Commit Graph

280 Commits

Author SHA1 Message Date
Tobias Grosser 74814e1a07 Disable invariant load hoisting temporarily
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
2016-08-15 16:43:36 +00:00
Michael Kruse a6cc0d3a2d [ScopDetection] Remove unused DetectionContexts during expansion.
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
2016-08-08 22:39:32 +00:00
Tobias Grosser 629109b633 GPGPU: Mark kernel functions as polly.skip
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
2016-08-03 12:00:07 +00:00
Weiming Zhao 7614e178cb Fix a build warning of unhandled enum in switch
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
2016-07-11 18:27:52 +00:00
Michael Kruse a1a303f31e Add comment on why loops/regions can overlap. NFC.
The case is described in llvm.org/PR28071 which was fixed in the
previous commit.

llvm-svn: 273906
2016-06-27 19:00:55 +00:00
Michael Kruse 41f046a282 Fix assertion due to loop overlap with nonaffine region.
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
2016-06-27 19:00:49 +00:00
Tobias Grosser 8dd653d983 clang-tidy: apply modern-use-nullptr fixes
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
2016-06-22 16:22:00 +00:00
Tobias Grosser ef6ae7030d ScopDetection: Make enum function-local
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
2016-06-11 09:00:37 +00:00
Johannes Doerfert 1dafea4114 Make the detection context non-constant [NFC]
llvm-svn: 270410
2016-05-23 09:07:08 +00:00
Johannes Doerfert 469db6a247 Move internal enum out of class declaration [NFC]
llvm-svn: 270054
2016-05-19 12:36:43 +00:00
Johannes Doerfert ffd222f2d6 Propagate the DetectionContext to the SCoP [NFC]
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
2016-05-19 12:34:57 +00:00
Johannes Doerfert f5841a66af Remove leftover debug output [NFC]
llvm-svn: 270051
2016-05-19 12:32:54 +00:00
Johannes Doerfert e6e3c9246a Check late for profitability
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
2016-05-12 20:21:50 +00:00
Johannes Doerfert 6c7639b380 Cleanup rejection log handling [NFC]
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
2016-05-12 18:50:01 +00:00
Johannes Doerfert bf9473b2d8 Weaken profitability constraints during ScopDetection
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
2016-05-10 14:42:30 +00:00
Johannes Doerfert 792374b941 Allow unsigned comparisons
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
2016-04-26 14:33:12 +00:00
Johannes Doerfert 517d8d2f94 Check only loop control of loops that are part of the region
This also removes a duplicated line of code in the region generator
  that caused a SPEC benchmark to fail with the new SCoPs.

llvm-svn: 267404
2016-04-25 13:37:24 +00:00
Johannes Doerfert ec8a217729 Remove unnecessary argument of the SCEVValidator [NFC]
llvm-svn: 267400
2016-04-25 13:32:36 +00:00
Johannes Doerfert 561d36b320 Allow pointer expressions in SCEVs again.
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
2016-04-10 09:50:10 +00:00
Johannes Doerfert fbb63b8028 [FIX] Do not allow select as a base pointer in the SCoP region
llvm-svn: 265884
2016-04-09 21:57:13 +00:00
Johannes Doerfert 81c41b99a7 Do not allow exception handling code in SCoPs
llvm-svn: 265883
2016-04-09 21:55:58 +00:00
Johannes Doerfert d5edbd61a1 [FIX] Do not create a SCoP in the presence of infinite loops
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
2016-04-03 23:09:06 +00:00
Tobias Grosser 151ae32dba Revert "[FIX] Do not create a SCoP in the presence of infinite loops"
This reverts commit r265260, as it caused the following 'make check-polly'
failures:

    Polly :: ScopDetect/index_from_unpredictable_loop.ll
    Polly :: ScopInfo/multiple_exiting_blocks.ll
    Polly :: ScopInfo/multiple_exiting_blocks_two_loop.ll
    Polly :: ScopInfo/schedule-const-post-dominator-walk-2.ll
    Polly :: ScopInfo/schedule-const-post-dominator-walk.ll
    Polly :: ScopInfo/switch-5.ll

llvm-svn: 265272
2016-04-03 19:36:52 +00:00
Johannes Doerfert 7dcceb82e9 [FIX] Do not create a SCoP in the presence of infinite loops
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
2016-04-03 11:12:39 +00:00
Tobias Grosser db6db505c9 ScoPDetection: Obtain a known free diagnostic ID
... 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
2016-04-01 07:15:19 +00:00
Johannes Doerfert 733ea34f38 [FIX] Handle accesses to "null" in MemIntrinsics
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
2016-03-24 13:50:04 +00:00
Johannes Doerfert 13d5d5b184 Remove weird comment [NFC]
llvm-svn: 264268
2016-03-24 13:16:49 +00:00
Tobias Grosser 898a636210 Add option to disallow modref function calls in scops.
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
2016-03-23 06:40:15 +00:00
Michael Kruse 09eb4451d2 Pass scope and LoopInfo to SCEVValidator. NFC.
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
2016-03-03 22:10:47 +00:00
Michael Kruse c7e0d9c216 Fix non-synthesizable loop exit values.
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
2016-03-01 21:44:06 +00:00
Michael Kruse 0b56681d21 [ScopDetection] Fix use-after-free.
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
2016-02-29 16:54:18 +00:00
Hongbin Zheng 8efb22ef25 Enable llvm's isa/cast/dyn_cast on MemAccInst.
Differential Revision: http://reviews.llvm.org/D17250

llvm-svn: 262100
2016-02-27 01:49:58 +00:00
Tobias Grosser 8fa3e4c3fb ScopDetect/Info: Add option to disable invariant load hoisting
This is helpful for test case reduction and other experiments.

llvm-svn: 262033
2016-02-26 16:43:35 +00:00
Michael Kruse 0ac2d3e217 ScopDetection: Fix mix-up of isLoad and isStore.
This was accidentally introduced in r258947.

Thanks to Hongbin Zheng for finding this.

Found-by: etherzhhb
llvm-svn: 262032
2016-02-26 16:40:35 +00:00
Hongbin Zheng f3d6612c0a [MemAccInst] Introduce the '->' operator and remove the simple wrapper functions. NFC
llvm-svn: 261994
2016-02-26 09:47:11 +00:00
Johannes Doerfert a792098047 Support calls with known ModRef function behaviour
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
2016-02-25 14:08:48 +00:00
Johannes Doerfert 8c83078449 Simplify code [NFC]
llvm-svn: 261864
2016-02-25 14:07:49 +00:00
Johannes Doerfert 9dd42ee7c1 Try to build alias checks even when non-affine accesses are allowed
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
2016-02-25 14:06:11 +00:00
Johannes Doerfert cea6193b79 Support memory intrinsics
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
2016-02-21 19:13:19 +00:00
Tobias Grosser a2ee003239 ScopDectect: Allow memory accesses with different element types by default (try 3)
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
2016-02-16 14:37:24 +00:00
Hongbin Zheng 226232044a [Refactor] Eliminate the global variable "InsnToMemAcc".
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
2016-02-15 00:20:58 +00:00
Tobias Grosser 5e27ec33ea Revert "[ScopDectect] Allow memory accesses with different element types by default"
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
2016-02-14 19:59:29 +00:00
Tobias Grosser 5f105f9bdd [ScopDectect] Allow memory accesses with different element types by default
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. This fixed the last known bug.

llvm-svn: 260853
2016-02-14 19:11:16 +00:00
Tobias Grosser 8ebdc2dd53 Make memory accesses with different element types optional
We also disable this feature by default, as there are still some issues in
combination with invariant load hoisting that slipped through my initial
testing.

llvm-svn: 260025
2016-02-07 08:48:57 +00:00
Tobias Grosser d840fc7277 Support accesses with differently sized types to the same array
This allows code such as:

void multiple_types(char *Short, char *Float, char *Double) {
  for (long i = 0; i < 100; i++) {
    Short[i] = *(short *)&Short[2 * i];
    Float[i] = *(float *)&Float[4 * i];
    Double[i] = *(double *)&Double[8 * i];
  }
}

To model such code we use as canonical element type of the modeled array the
smallest element type of all original array accesses, if type allocation sizes
are multiples of each other. Otherwise, we use a newly created iN type, where N
is the gcd of the allocation size of the types used in the accesses to this
array. Accesses with types larger as the canonical element type are modeled as
multiple accesses with the smaller type.

For example the second load access is modeled as:

  { Stmt_bb2[i0] -> MemRef_Float[o0] : 4i0 <= o0 <= 3 + 4i0 }

To support code-generating these memory accesses, we introduce a new method
getAccessAddressFunction that assigns each statement instance a single memory
location, the address we load from/store to. Currently we obtain this address by
taking the lexmin of the access function. We may consider keeping track of the
memory location more explicitly in the future.

We currently do _not_ handle multi-dimensional arrays and also keep the
restriction of not supporting accesses where the offset expression is not a
multiple of the access element type size. This patch adds tests that ensure
we correctly invalidate a scop in case these accesses are found. Both types of
accesses can be handled using the very same model, but are left to be added in
the future.

We also move the initialization of the scop-context into the constructor to
ensure it is already available when invalidating the scop.

Finally, we add this as a new item to the 2.9 release notes

Reviewers: jdoerfert, Meinersbur

Differential Revision: http://reviews.llvm.org/D16878

llvm-svn: 259784
2016-02-04 13:18:42 +00:00
Tobias Grosser e2c31210b2 Revert "Support loads with differently sized types from a single array"
This reverts commit (@259587). It needs some further discussions.

llvm-svn: 259629
2016-02-03 05:53:27 +00:00
Tobias Grosser 5d3fc1ea43 Support loads with differently sized types from a single array
We support now code such as:

void multiple_types(char *Short, char *Float, char *Double) {
  for (long i = 0; i < 100; i++) {
    Short[i] = *(short *)&Short[2 * i];
    Float[i] = *(float *)&Float[4 * i];
    Double[i] = *(double *)&Double[8 * i];
  }
}

To support such code we use as element type of the modeled array the smallest
element type of all original array accesses. Accesses with larger types are
modeled as multiple accesses with the smaller type.

For example the second load access is modeled as:

  { Stmt_bb2[i0] -> MemRef_Float[o0] : 4i0 <= o0 <= 3 + 4i0 }

To support jscop-rewritable memory accesses we need each statement instance to
only be assigned a single memory location, which will be the address at which
we load the value. Currently we obtain this address by taking the lexmin of
the access function. We may consider keeping track of the memory location more
explicitly in the future.

llvm-svn: 259587
2016-02-02 22:05:29 +00:00
Michael Kruse 70131d3416 Introduce MemAccInst helper class; NFC
MemAccInst wraps the common members of LoadInst and StoreInst. Also use
of this class in:
- ScopInfo::buildMemoryAccess
- BlockGenerator::generateLocationAccessed
- ScopInfo::addArrayAccess
- Scop::buildAliasGroups
- Replace every use of polly::getPointerOperand

Reviewers: jdoerfert, grosser

Differential Revision: http://reviews.llvm.org/D16530

llvm-svn: 258947
2016-01-27 17:09:17 +00:00
Tobias Grosser 1c3a6d7808 ScopDetection: Do not detect regions with irreducible control as scops
Polly currently does not support irreducible control and it is probably not
worth supporting. This patch adds code that checks for irreducible control
and refuses regions containing irreducible control.

Polly traditionally had rather restrictive checks on the control flow structure
which would have refused irregular control, but within the last couple of months
most of the control flow restrictions have been removed. As part of this
generalization we accidentally allowed irregular control flow.

Contributed-by: Karthik Senthil and Ajith Pandel
llvm-svn: 258497
2016-01-22 09:44:37 +00:00
Tobias Grosser c6424ae46c ScopDetection: Simplify std::distance(....) to BB->size()
Suggested by: Johannes Doerfert <doerfert@cs.uni-saarland.de>

llvm-svn: 256260
2015-12-22 17:38:59 +00:00