When introducing separate control flow for the original and optimized code we
introduce now a special 'ExitingBlock':
\ /
EnteringBB
|
SplitBlock---------\
_____|_____ |
/ EntryBB \ StartBlock
| (region) | |
\_ExitingBB_/ ExitingBlock
| |
MergeBlock---------/
|
ExitBB
/ \
This 'ExitingBlock' contains code such as the final_reloads for scalars, which
previously were just added to whichever statement/loop_exit/branch-merge block
had been generated last. Having an explicit basic block makes it easier to
find these constructs when looking at the CFG.
llvm-svn: 255107
This update brings in improvements to isl's 'isolate' option that reduce the
number of code versions generated. This results in both code-size and compile
time reduction for outer loop vectorization.
Thanks to Roman Garev and Sven Verdoolaege for working on this improvement.
llvm-svn: 254706
The motivation is to fix a compilation error with Visual Studio 2013.
See http://reviews.llvm.org/D14886.
Thanks to Sumanth Gundapaneni for finding the issue and suggesting a
patch.
llvm-svn: 254498
The script will checkout the most recent master from
http://repo.or.cz/isl.git into /tmp, create a distribution tarball, and
extract it as replacement of lib/External/isl. After that it can be
committed to the Polly repository.
llvm-svn: 254497
Acc==MA implies Acc->getAccessInstruction() == MA->getAccessInstruction().
Suggested as post-commit review for 254305 by Michael Kruse.
llvm-svn: 254327
The use of C++'s high-level iterator functionality instead of two while loops
and explicit iterator handling improves readability of this code.
Proposed-by: Michael Kruse <llvm@meinersbur.de>
Differential Revision: http://reviews.llvm.org/D15068
llvm-svn: 254305
Re-run canonicalization passes after Polly's code generation.
The set of passes currently added here are nearly all the passes between
--polly-position=early and --polly-position=before-vectorizer, i.e. all
passes that would usually run after Polly.
In order to run these only if Polly actually modified the code, we add a
function attribute "polly-optimzed" to a function that contains
generated code. The cleanup pass is skipped if the function does not
have this attribute.
There is no support by the (legacy) PassManager to run passes only under
some conditions. One could have wrapped all transformation passes to run
only when CodeGeneration changed the code, but the analyses would run
anyway. This patch creates an independent pass manager. The
disadvantages are that all analyses have to re-run even if preserved and
it does not honor compiler switches like the PassManagerBuilder does.
Differential Revision: http://reviews.llvm.org/D14333
llvm-svn: 254150
Previously, accesses that originate from PHI nodes in the exit block
were registered as SCALAR. In some context they are treated as scalars,
but it makes a difference in others. We used to check whether the
AccessInstruction is a terminator to differentiate the cases.
This patch introduces an MemoryAccess origin EXIT_PHI and a
ScopArrayInfo kind KIND_EXIT_PHI to make this case more explicit. No
behavioural change intended.
Differential Revision: http://reviews.llvm.org/D14688
llvm-svn: 254149
gfortran (and fortran in general?) does not compute the address of an array
element directly from the array sizes (e.g., %s0, %s1), but takes first the
maximum of the sizes and 0 (e.g., max(0, %s0)) before multiplying the resulting
value with the per-dimension array subscript expressions. To successfully
delinearize index expressions as we see them in fortran, we first filter 'smax'
expressions out of the SCEV expression, use them to guess array size parameters
and only then continue with the existing delinearization.
llvm-svn: 253995
Trying to build up access functions for any of these blocks is likely to fail,
as error blocks may contain invalid/non-representable instructions, and blocks
dominated by error blocks may reference such instructions, which wil also cause
failures. As all of these blocks are anyhow assumed to not be executed, we can
just remove them early on.
This fixes http://llvm.org/PR25596
llvm-svn: 253818
The most interesting change for Polly in this isl update is 4d5654af which
in certain cases can speed up the construction of run-time checks from an isl
set consisting of several disjuncts significantly.
llvm-svn: 253794
At some point we enforced lcssa for the loop surrounding the entry block.
This is not only questionable as it does not check any other loop but also
not needed any more.
llvm-svn: 253789
In case the original parameter instruction does not have a name, but it comes
from a load instruction where the base pointer has a name we used the name of
the load instruction to give some more intuition of where the parameter came
from. To ensure this works also through GEPs which may have complex offsets,
we originally just dropped the offsets and _only_ used the base pointer name.
As this can result in multiple parameters to get the same name, we now prefix
the parameter ID to ensure parameter names are unique. This will make it easier
to understand debug output.
This change does not affect correctness, as parameter IDs (even of the same
name) can always be distinguished through the SCEV pointer stored inside them.
llvm-svn: 253330
Without this change we may start to refuse scops in larger compilation units
just because a lot of code has already been compiled earlier.
Found by inspection. I do not yet have a good test case for this.
llvm-svn: 253050
Only when we check for wrapping we want to use the store size, for all
other cases we use the alloc size now.
Suggested by: Tobias Grosser <tobias@grosser.es>
llvm-svn: 252941
IVs of loops for which the loop header is in the subregion, but not the entire
loop may be incremented outside of the subregion and can consequently not be
kept private to the subregion. Instead, they need to and are modeled as virtual
loops in the iteration domains. As this is the case, generating new subregion
induction variables for such loops is not needed and indeed wrong as they would
hide the virtual induction variables modeled in the scop.
This fixes a miscompile in MultiSource/Benchmarks/Ptrdist/bc and
MultiSource/Benchmarks/nbench/. Thanks Michael and Johannes for their
investiagations and helpful observations regarding this bug.
llvm-svn: 252860
If an llvm.assume dominates the SCoP entry block and the assumed condition
can be expressed as an affine inequality we will now add it to the context.
Differential Revision: http://reviews.llvm.org/D14413
llvm-svn: 252851
Error blocks may contain arbitrary instructions, among them some which we can
not modeled correctly. As we do not generate ScopStmts for error blocks anyhow
there is no point in trying to generate access functions for them.
This fixes llvm.org/PR25494
llvm-svn: 252794
In certain cases isl will not free the return values of operations for which
a computeout has been triggered. Hence, make sure we free it explicitly.
No test, as I did not manage to reduce one yet.
llvm-svn: 252766
For complex inputs our current approach of construction the boundary context
may in rare cases become computationally so expensive that it is better to
abort. This change adds a compute out check that bounds the compuations we
spend on boundary context construction and bails out if this limit is reached.
We can probably make our boundary construction algorithm more efficient, but
this requires some more investigation and probably also some additional changes
to isl. Until these have been added, we bound the compile time to ensure our
buildbots are green.
llvm-svn: 252758
In certain rare cases (mostly -polly-process-unprofitable on large sequences
of conditions - often without any loop), we see some compile-time timeouts due
to the construction of an overly complex assumption context. This change limits
the number of disjuncts to 150 (adjustable), to prevent us from creating
assumptions contexts that are too large for even the compilation to finish.
The limit has been choosen as large as possible to make sure we do not
unnecessarily drop test coverage. If such cases also appear in
-polly-process-unprofitable=false mode we may need to think about this again,
as the current limitations may still allow assumptions that are way to complex
to be checked profitably at run-time.
There is also certainly room for improvement regarding how (and how efficient)
we construct an assumed context, but this requires some more thinking.
This completes llvm.org/PR25458
llvm-svn: 252750
Basic blocks that are always executed can not be error blocks as their execution
can not possibly be an unlikely event. In this commit we tighten the check
if an error block to basic blcoks that do not dominate the exit condition, but
that dominate all exiting blocks of the scop.
llvm-svn: 252726
r252713 introduced a couple of regressions due to later basic blocks refering
to instructions defined in error blocks which have not yet been modeled.
This commit is currently just encoding limitations of our modeling and code
generation backends to ensure correctness. In theory, we should be able to
generate and optimize such regions, as everything that is dominated by an error
region is assumed to not be executed anyhow. We currently just lack the code
to make this happen in practice.
llvm-svn: 252725
Thinking more about the last commit I came to realize that for testing the
new functionality it is sufficient to verify that the iteration domains
we construct for a simple test case do not contain any of the complexity that
caused compile time issues for larger inputs.
llvm-svn: 252714
Previously, we just skipped error blocks during scop construction. With
this change we make sure we can construct domains for error blocks such that
these domains can be forwarded to subsequent basic blocks.
This change ensures that basic blocks that post-dominate and are dominated by
a basic block that branches to an error condition have the very same iteration
domain as the branching basic block. Before, this change we would construct
a domain that excludes all error conditions. Such domains could become _very_
complex and were undesirable to build.
Another solution would have been to drop these constraints using a
dominance/post-dominance check instead of modeling the error blocks. Such
a solution could also work in case of unreachable statements or infinite
loops in the scop. However, as we currently (to my believe incorrectly) model
unreachable basic blocks in the post-dominance tree, such a solution is not
yet feasible and requires first a change to LLVM's post-dominance tree
construction.
This commit addresses the most sever compile time issue reported in:
http://llvm.org/PR25458
llvm-svn: 252713
Especially for structs, the SAI object of a base pointer does not
describe all the types that the user might expect when he loads from
that base pointer. While we will still cast integers and pointers we
will now reload the value with the correct type if floating point and
non-floating point values are involved. However, there are now TODOs
where we use bitcasts instead of a proper conversion or reloading.
This fixes bug 25479.
llvm-svn: 252706
We now create all invariant equivalence classes for required invariant loads
instead of creating them on-demand. This way we can check if a parameter
references an invariant load that is actually not executed and was therefor
not materialized. If that happens the parameter is not materialized either.
This fixes bug 25469.
llvm-svn: 252701
Since 252422 we do not only distinguish two ScopArrayInfo kinds, PHI nodes
and others, but work with three kind of ScopArrayInfo objects. SCALAR, PHI and
ARRAY objects. Instead of keeping two boolean flags isPHI and isScalar and
wonder what an ScopArrayInfo object of kind (!isScalar && isPHI) is, we
list now explicitly the three different possible types of memory objects.
This change also allows us to remove the confusing nested pairs that have
been used in ArrayInfoMapTy.
llvm-svn: 252620
In case we also model scalar reads it can happen that a pointer appears in both
a scalar read access as well as the base pointer of an array access. As this
is a little surprising, we add a specific test case to document this behaviour.
To my understanding it should be OK to have a read from an array A[] and
read/write accesses to A[...]. isl is treating these arrays as unrelated as
their dimensionality differs. This seems to be correct as A[] remains constant
throughout the execution of the scop and is not affected by the reads/writes to
A[...]. If this causes confusion, it might make sense to make this behaviour
more obvious by using different names (e.g., A_scalar[], A[...]).
llvm-svn: 252615
Tobias Grosser