. The proposed change to param_div_div_div_2.ll is not educated, but just patterns that match the output.
All LLVM files are already reviewed in D48338.
Reviewers: jdoerfert, bollu, efriedma
Subscribers: jlebar, sanjoy, hiraditya, llvm-commits, bixia
Differential Revision: https://reviews.llvm.org/D48453
llvm-svn: 335292
Add the options -polly-codegen-trace-stmts and
-polly-codegen-trace-scalars. When enabled, adds a call to the
beginning of every generated statement that prints the executed
statement instance. With -polly-codegen-trace-scalars, it also prints
the value of all scalars that are used in the statement, and PHIs
defined in the beginning of the statement.
Differential Revision: https://reviews.llvm.org/D45743
llvm-svn: 330864
A check in assert-builds was meant to verify that a load provides a
value in all statement instances (i.e. its domain). The domain is
commonly gist'ed within the parameter context to contain fewer
constraints. However, statement instances outside the context are
no valid executions, hence the value provided can be undefined.
Refine the check for valid loads to only needed to be defined within
the SCoP context.
In addition, the JSONImporter had to be changed to allow importing
access relations that are broader than the current access relation,
but still defined over all statement instances.
This should fix the compiler crash in test-suite's oggenc of the
-polly-process-unprofitable buildbot.
llvm-svn: 329655
Summary:
When checking the parallelism of a scheduling dimension, we first check if excluding reduction dependences the loop is parallel or not.
If the loop is not parallel, then we need to return the minimal dependence distance of all data dependences, including the previously subtracted reduction dependences.
Reviewers: grosser, Meinersbur, efriedma, eli.friedman, jdoerfert, bollu
Reviewed By: Meinersbur
Subscribers: llvm-commits, pollydev
Tags: #polly
Differential Revision: https://reviews.llvm.org/D45236
llvm-svn: 329214
Splitting basic blocks into multiple statements if there are now
additional scalar dependencies gives more freedom to the scheduler, but
more statements also means higher compile-time complexity. Switch to
finer statement granularity, the additional compile time should be
limited by the number of operations quota.
The regression tests are written for the -polly-stmt-granularity=bb
setting, therefore we add that flag to those tests that break with the
new default. Some of the tests only fail because the statements are
named differently due to a basic block resulting in multiple statements,
but which are removed during simplification of statements without
side-effects. Previous commits tried to reduce this effect, but it is
not completely avoidable.
Differential Revision: https://reviews.llvm.org/D42151
llvm-svn: 324169
Memory transfer instructions take two pointers. It is not defined to
which of those a noalias annotation applies. To ensure correctness,
do not add noalias annotations to memcpy/memmove instructions anymore.
The caused a miscompile with test-suite's MultiSource/Applications/obsequi.
Since r321138, the MemCpyOpt pass would remove memcpy/memmove calls if
known to copy uninitialized memory. In that case, it was initialized
by another memcpy, but the annotation for the target pointer said
it would not alias. The annotation was actually meant for the source
pointer, which was was an alloca and could not alias with the target
pointer.
llvm-svn: 321371
Isl does not allow generating isl_ast_expr from an isl_pw_aff that has an
empty domain (i.e. has no pieces). We already detected the case if the
isl_pw_aff comes with an empty domain.
isl_ast_build also considers the domain empty if it is disjoint with the
parameter context (e.g. parameters values that we exclude by runtime
versioning).
Intersect the access relation domain with the parameter context to
also detect such practically empty access domains. The effective
pointer used in the generated code is unimportand because it will never
be executed.
This fixes llvm.org/PR35362
llvm-svn: 318806
When collecting base pointers that need to be made available in parallel
subfunctions, use the base pointer associated with the latest
ScopArrayInfo, instead of the original one.
llvm-svn: 316983
After rL315683 (improve SCEV to calculate max BETakenCount when end
bound of loop is variant and loop is of form {Start,+1, Stride} LT End)
this test in polly started failing.
However, as discussed in https://reviews.llvm.org/rL315683,
this polly test is not a loops bound test and the MaxBECount calculated by
SCEV looks correct. The max BECount is the value calculated even when the end
bound of loop is invariant.
As discussed with Tobias offline, I'm marking this as an XFAIL, until he
gets a chance to update the testcase, so the build bot goes to green.
llvm-svn: 315912
This test XFAILs two test that start to fail when verifying DT's
DFS numbers, as per Tobias' suggestion.
Related VerifyDFSNumbers patch: D38331.
llvm-svn: 314800
In case a PHI node follows an error block we can assume that the incoming value
can only come from the node that is not an error block. As a result, conditions
that seemed non-affine before are now in fact affine.
This is a recommit of r312663 after fixing
test/Isl/CodeGen/phi_after_error_block_outside_of_scop.ll
llvm-svn: 314075
Such RTCs may introduce integer wrapping intrinsics with more than 64 bit,
which are translated to library calls on AOSP that are not part of the
runtime and will consequently cause linker errors.
Thanks to Eli Friedman for reporting this issue and reducing the test case.
llvm-svn: 314065
Since -polly-codegen reports itself to preserve DependenceInfo and IslAstInfo,
we might get those analysis that were computed by a different ScopInfo for a
different Scop structure. This would be unfortunate because DependenceInfo and
IslAstInfo hold references to resources allocated by
ScopInfo/ScopBuilder/Scop (e.g. isl_id). If -polly-codegen and
DependenceInfo/IslAstInfo do not agree on which Scop to use, unpredictable
things can happen.
When the ScopInfo/Scop object is freed, there is a high probability that the
new ScopInfo/Scop object will be created at the same heap position with the
same address. Comparing whether the Scop or ScopInfo address is the expected
therefore is unreliable.
Instead, we compare the address of the isl_ctx object. Both, DependenceInfo
and IslAstInfo must hold a reference to the isl_ctx object to ensure it is
not freed before the destruction of those analyses which might happen after
the destruction of the Scop/ScopInfo they refer to. Hence, the isl_ctx
will not be freed and its address not reused as long there is a
DependenceInfo or IslAstInfo around.
This fixes llvm.org/PR34441
llvm-svn: 313842
The type of NewValue might change due to ScalarEvolution
looking though bitcasts. The synthesized NewValue therefore
becomes the type before the bitcast.
llvm-svn: 312718
In certain situations, the context in the isl_ast_build could result for the
min/max locations of our alias sets to become empty, which would cause an
internal error in isl, which is then unable to derive a value for these
expressions. Check these conditions before code generating expressions and
instead assume that alias check succeeded. This is valid, as the corresponding
memory accesses will not be executed under any valid context.
This fixed llvm.org/PR34432. Thanks to Qirun Zhang for reporting.
llvm-svn: 312455
The adds code generation support for the previous commit.
This patch has been re-applied, after the memory issue in the previous patch
has been fixed.
llvm-svn: 312211
This patch allows annotating of metadata in ir instruction
(with "polly_split_after"), which specifies where to split a particular
scop statement.
Contributed-by: Nandini Singhal <cs15mtech01004@iith.ac.in>
Differential Revision: https://reviews.llvm.org/D36402
llvm-svn: 312107
Whether a partial write is tautological/unsatisfiable not only
depends on the access domain, but also on the domain covered
by its node in the AST.
In the example below, there are two instances of Stmt_cond_false. It may have a partial write access that is not executed in instance Stmt_cond_false(0).
for (int c0 = 0; c0 < tmp5; c0 += 1) {
Stmt_for_body344(c0);
if (tmp5 >= c0 + 2)
Stmt_cond_false(c0);
Stmt_cond_end(c0);
}
if (tmp5 <= 0) {
Stmt_for_body344(0);
Stmt_cond_false(0);
Stmt_cond_end(0);
}
Isl cannot derive a subscript for an array element that is never accessed.
This caused an error in that no subscript expression has been generated
in IslNodeBuilder::createNewAccesses, but BlockGenerator expected one
to exist because there is an execution of that write, just not in that
ast node.
Fixed by instead of determining whether the access domain is empty,
inspect whether isl generated a constant "false" ast expression in
the current ast node.
This should fix a compiler crash of the aosp buildbot.
llvm-svn: 311663
Summary:
There is no need to emit alias metadata for scalars, as basicaa will easily
distinguish them from arrays. This reduces the size of the metadata we generate.
This is especially useful after we moved to -polly-position=before-vectorizer,
where a lot more scalar dependences are introduced, which increased the size of
the alias analysis metadata and made us commonly reach the limits after which
we do not emit alias metadata that have been introduced to prevent quadratic
growth of this alias metadata.
This improves 2mm performance from 1.5 seconds to 0.17 seconds.
Reviewers: Meinersbur, bollu, singam-sanjay
Reviewed By: Meinersbur
Subscribers: pollydev, llvm-commits
Tags: #polly
Differential Revision: https://reviews.llvm.org/D37028
llvm-svn: 311498
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
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
Summary:
This consists instances of two changes:
- Accept any order of checks for a specific loop form, that appear in different order in the new vs legacy-PM.
- Remove checks for specific regions.
Reviewers: grosser
Reviewed By: grosser
Subscribers: pollydev, llvm-commits
Tags: #polly
Differential Revision: https://reviews.llvm.org/D35837
llvm-svn: 308976
When performing invariant load hoisting we check that invariant load expressions
are not too complex. Up to this commit, we performed this check by counting the
sum of dimensions in the access range as a very simple heuristic. This heuristic
is a little too conservative, as it prevents hoisting for any scops with a
very large number of parameters. Hence, we update the heuristic to only count
existentially quantified dimensions and set dimensions. We expect this to still
detect the problematic expressions in h264 because of which this check was
originally introduced.
For some unknown reason, this complexity check was originally committed in
IslNodeBuilder. It really belongs in ScopInfo, as there is no point in
optimizing a program which we could have known earlier cannot be code generated.
The benefit of running the check early is that we can avoid to even hoist checks
that are expensive to code generate as invariant loads. This can be seen in
the changed tests, where we now indeed detect the scop, but just not invariant
load hoist the complicated access.
We also improve the formatting of the code, document it, and use isl++ to
simplify expressions.
llvm-svn: 308659
Summary:
We do not keep domain constraints on access functions when building the
scop. Hence, for consistency reasons, it makes also sense to not include
them when storing a new access function. This change results in simpler
access functions that make output easier to read.
This patch also helps to make DeLICMed memory accesses to be understood by
our matrix multiplication pattern matching pass. Further changes to the
matrix multiplication pattern matching are needed for this to work, so the
corresponding test case will be added in a future commit.
Reviewers: Meinersbur, bollu, gareevroman, efriedma, huihuiz, sebpop, simbuerg
Subscribers: pollydev, llvm-commits
Tags: #polly
Differential Revision: https://reviews.llvm.org/D35237
llvm-svn: 308215
This patch makes sure that in case a loop is not fully contained within a region
that later forms a SCoP, none of the loop backedges are allowed to be part of
the region. We currently do not support the situation where only some of a loops
backedges are part of a scop. Today, this can break both scop modeling and code
generation. One such breaking test case is for example
test/ScopDetectionDiagnostics/loop_partially_in_scop-2.ll, where we totally
forgot to code generate some of the backedges. Fortunately, it is commonly not
necessary to support these partial loops, it is way more common that either
no backedge is included in a region or all loop backedge are included.
This fixes a recent miscompile in
MultiSource/Benchmarks/MiBench/consumer-typeset which was exposed after
r306477.
llvm-svn: 308113
We need to relax constraints on invariant loads so that they do not
create fake RAW dependences. So, we do not consider invariant loads as
scalar dependences in a region.
During these changes, it turned out that we do not consider `llvm::Value`
replacements correctly within `PPCGCodeGeneration` and `ISLNodeBuilder`.
The replacements dictated by `ValueMap` were not being followed in all
places. This was fixed in this commit. There is no clean way to decouple
this change because this bug only seems to arise when the relaxed
version of invariant load hoisting was enabled.
Differential Revision: https://reviews.llvm.org/D35120
llvm-svn: 307907
When providing the option "-polly-ast-print-accesses" Polly also prints the
memory accesses that are generated:
#pragma known-parallel
for (int c0 = 0; c0 <= 1023; c0 += 4)
#pragma simd
for (int c1 = c0; c1 <= c0 + 3; c1 += 1)
Stmt_for_body(
/* read */ &MemRef_B[0]
/* write */ MemRef_A[c1]
);
This makes writing and debugging memory layout transformations easier.
Based on a patch contributed by Thomas Lang (ETH Zurich)
llvm-svn: 307579
This patch aims to implement the option of allocating new arrays created
by polly on heap instead of stack. To enable this option, a key named
'allocation' must be written in the imported json file with the value
'heap'.
We need such a feature because in a next iteration, we will implement a
mechanism of maximal static expansion which will need a way to allocate
arrays on heap. Indeed, the expansion is very costly in terms of memory
and doing the allocation on stack is not worth considering.
The malloc and the free are added respectively at polly.start and
polly.exiting such that there is no use-after-free (for instance in case
of Scop in a loop) and such that all memory cells allocated with a
malloc are free'd when we don't need them anymore.
We also add :
- In the class ScopArrayInfo, we add a boolean as member called IsOnHeap
which represents the fact that the array in allocated on heap or not.
- A new branch in the method allocateNewArrays in the ISLNodeBuilder for
the case of heap allocation. allocateNewArrays now takes a BBPair
containing polly.start and polly.exiting. allocateNewArrays takes this
two blocks and add the malloc and free calls respectively to
polly.start and polly.exiting.
- As IntPtrTy for the malloc call, we use the DataLayout one.
To do that, we have modified :
- createScopArrayInfo and getOrCreateScopArrayInfo such that it returns
a non-const SAI, in order to be able to call setIsOnHeap in the
JSONImporter.
- executeScopConditionnaly such that it return both start block and end
block of the scop, because we need this two blocs to be able to add
the malloc and the free calls at the right position.
Differential Revision: https://reviews.llvm.org/D33688
llvm-svn: 306540
Ensure that all array base pointers are assigned before generating
aliasing metadata by allocating new arrays beforehand.
Before this patch, getBasePtr() returned nullptr for new arrays because
the arrays were created at a later point. Nullptr did not match to any
array after the created array base pointers have been assigned and when
the loads/stores are generated.
llvm-svn: 305675
Summary:
The RegionGenerator traditionally kept a BlockMap that mapped from original
basic blocks to newly generated basic blocks. With the introduction of partial
writes such a 1:1 mapping is not possible any more, as a single basic block
can be code generated into multiple basic blocks. Hence, depending on the use
case we need to either use the first basic block or the last basic block.
This is intended to address the last four cases of incorrect code generation
in our AOSP buildbot and hopefully should turn it green.
Reviewers: Meinersbur, bollu, gareevroman, efriedma, huihuiz, sebpop, simbuerg
Reviewed By: Meinersbur
Subscribers: pollydev, llvm-commits
Tags: #polly
Differential Revision: https://reviews.llvm.org/D33767
llvm-svn: 304808
This adds test coverage for regions with non-affine loops, which we
unfortunately missed when committing this features years ago. We will add
more test coverage over time.
llvm-svn: 304672
- Add a counter that is incremented once on exit from a scop.
- Test cases got split into two: one to test the cycles, and another one
to test trip counts.
- Sample output:
```name=sample-output.txt
scop function, entry block name, exit block name, total time, trip count
warmup, %entry.split, %polly.merge_new_and_old, 5180, 1
f, %entry.split, %polly.merge_new_and_old, 409944, 500
g, %entry.split, %polly.merge_new_and_old, 1226, 1
```
Differential Revision: https://reviews.llvm.org/D33822
llvm-svn: 304543
Previously, we would generate one performance counter for all scops.
Now, we generate both the old information, as well as a per-scop
performance counter to generate finer grained information.
This patch needed a way to generate a unique name for a `Scop`.
The start region, end region, and function name combined provides a
unique `Scop` name. So, `Scop` has a new public API to provide its start
and end region names.
Differential Revision: https://reviews.llvm.org/D33723
llvm-svn: 304528
A partial write is a write where the domain of the values written is a subset of
the execution domain of the parent statement containing the write. Originally,
we directly checked this subset relation whereas it is indeed only important
that the subset relation holds for the parameter values that are known to be
valid in the execution context of the scop. We update our check to avoid the
unnecessary introduction of partial writes in situations where the write appears
to be partial without context information, but where context information allows
us to understand that a full write can be generated.
This change fixes (hides) a recent regression introduced in r303517, which broke
our AOSP builds. The part that is correctly fixed in this change is that we do
not any more unnecessarily generate a partial write. This is good performance
wise and, as we currently do not yet explicitly introduce partial writes in the
default configuration, this also hides possible bugs in the partial writes
implementation. The crashes that we have originally seen were caused by such
a bug, where partial writes were incorrectly generated in region statements. An
additional patch in a subsequent commit is needed to address this problem.
Reported-by: Reported-by: Eli Friedman <efriedma@codeaurora.org>
Differential Revision: https://reviews.llvm.org/D33759
llvm-svn: 304398
The SCEVs of loops surrounding the escape users of a merge blocks are
forgotten, so that loop trip counts based on old values can be revoked.
This fixes llvm.org//PR32536
Contributed-by: Baranidharan Mohan <mbdharan@gmail.com>
Differential Revision: https://reviews.llvm.org/D33195
llvm-svn: 303561
Allow the BlockGenerator to generate memory writes that are not defined
over the complete statement domain, but only over a subset of it. It
generates a condition that evaluates to 1 if executing the subdomain,
and only then execute the access.
Only write accesses are supported. Read accesses would require a PHINode
which has a value if the access is not executed.
Partial write makes DeLICM able to apply mappings that are not defined
over the entire domain (for instance, a branch that leaves a loop with
a PHINode in its header; a MemoryKind::PHI write when leaving is never
read by its PHI read).
Differential Revision: https://reviews.llvm.org/D33255
llvm-svn: 303517
A test case with a GPU runline was added without setting 'REQUIRES=pollyacc'. We
drop the GPU run line, as the basic functionality can already be tested with
the normal code generation.
llvm-svn: 303485
- We use the outermost dimension of arrays since we need this
information to generate GPU transfers.
- In general, if we do not know the outermost dimension of the array
(because the indexing expression is non-affine, for example) then we
simply cannot generate transfer code.
- However, for Fortran arrays, we can use the Fortran array
representation which stores the dimensions of all arrays.
- This patch uses the Fortran array representation to generate code that
computes the outermost dimension size.
Differential Revision: https://reviews.llvm.org/D32967
llvm-svn: 303429
Today Polly generates induction variable in this way:
polly.indvar = phi 0, polly.indvar.next
...
polly.indvar.next = polly.indvar + stide
polly.loop_cond = predicate polly.indvar, (UB - stride)
Instead of:
polly.indvar = phi 0, polly.indvar.next
...
polly.indvar.next = polly.indvar + stide
polly.loop_cond = predicate polly.indvar.next, UB
The way Polly generate induction variable cause some problem in the indvar simplify pass.
This patch make polly generate the later form, by assuming the induction variable never overflow
Differential Revision: https://reviews.llvm.org/D33089
llvm-svn: 302866
Summary:
In case two arrays share base pointers in the same invariant load equivalence
class, we canonicalize all memory accesses to the first of these arrays
(according to their order in the equivalence class).
This enables us to optimize kernels such as boost::ublas by ensuring that
different references to the C array are interpreted as accesses to the same
array. Before this change the runtime alias check for ublas would fail, as it
would assume models of the C array with differing (but identically valued) base
pointers would reference distinct regions of memory whereas the referenced
memory regions were indeed identical.
As part of this change we remove most of the MemoryAccess::get*BaseAddr
interface. We removed already all references to get*BaseAddr in previous
commits to ensure that no code relies on matching base pointers between
memory accesses and scop arrays -- except for three remaining uses where we
need the original base pointer. We document for these situations that
MemoryAccess::getOriginalBaseAddr may return a base pointer that is distinct
to the base pointer of the scop array referenced by this memory access.
Reviewers: sebpop, Meinersbur, zinob, gareevroman, pollydev, huihuiz, efriedma, jdoerfert
Reviewed By: Meinersbur
Subscribers: etherzhhb
Tags: #polly
Differential Revision: https://reviews.llvm.org/D28518
llvm-svn: 302636
This makes sure we still test the case that a PHI-NODE cannot be analyzed by
scalar evolution and consequently must be code generated explicitly. As
Michael's optimization triggers only on a very specific "add %iv, %step"
pattern, just changing 'add' to 'mul' adds back test coverage.
llvm-svn: 302132
Tim Shen