Commit Graph

403 Commits

Author SHA1 Message Date
George Burgess IV 40dc63e1f0 [Analysis] Make LocationSizes carry an 'imprecise' bit
There are places where we need to merge multiple LocationSizes of
different sizes into one, and get a sensible result.

There are other places where we want to optimize aggressively based on
the value of a LocationSizes (e.g. how can a store of four bytes be to
an area of storage that's only two bytes large?)

This patch makes LocationSize hold an 'imprecise' bit to note whether
the LocationSize can be treated as an upper-bound and lower-bound for
the size of a location, or just an upper-bound.

This concludes the series of patches leading up to this. The most recent
of which is r344108.

Fixes PR36228.

Differential Revision: https://reviews.llvm.org/D44748

llvm-svn: 344114
2018-10-10 06:39:40 +00:00
Thomas Lively d47b5c7bed [ValueTracking] Allow select patterns to work on FP vectors
Summary:
This CL allows constant vectors of floats to be recognized as non-NaN
and non-zero in select patterns. This change makes
`matchSelectPattern` more powerful generally, but was motivated
specifically because I wanted fminnan and fmaxnan to be created for
vector versions of the scalar patterns they are created for.

Tested with check-all on all targets. A testcase in the WebAssembly
backend that tests the non-nan codepath is in an upcoming CL.

Reviewers: aheejin, dschuff

Subscribers: sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D52324

llvm-svn: 343364
2018-09-28 21:36:43 +00:00
Fangrui Song 0cac726a00 llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...)
Summary: The convenience wrapper in STLExtras is available since rL342102.

Reviewers: dblaikie, javed.absar, JDevlieghere, andreadb

Subscribers: MatzeB, sanjoy, arsenm, dschuff, mehdi_amini, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, eraman, aheejin, kbarton, JDevlieghere, javed.absar, gbedwell, jrtc27, mgrang, atanasyan, steven_wu, george.burgess.iv, dexonsmith, kristina, jsji, llvm-commits

Differential Revision: https://reviews.llvm.org/D52573

llvm-svn: 343163
2018-09-27 02:13:45 +00:00
Fedor Sergeev ee8d31c49e [New PM] Introducing PassInstrumentation framework
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@

The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.

Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
  and access to them.

* PassInstrumentation class that handles instrumentation-point interfaces
  that call into PassInstrumentationCallbacks.

* Callbacks accept StringRef which is just a name of the Pass right now.
  There were some ideas to pass an opaque wrapper for the pointer to pass instance,
  however it appears that pointer does not actually identify the instance
  (adaptors and managers might have the same address with the pass they govern).
  Hence it was decided to go simple for now and then later decide on what the proper
  mental model of identifying a "pass in a phase of pipeline" is.

* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
  on different IRUnits (e.g. Analyses).

* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
  usual AnalysisManager::getResult. All pass managers were updated to run that
  to get PassInstrumentation object for instrumentation calls.

* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
  args out of a generic PassManager's extra args. This is the only way I was able to explicitly
  run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
  RepeatedPass::run.
  TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
  and then get rid of getAnalysisResult by improving RepeatedPass implementation.

* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
  PassInstrumentationAnalysis. Callbacks registration should be performed directly
  through PassInstrumentationCallbacks.

* new-pm tests updated to account for PassInstrumentationAnalysis being run

* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
  Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.

  Made getName helper to return std::string (instead of StringRef initially) to fix
  asan builtbot failures on CGSCC tests.

Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858

llvm-svn: 342664
2018-09-20 17:08:45 +00:00
Eric Christopher 019889374b Temporarily Revert "[New PM] Introducing PassInstrumentation framework"
as it was causing failures in the asan buildbot.

This reverts commit r342597.

llvm-svn: 342616
2018-09-20 05:16:29 +00:00
Fedor Sergeev a5f279ea89 [New PM] Introducing PassInstrumentation framework
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@

The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.

Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
  and access to them.

* PassInstrumentation class that handles instrumentation-point interfaces
  that call into PassInstrumentationCallbacks.

* Callbacks accept StringRef which is just a name of the Pass right now.
  There were some ideas to pass an opaque wrapper for the pointer to pass instance,
  however it appears that pointer does not actually identify the instance
  (adaptors and managers might have the same address with the pass they govern).
  Hence it was decided to go simple for now and then later decide on what the proper
  mental model of identifying a "pass in a phase of pipeline" is.

* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
  on different IRUnits (e.g. Analyses).

* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
  usual AnalysisManager::getResult. All pass managers were updated to run that
  to get PassInstrumentation object for instrumentation calls.

* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
  args out of a generic PassManager's extra args. This is the only way I was able to explicitly
  run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
  RepeatedPass::run.
  TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
  and then get rid of getAnalysisResult by improving RepeatedPass implementation.

* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
  PassInstrumentationAnalysis. Callbacks registration should be performed directly
  through PassInstrumentationCallbacks.

* new-pm tests updated to account for PassInstrumentationAnalysis being run

* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
  Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.

Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858

llvm-svn: 342597
2018-09-19 22:42:57 +00:00
Fedor Sergeev 25de3f83be Revert rL342544: [New PM] Introducing PassInstrumentation framework
A bunch of bots fail to compile unittests. Reverting.

llvm-svn: 342552
2018-09-19 14:54:48 +00:00
Fedor Sergeev 875c938fec [New PM] Introducing PassInstrumentation framework
Summary:
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@

The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.

Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
  and access to them.

* PassInstrumentation class that handles instrumentation-point interfaces
  that call into PassInstrumentationCallbacks.

* Callbacks accept StringRef which is just a name of the Pass right now.
  There were some ideas to pass an opaque wrapper for the pointer to pass instance,
  however it appears that pointer does not actually identify the instance
  (adaptors and managers might have the same address with the pass they govern).
  Hence it was decided to go simple for now and then later decide on what the proper
  mental model of identifying a "pass in a phase of pipeline" is.

* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
  on different IRUnits (e.g. Analyses).

* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
  usual AnalysisManager::getResult. All pass managers were updated to run that
  to get PassInstrumentation object for instrumentation calls.

* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
  args out of a generic PassManager's extra args. This is the only way I was able to explicitly
  run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
  RepeatedPass::run.
  TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
  and then get rid of getAnalysisResult by improving RepeatedPass implementation.

* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
  PassInstrumentationAnalysis. Callbacks registration should be performed directly
  through PassInstrumentationCallbacks.

* new-pm tests updated to account for PassInstrumentationAnalysis being run

* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
  Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.

Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858

llvm-svn: 342544
2018-09-19 12:25:52 +00:00
Johannes Doerfert 8b7b743cc1 [LoopInfo][FIX] Remove leftover dump in unit test
llvm-svn: 341968
2018-09-11 17:49:43 +00:00
Johannes Doerfert a58e9214ac [LoopInfo] Fix Loop::getLoopID() for loops with multiple latches
The previous implementation traversed all loop blocks and bailed if one
was not a latch block. Since we are only interested in latch blocks, we
should only traverse those.

llvm-svn: 341926
2018-09-11 11:44:17 +00:00
Alina Sbirlea 7980099adb API to update MemorySSA for cloned blocks and added CFG edges.
Summary:
End goal is to update MemorySSA in all loop passes. LoopUnswitch clones all blocks in a loop. SimpleLoopUnswitch clones some blocks. LoopRotate clones some instructions.
Some of these loop passes also make CFG changes.
This is an API based on what I found needed in LoopUnswitch, SimpleLoopUnswitch, LoopRotate, LoopInstSimplify, LoopSimplifyCFG.
Adding dependent patches using this API for context.

Reviewers: george.burgess.iv, dberlin

Subscribers: sanjoy, jlebar, Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D45299

llvm-svn: 341855
2018-09-10 20:13:01 +00:00
Nico Weber 8267b333ee Rename a few unittests/.../Foo.cpp files to FooTest.cpp
The convention for unit test sources is that they're called FooTest.cpp.

No behavior change.
https://reviews.llvm.org/D51579

llvm-svn: 341313
2018-09-03 12:43:26 +00:00
Max Kazantsev d3a4cbe153 [NFC] Move OrderedInstructions and InstructionPrecedenceTracking to Analysis
These classes don't make any changes to IR and have no reason to be in
Transform/Utils. This patch moves them to Analysis folder. This will allow
us reusing these classes in some analyzes, like MustExecute.

llvm-svn: 341015
2018-08-30 04:49:03 +00:00
George Burgess IV 6f6fe701a0 [MemorySSA] Fix def optimization handling
In order for more complex updates of MSSA to happen (e.g. those in
D45299), MemoryDefs need to be actual `Use`s of what they're optimized
to. This patch makes that happen.

In addition, this patch changes our optimization behavior for Defs
slightly: we'll now consider a Def optimization invalid if the
MemoryAccess it's optimized to changes. That we weren't doing this
before was a bug, but given that we were tracking these with a WeakVH
before, it was sort of difficult for that to matter.

We're already have both of these behaviors for MemoryUses. The
difference is that a MemoryUse's defining access is always its optimized
access, and defining accesses are always `Use`s (in the LLVM sense).

Nothing exploded when testing a stage3 clang+llvm locally, so...

This also includes the test-case promised in r340461.

llvm-svn: 340577
2018-08-23 21:29:11 +00:00
Easwaran Raman aca738b742 [BFI] Use rounding while computing profile counts.
Summary:
Profile count of a block is computed by multiplying its block frequency
by entry count and dividing the result by entry block frequency. Do
rounded division in the last step and update test cases appropriately.

Reviewers: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50822

llvm-svn: 339835
2018-08-16 00:26:59 +00:00
George Burgess IV ff08c80efc [MemorySSA] "Fix" lifetime intrinsic handling
MemorySSA currently creates MemoryAccesses for lifetime intrinsics, and
sometimes treats them as clobbers. This may/may not be the best way
forward, but while we're doing it, we should consider
MayAlias/PartialAlias to be clobbers.

The ideal fix here is probably to remove all of this reasoning about
lifetimes from MemorySSA + put it into the passes that need to care. But
that's a wayyy broader fix that needs some consensus, and we have
miscompiles + a release branch today, and this should solve the
miscompiles just as well.

differential revision is D43269. Landing without an explicit LGTM (and
without using the special please-autoclose-this syntax) so we can still
use that revision as a place to decide what the right fix here is.

llvm-svn: 339411
2018-08-10 05:14:43 +00:00
Manoj Gupta 77eeac3d9e llvm: Add support for "-fno-delete-null-pointer-checks"
Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.

More details : https://lkml.org/lkml/2018/4/4/601

GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.

-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.

This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.

Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv

Reviewed By: efriedma, george.burgess.iv

Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47895

llvm-svn: 336613
2018-07-09 22:27:23 +00:00
John Brawn aa8a88af05 [PhiValues] Adjust unit test to invalidate instructions before deleting them
This should fix a sanitizer buildbot failure.

llvm-svn: 335862
2018-06-28 15:17:07 +00:00
John Brawn bdbbd8381f Add a PhiValuesAnalysis pass to calculate the underlying values of phis
This pass is being added in order to make the information available to BasicAA,
which can't do caching of this information itself, but possibly this information
may be useful for other passes.

Incorporates code based on Daniel Berlin's implementation of Tarjan's algorithm.

Differential Revision: https://reviews.llvm.org/D47893

llvm-svn: 335857
2018-06-28 14:13:06 +00:00
Florian Hahn f681413e67 [ValueLattice] Return false if value range did not change in mergeIn.
llvm-svn: 335729
2018-06-27 12:57:51 +00:00
David Bolvansky ca22d427b9 [SimplifyLibcalls] Replace locked IO with unlocked IO
Summary: If file stream arg is not captured and source is fopen, we could replace IO calls by unlocked IO ("_unlocked" function variants) to gain better speed,

Reviewers: efriedma, RKSimon, spatel, sanjoy, hfinkel, majnemer, lebedev.ri, rja

Reviewed By: rja

Subscribers: rja, srhines, efriedma, lebedev.ri, llvm-commits

Differential Revision: https://reviews.llvm.org/D45736

llvm-svn: 332452
2018-05-16 11:39:52 +00:00
Mandeep Singh Grang 13e70cb181 [unittests] Change std::sort to llvm::sort in response to r327219
r327219 added wrappers to std::sort which randomly shuffle the container before
sorting.  This will help in uncovering non-determinism caused due to undefined
sorting order of objects having the same key.

To make use of that infrastructure we need to invoke llvm::sort instead of
std::sort.

Note: This patch is one of a series of patches to replace *all* std::sort to
llvm::sort.  Refer the comments section in D44363 for a list of all the
required patches.

llvm-svn: 329475
2018-04-07 01:29:45 +00:00
Eric Fiselier 96bbec79b4 [Analysis] Support aligned new/delete functions.
Summary:
Clang's __builtin_operator_new/delete was recently taught about the aligned allocation overloads (r328134). This patch makes LLVM aware of them as well.
This allows the compiler to perform certain optimizations including eliding new/delete calls.

Reviewers: rsmith, majnemer, dblaikie, vsk, bkramer

Reviewed By: bkramer

Subscribers: ckennelly, llvm-commits

Differential Revision: https://reviews.llvm.org/D44769

llvm-svn: 329218
2018-04-04 19:01:51 +00:00
Alina Sbirlea d90c9f4a3c Expose must/may alias info in MemorySSA.
Summary:
Building MemorySSA gathers alias information for Defs/Uses.
Store and expose this information when optimizing uses (when building MemorySSA),
and when optimizing defs or updating uses (getClobberingMemoryAccess).
Current patch does not propagate alias information through MemoryPhis.

Reviewers: gbiv, dberlin

Subscribers: Prazek, sanjoy, llvm-commits

Differential Revision: https://reviews.llvm.org/D38569

llvm-svn: 327035
2018-03-08 18:03:14 +00:00
Florian Hahn 0b7c6422fb [IPSCCP] Add getCompare which returns either true, false, undef or null.
getCompare returns true, false or undef constants if the comparison can
be evaluated, or nullptr if it cannot. This is in line with what
ConstantExpr::getCompare returns. It also allows us to use
ConstantExpr::getCompare for comparing constants.

Reviewers: davide, mssimpso, dberlin, anna

Reviewed By: davide

Differential Revision: https://reviews.llvm.org/D43761

llvm-svn: 326720
2018-03-05 17:33:50 +00:00
George Burgess IV debfbcf86e [MemorySSA] Invalidate def caches on deletion
The only cases I can come up with where this invalidation needs to
happen is when there's a deletion somewhere. If we find more creative
test-cases, we can probably go with another approach mentioned on
PR36529.

Fixes PR36529.

llvm-svn: 326177
2018-02-27 07:20:49 +00:00
George Burgess IV 68ac941780 [MemorySSA] Fix a cache invalidation bug with removed accesses
I suspect there's a deeper issue here, but we probably shouldn't be
using INVALID_MEMORYSSA_ID as liveOnEntry's ID anyway.

llvm-svn: 325971
2018-02-23 23:07:18 +00:00
Serguei Katkov 6a7a4c6a55 [SCEV] Do not cache S -> V if S is not equivalent of V
SCEV tracks the correspondence of created SCEV to original instruction.
However during creation of SCEV it is possible that nuw/nsw/exact flags are
lost.

As a result during expansion of the SCEV the instruction with nuw/nsw/exact
will be used where it was expected and we produce poison incorreclty.

Reviewers: sanjoy, mkazantsev, sebpop, jbhateja
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41578

llvm-svn: 322058
2018-01-09 06:47:14 +00:00
Serguei Katkov da56a7f388 [SCEV] Be careful with nuw/nsw/exact in InsertBinop
InsertBinop tries to find an appropriate instruction instead of
creating a new instruction. When it checks whether instruction is
the same as we need to create it ignores nuw/nsw/exact flags.

It leads to invalid behavior when poison instruction can be used
when it was not expected. Specifically, for example Expander
expands the SCEV built for instruction
%a = add i32 %v, 1
It is possible that InsertBinop can find an instruction
% b = add nuw nsw i32 %v, 1
and will use it instead of version w/o nuw nsw.
It is incorrect.

The patch conservatively ignores all instructions with any of
poison flags installed.

Reviewers: sanjoy, mkazantsev, sebpop, jbhateja
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41576

llvm-svn: 321475
2017-12-27 08:26:22 +00:00
Hal Finkel 2ff24731bb [SimplifyLibCalls] Inline calls to cabs when it's safe to do so
When unsafe algerbra is allowed calls to cabs(r) can be replaced by:

  sqrt(creal(r)*creal(r) + cimag(r)*cimag(r))

Patch by Paul Walker, thanks!

Differential Revision: https://reviews.llvm.org/D40069

llvm-svn: 320901
2017-12-16 01:26:25 +00:00
Michael Zolotukhin 5c0ab473f2 Remove redundant includes from unittests.
llvm-svn: 320630
2017-12-13 21:31:05 +00:00
Simon Dardis 70dbd5fbd0 Infer lowest bits of an integer Multiply when the low bits of the operands are known
When the lowest bits of the operands to an integer multiply are known, the low bits of the result are deducible.
Code to deduce known-zero bottom bits already existed, but this change improves on that by deducing known-ones.

Patch by: Pedro Ferreira

Reviewers: craig.topper, sanjoy, efriedma

Differential Revision: https://reviews.llvm.org/D34029

llvm-svn: 320269
2017-12-09 23:25:57 +00:00
Alina Sbirlea 193429f0c8 [ModRefInfo] Make enum ModRefInfo an enum class [NFC].
Summary:
Make enum ModRefInfo an enum class. Changes to ModRefInfo values should
be done using inline wrappers.
This should prevent future bit-wise opearations from being added, which can be more error-prone.

Reviewers: sanjoy, dberlin, hfinkel, george.burgess.iv

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D40933

llvm-svn: 320107
2017-12-07 22:41:34 +00:00
Max Kazantsev 87f4a3de45 [SCEV][NFC] Introduce isSafeToExpandAt function to SCEVExpander
This function checks that:
1) It is safe to expand a SCEV;
2) It is OK to materialize it at the specified location.
For example, attempt to expand a loop's AddRec to the same loop's preheader should fail.

Differential Revision: https://reviews.llvm.org/D39236

llvm-svn: 318377
2017-11-16 05:10:56 +00:00
Sanjoy Das 3a5e25278a Revert "[SCEV] Maintain and use a loop->loop invalidation dependency"
This reverts commit r315713.  It causes PR34968.

I think I know what the problem is, but I don't think I'll have time to fix it
this week.

llvm-svn: 315962
2017-10-17 01:03:56 +00:00
Matthew Simpson 28799a2509 [SparsePropagation] Enable interprocedural analysis
This patch adds the ability to perform IPSCCP-like interprocedural analysis to
the generic sparse propagation solver. The patch gives clients the ability to
define their own custom LatticeKey types that the generic solver maps to custom
LatticeVal types. The custom lattice keys can be used, for example, to
distinguish among mappings for regular values, values returned from functions,
and values stored in global variables. Clients are responsible for defining how
to convert between LatticeKeys and LLVM Values by providing a specialization of
the LatticeKeyInfo template.

The added unit tests demonstrate how the generic solver can be used to perform
a simplified version of interprocedural constant propagation.

Differential Revision: https://reviews.llvm.org/D37353

llvm-svn: 315919
2017-10-16 17:44:17 +00:00
Sanjoy Das c70a7a02ea [SCEV] Maintain and use a loop->loop invalidation dependency
Summary:
This change uses the loop use list added in the previous change to remember the
loops that appear in the trip count expressions of other loops; and uses it in
forgetLoop.  This lets us not scan every loop in the function on a forgetLoop
call.

With this change we no longer invalidate clear out backedge taken counts on
forgetValue.  I think this is fine -- the contract is that SCEV users must call
forgetLoop(L) if their change to the IR could have changed the trip count of L;
solely calling forgetValue on a value feeding into the backedge condition of L
is not enough.  Moreover, I don't think we can strengthen forgetValue to be
sufficient for invalidating trip counts without significantly re-architecting
SCEV.  For instance, if we have the loop:

  I = *Ptr;
  E = I + 10;
  do {
    // ...
  } while (++I != E);

then the backedge taken count of the loop is 9, and it has no reference to
either I or E, i.e. there is no way in SCEV today to re-discover the dependency
of the loop's trip count on E or I.  So a SCEV client cannot change E to (say)
"I + 20", call forgetValue(E) and expect the loop's trip count to be updated.

Reviewers: atrick, sunfish, mkazantsev

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D38435

llvm-svn: 315713
2017-10-13 17:13:44 +00:00
Sanjoy Das e6b995f2b2 [SCEV] Maintain loop use lists, and use them in forgetLoop
Summary:
Currently we do not correctly invalidate memoized results for add recurrences
that were created directly (i.e. they were not created from a `Value`).  This
change fixes this by keeping loop use lists and using the loop use lists to
determine which SCEV expressions to invalidate.

Here are some statistics on the number of uses of in the use lists of all loops
on a clang bootstrap (config: release, no asserts):

     Count: 731310
       Min: 1
      Mean: 8.555150
50th %time: 4
95th %tile: 25
99th %tile: 53
       Max: 433

Reviewers: atrick, sunfish, mkazantsev

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D38434

llvm-svn: 315672
2017-10-13 05:50:52 +00:00
Daniel Neilson 5acfd1dd78 [SCEV] Properly handle the case of a non-constant start with a zero accum in ScalarEvolution::createAddRecFromPHIWithCastsImpl
Summary:
 This patch fixes an error in the patch to ScalarEvolution::createAddRecFromPHIWithCastsImpl
made in D37265. In that patch we handle the cases where the either the start or accum values can be
zero after truncation. But, we assume that the start value must be a constant if the accum is
zero. This is clearly an erroneous assumption. This change removes that assumption.

Reviewers: sanjoy, dorit, mkazantsev

Reviewed By: sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38814

llvm-svn: 315491
2017-10-11 19:05:14 +00:00
Florian Hahn 8af01573a3 [LVI] Move LVILatticeVal class to separate header file (NFC).
Summary:
This allows sharing the lattice value code between LVI and SCCP (D36656). 

It also adds a `satisfiesPredicate` function, used by D36656.

Reviewers: davide, sanjoy, efriedma

Reviewed By: sanjoy

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D37591

llvm-svn: 314411
2017-09-28 11:09:22 +00:00
Daniel Neilson 1341ac2ced [SCEV] Generalize folding of trunc(x)+n*trunc(y) into folding m*trunc(x)+n*trunc(y)
Summary:
A SCEV such as:
 {%v2,+,((-1 * (trunc i64 (-1 * %v1) to i32)) + (-1 * (trunc i64 %v1 to i32)))}<%loop>

can be folded into, simply, {%v2,+,0}. However, the current code in ::getAddExpr()
will not try to apply the simplification m*trunc(x)+n*trunc(y) -> trunc(trunc(m)*x+trunc(n)*y)
because it only keys off having a non-multiplied trunc as the first term in the simplification.

This patch generalizes this code to try to do a more generic fold of these trunc
expressions.

Reviewers: sanjoy

Reviewed By: sanjoy

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37888

llvm-svn: 313988
2017-09-22 15:47:57 +00:00
Sanjoy Das 76ab23234c [LoopInfo] Make LoopBase and Loop destructors non-public
Summary:
See comment for why I think this is a good idea.

This change also:

 - Removes an SCEV test case.  The SCEV test was not testing anything useful (most of it was `#if 0` ed out) and it would need to be updated to deal with a private ~Loop::Loop.
 - Updates the loop pass manager test case to deal with a private ~Loop::Loop.
 - Renames markAsRemoved to markAsErased to contrast with removeLoop, via the usual remove vs. erase idiom we already have for instructions and basic blocks.

Reviewers: chandlerc

Subscribers: mehdi_amini, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D37996

llvm-svn: 313695
2017-09-19 23:19:00 +00:00
Daniel Neilson 3f0e4ad833 [SCEV] Ensure ScalarEvolution::createAddRecFromPHIWithCastsImpl properly handles out of range truncations of the start and accum values
Summary:
 When constructing the predicate P1 in ScalarEvolution::createAddRecFromPHIWithCastsImpl() it is possible
for the PHISCEV from which the predicate is constructed to be a SCEVConstant instead of a SCEVAddRec. If
this happens, then the cast<SCEVAddRec>(PHISCEV) in the code will assert.

 Such a PHISCEV is possible if either the start value or the accumulator value is a constant value
that not equal to its truncated value, and if the truncated value is zero.

 This patch adds tests that demonstrate the cast<> assertion, and fixes this problem by checking
whether the PHISCEV is a constant before constructing the P1 predicate; if it is, then P1 is
equivalent to one of P2 or P3. Additionally, if we know that the start value or accumulator
value are constants then we check whether the P2 and/or P3 predicates are known false at compile
time; if either is, then we bail out of constructing the AddRec.

Reviewers: sanjoy, mkazantsev, silviu.baranga

Reviewed By: mkazantsev

Subscribers: mkazantsev, llvm-commits

Differential Revision: https://reviews.llvm.org/D37265

llvm-svn: 312568
2017-09-05 19:54:03 +00:00
Chandler Carruth 19913b22c0 [PM] Switch the CGSCC debug messages to use the standard LLVM debug
printing techniques with a DEBUG_TYPE controlling them.

It was a mistake to start re-purposing the pass manager `DebugLogging`
variable for generic debug printing -- those logs are intended to be
very minimal and primarily used for testing. More detailed and
comprehensive logging doesn't make sense there (it would only make for
brittle tests).

Moreover, we kept forgetting to propagate the `DebugLogging` variable to
various places making it also ineffective and/or unavailable. Switching
to `DEBUG_TYPE` makes this a non-issue.

llvm-svn: 310695
2017-08-11 05:47:13 +00:00
Chandler Carruth 23c2f44cc7 [LCG] Switch one of the update methods for the LazyCallGraph to support
limited batch updates.

Specifically, allow removing multiple reference edges starting from
a common source node. There are a few constraints that play into
supporting this form of batching:

1) The way updates occur during the CGSCC walk, about the most we can
   functionally batch together are those with a common source node. This
   also makes the batching simpler to implement, so it seems
   a worthwhile restriction.
2) The far and away hottest function for large C++ files I measured
   (generated code for protocol buffers) showed a huge amount of time
   was spent removing ref edges specifically, so it seems worth focusing
   there.
3) The algorithm for removing ref edges is very amenable to this
   restricted batching. There are just both API and implementation
   special casing for the non-batch case that gets in the way. Once
   removed, supporting batches is nearly trivial.

This does modify the API in an interesting way -- now, we only preserve
the target RefSCC when the RefSCC structure is unchanged. In the face of
any splits, we create brand new RefSCC objects. However, all of the
users were OK with it that I could find. Only the unittest needed
interesting updates here.

How much does batching these updates help? I instrumented the compiler
when run over a very large generated source file for a protocol buffer
and found that the majority of updates are intrinsically updating one
function at a time. However, nearly 40% of the total ref edges removed
are removed as part of a batch of removals greater than one, so these
are the cases batching can help with.

When compiling the IR for this file with 'opt' and 'O3', this patch
reduces the total time by 8-9%.

Differential Revision: https://reviews.llvm.org/D36352

llvm-svn: 310450
2017-08-09 09:05:27 +00:00
Max Kazantsev 6e724762b1 Avoid comparison between signed and unsigned in SCEVExitLimitForget tests
llvm-svn: 310029
2017-08-04 06:03:51 +00:00
Max Kazantsev ba1e70e060 Fix SCEVExitLimitForget tests to make Sanitizer happy
llvm-svn: 310023
2017-08-04 05:06:44 +00:00
Dehao Chen f58df39529 Do not want to use BFI to get profile count for sample pgo
Summary: For SamplePGO, we already record the callsite count in the call instruction itself. So we do not want to use BFI to get profile count as it is less accurate.

Reviewers: tejohnson, davidxl, eraman

Reviewed By: eraman

Subscribers: sanjoy, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D36025

llvm-svn: 309964
2017-08-03 17:11:41 +00:00
Benjamin Kramer a73b410805 Fix use after free in unit test.
llvm-svn: 309952
2017-08-03 15:59:37 +00:00
Max Kazantsev cd50b5cb89 Removed unused variabled from unit test
llvm-svn: 309929
2017-08-03 09:25:44 +00:00
Max Kazantsev 2cb3653404 [SCEV] Re-enable "Cache results of computeExitLimit"
The patch rL309080 was reverted because it did not clean up the cache on "forgetValue"
method call. This patch re-enables this change, adds the missing check and introduces
two new unit tests that make sure that the cache is cleaned properly.

Differential Revision: https://reviews.llvm.org/D36087

llvm-svn: 309925
2017-08-03 08:41:30 +00:00
Alina Sbirlea 967e7966fc Allow None as a MemoryLocation to getModRefInfo
Summary:
Adding part of the changes in D30369 (needed to make progress):
Current patch updates AliasAnalysis and MemoryLocation, but does _not_ clean up MemorySSA.

Original summary from D30369, by dberlin:
Currently, we have instructions which affect memory but have no memory
location. If you call, for example, MemoryLocation::get on a fence,
it asserts. This means things specifically have to avoid that. It
also means we end up with a copy of each API, one taking a memory
location, one not.

This starts to fix that.

We add MemoryLocation::getOrNone as a new call, and reimplement the
old asserting version in terms of it.

We make MemoryLocation optional in the (Instruction, MemoryLocation)
version of getModRefInfo, and kill the old one argument version in
favor of passing None (it had one caller). Now both can handle fences
because you can just use MemoryLocation::getOrNone on an instruction
and it will return a correct answer.

We use all this to clean up part of MemorySSA that had to handle this difference.

Note that literally every actual getModRefInfo interface we have could be made private and replaced with:

getModRefInfo(Instruction, Optional<MemoryLocation>)
and
getModRefInfo(Instruction, Optional<MemoryLocation>, Instruction, Optional<MemoryLocation>)

and delegating to the right ones, if we wanted to.

I have not attempted to do this yet.

Reviewers: dberlin, davide, dblaikie

Subscribers: sanjoy, hfinkel, chandlerc, llvm-commits

Differential Revision: https://reviews.llvm.org/D35441

llvm-svn: 309641
2017-08-01 00:28:29 +00:00
Chandler Carruth f59a838720 [PM/LCG] Teach the LazyCallGraph to maintain reference edges from every
function to every defined function known to LLVM as a library function.

LLVM can introduce calls to these functions either by replacing other
library calls or by recognizing patterns (such as memset_pattern or
vector math patterns) and replacing those with calls. When these library
functions are actually defined in the module, we need to have reference
edges to them initially so that we visit them during the CGSCC walk in
the right order and can effectively rebuild the call graph afterward.

This was discovered when building code with Fortify enabled as that is
a common case of both inline definitions of library calls and
simplifications of code into calling them.

This can in extreme cases of LTO-ing with libc introduce *many* more
reference edges. I discussed a bunch of different options with folks but
all of them are unsatisfying. They either make the graph operations
substantially more complex even when there are *no* defined libfuncs, or
they introduce some other complexity into the callgraph. So this patch
goes with the simplest possible solution of actual synthetic reference
edges. If this proves to be a memory problem, I'm happy to implement one
of the clever techniques to save memory here.

llvm-svn: 308088
2017-07-15 08:08:19 +00:00
Chandler Carruth 051bdb0b22 [PM] Fix a silly bug in my recent update to the CG update logic.
I used the wrong variable to update. This was even covered by a unittest
I wrote, and the comments for the unittest were correct (if confusing)
but the test itself just matched the buggy behavior. =[

llvm-svn: 307764
2017-07-12 09:08:11 +00:00
Konstantin Zhuravlyov bb80d3e1d3 Enhance synchscope representation
OpenCL 2.0 introduces the notion of memory scopes in atomic operations to
  global and local memory. These scopes restrict how synchronization is
  achieved, which can result in improved performance.

  This change extends existing notion of synchronization scopes in LLVM to
  support arbitrary scopes expressed as target-specific strings, in addition to
  the already defined scopes (single thread, system).

  The LLVM IR and MIR syntax for expressing synchronization scopes has changed
  to use *syncscope("<scope>")*, where <scope> can be "singlethread" (this
  replaces *singlethread* keyword), or a target-specific name. As before, if
  the scope is not specified, it defaults to CrossThread/System scope.

  Implementation details:
    - Mapping from synchronization scope name/string to synchronization scope id
      is stored in LLVM context;
    - CrossThread/System and SingleThread scopes are pre-defined to efficiently
      check for known scopes without comparing strings;
    - Synchronization scope names are stored in SYNC_SCOPE_NAMES_BLOCK in
      the bitcode.

Differential Revision: https://reviews.llvm.org/D21723

llvm-svn: 307722
2017-07-11 22:23:00 +00:00
NAKAMURA Takumi 3733fc4011 CGSCCPassManagerTest.cpp: Fix warnings. [-Wunused-variable]
llvm-svn: 307511
2017-07-09 23:06:05 +00:00
Chandler Carruth c213c67df8 [PM] Fix a nasty bug in the new PM where we failed to properly
invalidation of analyses when merging SCCs.

While I've added a bunch of testing of this, it takes something much
more like the inliner to really trigger this as you need to have
partially-analyzed SCCs with updates at just the right time. So I've
added a direct test for this using the inliner and verifying the
domtree. Without the changes here, this test ends up finding a stale
dominator tree.

However, to handle this properly, we need to invalidate analyses
*before* merging the SCCs. After talking to Philip and Sanjoy about this
they convinced me this was the right approach. To do this, we need
a callback mechanism when merging SCCs so we can observe the cycle that
will be merged before the merge happens. This API update ended up being
surprisingly easy.

With this commit, the new PM passes the test-suite again. It hadn't
since MemorySSA was enabled for EarlyCSE as that also will find this bug
very quickly.

llvm-svn: 307498
2017-07-09 13:45:11 +00:00
Chandler Carruth 7c8964d885 [PM] Add unittesting of the call graph update logic with complex
dependencies between analyses.

This uncovers even more issues with the proxies and the splitting apart
of SCCs which are fixed in this patch. I discovered this while trying to
add more rigorous testing for a change I'm making to the call graph
update invalidation logic.

llvm-svn: 307497
2017-07-09 13:16:55 +00:00
Chandler Carruth bd9c29039e [PM] Finish implementing and fix a chain of bugs uncovered by testing
the invalidation propagation logic from an SCC to a Function.

I wrote the infrastructure to test this but didn't actually use it in
the unit test where it was designed to be used. =[ My bad. Once
I actually added it to the test case I discovered that it also hadn't
been properly implemented, so I've implemented it. The logic in the FAM
proxy for an SCC pass to propagate invalidation follows the same ideas
as the FAM proxy for a Module pass, but the implementation is a bit
different to reflect the fact that it is forwarding just for an SCC.

However, implementing this correctly uncovered a surprising "bug" (it
was conservatively correct but relatively very expensive) in how we
handle invalidation when splitting one SCC into multiple SCCs. We did an
eager invalidation when in reality we should be deferring invaliadtion
for the *current* SCC to the CGSCC pass manager and just invaliating the
newly constructed SCCs. Otherwise we end up invalidating too much too
soon. This was exposed by the inliner test case that I've updated. Now,
we invalidate *just* the split off '(test1_f)' SCC when doing the CG
update, and then the inliner finishes and invalidates the '(test1_g,
test1_h)' SCC's analyses. The first few attempts at fixing this hit
still more bugs, but all of those are covered by existing tests. For
example, the inliner should also preserve the FAM proxy to avoid
unnecesasry invalidation, and this is safe because the CG update
routines it uses handle any necessary adjustments to the FAM proxy.

Finally, the unittests for the CGSCC pass manager needed a bunch of
updates where we weren't correctly preserving the FAM proxy because it
hadn't been fully implemented and failing to preserve it didn't matter.

Note that this doesn't yet fix the current crasher due to MemSSA finding
a stale dominator tree, but without this the fix to that crasher doesn't
really make any sense when testing because it relies on the proxy
behavior.

llvm-svn: 307487
2017-07-09 03:59:31 +00:00
Xin Tong 70f7512add [AST] Fix a bug in aliasesUnknownInst. Make sure we are comparing the unknown instructions in the alias set and the instruction interested in.
Summary:
Make sure we are comparing the unknown instructions in the alias set and the instruction interested in.
I believe this is clearly a bug (missed opportunity). I can also add some test cases if desired.

Reviewers: hfinkel, davide, dberlin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34597

llvm-svn: 306241
2017-06-25 12:55:11 +00:00
David Blaikie 7a9b788830 GlobalsModRef: Ensure optnone+readonly/readnone attributes are respected
llvm-svn: 304945
2017-06-07 21:37:39 +00:00
Alina Sbirlea 33e5872367 [mssa] Fix case when there is no definition in a block prior to an inserted use.
Summary:
Check that the first access before one being tested is valid.
Before this patch, if there was no definition prior to the Use being tested,
the first time Iter was deferenced, it hit the sentinel.

Reviewers: dberlin, gbiv

Subscribers: sanjoy, Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D33950

llvm-svn: 304926
2017-06-07 16:46:53 +00:00
David Blaikie c662b50150 GlobalsModRef+OptNone: Don't prove readnone/other properties from an optnone function
Seems like at least one reasonable interpretation of optnone is that the
optimizer never "looks inside" a function. This fix is consistent with
that interpretation.

Specifically this came up in the situation:

f3 calls f2 calls f1
f2 is always_inline
f1 is optnone

The application of readnone to f1 (& thus to f2) caused the inliner to
kill the call to f2 as being trivially dead (without even checking the
cost function, as it happens - not sure if that's also a bug).

llvm-svn: 304833
2017-06-06 20:51:15 +00:00
Chandler Carruth 9a67b07398 Re-sort #include lines for unittests. This uses a slightly modified
clang-format (https://reviews.llvm.org/D33932) to keep primary headers
at the top and handle new utility headers like 'gmock' consistently with
other utility headers.

No other change was made. I did no manual edits, all of this is
clang-format.

This should allow other changes to have more clear and focused diffs,
and is especially motivated by moving some headers into more focused
libraries.

llvm-svn: 304786
2017-06-06 11:06:56 +00:00
Benjamin Kramer c1f5ae236c [OrderedBasicBlock] Return false for comesBefore(A, A)
So far it would return true for the first uncached query, then cached
queries return false.

llvm-svn: 304545
2017-06-02 13:10:31 +00:00
Gor Nishanov e5d2911856 ScalarEvolution unit test: fix typo that breaks check-all
llvm-svn: 304063
2017-05-27 05:24:30 +00:00
Keno Fischer 090f1959c1 [SCEVExpander] Try harder to avoid introducing inttoptr
Summary:
This fixes introduction of an incorrect inttoptr/ptrtoint pair in
the included test case which makes use of non-integral pointers. I
suspect there are more cases like this left, but this takes care of
the one I was seeing at the moment.

Reviewers: sanjoy

Subscribers: mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D33129

llvm-svn: 304058
2017-05-27 03:22:55 +00:00
Xin Tong 9fbfeefadf Revert "Add pthread_self function prototype and make it speculatable."
This reverts commit 143d7445b5dfa2f6d6c45bdbe0433d9fc531be21.

Build breaking

llvm-svn: 303496
2017-05-21 00:37:55 +00:00
Xin Tong 75af3af957 Add pthread_self function prototype and make it speculatable.
Summary: This allows pthread_self to be pulled out of a loop by LICM.

Reviewers: hfinkel, arsenm, davide

Reviewed By: davide

Subscribers: davide, wdng, llvm-commits

Differential Revision: https://reviews.llvm.org/D32782

llvm-svn: 303495
2017-05-20 22:40:25 +00:00
Easwaran Raman dadc0f11ad Add hasProfileSummary and has{Sample|Instrumentation}Profile methods
ProfileSummaryInfo already checks whether the module has sample profile
in determining profile counts. This will also be useful in inliner to
clean up threshold updates.

llvm-svn: 303204
2017-05-16 20:14:39 +00:00
Andrew Kaylor 3cd8c16d7f [TLI] Add declarations for various math header file routines from math-finite.h that create '__<func>_finite as functions
Patch by Chris Chrulski

Differential Revision: https://reviews.llvm.org/D31787

llvm-svn: 302955
2017-05-12 22:11:12 +00:00
Teresa Johnson 2a6b7991d4 Restrict call metadata based hotness detection to Sample PGO mode
Summary:
Don't use the metadata on call instructions for determining hotness
unless we are in sample PGO mode, where it is needed because profile
counts are not accurate. In instrumentation mode this is not necessary
and does more harm than good when calls have VP metadata that hasn't
been properly scaled after transformations or dropped after constant
prop based devirtualization (both should be fixed, but we don't need
to do this in the first place for instrumentation PGO).

This required adjusting a number of tests to distinguish between sample
and instrumentation PGO handling, and to add in profile summary metadata
so that getProfileCount can get the summary.

Reviewers: davidxl, danielcdh

Subscribers: aemerson, rengolin, mehdi_amini, Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D32877

llvm-svn: 302844
2017-05-11 23:18:05 +00:00
Matthias Braun 60b40b8fec TargetLibraryInfo: Introduce wcslen
wcslen is part of the C99 and C++98 standards.

- This introduces the function to TargetLibraryInfo.
- Also set attributes for wcslen in llvm::inferLibFuncAttributes().

Differential Revision: https://reviews.llvm.org/D32837

llvm-svn: 302278
2017-05-05 20:25:50 +00:00
Sanjoy Das bbebcb6c4d Teach SCEV normalization to de/normalize non-affine add recs
Summary:
Before this change, SCEV Normalization would incorrectly normalize
non-affine add recurrences.  To work around this there was (still is)
a check in place to make sure we only tried to normalize affine add
recurrences.

We recently found a bug in aforementioned check to bail out of
normalizing non-affine add recurrences.  However, instead of fixing
the bailout, I have decided to teach SCEV normalization to work
correctly with non-affine add recurrences, making the bailout
unnecessary (I'll remove it in a subsequent change).

I've also added some unit tests (which would have failed before this
change).

Reviewers: atrick, sunfish, efriedma

Reviewed By: atrick

Subscribers: mcrosier, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D32104

llvm-svn: 301281
2017-04-25 00:09:19 +00:00
Wei Mi 8c4053372e [SCEV] Add a local cache for getZeroExtendExpr and getSignExtendExpr to prevent
the exponential behavior.

The patch is to fix PR32043. Functions getZeroExtendExpr and getSignExtendExpr
may call themselves recursively more than once. This is potentially a 2^N
complexity behavior. The exponential behavior was not commonly exposed before
because of existing global cache mechnism like UniqueSCEVs or some early return
mechanism when flags FlagNSW or FlagNUW are seen. However, we still have case
which can expose the exponential behavior, like the case in PR32043, so we add
a local cache in getZeroExtendExpr and getSignExtendExpr. If the input of the
functions -- SCEV and type pair have been seen before, we can find the extended
expression directly in the local cache.

Differential Revision: https://reviews.llvm.org/D30350

llvm-svn: 300494
2017-04-17 20:40:05 +00:00
Sanjoy Das 044f956f9a Generalize SCEV's unit testing helper a bit
llvm-svn: 300379
2017-04-14 23:47:53 +00:00
Craig Topper 8580cd4e1a [ValueTracking] Avoid undefined behavior in unittest by not making a named ArrayRef from a std::initializer_list
One of the ValueTracking unittests creates a named ArrayRef initialized by a std::initializer_list. The underlying array for an std::initializer_list is only guaranteed to have a lifetime as long as the initializer_list object itself. So this can leave the ArrayRef pointing at an array that no long exists.

This fixes this to just create an explicit array instead of an ArrayRef.

Differential Revision: https://reviews.llvm.org/D32089

llvm-svn: 300354
2017-04-14 17:59:19 +00:00
Sanjoy Das b600d3f2c4 Add a unit test for SCEV Normalization
llvm-svn: 300332
2017-04-14 15:50:04 +00:00
Daniel Berlin 554dcd8c89 MemorySSA: Move to Analysis, from Transforms/Utils. It's used as
Analysis, it has Analysis passes, and once NewGVN is made an Analysis,
this removes the cross dependency from Analysis to Transform/Utils.
NFC.

llvm-svn: 299980
2017-04-11 20:06:36 +00:00
Matt Arsenault 3c1fc768ed Allow DataLayout to specify addrspace for allocas.
LLVM makes several assumptions about address space 0. However,
alloca is presently constrained to always return this address space.
There's no real way to avoid using alloca, so without this
there is no way to opt out of these assumptions.

The problematic assumptions include:
- That the pointer size used for the stack is the same size as
  the code size pointer, which is also the maximum sized pointer.

- That 0 is an invalid, non-dereferencable pointer value.

These are problems for AMDGPU because alloca is used to
implement the private address space, which uses a 32-bit
index as the pointer value. Other pointers are 64-bit
and behave more like LLVM's notion of generic address
space. By changing the address space used for allocas,
we can change our generic pointer type to be LLVM's generic
pointer type which does have similar properties.

llvm-svn: 299888
2017-04-10 22:27:50 +00:00
Simon Pilgrim bd83f83b56 Fix signed/unsigned comparison warnings
llvm-svn: 297561
2017-03-11 13:02:31 +00:00
Dehao Chen c2048155a0 Refactor the PSI to extract getCallSiteCount and remove checks for profile type.
Summary: There is no need to check profile count as only CallInst will have metadata attached.

Reviewers: eraman

Reviewed By: eraman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D30799

llvm-svn: 297500
2017-03-10 19:45:16 +00:00
Sanjoy Das 1bd479dd5c [SCEV] Decrease the recursion threshold for CompareValueComplexity
Fixes PR32142.

r287232 accidentally increased the recursion threshold for
CompareValueComplexity from 2 to 32.  This change reverses that change
by introducing a separate flag for CompareValueComplexity's threshold.

llvm-svn: 296992
2017-03-05 23:49:17 +00:00
Sanjoy Das 4897cea4ed Fix signed-unsigned comparison warning
llvm-svn: 296274
2017-02-25 22:25:48 +00:00
Sanjoy Das 39a684d117 [ValueTracking] Don't do an unchecked shift in ComputeNumSignBits
Summary:
Previously we used to return a bogus result, 0, for IR like `ashr %val,
-1`.

I've also added an assert checking that `ComputeNumSignBits` at least
returns 1.  That assert found an already checked in test case where we
were returning a bad result for `ashr %val, -1`.

Fixes PR32045.

Reviewers: spatel, majnemer

Reviewed By: spatel, majnemer

Subscribers: efriedma, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D30311

llvm-svn: 296273
2017-02-25 20:30:45 +00:00
Chandler Carruth 1f8fcfeac5 [PM/LCG] Teach LCG to support spurious reference edges.
Somewhat amazingly, this only requires teaching it to clean them up when
deleting a dead function from the graph. And we already have exactly the
necessary data structures to do that in the parent RefSCCs.

This allows ArgPromote to work in a much simpler way be merely letting
reference edges linger in the graph after the causing IR is deleted. We
will clean up these edges when we run any function pass over the IR, but
don't remove them eagerly.

This avoids all of the quadratic update issues both in the current pass
manager and in my previous attempt with the new pass manager.

Differential Revision: https://reviews.llvm.org/D29579

llvm-svn: 294663
2017-02-09 23:30:14 +00:00
Chandler Carruth aaad9f84be [PM/LCG] Teach the LazyCallGraph how to replace a function without
disturbing the graph or having to update edges.

This is motivated by porting argument promotion to the new pass manager.
Because of how LLVM IR Function objects work, in order to change their
signature a new object needs to be created. This is efficient and
straight forward in the IR but previously was very hard to implement in
LCG. We could easily replace the function a node in the graph
represents. The challenging part is how to handle updating the edges in
the graph.

LCG previously used an edge to a raw function to represent a node that
had not yet been scanned for calls and references. This was the core
of its laziness. However, that model causes this kind of update to be
very hard:
1) The keys to lookup an edge need to be `Function*`s that would all
   need to be updated when we update the node.
2) There will be some unknown number of edges that haven't transitioned
   from `Function*` edges to `Node*` edges.

All of this complexity isn't necessary. Instead, we can always build
a node around any function, always pointing edges at it and always using
it as the key to lookup an edge. To maintain the laziness, we need to
sink the *edges* of a node into a secondary object and explicitly model
transitioning a node from empty to populated by scanning the function.
This design seems much cleaner in a number of ways, but importantly
there is now exactly *one* place where the `Function*` has to be
updated!

Some other cleanups that fall out of this include having something to
model the *entry* edges more accurately. Rather than hand rolling parts
of the node in the graph itself, we have an explicit `EdgeSequence`
object that gives us exactly the functionality needed. We also have
a consistent place to define the edge iterators and can use them for
both the entry edges and the internal edges of the graph.

The API used to model the separation between a node and its edges is
intentionally very thin as most clients are expected to deal with nodes
that have populated edges. We model this exactly as an optional does
with an additional method to populate the edges when that is
a reasonable thing for a client to do. This is based on API design
suggestions from Richard Smith and David Blaikie, credit goes to them
for helping pick how to model this without it being either too explicit
or too implicit.

The patch is somewhat noisy due to shifting around iterator types and
new syntax for walking the edges of a node, but most of the
functionality change is in the `Edge`, `EdgeSequence`, and `Node` types.

Differential Revision: https://reviews.llvm.org/D29577

llvm-svn: 294653
2017-02-09 23:24:13 +00:00
Chandler Carruth cd07efc793 [SCEV] Scale back the test added in r294181 as it goes quadratic in
SCEV.

This test was immediately the slowest test in 'check-llvm' even in an
optimized build and was driving up the total test time by 50% for me.

Sanjoy has filed a PR about the quadratic behavior in SCEV but it is
also concerning that the test still passes given that r294181 added
a threshold at 32 to SCEV. I've followed up on the original patch to
figure out how this test should work long-term, but for now I want to
get check-llvm to be fast again.

llvm-svn: 294241
2017-02-06 21:27:12 +00:00
Chandler Carruth 2e0fe3e65b [PM/LCG] Remove the lazy RefSCC formation from the LazyCallGraph during
iteration.

The lazy formation of RefSCCs isn't really the most important part of
the laziness here -- that has to do with walking the functions
themselves -- and isn't essential to maintain. Originally, there were
incremental update algorithms that relied on updates happening
predominantly near the most recent RefSCC formed, but those have been
replaced with ones that have much tighter general case bounds at this
point. We do still perform asserts that only scale well due to this
incrementality, but those are easy to place behind EXPENSIVE_CHECKS.

Removing this simplifies the entire analysis by having a single up-front
step that builds all of the RefSCCs in a direct Tarjan walk. We can even
easily replace this with other or better algorithms at will and with
much less confusion now that there is no iterator-based incremental
logic involved. This removes a lot of complexity from LCG.

Another advantage of moving in this direction is that it simplifies
testing the system substantially as we no longer have to worry about
observing and mutating the graph half-way through the RefSCC formation.

We still need a somewhat special iterator for RefSCCs because we want
the iterator to remain stable in the face of graph updates. However,
this now merely involves relative indexing to the current RefSCC's
position in the sequence which isn't too hard.

Differential Revision: https://reviews.llvm.org/D29381

llvm-svn: 294227
2017-02-06 19:38:06 +00:00
Daniil Fukalov 6378bdb2dd [SCEV] limit recursion depth and operands number in getAddExpr
for a quite big function with source like

%add = add nsw i32 %mul, %conv
%mul1 = mul nsw i32 %add, %conv
%add2 = add nsw i32 %mul1, %add
%mul3 = mul nsw i32 %add2, %add
; repeat couple of thousands times
that can be produced by loop unroll, getAddExpr() tries to recursively construct SCEV and runs almost infinite time.

Added recursion depth restriction (with new parameter to set it)

Reviewers: sanjoy

Subscribers: hfinkel, llvm-commits, mzolotukhin

Differential Revision: https://reviews.llvm.org/D28158

llvm-svn: 294181
2017-02-06 12:38:06 +00:00
David L. Jones d21529fa0d [Analysis] Add LibFunc_ prefix to enums in TargetLibraryInfo. (NFC)
Summary:
The LibFunc::Func enum holds enumerators named for libc functions.
Unfortunately, there are real situations, including libc implementations, where
function names are actually macros (musl uses "#define fopen64 fopen", for
example; any other transitively visible macro would have similar effects).

Strictly speaking, a conforming C++ Standard Library should provide any such
macros as functions instead (via <cstdio>). However, there are some "library"
functions which are not part of the standard, and thus not subject to this
rule (fopen64, for example). So, in order to be both portable and consistent,
the enum should not use the bare function names.

The old enum naming used a namespace LibFunc and an enum Func, with bare
enumerators. This patch changes LibFunc to be an enum with enumerators prefixed
with "LibFFunc_". (Unfortunately, a scoped enum is not sufficient to override
macros.)

There are additional changes required in clang.

Reviewers: rsmith

Subscribers: mehdi_amini, mzolotukhin, nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D28476

llvm-svn: 292848
2017-01-23 23:16:46 +00:00
Chandler Carruth f002264d49 [LoopInfo] Add helper methods to compute two useful orderings of the
loops in a function.

These are relatively confusing to talk about and compute correctly so it
seems really good to write down their implementation in one place. I've
replaced one place we needed this in the loop PM infrastructure and
I have another place in a pending patch that wants it.

We can't quite use this for the core loop PM walk because there we're
sometimes working on a sub-forest.

I'll add the expected unittests before committing this but wanted to
make sure folks were happy with these names / comments.

Credit goes to Richard Smith for the idea for naming the order where siblings
are in reverse program order but the tree traversal remains preorder.

Differential Revision: https://reviews.llvm.org/D28932

llvm-svn: 292569
2017-01-20 02:41:20 +00:00
Easwaran Raman 6c8f511f82 Add an interface to scale the frequencies of a set of blocks.
The scaling is done with reference to the the new frequency of a reference block.

Differential Revision: https://reviews.llvm.org/D28535

llvm-svn: 292507
2017-01-19 18:53:16 +00:00
Xin Tong 43c1a26400 Refactor out LoopInfo computation so that it can be used by
other test cases.

Summary: Refactor out LoopInfo computation so that it can be
used by other test cases.

So i am changing this test proactively for later commit, which will use
this function.

Reviewers: sanjoy, hfinkel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28778

llvm-svn: 292250
2017-01-17 20:24:39 +00:00
Ahmed Bougacha 6b9be1dbe1 [TLI] Add prototype checking for all remaining LibFuncs.
This is another step towards unifying all LibFunc prototype checks.
This work started in r267758 (D19469);  add the remaining checks.

Also add a unittest that checks each libfunc declared with a known-valid
and known-invalid prototype.  New libfuncs added in the future are
required to have prototype checking in place; the known-valid test will
fail otherwise.

Differential Revision: https://reviews.llvm.org/D28030

llvm-svn: 292188
2017-01-17 03:10:02 +00:00
Ahmed Bougacha 1539d1de75 [unittests] Alphabetize cmake file list. NFC.
llvm-svn: 292186
2017-01-17 03:09:55 +00:00
Xin Tong 5060fe9dc0 Empty line. NFC.
llvm-svn: 292081
2017-01-15 23:32:11 +00:00
Xin Tong ca02360f46 Use getLoopLatch in place of isLoopSimplifyForm
Summary:
Use getLoopLatch in place of isLoopSimplifyForm. we do not need
to know whether the loop has a preheader nor dedicated exits.

Reviewers: hfinkel, sanjoy, atrick, mkuper

Subscribers: mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D28724

llvm-svn: 292078
2017-01-15 21:17:52 +00:00
Xin Tong b0d60574ff Delete a dead argument. NFC
llvm-svn: 292074
2017-01-15 19:53:59 +00:00
Easwaran Raman a7bdb8a513 Compute summary before calling extractProfTotalWeight
extractProfTotalWeight checks if the profile type is sample profile, but
before that we have to ensure that summary is available. Also expanded
the unittest to test the case where there is no summar

Differential Revision: https://reviews.llvm.org/D28708

llvm-svn: 291982
2017-01-14 00:32:37 +00:00
Easwaran Raman b035f914e4 ProfileSummaryInfo improvements.
* Add is{Hot|Cold}CallSite methods
* Fix a bug in isHotBB where it was looking for MD_prof on a return instruction
* Use MD_prof data only if sample profiling was used to collect profiles.
* Add an unit test to ProfileSummaryInfo

Differential Revision: https://reviews.llvm.org/D28584

llvm-svn: 291878
2017-01-13 01:34:00 +00:00
Chandler Carruth 3bab7e1a79 [PM] Separate the LoopAnalysisManager from the LoopPassManager and move
the latter to the Transforms library.

While the loop PM uses an analysis to form the IR units, the current
plan is to have the PM itself establish and enforce both loop simplified
form and LCSSA. This would be a layering violation in the analysis
library.

Fundamentally, the idea behind the loop PM is to *transform* loops in
addition to running passes over them, so it really seemed like the most
natural place to sink this was into the transforms library.

We can't just move *everything* because we also have loop analyses that
rely on a subset of the invariants. So this patch splits the the loop
infrastructure into the analysis management that has to be part of the
analysis library, and the transform-aware pass manager.

This also required splitting the loop analyses' printer passes out to
the transforms library, which makes sense to me as running these will
transform the code into LCSSA in theory.

I haven't split the unittest though because testing one component
without the other seems nearly intractable.

Differential Revision: https://reviews.llvm.org/D28452

llvm-svn: 291662
2017-01-11 09:43:56 +00:00
Chandler Carruth 3410eb21b6 [PM] Take more drastic measures to work around MSVC's failure on this
code. If this doesn't work and I can't find someone to help who has MSVC
installed, I'll back everything out I guess. =[

llvm-svn: 291661
2017-01-11 09:20:24 +00:00
Chandler Carruth babd4476b2 [PM] Pull a lambda out of an argument into a named variable to try and
get a little more clarity about the nature of the issue MSVC is having
with this code.

llvm-svn: 291656
2017-01-11 08:23:29 +00:00
Chandler Carruth 80813b157e [PM] Another attempt to satisfy MSVC.
llvm-svn: 291655
2017-01-11 07:53:12 +00:00
Chandler Carruth d3435487bf [PM] Try to appease MSVC by explicitly disambiguating a member name as
a template.

llvm-svn: 291654
2017-01-11 07:37:50 +00:00
Chandler Carruth 410eaeb064 [PM] Rewrite the loop pass manager to use a worklist and augmented run
arguments much like the CGSCC pass manager.

This is a major redesign following the pattern establish for the CGSCC layer to
support updates to the set of loops during the traversal of the loop nest and
to support invalidation of analyses.

An additional significant burden in the loop PM is that so many passes require
access to a large number of function analyses. Manually ensuring these are
cached, available, and preserved has been a long-standing burden in LLVM even
with the help of the automatic scheduling in the old pass manager. And it made
the new pass manager extremely unweildy. With this design, we can package the
common analyses up while in a function pass and make them immediately available
to all the loop passes. While in some cases this is unnecessary, I think the
simplicity afforded is worth it.

This does not (yet) address loop simplified form or LCSSA form, but those are
the next things on my radar and I have a clear plan for them.

While the patch is very large, most of it is either mechanically updating loop
passes to the new API or the new testing for the loop PM. The code for it is
reasonably compact.

I have not yet updated all of the loop passes to correctly leverage the update
mechanisms demonstrated in the unittests. I'll do that in follow-up patches
along with improved FileCheck tests for those passes that ensure things work in
more realistic scenarios. In many cases, there isn't much we can do with these
until the loop simplified form and LCSSA form are in place.

Differential Revision: https://reviews.llvm.org/D28292

llvm-svn: 291651
2017-01-11 06:23:21 +00:00
Sanjoy Das 3bb2dbd665 Fix an issue with isGuaranteedToTransferExecutionToSuccessor
I'm not sure if this was intentional, but today
isGuaranteedToTransferExecutionToSuccessor returns true for readonly and
argmemonly calls that may throw.  This commit changes the function to
not implicitly infer nounwind this way.

Even if we eventually specify readonly calls as not throwing,
isGuaranteedToTransferExecutionToSuccessor is not the best place to
infer that.  We should instead teach FunctionAttrs or some other such
pass to tag readonly functions / calls as nounwind instead.

llvm-svn: 290794
2016-12-31 22:12:34 +00:00
Chandler Carruth 443e57e01d [PM] Teach the CGSCC's CG update utility to more carefully invalidate
analyses when we're about to break apart an SCC.

We can't wait until after breaking apart the SCC to invalidate things:
1) Which SCC do we then invalidate? All of them?
2) Even if we invalidate all of them, a newly created SCC may not have
   a proxy that will convey the invalidation to functions!

Previously we only invalidated one of the SCCs and too late. This led to
stale analyses remaining in the cache. And because the caching strategy
actually works, they would get used and chaos would ensue.

Doing invalidation early is somewhat pessimizing though if we *know*
that the SCC structure won't change. So it turns out that the design to
make the mutation API force the caller to know the *kind* of mutation in
advance was indeed 100% correct and we didn't do enough of it. So this
change also splits two cases of switching a call edge to a ref edge into
two separate APIs so that callers can clearly test for this and take the
easy path without invalidating when appropriate. This is particularly
important in this case as we expect most inlines to be between functions
in separate SCCs and so the common case is that we don't have to so
aggressively invalidate analyses.

The LCG API change in turn needed some basic cleanups and better testing
in its unittest. No interesting functionality changed there other than
more coverage of the returned sequence of SCCs.

While this seems like an obvious improvement over the current state, I'd
like to revisit the core concept of invalidating within the CG-update
layer at all. I'm wondering if we would be better served forcing the
callers to handle the invalidation beforehand in the cases that they
can handle it. An interesting example is when we want to teach the
inliner to *update and preserve* analyses. But we can cross that bridge
when we get there.

With this patch, the new pass manager an build all of the LLVM test
suite at -O3 and everything passes. =D I haven't bootstrapped yet and
I'm sure there are still plenty of bugs, but this gives a nice baseline
so I'm going to increasingly focus on fleshing out the missing
functionality, especially the bits that are just turned off right now in
order to let us establish this baseline.

llvm-svn: 290664
2016-12-28 10:34:50 +00:00
Chandler Carruth c6334579e9 [LCG] Teach the ref edge removal to handle a ref edge that is trivial
due to a call cycle.

This actually crashed the ref removal before.

I've added a unittest that covers this kind of interesting graph
structure and mutation.

llvm-svn: 290645
2016-12-28 02:24:58 +00:00
Chandler Carruth ba90ae969c [PM] Introduce the facilities for registering cross-IR-unit dependencies
that require deferred invalidation.

This handles the other real-world invalidation scenario that we have
cases of: a function analysis which caches references to a module
analysis. We currently do this in the AA aggregation layer and might
well do this in other places as well.

Since this is relative rare, the technique is somewhat more cumbersome.
Analyses need to register themselves when accessing the outer analysis
manager's proxy. This proxy is already necessarily present to allow
access to the outer IR unit's analyses. By registering here we can track
and trigger invalidation when that outer analysis goes away.

To make this work we need to enhance the PreservedAnalyses
infrastructure to support a (slightly) more explicit model for "sets" of
analyses, and allow abandoning a single specific analyses even when
a set covering that analysis is preserved. That allows us to describe
the scenario of preserving all Function analyses *except* for the one
where deferred invalidation has triggered.

We also need to teach the invalidator API to support direct ID calls
instead of always going through a template to dispatch so that we can
just record the ID mapping.

I've introduced testing of all of this both for simple module<->function
cases as well as for more complex cases involving a CGSCC layer.

Much like the previous patch I've not tried to fully update the loop
pass management layer because that layer is due to be heavily reworked
to use similar techniques to the CGSCC to handle updates. As that
happens, we'll have a better testing basis for adding support like this.

Many thanks to both Justin and Sean for the extensive reviews on this to
help bring the API design and documentation into a better state.

Differential Revision: https://reviews.llvm.org/D27198

llvm-svn: 290594
2016-12-27 08:40:39 +00:00
Chandler Carruth 162504578b [LCG] Teach the LazyCallGraph to handle visiting the blockaddress
constant expression and to correctly form function reference edges
through them without crashing because one of the operands (the
`BasicBlock` isn't actually a constant despite being an operand of
a constant).

llvm-svn: 290581
2016-12-27 05:00:45 +00:00
George Burgess IV ccae43a247 Don't consider allocsize functions to be allocation functions.
This patch fixes some ASAN unittest failures on FreeBSD. See the
cfe-commits email thread for r290169 for more on those.

According to the LangRef, the allocsize attribute only tells us about
the number of bytes that exist at the memory location pointed to by the
return value of a function. It does not necessarily mean that the
function will only ever allocate. So, we need to be very careful about
treating functions with allocsize as general allocation functions. This
patch makes us fully conservative in this regard, though I suspect that
we have room to be a bit more aggressive if we want.

This has a FIXME that can be fixed by a relatively straightforward
refactor; I just wanted to keep this patch minimal. If this sticks, I'll
come back and fix it in a few days.

llvm-svn: 290397
2016-12-23 01:18:09 +00:00
Chandler Carruth e3f5064b72 [PM] Introduce a reasonable port of the main per-module pass pipeline
from the old pass manager in the new one.

I'm not trying to support (initially) the numerous options that are
currently available to customize the pass pipeline. If we end up really
wanting them, we can add them later, but I suspect many are no longer
interesting. The simplicity of omitting them will help a lot as we sort
out what the pipeline should look like in the new PM.

I've also documented to the best of my ability *why* each pass or group
of passes is used so that reading the pipeline is more helpful. In many
cases I think we have some questionable choices of ordering and I've
left FIXME comments in place so we know what to come back and revisit
going forward. But for now, I've left it as similar to the current
pipeline as I could.

Lastly, I've had to comment out several places where passes are not
ported to the new pass manager or where the loop pass infrastructure is
not yet ready. I did at least fix a few bugs in the loop pass
infrastructure uncovered by running the full pipeline, but I didn't want
to go too far in this patch -- I'll come back and re-enable these as the
infrastructure comes online. But I'd like to keep the comments in place
because I don't want to lose track of which passes need to be enabled
and where they go.

One thing that seemed like a significant API improvement was to require
that we don't build pipelines for O0. It seems to have no real benefit.

I've also switched back to returning pass managers by value as at this
API layer it feels much more natural to me for composition. But if
others disagree, I'm happy to go back to an output parameter.

I'm not 100% happy with the testing strategy currently, but it seems at
least OK. I may come back and try to refactor or otherwise improve this
in subsequent patches but I wanted to at least get a good starting point
in place.

Differential Revision: https://reviews.llvm.org/D28042

llvm-svn: 290325
2016-12-22 06:59:15 +00:00
Daniel Jasper aec2fa352f Revert @llvm.assume with operator bundles (r289755-r289757)
This creates non-linear behavior in the inliner (see more details in
r289755's commit thread).

llvm-svn: 290086
2016-12-19 08:22:17 +00:00
Vedant Kumar a4bd1463c8 Retry: [BPI] Use a safer constructor to calculate branch probabilities
BPI may trigger signed overflow UB while computing branch probabilities for
cold calls or to unreachables. For example, with our current choice of weights,
we'll crash if there are >= 2^12 branches to an unreachable.

Use a safer BranchProbability constructor which is better at handling fractions
with large denominators.

Changes since the initial commit:
  - Use explicit casts to ensure that multiplication operands are 64-bit
    ints.

rdar://problem/29368161

Differential Revision: https://reviews.llvm.org/D27862

llvm-svn: 290022
2016-12-17 01:02:08 +00:00
Vedant Kumar a8871b73bb Revert "[BPI] Use a safer constructor to calculate branch probabilities"
This reverts commit r290016. It breaks this bot, even though the test
passes locally:

  http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/32956/

AnalysisTests: /home/bb/ninja-x64-msvc-RA-centos6/llvm-project/llvm/lib/Support/BranchProbability.cpp:52: static llvm::BranchProbability llvm::BranchProbability::getBranchProbability(uint64_t, uint64_t): Assertion `Numerator <= Denominator && "Probability cannot be bigger than 1!"' failed.
llvm-svn: 290019
2016-12-17 00:19:06 +00:00
Vedant Kumar 9529643e64 [BPI] Use a safer constructor to calculate branch probabilities
BPI may trigger signed overflow UB while computing branch probabilities
for cold calls or to unreachables. For example, with our current choice
of weights, we'll crash if there are >= 2^12 branches to an unreachable.

Use a safer BranchProbability constructor which is better at handling
fractions with large denominators.

rdar://problem/29368161

Differential Revision: https://reviews.llvm.org/D27862

llvm-svn: 290016
2016-12-17 00:09:51 +00:00
Hal Finkel 3ca4a6bcf1 Remove the AssumptionCache
After r289755, the AssumptionCache is no longer needed. Variables affected by
assumptions are now found by using the new operand-bundle-based scheme. This
new scheme is more computationally efficient, and also we need much less
code...

llvm-svn: 289756
2016-12-15 03:02:15 +00:00
Reid Kleckner 30422eea0f Revert "[SCEVExpand] do not hoist divisions by zero (PR30935)"
Reverts r289412. It caused an OOB PHI operand access in instcombine when
ASan is enabled. Reduction in progress.

Also reverts "[SCEVExpander] Add a test case related to r289412"

llvm-svn: 289453
2016-12-12 18:52:32 +00:00
Sanjoy Das b1227db1f4 [SCEVExpander] Add a test case related to r289412
llvm-svn: 289435
2016-12-12 14:57:11 +00:00
Sebastian Pop 8c9cc8c86b [SCEVExpand] do not hoist divisions by zero (PR30935)
SCEVExpand computes the insertion point for the components of a SCEV to be code
generated.  When it comes to generating code for a division, SCEVexpand would
not be able to check (at compilation time) all the conditions necessary to avoid
a division by zero.  The patch disables hoisting of expressions containing
divisions by anything other than non-zero constants in order to avoid hoisting
these expressions past conditions that should hold before doing the division.

The patch passes check-all on x86_64-linux.

Differential Revision: https://reviews.llvm.org/D27216

llvm-svn: 289412
2016-12-12 02:52:51 +00:00
Sanjoy Das 6de678815c [TBAA] Don't generate invalid TBAA when merging nodes
Summary:
Fix a corner case in `MDNode::getMostGenericTBAA` where we can sometimes
generate invalid TBAA metadata.

Reviewers: chandlerc, hfinkel, mehdi_amini, manmanren

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D26635

llvm-svn: 289403
2016-12-11 20:07:25 +00:00
Chandler Carruth 6b9816477b [PM] Support invalidation of inner analysis managers from a pass over the outer IR unit.
Summary:
This never really got implemented, and was very hard to test before
a lot of the refactoring changes to make things more robust. But now we
can test it thoroughly and cleanly, especially at the CGSCC level.

The core idea is that when an inner analysis manager proxy receives the
invalidation event for the outer IR unit, it needs to walk the inner IR
units and propagate it to the inner analysis manager for each of those
units. For example, each function in the SCC needs to get an
invalidation event when the SCC gets one.

The function / module interaction is somewhat boring here. This really
becomes interesting in the face of analysis-backed IR units. This patch
effectively handles all of the CGSCC layer's needs -- both invalidating
SCC analysis and invalidating function analysis when an SCC gets
invalidated.

However, this second aspect doesn't really handle the
LoopAnalysisManager well at this point. That one will need some change
of design in order to fully integrate, because unlike the call graph,
the entire function behind a LoopAnalysis's results can vanish out from
under us, and we won't even have a cached API to access. I'd like to try
to separate solving the loop problems into a subsequent patch though in
order to keep this more focused so I've adapted them to the API and
updated the tests that immediately fail, but I've not added the level of
testing and validation at that layer that I have at the CGSCC layer.

An important aspect of this change is that the proxy for the
FunctionAnalysisManager at the SCC pass layer doesn't work like the
other proxies for an inner IR unit as it doesn't directly manage the
FunctionAnalysisManager and invalidation or clearing of it. This would
create an ever worsening problem of dual ownership of this
responsibility, split between the module-level FAM proxy and this
SCC-level FAM proxy. Instead, this patch changes the SCC-level FAM proxy
to work in terms of the module-level proxy and defer to it to handle
much of the updates. It only does SCC-specific invalidation. This will
become more important in subsequent patches that support more complex
invalidaiton scenarios.

Reviewers: jlebar

Subscribers: mehdi_amini, mcrosier, mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D27197

llvm-svn: 289317
2016-12-10 06:34:44 +00:00
Chandler Carruth 3ab2a5a824 [PM] Extend the explicit 'invalidate' method API on analysis results to
accept an Invalidator that allows them to invalidate themselves if their
dependencies are in turn invalidated.

Rather than recording the dependency graph ahead of time when analysis
get results from other analyses, this simply lets each result trigger
the immediate invalidation of any analyses they actually depend on. They
do this in a way that has three nice properties:

1) They don't have to handle transitive dependencies because the
   infrastructure will recurse for them.
2) The invalidate methods are still called only once. We just
   dynamically discover the necessary topological ordering, everything
   is memoized nicely.
3) The infrastructure still provides a default implementation and can
   access it so that only analyses which have dependencies need to do
   anything custom.

To make this work at all, the invalidation logic also has to defer the
deletion of the result objects themselves so that they can remain alive
until we have collected the complete set of results to invalidate.

A unittest is added here that has exactly the dependency pattern we are
concerned with. It hit the use-after-free described by Sean in much
detail in the long thread about analysis invalidation before this
change, and even in an intermediate form of this change where we failed
to defer the deletion of the result objects.

There is an important problem with doing dependency invalidation that
*isn't* solved here: we don't *enforce* that results correctly
invalidate all the analyses whose results they depend on.

I actually looked at what it would take to do that, and it isn't as hard
as I had thought but the complexity it introduces seems very likely to
outweigh the benefit. The technique would be to provide a base class for
an analysis result that would be populated with other results, and
automatically provide the invalidate method which immediately does the
correct thing. This approach has some nice pros IMO:
- Handles the case we care about and nothing else: only *results*
  that depend on other analyses trigger extra invalidation.
- Localized to the result rather than centralized in the analysis
  manager.
- Ties the storage of the reference to another result to the triggering
  of the invalidation of that analysis.
- Still supports extending invalidation in customized ways.

But the down sides here are:
- Very heavy-weight meta-programming is needed to provide this base
  class.
- Requires a pretty awful API for accessing the dependencies.

Ultimately, I fear it will not pull its weight. But we can re-evaluate
this at any point if we start discovering consistent problems where the
invalidation and dependencies get out of sync. It will fit as a clean
layer on top of the facilities in this patch that we can add if and when
we need it.

Note that I'm not really thrilled with the names for these APIs... The
name "Invalidator" seems ok but not great. The method name "invalidate"
also. In review some improvements were suggested, but they really need
*other* uses of these terms to be updated as well so I'm going to do
that in a follow-up commit.

I'm working on the actual fixes to various analyses that need to use
these, but I want to try to get tests for each of them so we don't
regress. And those changes are seperable and obvious so once this goes
in I should be able to roll them out throughout LLVM.

Many thanks to Sean, Justin, and others for help reviewing here.

Differential Revision: https://reviews.llvm.org/D23738

llvm-svn: 288077
2016-11-28 22:04:31 +00:00
Chandler Carruth 4cf2c89883 [PM] Add an ASCII-art diagram for the call graph in the CGSCC unit test.
No functionality changed.

llvm-svn: 288013
2016-11-28 03:40:33 +00:00
Chandler Carruth dab4eae274 [PM] Change the static object whose address is used to uniquely identify
analyses to have a common type which is enforced rather than using
a char object and a `void *` type when used as an identifier.

This has a number of advantages. First, it at least helps some of the
confusion raised in Justin Lebar's code review of why `void *` was being
used everywhere by having a stronger type that connects to documentation
about this.

However, perhaps more importantly, it addresses a serious issue where
the alignment of these pointer-like identifiers was unknown. This made
it hard to use them in pointer-like data structures. We were already
dodging this in dangerous ways to create the "all analyses" entry. In
a subsequent patch I attempted to use these with TinyPtrVector and
things fell apart in a very bad way.

And it isn't just a compile time or type system issue. Worse than that,
the actual alignment of these pointer-like opaque identifiers wasn't
guaranteed to be a useful alignment as they were just characters.

This change introduces a type to use as the "key" object whose address
forms the opaque identifier. This both forces the objects to have proper
alignment, and provides type checking that we get it right everywhere.
It also makes the types somewhat less mysterious than `void *`.

We could go one step further and introduce a truly opaque pointer-like
type to return from the `ID()` static function rather than returning
`AnalysisKey *`, but that didn't seem to be a clear win so this is just
the initial change to get to a reliably typed and aligned object serving
is a key for all the analyses.

Thanks to Richard Smith and Justin Lebar for helping pick plausible
names and avoid making this refactoring many times. =] And thanks to
Sean for the super fast review!

While here, I've tried to move away from the "PassID" nomenclature
entirely as it wasn't really helping and is overloaded with old pass
manager constructs. Now we have IDs for analyses, and key objects whose
address can be used as IDs. Where possible and clear I've shortened this
to just "ID". In a few places I kept "AnalysisID" to make it clear what
was being identified.

Differential Revision: https://reviews.llvm.org/D27031

llvm-svn: 287783
2016-11-23 17:53:26 +00:00
Chandler Carruth f8c09d63b0 [LCG] Start using SCC relationship predicates in the unittest.
This mostly gives us nice unittesting of the predicates themselves. I'll
start using them further in subsequent commits to help test the actual
operations performed on the graph.

llvm-svn: 287698
2016-11-22 20:35:32 +00:00
Daniil Fukalov 4c3322cc84 [SCEV] limit recursion depth of CompareSCEVComplexity
Summary:
CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled loop) and runs almost infinite time.

Added cache of "equal" SCEV pairs to earlier cutoff of further estimation. Recursion depth limit was also introduced as a parameter.

Reviewers: sanjoy

Subscribers: mzolotukhin, tstellarAMD, llvm-commits

Differential Revision: https://reviews.llvm.org/D26389

llvm-svn: 287232
2016-11-17 16:07:52 +00:00
Nico Weber 85740f6b86 Revert r286437 r286438, they caused PR30976
llvm-svn: 286483
2016-11-10 17:55:41 +00:00
Sanjoy Das 3d75b62ffe [SCEVExpander] Hoist unsigned divisons when safe
That is, when the divisor is a constant non-zero.

llvm-svn: 286438
2016-11-10 07:56:12 +00:00
Sanjoy Das e30a281449 [SCEVExpander] Don't hoist divisions
Fixes PR30942.

llvm-svn: 286437
2016-11-10 07:56:09 +00:00
Sanjoy Das 6764b9aa31 Lift out a helper lambda; NFC
llvm-svn: 286436
2016-11-10 07:56:05 +00:00
Sanjoy Das 2582e690b7 [TBAA] Drop support for "old style" scalar TBAA tags
Summary:
We've had support for auto upgrading old style scalar TBAA access
metadata tags into the "new" struct path aware TBAA metadata for 3 years
now.  The only way to actually generate old style TBAA was explicitly
through the IRBuilder API.  I think this is a good time for dropping
support for old style scalar TBAA.

I'm not removing support for textual or bitcode upgrade -- if you have
IR with the old style scalar TBAA tags that go through the AsmParser orf
the bitcode parser before LLVM sees them, they will keep working as
usual.

Note:

  %val = load i32, i32* %ptr, !tbaa !N
  !N = < scalar tbaa node >

is equivalent to

  %val = load i32, i32* %ptr, !tbaa !M
  !N = < scalar tbaa node >
  !M = !{!N, !N, 0}

Reviewers: manmanren, chandlerc, sunfish

Subscribers: mcrosier, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D26229

llvm-svn: 286291
2016-11-08 20:46:01 +00:00
Sanjoy Das fd080904b7 Make a test case more rigorous; NFC
llvm-svn: 285536
2016-10-31 03:32:45 +00:00
Sanjoy Das 1707869db5 [SCEV] Try to order n-ary expressions in CompareValueComplexity
llvm-svn: 285535
2016-10-31 03:32:43 +00:00
Sanjoy Das 3d6e3df5f9 [SCEV] Reduce boilerplate in unit tests
llvm-svn: 285534
2016-10-31 03:32:39 +00:00
Sanjoy Das 299e67291c [SCEV] In CompareValueComplexity, order global values by their name
llvm-svn: 285529
2016-10-30 23:52:56 +00:00
Sanjoy Das b53021d71f Clean up test a little bit; NFC
llvm-svn: 285527
2016-10-30 23:52:50 +00:00
Sanjoy Das 507dd40a4a [SCEV] Make CompareValueComplexity a little bit smarter
This helps canonicalization in some cases.

Thanks to Pankaj Chawla for the investigation and the test case!

llvm-svn: 284501
2016-10-18 17:45:16 +00:00
Chandler Carruth 5dbc164d15 [LCG] Add the necessary functionality to the LazyCallGraph to support inlining.
The basic inlining operation makes the following changes to the call graph:
1) Add edges that were previously transitive edges. This is always trivial and
   this patch gives the LCG helper methods to make this more convenient.
2) Remove the inlined edge. We had existing support for this, but it contained
   bugs that needed to be fixed. Testing in the same pattern as the inliner
   exposes these bugs very nicely.
3) Delete a function when it becomes dead because it is internal and all calls
   have been inlined. The LCG had no support at all for this operation, so this
   adds that support.

Two unittests have been added that exercise this specific mutation pattern to
the call graph. They were extremely effective in uncovering bugs. Sadly,
a large fraction of the code here is just to implement those unit tests, but
I think they're paying for themselves. =]

This was split out of a patch that actually uses the routines to
implement inlining in the new pass manager in order to isolate (with
unit tests) the logic that was entirely within the LCG.

Many thanks for the careful review from folks! There will be a few minor
follow-up patches based on the comments in the review as well.

Differential Revision: https://reviews.llvm.org/D24225

llvm-svn: 283982
2016-10-12 07:59:56 +00:00
Chandler Carruth dc288a896e [PM] Refactor this unittest a bit to remove duplicated code. This was
suggested at one point during code review and I deferred it to
a follow-up commit.

llvm-svn: 282383
2016-09-26 06:29:21 +00:00
Chandler Carruth e35f84a2f0 [PM] Add a unittest covering the invalidation of a Module analysis from
a function pass nested inside of a CGSCC pass manager.

This is very similar to the previous unittest but makes sure the
invalidation logic works across all the layers here.

llvm-svn: 282378
2016-09-26 04:17:12 +00:00
Chandler Carruth b52b573deb [PM] Add a unittest for invalidating module analyses with an SCC pass.
This reinstates r280447. Original commit log:
This wasn't really well explicitly tested with a nice unittest before.
It seems good to have reasonably broken out unittests for this kind of
functionality as I'm workin go other invalidation features to make sure
none of the existing ones regress.

This still has too much duplicated code, I plan to factor that out in
a subsequent commit to use common helpers for repeated parts of this.

llvm-svn: 282377
2016-09-26 04:01:55 +00:00
Chandler Carruth 49d728ad21 [LCG] Redesign the lazy post-order iteration mechanism for the
LazyCallGraph to support repeated, stable iterations, even in the face
of graph updates.

This is particularly important to allow the CGSCC pass manager to walk
the RefSCCs (and thus everything else) in a module more than once. Lots
of unittests and other tests were hard or impossible to write because
repeated CGSCC pass managers which didn't invalidate the LazyCallGraph
would conclude the module was empty after the first one. =[ Really,
really bad.

The interesting thing is that in many ways this simplifies the code. We
can now re-use the same code for handling reference edge insertion
updates of the RefSCC graph as we use for handling call edge insertion
updates of the SCC graph. Outside of adapting to the shared logic for
this (which isn't trivial, but is *much* simpler than the DFS it
replaces!), the new code involves putting newly created RefSCCs when
deleting a reference edge into the cached list in the correct way, and
to re-formulate the iterator to be stable and effective even in the face
of these kinds of updates.

I've updated the unittests for the LazyCallGraph to re-iterate the
postorder sequence and verify that this all works. We even check for
using alternating iterators to trigger the lazy formation of RefSCCs
after mutation has occured.

It's worth noting that there are a reasonable number of likely
simplifications we can make past this. It isn't clear that we need to
keep the "LeafRefSCCs" around any more. But I've not removed that mostly
because I want this to be a more isolated change.

Differential Revision: https://reviews.llvm.org/D24219

llvm-svn: 281716
2016-09-16 10:20:17 +00:00
Wei Mi 3076cc398d Add a C++ unittest to test the fix for PR30213.
The test exercises the branch in scev expansion when the value in ValueOffsetPair
is a ptr and the offset is not divisible by the elem type size of value.

Differential Revision: https://reviews.llvm.org/D24088

llvm-svn: 281575
2016-09-15 04:06:44 +00:00
Chandler Carruth ccd44939ef [PM] Revert r280447: Add a unittest for invalidating module analyses with an SCC pass.
This was mistakenly committed. The world isn't ready for this test, the
test code has horrible debugging code in it that should never have
landed in tree, it currently passes because of bugs elsewhere, and it
needs to be rewritten to not be susceptible to passing for the wrong
reasons.

I'll re-land this in a better form when the prerequisite patches land.

So sorry that I got this mixed into a series of commits that *were*
ready to land. I shouldn't have. =[ What's worse is that it stuck around
for so long and I discovered it while fixing the underlying bug that
caused it to pass.

llvm-svn: 280620
2016-09-04 08:42:31 +00:00
Chandler Carruth 0f0ef132af [PM] Try to fix an MSVC2013 failure due to finding a template
constructor when trying to do copy construction by adding an explicit
move constructor.

Will watch the bots to discover if this is sufficient.

llvm-svn: 280479
2016-09-02 10:49:58 +00:00
Chandler Carruth c906ff63da [PM] Add a unittest for invalidating module analyses with an SCC pass.
This wasn't really well explicitly tested with a nice unittest before.
It seems good to have reasonably broken out unittests for this kind of
functionality as I'm workin go other invalidation features to make sure
none of the existing ones regress.

This still has too much duplicated code, I plan to factor that out in
a subsequent commit to use common helpers for repeated parts of this.

llvm-svn: 280447
2016-09-02 01:16:27 +00:00
Chandler Carruth 4f83742ab6 [PM] (NFC) Split the IR parsing into a fixture so that I can split out
more testing into other test routines while using the same core module.

llvm-svn: 280446
2016-09-02 01:14:05 +00:00
Chandler Carruth d4e80a9615 [PM] (NFC) Refactor the CGSCC pass manager tests to use lambda-based
passes.

This simplifies the test some and makes it more focused and clear what
is being tested. It will also make it much easier to extend with further
testing of different pass behaviors.

I've also replaced a pointless module pass with running the requires
pass directly as that is all that it was really doing.

llvm-svn: 280444
2016-09-02 01:08:04 +00:00
Chandler Carruth 8882346842 [PM] Introduce basic update capabilities to the new PM's CGSCC pass
manager, including both plumbing and logic to handle function pass
updates.

There are three fundamentally tied changes here:
1) Plumbing *some* mechanism for updating the CGSCC pass manager as the
   CG changes while passes are running.
2) Changing the CGSCC pass manager infrastructure to have support for
   the underlying graph to mutate mid-pass run.
3) Actually updating the CG after function passes run.

I can separate them if necessary, but I think its really useful to have
them together as the needs of #3 drove #2, and that in turn drove #1.

The plumbing technique is to extend the "run" method signature with
extra arguments. We provide the call graph that intrinsically is
available as it is the basis of the pass manager's IR units, and an
output parameter that records the results of updating the call graph
during an SCC passes's run. Note that "...UpdateResult" isn't a *great*
name here... suggestions very welcome.

I tried a pretty frustrating number of different data structures and such
for the innards of the update result. Every other one failed for one
reason or another. Sometimes I just couldn't keep the layers of
complexity right in my head. The thing that really worked was to just
directly provide access to the underlying structures used to walk the
call graph so that their updates could be informed by the *particular*
nature of the change to the graph.

The technique for how to make the pass management infrastructure cope
with mutating graphs was also something that took a really, really large
number of iterations to get to a place where I was happy. Here are some
of the considerations that drove the design:

- We operate at three levels within the infrastructure: RefSCC, SCC, and
  Node. In each case, we are working bottom up and so we want to
  continue to iterate on the "lowest" node as the graph changes. Look at
  how we iterate over nodes in an SCC running function passes as those
  function passes mutate the CG. We continue to iterate on the "lowest"
  SCC, which is the one that continues to contain the function just
  processed.

- The call graph structure re-uses SCCs (and RefSCCs) during mutation
  events for the *highest* entry in the resulting new subgraph, not the
  lowest. This means that it is necessary to continually update the
  current SCC or RefSCC as it shifts. This is really surprising and
  subtle, and took a long time for me to work out. I actually tried
  changing the call graph to provide the opposite behavior, and it
  breaks *EVERYTHING*. The graph update algorithms are really deeply
  tied to this particualr pattern.

- When SCCs or RefSCCs are split apart and refined and we continually
  re-pin our processing to the bottom one in the subgraph, we need to
  enqueue the newly formed SCCs and RefSCCs for subsequent processing.
  Queuing them presents a few challenges:
  1) SCCs and RefSCCs use wildly different iteration strategies at
     a high level. We end up needing to converge them on worklist
     approaches that can be extended in order to be able to handle the
     mutations.
  2) The order of the enqueuing need to remain bottom-up post-order so
     that we don't get surprising order of visitation for things like
     the inliner.
  3) We need the worklists to have set semantics so we don't duplicate
     things endlessly. We don't need a *persistent* set though because
     we always keep processing the bottom node!!!! This is super, super
     surprising to me and took a long time to convince myself this is
     correct, but I'm pretty sure it is... Once we sink down to the
     bottom node, we can't re-split out the same node in any way, and
     the postorder of the current queue is fixed and unchanging.
  4) We need to make sure that the "current" SCC or RefSCC actually gets
     enqueued here such that we re-visit it because we continue
     processing a *new*, *bottom* SCC/RefSCC.

- We also need the ability to *skip* SCCs and RefSCCs that get merged
  into a larger component. We even need the ability to skip *nodes* from
  an SCC that are no longer part of that SCC.

This led to the design you see in the patch which uses SetVector-based
worklists. The RefSCC worklist is always empty until an update occurs
and is just used to handle those RefSCCs created by updates as the
others don't even exist yet and are formed on-demand during the
bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and
we push new SCCs onto it and blacklist existing SCCs on it to get the
desired processing.

We then *directly* update these when updating the call graph as I was
never able to find a satisfactory abstraction around the update
strategy.

Finally, we need to compute the updates for function passes. This is
mostly used as an initial customer of all the update mechanisms to drive
their design to at least cover some real set of use cases. There are
a bunch of interesting things that came out of doing this:

- It is really nice to do this a function at a time because that
  function is likely hot in the cache. This means we want even the
  function pass adaptor to support online updates to the call graph!

- To update the call graph after arbitrary function pass mutations is
  quite hard. We have to build a fairly comprehensive set of
  data structures and then process them. Fortunately, some of this code
  is related to the code for building the cal graph in the first place.
  Unfortunately, very little of it makes any sense to share because the
  nature of what we're doing is so very different. I've factored out the
  one part that made sense at least.

- We need to transfer these updates into the various structures for the
  CGSCC pass manager. Once those were more sanely worked out, this
  became relatively easier. But some of those needs necessitated changes
  to the LazyCallGraph interface to make it significantly easier to
  extract the changed SCCs from an update operation.

- We also need to update the CGSCC analysis manager as the shape of the
  graph changes. When an SCC is merged away we need to clear analyses
  associated with it from the analysis manager which we didn't have
  support for in the analysis manager infrsatructure. New SCCs are easy!
  But then we have the case that the original SCC has its shape changed
  but remains in the call graph. There we need to *invalidate* the
  analyses associated with it.

- We also need to invalidate analyses after we *finish* processing an
  SCC. But the analyses we need to invalidate here are *only those for
  the newly updated SCC*!!! Because we only continue processing the
  bottom SCC, if we split SCCs apart the original one gets invalidated
  once when its shape changes and is not processed farther so its
  analyses will be correct. It is the bottom SCC which continues being
  processed and needs to have the "normal" invalidation done based on
  the preserved analyses set.

All of this is mostly background and context for the changes here.

Many thanks to all the reviewers who helped here. Especially Sanjoy who
caught several interesting bugs in the graph algorithms, David, Sean,
and others who all helped with feedback.

Differential Revision: http://reviews.llvm.org/D21464

llvm-svn: 279618
2016-08-24 09:37:14 +00:00
Tim Shen f2187ed321 [GraphTraits] Replace all NodeType usage with NodeRef
This should finish the GraphTraits migration.

Differential Revision: http://reviews.llvm.org/D23730

llvm-svn: 279475
2016-08-22 21:09:30 +00:00
Tim Shen b5e0f5ac95 [GraphTraits] Make nodes_iterator dereference to NodeType*/NodeRef
Currently nodes_iterator may dereference to a NodeType* or a NodeType&. Make them all dereference to NodeType*, which is NodeRef later.

Differential Revision: https://reviews.llvm.org/D23704
Differential Revision: https://reviews.llvm.org/D23705

llvm-svn: 279326
2016-08-19 21:20:13 +00:00
Sean Silva 0746f3bfa4 Consistently use LoopAnalysisManager
One exception here is LoopInfo which must forward-declare it (because
the typedef is in LoopPassManager.h which depends on LoopInfo).

Also, some includes for LoopPassManager.h were needed since that file
provides the typedef.

Besides a general consistently benefit, the extra layer of indirection
allows the mechanical part of https://reviews.llvm.org/D23256 that
requires touching every transformation and analysis to be factored out
cleanly.

Thanks to David for the suggestion.

llvm-svn: 278079
2016-08-09 00:28:52 +00:00
Sean Silva 36e0d01e13 Consistently use FunctionAnalysisManager
Besides a general consistently benefit, the extra layer of indirection
allows the mechanical part of https://reviews.llvm.org/D23256 that
requires touching every transformation and analysis to be factored out
cleanly.

Thanks to David for the suggestion.

llvm-svn: 278077
2016-08-09 00:28:15 +00:00
Chandler Carruth 6c138ce31c [PM] Sink the module parsing from the fixture to the test as subsequent
tests will want different IR.

Wanted this when writing tests for the proposed CG update stuff, and
this is an easily separable piece.

llvm-svn: 273973
2016-06-28 00:38:42 +00:00
Chandler Carruth 74a8a2214a [PM] Run clang-format over various parts of the new pass manager code
prior to some very substantial patches to isolate any formatting-only
changes.

llvm-svn: 272991
2016-06-17 07:15:29 +00:00
Chandler Carruth 164a2aa6f4 [PM] Remove support for omitting the AnalysisManager argument to new
pass manager passes' `run` methods.

This removes a bunch of SFINAE goop from the pass manager and just
requires pass authors to accept `AnalysisManager<IRUnitT> &` as a dead
argument. This is a small price to pay for the simplicity of the system
as a whole, despite the noise that changing it causes at this stage.

This will also helpfull allow us to make the signature of the run
methods much more flexible for different kinds af passes to support
things like intelligently updating the pass's progression over IR units.

While this touches many, many, files, the changes are really boring.
Mostly made with the help of my trusty perl one liners.

Thanks to Sean and Hal for bouncing ideas for this with me in IRC.

llvm-svn: 272978
2016-06-17 00:11:01 +00:00
Igor Laevsky 87f0d0e185 Revert r272891 "[JumpThreading] Prevent dangling pointer problems in BranchProbabilityInfo"
It was causing failures in Profile-i386 and Profile-x86_64 tests.

llvm-svn: 272912
2016-06-16 16:25:53 +00:00
Igor Laevsky c9179fd2c2 [JumpThreading] Prevent dangling pointer problems in BranchProbabilityInfo
We should update results of the BranchProbabilityInfo after removing block in JumpThreading. Otherwise 
we will get dangling pointer inside BranchProbabilityInfo cache.

Differential Revision: http://reviews.llvm.org/D20957

llvm-svn: 272891
2016-06-16 13:28:25 +00:00
Michael Zolotukhin 963a6d9c69 Revert "Revert "[Unroll] Implement a conservative and monotonically increasing cost tracking system during the full unroll heuristic analysis that avoids counting any instruction cost until that instruction becomes "live" through a side-effect or use outside the...""
This reverts commit r269395.

Try to reapply with a fix from chapuni.

llvm-svn: 269486
2016-05-13 21:23:25 +00:00
Michael Zolotukhin 9be3b8b9bb Revert "[Unroll] Implement a conservative and monotonically increasing cost tracking system during the full unroll heuristic analysis that avoids counting any instruction cost until that instruction becomes "live" through a side-effect or use outside the..."
This reverts commit r269388.

It caused some bots to fail, I'm reverting it until I investigate the
issue.

llvm-svn: 269395
2016-05-13 06:32:25 +00:00
Michael Zolotukhin b7b8052982 [Unroll] Implement a conservative and monotonically increasing cost tracking system during the full unroll heuristic analysis that avoids counting any instruction cost until that instruction becomes "live" through a side-effect or use outside the...
Summary:
...loop after the last iteration.

This is really hard to do correctly. The core problem is that we need to
model liveness through the induction PHIs from iteration to iteration in
order to get the correct results, and we need to correctly de-duplicate
the common subgraphs of instructions feeding some subset of the
induction PHIs. All of this can be driven either from a side effect at
some iteration or from the loop values used after the loop finishes.

This patch implements this by storing the forward-propagating analysis
of each instruction in a cache to recall whether it was free and whether
it has become live and thus counted toward the total unroll cost. Then,
at each sink for a value in the loop, we recursively walk back through
every value that feeds the sink, including looping back through the
iterations as needed, until we have marked the entire input graph as
live. Because we cache this, we never visit instructions more than twice
-- once when we analyze them and put them into the cache, and once when
we count their cost towards the unrolled loop. Also, because the cache
is only two bits and because we are dealing with relatively small
iteration counts, we can store all of this very densely in memory to
avoid this from becoming an excessively slow analysis.

The code here is still pretty gross. I would appreciate suggestions
about better ways to factor or split this up, I've stared too long at
the algorithmic side to really have a good sense of what the design
should probably look at.

Also, it might seem like we should do all of this bottom-up, but I think
that is a red herring. Specifically, the simplification power is *much*
greater working top-down. We can forward propagate very effectively,
even across strange and interesting recurrances around the backedge.
Because we use data to propagate, this doesn't cause a state space
explosion. Doing this level of constant folding, etc, would be very
expensive to do bottom-up because it wouldn't be until the last moment
that you could collapse everything. The current solution is essentially
a top-down simplification with a bottom-up cost accounting which seems
to get the best of both worlds. It makes the simplification incremental
and powerful while leaving everything dead until we *know* it is needed.

Finally, a core property of this approach is its *monotonicity*. At all
times, the current UnrolledCost is a conservatively low estimate. This
ensures that we will never early-exit from the analysis due to exceeding
a threshold when if we had continued, the cost would have gone back
below the threshold. These kinds of bugs can cause incredibly hard to
track down random changes to behavior.

We could use a techinque similar (but much simpler) within the inliner
as well to avoid considering speculated code in the inline cost.

Reviewers: chandlerc

Subscribers: sanjoy, mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D11758

llvm-svn: 269388
2016-05-13 01:42:39 +00:00
Justin Bogner e839c3e6ab PM: Check that loop passes preserve a basic set of analyses
A loop pass that didn't preserve this entire set of passes wouldn't
play well with other loop passes, since these are generally a basic
requirement to do any interesting transformations to a loop.

Adds a helper to get the set of analyses a loop pass should preserve,
and checks that any loop pass we run satisfies the requirement.

llvm-svn: 268444
2016-05-03 21:35:08 +00:00
Mehdi Amini b550cb1750 [NFC] Header cleanup
Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
2016-04-18 09:17:29 +00:00
Mehdi Amini 03b42e41bf Remove every uses of getGlobalContext() in LLVM (but the C API)
At the same time, fixes InstructionsTest::CastInst unittest: yes
you can leave the IR in an invalid state and exit when you don't
destroy the context (like the global one), no longer now.

This is the first part of http://reviews.llvm.org/D19094

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266379
2016-04-14 21:59:01 +00:00
JF Bastien 800f87a871 NFC: make AtomicOrdering an enum class
Summary:
In the context of http://wg21.link/lwg2445 C++ uses the concept of
'stronger' ordering but doesn't define it properly. This should be fixed
in C++17 barring a small question that's still open.

The code currently plays fast and loose with the AtomicOrdering
enum. Using an enum class is one step towards tightening things. I later
also want to tighten related enums, such as clang's
AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI'
enum).

This change touches a few lines of code which can be improved later, I'd
like to keep it as NFC for now as it's already quite complex. I have
related changes for clang.

As a follow-up I'll add:
  bool operator<(AtomicOrdering, AtomicOrdering) = delete;
  bool operator>(AtomicOrdering, AtomicOrdering) = delete;
  bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
  bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
This is separate so that clang and LLVM changes don't need to be in sync.

Reviewers: jyknight, reames

Subscribers: jyknight, llvm-commits

Differential Revision: http://reviews.llvm.org/D18775

llvm-svn: 265602
2016-04-06 21:19:33 +00:00
Easwaran Raman 12b79aa0f1 Add getBlockProfileCount method to BlockFrequencyInfo
Differential Revision: http://reviews.llvm.org/D18233

llvm-svn: 264179
2016-03-23 18:18:26 +00:00
Michael Zolotukhin 789ac4531c [LoopUnroll] Convert some existing tests to unit-tests.
Summary: As we now have unit-tests for UnrollAnalyzer, we can convert some existing tests to this format. It should make the tests more robust.

Reviewers: chandlerc, sanjoy

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D17904

llvm-svn: 263318
2016-03-12 01:28:56 +00:00
Chandler Carruth b47f8010a9 [PM] Make the AnalysisManager parameter to run methods a reference.
This was originally a pointer to support pass managers which didn't use
AnalysisManagers. However, that doesn't realistically come up much and
the complexity of supporting it doesn't really make sense.

In fact, *many* parts of the pass manager were just assuming the pointer
was never null already. This at least makes it much more explicit and
clear.

llvm-svn: 263219
2016-03-11 11:05:24 +00:00
Chandler Carruth 12884f7f80 [AA] Hoist the logic to reformulate various AA queries in terms of other
parts of the AA interface out of the base class of every single AA
result object.

Because this logic reformulates the query in terms of some other aspect
of the API, it would easily cause O(n^2) query patterns in alias
analysis. These could in turn be magnified further based on the number
of call arguments, and then further based on the number of AA queries
made for a particular call. This ended up causing problems for Rust that
were actually noticable enough to get a bug (PR26564) and probably other
places as well.

When originally re-working the AA infrastructure, the desire was to
regularize the pattern of refinement without losing any generality.
While I think it was successful, that is clearly proving to be too
costly. And the cost is needless: we gain no actual improvement for this
generality of making a direct query to tbaa actually be able to
re-use some other alias analysis's refinement logic for one of the other
APIs, or some such. In short, this is entirely wasted work.

To the extent possible, delegation to other API surfaces should be done
at the aggregation layer so that we can avoid re-walking the
aggregation. In fact, this significantly simplifies the logic as we no
longer need to smuggle the aggregation layer into each alias analysis
(or the TargetLibraryInfo into each alias analysis just so we can form
argument memory locations!).

However, we also have some delegation logic inside of BasicAA and some
of it even makes sense. When the delegation logic is baking in specific
knowledge of aliasing properties of the LLVM IR, as opposed to simply
reformulating the query to utilize a different alias analysis interface
entry point, it makes a lot of sense to restrict that logic to
a different layer such as BasicAA. So one aspect of the delegation that
was in every AA base class is that when we don't have operand bundles,
we re-use function AA results as a fallback for callsite alias results.
This relies on the IR properties of calls and functions w.r.t. aliasing,
and so seems a better fit to BasicAA. I've lifted the logic up to that
point where it seems to be a natural fit. This still does a bit of
redundant work (we query function attributes twice, once via the
callsite and once via the function AA query) but it is *exactly* twice
here, no more.

The end result is that all of the delegation logic is hoisted out of the
base class and into either the aggregation layer when it is a pure
retargeting to a different API surface, or into BasicAA when it relies
on the IR's aliasing properties. This should fix the quadratic query
pattern reported in PR26564, although I don't have a stand-alone test
case to reproduce it.

It also seems general goodness. Now the numerous AAs that don't need
target library info don't carry it around and depend on it. I think
I can even rip out the general access to the aggregation layer and only
expose that in BasicAA as it is the only place where we re-query in that
manner.

However, this is a non-trivial change to the AA infrastructure so I want
to get some additional eyes on this before it lands. Sadly, it can't
wait long because we should really cherry pick this into 3.8 if we're
going to go this route.

Differential Revision: http://reviews.llvm.org/D17329

llvm-svn: 262490
2016-03-02 15:56:53 +00:00
Michael Zolotukhin 9f520ebc54 [LoopUnrollAnalyzer] Check that we're using SCEV for the same loop we're simulating.
Summary: Check that we're using SCEV for the same loop we're simulating. Otherwise, we might try to use the iteration number of the current loop in SCEV expressions for inner/outer loops IVs, which is clearly incorrect.

Reviewers: chandlerc, hfinkel

Subscribers: sanjoy, llvm-commits, mzolotukhin

Differential Revision: http://reviews.llvm.org/D17632

llvm-svn: 261958
2016-02-26 02:57:05 +00:00
Michael Zolotukhin 374651d9aa [UnitTests] UnrollAnalyzer: make unit-test more general so that it can cover more cases in future.
llvm-svn: 261954
2016-02-26 01:44:04 +00:00
Justin Bogner eecc3c826a PM: Implement a basic loop pass manager
This creates the new-style LoopPassManager and wires it up with dummy
and print passes.

This version doesn't support modifying the loop nest at all. It will
be far easier to discuss and evaluate the approaches to that with this
in place so that the boilerplate is out of the way.

llvm-svn: 261831
2016-02-25 07:23:08 +00:00
Chandler Carruth c5d211ef2c [PM] Remove an overly aggressive assert now that I can actually test the
pattern that triggers it. This essentially requires an immutable
function analysis, as that will survive anything we do to invalidate it.
When we have such patterns, the function analysis manager will not get
cleared between runs of the proxy.

If we actually need an assert about how things are queried, we can add
more elaborate machinery for computing it, but so far I'm not aware of
significant value provided.

Thanks to Justin Lebar for noticing this when he made a (seemingly
innocuous) change to FunctionAttrs that is enough to trigger it in one
test there. Now it is covered by a direct test of the pass manager code.

llvm-svn: 261627
2016-02-23 10:47:57 +00:00
Chandler Carruth 743199221b [PM] Add a unittest for the CGSCC pass manager in the new pass manager
system.

Previously, this was only being tested with larger integration tests.
That makes it hard to isolated specific issues with it, and makes the
APIs themselves less well tested. Add a unittest based around the same
patterns used for testing the general pass manager.

llvm-svn: 261624
2016-02-23 10:02:02 +00:00
Tobias Grosser 946ca0a946 Use EXPECT_EQ in the unittests instead of plain assert
This addresses post-review comments from Duncan P. N. Exon Smith to r261485.

llvm-svn: 261514
2016-02-22 07:20:40 +00:00
Tobias Grosser 11332e5ec5 ScalarEvolution: Do not keep temporary PHI values in ValueExprMap
Before this patch simplified SCEV expressions for PHI nodes were only returned
the very first time getSCEV() was called, but later calls to getSCEV always
returned the non-simplified value, which had "temporarily" been stored in the
ValueExprMap, but was never removed and consequently blocked the caching of the
simplified PHI expression.

llvm-svn: 261485
2016-02-21 17:42:10 +00:00
Chandler Carruth 4f846a5f15 [PM/AA] Port alias analysis evaluator to the new pass manager, and use
it to actually test the new pass manager AA wiring.

This patch was extracted from the (somewhat too large) D12357 and
rebosed on top of the slightly different design of the new pass manager
AA wiring that I just landed. With this we can start testing the AA in
a thorough way with the new pass manager.

Some minor cleanups to the code in the pass was necessitated here, but
otherwise it is a very minimal change.

Differential Revision: http://reviews.llvm.org/D17372

llvm-svn: 261403
2016-02-20 03:46:03 +00:00
Chandler Carruth e5944d97d8 [LCG] Construct an actual call graph with call-edge SCCs nested inside
reference-edge SCCs.

This essentially builds a more normal call graph as a subgraph of the
"reference graph" that was the old model. This allows both to exist and
the different use cases to use the aspect which addresses their needs.
Specifically, the pass manager and other *ordering* constrained logic
can use the reference graph to achieve conservative order of visit,
while analyses reasoning about attributes and other properties derived
from reachability can reason about the direct call graph.

Note that this isn't necessarily complete: it doesn't model edges to
declarations or indirect calls. Those can be found by scanning the
instructions of the function if desirable, and in fact every user
currently does this in order to handle things like calls to instrinsics.
If useful, we could consider caching this information in the call graph
to save the instruction scans, but currently that doesn't seem to be
important.

An important realization for why the representation chosen here works is
that the call graph is a formal subset of the reference graph and thus
both can live within the same data structure. All SCCs of the call graph
are necessarily contained within an SCC of the reference graph, etc.

The design is to build 'RefSCC's to model SCCs of the reference graph,
and then within them more literal SCCs for the call graph.

The formation of actual call edge SCCs is not done lazily, unlike
reference edge 'RefSCC's. Instead, once a reference SCC is formed, it
directly builds the call SCCs within it and stores them in a post-order
sequence. This is used to provide a consistent platform for mutation and
update of the graph. The post-order also allows for very efficient
updates in common cases by bounding the number of nodes (and thus edges)
considered.

There is considerable common code that I'm still looking for the best
way to factor out between the various DFS implementations here. So far,
my attempts have made the code harder to read and understand despite
reducing the duplication, which seems a poor tradeoff. I've not given up
on figuring out the right way to do this, but I wanted to wait until
I at least had the system working and tested to continue attempting to
factor it differently.

This also requires introducing several new algorithms in order to handle
all of the incremental update scenarios for the more complex structure
involving two edge colorings. I've tried to comment the algorithms
sufficiently to make it clear how this is expected to work, but they may
still need more extensive documentation.

I know that there are some changes which are not strictly necessarily
coupled here. The process of developing this started out with a very
focused set of changes for the new structure of the graph and
algorithms, but subsequent changes to bring the APIs and code into
consistent and understandable patterns also ended up touching on other
aspects. There was no good way to separate these out without causing
*massive* merge conflicts. Ultimately, to a large degree this is
a rewrite of most of the core algorithms in the LCG class and so I don't
think it really matters much.

Many thanks to the careful review by Sanjoy Das!

Differential Revision: http://reviews.llvm.org/D16802

llvm-svn: 261040
2016-02-17 00:18:16 +00:00
Michael Zolotukhin 1da4afdfc9 Factor out UnrollAnalyzer to Analysis, and add unit tests for it.
Summary:
Unrolling Analyzer is already pretty complicated, and it becomes harder and harder to exercise it with usual IR tests, as with them we can only check the final decision: whether the loop is unrolled or not. This change factors this framework out from LoopUnrollPass to analyses, which allows to use unit tests.
The change itself is supposed to be NFC, except adding a couple of tests.

I plan to add more tests as I add new functionality and find/fix bugs.

Reviewers: chandlerc, hfinkel, sanjoy

Subscribers: zzheng, sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D16623

llvm-svn: 260169
2016-02-08 23:03:59 +00:00
Chandler Carruth a4499e9f73 [LCG] Build an edge abstraction for the LazyCallGraph and use it to
differentiate between indirect references to functions an direct calls.

This doesn't do a whole lot yet other than change the print out produced
by the analysis, but it lays the groundwork for a very major change I'm
working on next: teaching the call graph to actually be a call graph,
modeling *both* the indirect reference graph and the call graph
simultaneously. More details on that in the next patch though.

The rest of this is essentially a bunch of over-engineering that won't
be interesting until the next patch. But this also isolates essentially
all of the churn necessary to introduce the edge abstraction from the
very important behavior change necessary in order to separately model
the two graphs. So it should make review of the subsequent patch a bit
easier at the cost of making this patch seem poorly motivated. ;]

Differential Revision: http://reviews.llvm.org/D16038

llvm-svn: 259463
2016-02-02 03:57:13 +00:00
Chris Bieneman e49730d4ba Remove autoconf support
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html

"I felt a great disturbance in the [build system], as if millions of [makefiles] suddenly cried out in terror and were suddenly silenced. I fear something [amazing] has happened."
- Obi Wan Kenobi

Reviewers: chandlerc, grosbach, bob.wilson, tstellarAMD, echristo, whitequark

Subscribers: chfast, simoncook, emaste, jholewinski, tberghammer, jfb, danalbert, srhines, arsenm, dschuff, jyknight, dsanders, joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D16471

llvm-svn: 258861
2016-01-26 21:29:08 +00:00
Chandler Carruth 2be10754a9 [AA] Enhance the new AliasAnalysis infrastructure with an optional
"external" AA wrapper pass.

This is a generic hook that can be used to thread custom code into the
primary AAResultsWrapperPass for the legacy pass manager in order to
allow it to merge external AA results into the AA results it is
building. It does this by threading in a raw callback and so it is
*very* powerful and should serve almost any use case I have come up with
for extending the set of alias analyses used. The only thing not well
supported here is using a *different order* of alias analyses. That form
of extension *is* supportable with the new pass manager, and I can make
the callback structure here more elaborate to support it in the legacy
pass manager if this is a critical use case that people are already
depending on, but the only use cases I have heard of thus far should be
reasonably satisfied by this simpler extension mechanism.

It is hard to test this using normal facilities (the built-in AAs don't
use this for obvious reasons) so I've written a fairly extensive set of
custom passes in the alias analysis unit test that should be an
excellent test case because it models the out-of-tree users: it adds
a totally custom AA to the system. This should also serve as
a reasonably good example and guide for out-of-tree users to follow in
order to rig up their existing alias analyses.

No support in opt for commandline control is provided here however. I'm
really unhappy with the kind of contortions that would be required to
support that. It would fully re-introduce the analysis group
self-recursion kind of patterns. =/

I've heard from out-of-tree users that this will unblock their use cases
with extending AAs on top of the new infrastructure and let us retain
the new analysis-group-free-world.

Differential Revision: http://reviews.llvm.org/D13418

llvm-svn: 250894
2015-10-21 12:15:19 +00:00
Duncan P. N. Exon Smith c8925b1871 unittests: Remove implicit ilist iterator conversions, NFC
llvm-svn: 250843
2015-10-20 18:30:20 +00:00
Chandler Carruth 7b560d40bd [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible
with the new pass manager, and no longer relying on analysis groups.

This builds essentially a ground-up new AA infrastructure stack for
LLVM. The core ideas are the same that are used throughout the new pass
manager: type erased polymorphism and direct composition. The design is
as follows:

- FunctionAAResults is a type-erasing alias analysis results aggregation
  interface to walk a single query across a range of results from
  different alias analyses. Currently this is function-specific as we
  always assume that aliasing queries are *within* a function.

- AAResultBase is a CRTP utility providing stub implementations of
  various parts of the alias analysis result concept, notably in several
  cases in terms of other more general parts of the interface. This can
  be used to implement only a narrow part of the interface rather than
  the entire interface. This isn't really ideal, this logic should be
  hoisted into FunctionAAResults as currently it will cause
  a significant amount of redundant work, but it faithfully models the
  behavior of the prior infrastructure.

- All the alias analysis passes are ported to be wrapper passes for the
  legacy PM and new-style analysis passes for the new PM with a shared
  result object. In some cases (most notably CFL), this is an extremely
  naive approach that we should revisit when we can specialize for the
  new pass manager.

- BasicAA has been restructured to reflect that it is much more
  fundamentally a function analysis because it uses dominator trees and
  loop info that need to be constructed for each function.

All of the references to getting alias analysis results have been
updated to use the new aggregation interface. All the preservation and
other pass management code has been updated accordingly.

The way the FunctionAAResultsWrapperPass works is to detect the
available alias analyses when run, and add them to the results object.
This means that we should be able to continue to respect when various
passes are added to the pipeline, for example adding CFL or adding TBAA
passes should just cause their results to be available and to get folded
into this. The exception to this rule is BasicAA which really needs to
be a function pass due to using dominator trees and loop info. As
a consequence, the FunctionAAResultsWrapperPass directly depends on
BasicAA and always includes it in the aggregation.

This has significant implications for preserving analyses. Generally,
most passes shouldn't bother preserving FunctionAAResultsWrapperPass
because rebuilding the results just updates the set of known AA passes.
The exception to this rule are LoopPass instances which need to preserve
all the function analyses that the loop pass manager will end up
needing. This means preserving both BasicAAWrapperPass and the
aggregating FunctionAAResultsWrapperPass.

Now, when preserving an alias analysis, you do so by directly preserving
that analysis. This is only necessary for non-immutable-pass-provided
alias analyses though, and there are only three of interest: BasicAA,
GlobalsAA (formerly GlobalsModRef), and SCEVAA. Usually BasicAA is
preserved when needed because it (like DominatorTree and LoopInfo) is
marked as a CFG-only pass. I've expanded GlobalsAA into the preserved
set everywhere we previously were preserving all of AliasAnalysis, and
I've added SCEVAA in the intersection of that with where we preserve
SCEV itself.

One significant challenge to all of this is that the CGSCC passes were
actually using the alias analysis implementations by taking advantage of
a pretty amazing set of loop holes in the old pass manager's analysis
management code which allowed analysis groups to slide through in many
cases. Moving away from analysis groups makes this problem much more
obvious. To fix it, I've leveraged the flexibility the design of the new
PM components provides to just directly construct the relevant alias
analyses for the relevant functions in the IPO passes that need them.
This is a bit hacky, but should go away with the new pass manager, and
is already in many ways cleaner than the prior state.

Another significant challenge is that various facilities of the old
alias analysis infrastructure just don't fit any more. The most
significant of these is the alias analysis 'counter' pass. That pass
relied on the ability to snoop on AA queries at different points in the
analysis group chain. Instead, I'm planning to build printing
functionality directly into the aggregation layer. I've not included
that in this patch merely to keep it smaller.

Note that all of this needs a nearly complete rewrite of the AA
documentation. I'm planning to do that, but I'd like to make sure the
new design settles, and to flesh out a bit more of what it looks like in
the new pass manager first.

Differential Revision: http://reviews.llvm.org/D12080

llvm-svn: 247167
2015-09-09 17:55:00 +00:00
James Molloy 687a8448f4 [ValueTracking] Minor comment change in test
This test was updated in r246678 - fix a copypasta in a comment noticed post-commit.

llvm-svn: 246679
2015-09-02 17:29:54 +00:00
James Molloy 569cea65f0 [ValueTracking] Look through casts when both operands are casts.
We only looked through casts when one operand was a constant. We can also look through casts when both operands are non-constant, but both are in fact the same cast type. For example:

%1 = icmp ult i8 %a, %b
%2 = zext i8 %a to i32
%3 = zext i8 %b to i32
%4 = select i1 %1, i32 %2, i32 %3

llvm-svn: 246678
2015-09-02 17:25:25 +00:00
Chandler Carruth 7adc3a2b0e [PM/AA] Remove the last relics of the separate IPA library from LLVM,
folding the code into the main Analysis library.

There already wasn't much of a distinction between Analysis and IPA.
A number of the passes in Analysis are actually IPA passes, and there
doesn't seem to be any advantage to separating them.

Moreover, it makes it hard to have interactions between analyses that
are both local and interprocedural. In trying to make the Alias Analysis
infrastructure work with the new pass manager, it becomes particularly
awkward to navigate this split.

I've tried to find all the places where we referenced this, but I may
have missed some. I have also adjusted the C API to continue to be
equivalently functional after this change.

Differential Revision: http://reviews.llvm.org/D12075

llvm-svn: 245318
2015-08-18 17:51:53 +00:00
Chandler Carruth 2f1fd1658f [PM] Port ScalarEvolution to the new pass manager.
This change makes ScalarEvolution a stand-alone object and just produces
one from a pass as needed. Making this work well requires making the
object movable, using references instead of overwritten pointers in
a number of places, and other refactorings.

I've also wired it up to the new pass manager and added a RUN line to
a test to exercise it under the new pass manager. This includes basic
printing support much like with other analyses.

But there is a big and somewhat scary change here. Prior to this patch
ScalarEvolution was never *actually* invalidated!!! Re-running the pass
just re-wired up the various other analyses and didn't remove any of the
existing entries in the SCEV caches or clear out anything at all. This
might seem OK as everything in SCEV that can uses ValueHandles to track
updates to the values that serve as SCEV keys. However, this still means
that as we ran SCEV over each function in the module, we kept
accumulating more and more SCEVs into the cache. At the end, we would
have a SCEV cache with every value that we ever needed a SCEV for in the
entire module!!! Yowzers. The releaseMemory routine would dump all of
this, but that isn't realy called during normal runs of the pipeline as
far as I can see.

To make matters worse, there *is* actually a key that we don't update
with value handles -- there is a map keyed off of Loop*s. Because
LoopInfo *does* release its memory from run to run, it is entirely
possible to run SCEV over one function, then over another function, and
then lookup a Loop* from the second function but find an entry inserted
for the first function! Ouch.

To make matters still worse, there are plenty of updates that *don't*
trip a value handle. It seems incredibly unlikely that today GVN or
another pass that invalidates SCEV can update values in *just* such
a way that a subsequent run of SCEV will incorrectly find lookups in
a cache, but it is theoretically possible and would be a nightmare to
debug.

With this refactoring, I've fixed all this by actually destroying and
recreating the ScalarEvolution object from run to run. Technically, this
could increase the amount of malloc traffic we see, but then again it is
also technically correct. ;] I don't actually think we're suffering from
tons of malloc traffic from SCEV because if we were, the fact that we
never clear the memory would seem more likely to have come up as an
actual problem before now. So, I've made the simple fix here. If in fact
there are serious issues with too much allocation and deallocation,
I can work on a clever fix that preserves the allocations (while
clearing the data) between each run, but I'd prefer to do that kind of
optimization with a test case / benchmark that shows why we need such
cleverness (and that can test that we actually make it faster). It's
possible that this will make some things faster by making the SCEV
caches have higher locality (due to being significantly smaller) so
until there is a clear benchmark, I think the simple change is best.

Differential Revision: http://reviews.llvm.org/D12063

llvm-svn: 245193
2015-08-17 02:08:17 +00:00
Chandler Carruth 1db22822b4 [PM/AA] Hoist the interface to TBAA into a dedicated header along with
its creation function. Update the relevant includes accordingly.

llvm-svn: 245019
2015-08-14 03:33:48 +00:00
James Molloy 134bec2722 Add support for floating-point minnum and maxnum
The select pattern recognition in ValueTracking (as used by InstCombine
and SelectionDAGBuilder) only knew about integer patterns. This teaches
it about minimum and maximum operations.

matchSelectPattern() has been extended to return a struct containing the
existing Flavor and a new enum defining the pattern's behavior when
given one NaN operand.

C minnum() is defined to return the non-NaN operand in this case, but
the idiomatic C "a < b ? a : b" would return the NaN operand.

ARM and AArch64 at least have different instructions for these different cases.

llvm-svn: 244580
2015-08-11 09:12:57 +00:00
Chandler Carruth 17e0bc37fd [PM/AA] Hoist the interface for BasicAA into a header file.
This is the first mechanical step in preparation for making this and all
the other alias analysis passes available to the new pass manager. I'm
factoring out all the totally boring changes I can so I'm moving code
around here with no other changes. I've even minimized the formatting
churn.

I'll reformat and freshen comments on the interface now that its located
in the right place so that the substantive changes don't triger this.

llvm-svn: 244197
2015-08-06 07:33:15 +00:00
Chandler Carruth 194f59ca5d [PM/AA] Extract the ModRef enums from the AliasAnalysis class in
preparation for de-coupling the AA implementations.

In order to do this, they had to become fake-scoped using the
traditional LLVM pattern of a leading initialism. These can't be actual
scoped enumerations because they're bitfields and thus inherently we use
them as integers.

I've also renamed the behavior enums that are specific to reasoning
about the mod/ref behavior of functions when called. This makes it more
clear that they have a very narrow domain of applicability.

I think there is a significantly cleaner API for all of this, but
I don't want to try to do really substantive changes for now, I just
want to refactor the things away from analysis groups so I'm preserving
the exact original design and just cleaning up the names, style, and
lifting out of the class.

Differential Revision: http://reviews.llvm.org/D10564

llvm-svn: 242963
2015-07-22 23:15:57 +00:00
Chandler Carruth ac80dc7532 [PM/AA] Remove the Location typedef from the AliasAnalysis class now
that it is its own entity in the form of MemoryLocation, and update all
the callers.

This is an entirely mechanical change. References to "Location" within
AA subclases become "MemoryLocation", and elsewhere
"AliasAnalysis::Location" becomes "MemoryLocation". Hope that helps
out-of-tree folks update.

llvm-svn: 239885
2015-06-17 07:18:54 +00:00
Daniel Berlin ec1de3fb19 Make getModRefInfo(Instruction *) not crash on certain types of instructions
llvm-svn: 236023
2015-04-28 19:19:14 +00:00
Daniel Berlin b2d227693f Make getModRefInfo with a default location not crash.
Add getModRefInfo that works without location.
Add unit tests.

llvm-svn: 234811
2015-04-13 23:05:45 +00:00
Alexander Kornienko f817c1cb9a Use 'override/final' instead of 'virtual' for overridden methods
The patch is generated using clang-tidy misc-use-override check.

This command was used:

  tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py \
    -checks='-*,misc-use-override' -header-filter='llvm|clang' \
    -j=32 -fix -format

http://reviews.llvm.org/D8925

llvm-svn: 234679
2015-04-11 02:11:45 +00:00
Chandler Carruth 30d69c2e36 [PM] Remove the old 'PassManager.h' header file at the top level of
LLVM's include tree and the use of using declarations to hide the
'legacy' namespace for the old pass manager.

This undoes the primary modules-hostile change I made to keep
out-of-tree targets building. I sent an email inquiring about whether
this would be reasonable to do at this phase and people seemed fine with
it, so making it a reality. This should allow us to start bootstrapping
with modules to a certain extent along with making it easier to mix and
match headers in general.

The updates to any code for users of LLVM are very mechanical. Switch
from including "llvm/PassManager.h" to "llvm/IR/LegacyPassManager.h".
Qualify the types which now produce compile errors with "legacy::". The
most common ones are "PassManager", "PassManagerBase", and
"FunctionPassManager".

llvm-svn: 229094
2015-02-13 10:01:29 +00:00