We do not have buildbots or anything that tests this functionality, hence it
most likely bitrots. People interested to use this functionality can always
recover it from svn history.
llvm-svn: 233570
This allows us to delinerize code such as:
A[][n]
for (i
for (j
A[i][n-j-1] = ...
which would previously have been delinearize to an access A[i+1][-j-1].
To recover the correct access we apply the piecewise expression:
{ A[i][j] -> A[i-1][i+N]: i < 0; A[i][j] -> A[i][i]: i >= 0}
This approach generalizes to higher dimensions.
llvm-svn: 233566
This will strip the constant factor of a parameter befor we add it to
the SCoP. As a result the access functions are simplified, e.g., for
the attached test case.
llvm-svn: 233501
This options was earlier used for experiments with the vectorizer, but to my
knowledge is not really used anymore. If anybody needs this, we can always
reintroduce this feature.
llvm-svn: 232934
The BB vectorizer is deprecated and there is no point in generating code for it
any more. This option was introduced when there was not yet any loop vectorizer
in sight. Now being matured, Polly should target the loop vectorizer.
llvm-svn: 232099
The new Dependences struct in the DependenceInfo holds all information
that was formerly part of the DependenceInfo. It also provides the
same interface for the user to access this information.
This is another step to a more general ScopPass interface that does
allow multiple SCoPs to be "in flight".
llvm-svn: 231327
We rename the Dependences pass to DependenceInfo as a first step to a
caching pass policy. The new DependenceInfo pass will later provide
"Dependences" for a SCoP.
To keep consistency the test folder is renamed too.
llvm-svn: 231308
No test cases unfortunately as we do not yet generate isl_ast_op_and_then or
isl_ast_op_or_else. Those will be added in a later commit.
llvm-svn: 231268
If a scalar was defined and used only in a non-affine subregion we do
not need to model the accesses. However, if the scalar was defined
inside the region and escapes the region we have to model the access.
The same is true if the scalar was defined outside and used inside the
region.
llvm-svn: 230960
When we generate code for a whole region we have to respect dominance
and update it too.
The first is achieved with multiple "BBMap"s. Each copied block in the
region gets its own map. It is initialized only with values mapped in
the immediate dominator block, if this block is in the region and was
therefor already copied. This way no values defined in a block that
doesn't dominate the current one will be used.
To update dominance information we check if the immediate dominator of
the original block we want to copy is in the region. If so we set the
immediate dominator of the current block to the copy of the immediate
dominator of the original block.
llvm-svn: 230774
This is the code generation for region statements that are created
when non-affine control flow was present in the input. A new
generator, similar to the block or vector generator, for regions is
used to traverse and copy the region statement and to adjust the
control flow inside the new region in the end.
llvm-svn: 230340
This allows us to model non-affine regions in the SCoP representation.
SCoP statements can now describe either basic blocks or non-affine
regions. In the latter case all accesses in the region are accumulated
for the statement and write accesses, except in the entry, have to be
marked as may-write.
Differential Revision: http://reviews.llvm.org/D7846
llvm-svn: 230329
With this patch we allow the SCoP detection to detect regions as SCoPs
which have non-affine control flow inside. All non-affine regions are
tracked and later accessible to the ScopInfo.
As there is no real difference, non-affine branches as well as
floating point branches are covered (and both called non-affine
control flow). However, the detection is restricted to
overapproximate only loop free regions.
llvm-svn: 230325
Scops that only read seem generally uninteresting and scops that only write are
most likely initializations where there is also little to optimize. To not
waste compile time we bail early.
Differential Revision: http://reviews.llvm.org/D7735
llvm-svn: 229820
namespace and header rather than the top-level header and using
declarations. These helpers impede modular builds and are going away.
Migrating away from them will also be necessary to start mixing in any
usage of the new pass manager.
llvm-svn: 229091
This allows us to skip ast and code generation if we did not optimize
a SCoP and will not generate parallel or alias annotations. The
initial heuristic to exit is simple but allows improvements later on.
All failing test cases have been modified to disable early exit, thus
to keep their coverage.
Differential Revision: http://reviews.llvm.org/D7254
llvm-svn: 228851
This change has two main purposes:
1) We do not use a static interface to hide an object we create and
destroy for every basic block we copy.
2) We allow the BlockGenerator to store information between calls to
the copyBB method. This will ease scalar/phi code generation
later on.
While a lot of method signatures were changed this should not cause
any real behaviour change.
Differential Revision: http://reviews.llvm.org/D7467
llvm-svn: 228443
This allows us to model PHI nodes in the polyhedral description
without demoting them. The modeling however will result in the
same accesses as the demotion would have introduced.
Differential Revision: http://reviews.llvm.org/D7415
llvm-svn: 228433
Schedule dimensions that have the same constant value accross all statements do
not carry any information, but due to the increased dimensionality of the
schedule cost compile time. To not pay this cost, we remove constant dimensions
if possible.
llvm-svn: 225067
Without updating dependences we may lose implicit transitive dependences for
which all explicit dependences have gone through the statement iterations we
have just eliminated.
No test case. We should probably implement a -verify-dependences option.
This fixes llvm.org/PR21227
llvm-svn: 224459
This commit drops the Cloog support for Polly. The scripts and
documentation are changed to only use isl as prerequisity. In the code
all Cloog specific parts have been removed and all relevant tests have
been ported to the isl backend when it was created.
llvm-svn: 223141
Polly had a copy of this pass to create the canonical induction variables
necessary for the non-scev-based code generation. As we now always use SCEV
based code generation, canonical induction variables are not needed any more.
llvm-svn: 222979
SCEV based code generation has been the default for two weeks after having
been tested for a long time. We now drop the support the non-scev-based code
generation.
llvm-svn: 222978
In case a GEP instruction references into a fixed size array e.g., an access
A[i][j] into an array A[100x100], LLVM-IR does not guarantee that the subscripts
always compute values that are within array bounds. We now derive the set of
parameter values for which all accesses are within bounds and add the assumption
that the scop is only every executed with this set of parameter values.
Example:
void foo(float A[][20], long n, long m {
for (long i = 0; i < n; i++)
for (long j = 0; j < m; j++)
A[i][j] = ...
This loop yields out-of-bound accesses if m is at least 20 and at the same time
at least one iteration of the outer loop is executed. Hence, we assume:
n <= 0 or m <= 20.
Doing so simplifies the dependence analysis problem, allows us to perform
more optimizations and generate better code.
TODO: The location where the GEP instruction is executed is not necessarily the
location where the memory is actually accessed. As a result scanning for GEP[s]
is imprecise. Even though this is not a correctness problem, this imprecision
may result in missed optimizations or non-optimal run-time checks.
In polybench where this mismatch between parametric loop bounds and fixed size
arrays is common, we see with this patch significant reductions in compile time
(up to 50%) and execution time (up to 70%). We see two significant compile time
regressions (fdtd-2d, jacobi-2d-imper), and one execution time regression
(trmm). Both regressions arise due to additional optimizations that have been
enabled by this patch. They can be addressed in subsequent commits.
http://reviews.llvm.org/D6369
llvm-svn: 222754
This backend supports besides the classical code generation the upcoming SCEV
based code generation (which the existing CLooG backend does not support
robustly).
OpenMP code generation in the isl backend benefits from our run-time alias
checks such that the set of loops that can possibly be parallelized is a lot
larger.
The code was tested on LNT. We do not regress on builds without -polly-parallel.
When using -polly-parallel most tests work flawlessly, but a few issues still
remain and will be addressed in follow up commits.
SCEV/non-SCEV codegen:
- Compile time failure in ldecod and TimberWolfMC due a problem in our
run-time alias check generation triggered by pointers that escape through
the OpenMP subfunction (OpenMP specific).
- Several execution time failures. Due to the larger set of loops that we now
parallelize (compared to the classical code generation), we currently run
into some timeouts in tests with a lot loops that have a low trip count and
are slowed down by parallelizing them.
SCEV only:
- One existing failure in lencod due to llvm.org/PR21204 (not OpenMP specific)
OpenMP code generation is the last feature that was only available in the CLooG
backend. With the isl backend being the only one supporting features such as
run-time alias checks and delinearization, we will soon switch to use the isl
ast generator by the default and subsequently remove our dependency on CLooG.
http://reviews.llvm.org/D5517
llvm-svn: 222088
David Blaikie