Commit r286294 introduced support for inaccessiblememonly and
inaccessiblemem_or_argmemonly attributes to BasicAA, which we need to
support to avoid undefined behavior. This change just refuses all calls
which are annotated with these attributes, which is conservatively correct.
In the future we may consider to model and support such function calls
in Polly.
llvm-svn: 286771
The validity of a branch condition must be verified at the location of the
branch (the branch instruction), not the location of the icmp that is
used in the branch instruction. When verifying at the wrong location, we
may accept an icmp that is defined within a loop which itself dominates, but
does not contain the branch instruction. Such loops cannot be modeled as
we only introduce domain dimensions for surrounding loops. To address this
problem we change the scop detection to evaluate and verify SCEV expressions at
the right location.
This issue has been around since at least r179148 "scop detection: properly
instantiate SCEVs to the place where they are used", where we explicitly
set the scope to the wrong location. Before this commit the scope
was not explicitly set, which probably also resulted in the scope around the
ICmp to be choosen.
This resolves http://llvm.org/PR30989
Reported-by: Eli Friedman <efriedma@codeaurora.org>
llvm-svn: 286769
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
Summary:
Both `canUseISLTripCount()` and `addOverApproximatedRegion()` contained checks
to reject endless loops which are now removed and replaced by a single check
in `isValidLoop()`.
For reporting such loops the `ReportLoopOverlapWithNonAffineSubRegion` is
renamed to `ReportLoopHasNoExit`. The test case
`ReportLoopOverlapWithNonAffineSubRegion.ll` is adapted and renamed as well.
The schedule generation in `buildSchedule()` is based on the following
assumption:
Given some block B that is contained in a loop L and a SESE region R,
we assume that L is contained in R or the other way around.
However, this assumption is broken in the presence of endless loops that are
nested inside other loops. Therefore, in order to prevent erroneous behavior
in `buildSchedule()`, r265280 introduced a corresponding check in
`canUseISLTripCount()` to reject endless loops. Unfortunately, it was possible
to bypass this check with -polly-allow-nonaffine-loops which was fixed by adding
another check to reject endless loops in `allowOverApproximatedRegion()` in
r273905. Hence there existed two separate locations that handled this case.
Thank you Johannes Doerfert for helping to provide the above background
information.
Reviewers: Meinersbur, grosser
Subscribers: _jdoerfert, pollydev
Differential Revision: https://reviews.llvm.org/D24560
Contributed-by: Matthias Reisinger <d412vv1n@gmail.com>
llvm-svn: 281987
LLVM's coding guideline suggests to not use @brief for one-sentence doxygen
comments to improve readability. Switch this once and for all to ensure people
do not copy @brief comments from other parts of Polly, when writing new code.
llvm-svn: 280468
With invariant load hoisting enabled the LLVM buildbots currently show some
miscompiles, which are possibly caused by invariant load hosting itself.
Confirming and fixing this requires a more in-depth analysis. To meanwhile get
back green buildbots that allow us to observe other regressions, we disable
invariant code hoisting temporarily. The relevant bug is tracked at:
http://llvm.org/PR28985
llvm-svn: 278681
The function expandRegion() frees Region* objects again when it determines that
these are not valid SCoPs. However, the DetectionContext added to the
DetectionContextMap still holds a reference. The validity is checked using the
ValidRegions lookup table. When a new Region is added to that list, it might
share the same address, such that the DetectionContext contains two
Region* associations that are in ValidRegions, but that are unrelated and of
which one has already been free.
Also remove the DetectionContext when not a valid expansion.
llvm-svn: 278062
Otherwise, we would try to re-optimize them with Polly-ACC and possibly even
generate kernels that try to offload themselves, which does not work as the
GPURuntime is not available on the accelerator and also does not make any
sense.
llvm-svn: 277589
Summary: LLVM adds a new value FMRB_DoesNotReadMemory in the enumeration.
Reviewers: andrew.w.kaylor, chrisj, zinob, grosser, jdoerfert
Subscribers: Meinersbur, pollydev
Differential Revision: http://reviews.llvm.org/D22109
llvm-svn: 275085
Reject and report regions that contains loops overlapping nonaffine region.
This situation typically happens in the presence of inifinite loops.
This addresses bug llvm.org/PR28071.
Differential Revision: http://reviews.llvm.org/D21312
Contributed-by: Huihui Zhang <huihuiz@codeaurora.org>
llvm-svn: 273905
Instead of using 0 or NULL use the C++11 nullptr symbol when referencing null
pointers.
This cleanup was suggested by Eugene Zelenko <eugene.zelenko@gmail.com> in
http://reviews.llvm.org/D21488 and was split out to increase readability.
llvm-svn: 273435
The 'Color' enum is only used for irreducible control flow detection. Johannes
already moved this enum in r270054 from ScopDetection.h to ScopDetection.cpp to
limit its scope to a single cpp file. We now move it into the only function
where this enum is needed to make clear that it is only needed locally in this
single function.
Thanks to Johannes for pointing out this cleanup opportunity.
llvm-svn: 272462
The SCoP now holds a reference to the ScopDetection::DetectionContext
which allows to simplify the type of various methods and remove code.
llvm-svn: 270053
Before this patch we only expanded valid __and__ profitable region. Therefor
we did not allow the expansion to create a profitable region from a
non-profitable one. With this patch we will remember and expand all valid
regions and check for profitability only at the end.
This patch increases the number of valid SCoPs in the LLVM-TS and SPEC
2000/2006 by 28% (from 303 to 390), including the hot loop in hmmer.
llvm-svn: 269343
This patch cleans up the rejection log handling during the
ScopDetection. It consists of two interconnected parts:
- We keep all detection contexts for a function in order to provide
more information to the user, e.g., about the rejection of
extended/intermediate regions.
- We remove the mutable "RejectLogs" member as the information is
available through the detection contexts.
llvm-svn: 269323
Regions with one affine loop can be profitable if the loop is
distributable. To this end we will allow them to be treated as
profitable if they contain at least two non-trivial basic blocks.
llvm-svn: 269064
With this patch we will optimistically assume that the result of an unsigned
comparison is the same as the result of the same comparison interpreted as
signed.
llvm-svn: 267559
In r247147 we disabled pointer expressions because the IslExprBuilder did not
fully support them. This patch reintroduces them by simply treating them as
integers. The only special handling for pointers that is left detects the
comparison of two address_of operands and uses an unsigned compare.
llvm-svn: 265894
If a loop has no exiting blocks the region covering we use during
schedule genertion might not cover that loop properly. For now we bail
out as we would not optimize these loops anyway.
llvm-svn: 265280
If a loop has no exiting blocks the region covering we use during
schedule genertion might not cover that loop properly. For now we bail
out as we would not optimize these loops anyway.
llvm-svn: 265260
... instead of hardcoding something that has been free at some point. This fixes
a crash triggered by r265084, where the diagnostic IDs have been shifted in a
way that resulted our hardcode ID to not be assigned any implementation. Our ID
was likely already wrong earlier on, but this time we really crashed nicely.
llvm-svn: 265114
This fixes PR27035. While we now exclude MemIntrinsics from the
polyhedral model if they would access "null" we could exploit this
even more, e.g., remove all parameter combinations that would lead to
the execution of this statement from the context.
llvm-svn: 264284
This might be useful to evaluate the benefit of us handling modref funciton
calls. Also, a new bug that was triggered by modref function calls was
recently reported http://llvm.org/PR27035. To ensure the same issue does not
cause troubles for other people, we temporarily disable this until the bug
is resolved.
llvm-svn: 264140
The scope will be required in the following fix. This commit separates
the large changes that do not change behaviour from the small, but
functional change.
llvm-svn: 262664
Polly recognizes affine loops that ScalarEvolution does not, in
particular those with loop conditions that depend on hoisted invariant
loads. Check for SCEVAddRec dependencies on such loops and do not
consider their exit values as synthesizable because SCEVExpander would
generate them as expressions that depend on the original induction
variables. These are not available in generated code.
llvm-svn: 262404
removeCachedResults deletes the DetectionContext from
DetectionContextMap such that any it cannot be used anymore.
Unfortunately invalid<ReportUnprofitable> and RejectLogs.insert still do
use it. Because the memory is part of a map and not returned to to the
OS immediatly, such that the observable effect was only a memory leak
due to reference counters not decreased when the second call to
removeCachedResults does not remove the DetectionContext because because
it already has been removed.
Fix by not removing the DetectionContext prematurely. The second call to
removeCachedResults will handle it anyway.
llvm-svn: 262235
Check the ModRefBehaviour of functions in order to decide whether or
not a call instruction might be acceptable.
Differential Revision: http://reviews.llvm.org/D5227
llvm-svn: 261866
From now on we bail only if a non-trivial alias group contains a non-affine
access, not when we discover aliasing and non-affine accesses are allowed.
llvm-svn: 261863
This patch adds support for memcpy, memset and memmove intrinsics. They are
represented as one (memset) or two (memcpy, memmove) memory accesses in the
polyhedral model. These accesses have an access range that describes the
summarized effect of the intrinsic, i.e.,
memset(&A[i], '$', N);
is represented as a write access from A[i] to A[i+N].
Differential Revision: http://reviews.llvm.org/D5226
llvm-svn: 261489
First support for this feature was committed in r259784. Support for
loop invariant load hoisting with different types was added by
Johannes Doerfert in r260045 and r260886.
llvm-svn: 260965
Eliminate the global variable "InsnToMemAcc" to make Scop/ScopInfo become
more protable, such that we can safely use them in a CallGraphSCC pass.
Differential Revision: http://reviews.llvm.org/D17238
llvm-svn: 260863
This reverts commit https://llvm.org/svn/llvm-project/polly/trunk@260853
We unfortunately still have two bugs left which show only up with
-polly-process-unprofitable and which I forgot to test before committing.
llvm-svn: 260854
Tobias Grosser