[NFC] Revert rL353274

llvm-svn: 353275

[NFC] Extend API of DeleteDeadBlock(s) to collect updates without DTU

llvm-svn: 353274

[NFC] Replace readonly SmallVectorImpl with ArrayRef

llvm-svn: 353273

Move DomTreeUpdater from IR to Analysis

DomTreeUpdater depends on headers from Analysis, but is in IR. This is a
layering violation since Analysis depends on IR. Relocate this code from IR
to Anal

Move DomTreeUpdater from IR to Analysis

DomTreeUpdater depends on headers from Analysis, but is in IR. This is a
layering violation since Analysis depends on IR. Relocate this code from IR
to Analysis to fix the layering violation.

llvm-svn: 353265

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Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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[BasicBlockUtils] Generalize DeleteDeadBlock to deal with multiple dead blocks

Utility function `DeleteDeadBlock` expects that all predecessors of a block being
deleted are already deleted, with the

[BasicBlockUtils] Generalize DeleteDeadBlock to deal with multiple dead blocks

Utility function `DeleteDeadBlock` expects that all predecessors of a block being
deleted are already deleted, with the exception of single-block loop. It makes it
hard to use for deletion of a set of blocks that may contain cyclic dependencies.
The is no correct order of invocations of this function that does not produce
dangling pointers on already deleted blocks.

This patch introduces a generalized version of this function `DeleteDeadBlocks`
that allows us to remove multiple blocks at once, even if there are cycles among
them. The only requirement is that no block being deleted should have a predecessor
that is not being deleted.

The logic of `DeleteDeadBlocks` is following:
for each block
create relevant DT updates;
remove all instructions (replace with undef if needed);
replace terminator with unreacheable;
apply DT updates;
for each block
delete block;

Therefore, `DeleteDeadBlock` becomes a particular case of
the general algorithm called for a single block.

Differential Revision: https://reviews.llvm.org/D56120
Reviewed By: skatkov

llvm-svn: 351045

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[TI removal] Remove `TerminatorInst` from BasicBlockUtils.h

This requires updating a number of .cpp files to adapt to the new API.
I've just systematically updated all uses of `TerminatorInst` withi

[TI removal] Remove `TerminatorInst` from BasicBlockUtils.h

This requires updating a number of .cpp files to adapt to the new API.
I've just systematically updated all uses of `TerminatorInst` within
these files te `Instruction` so thta I won't have to touch them again in
the future.

llvm-svn: 344498

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[IR] Sink `isExceptional` predicate to `Instruction`, rename it to
`isExceptionalTermiantor` and implement it for opcodes as well following
the common pattern in `Instruction`.

Part of removing `Ter

[IR] Sink `isExceptional` predicate to `Instruction`, rename it to
`isExceptionalTermiantor` and implement it for opcodes as well following
the common pattern in `Instruction`.

Part of removing `TerminatorInst` from the `Instruction` type hierarchy
to make it easier to share logic and interfaces between instructions
that are both terminators and not terminators.

llvm-svn: 340699

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[IR] Begin removal of TerminatorInst by removing successor manipulation.

The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which ar

[IR] Begin removal of TerminatorInst by removing successor manipulation.

The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which are terminators.

The iterator and *generic* range based access move to `CFG.h` where all
the other generic successor and predecessor access lives. While moving
the iterator here, simplify it using the iterator utilities LLVM
provides and updates coding style as much as reasonable. The APIs remain
pointer-heavy when they could better use references, and retain the odd
behavior of `operator*` and `operator->` that is common in LLVM
iterators. Adjusting this API, if desired, should be a follow-up step.

Non-generic range iteration is added for the two instructions where
there is an especially easy mechanism and where there was code
attempting to use the range accessor from a specific subclass:
`indirectbr` and `br`. In both cases, the successors are contiguous
operands and can be easily iterated via the operand list.

This is the first major patch in removing the `TerminatorInst` type from
the IR's instruction type hierarchy. This change was discussed in an RFC
here and was pretty clearly positive:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html

There will be a series of much more mechanical changes following this
one to complete this move.

Differential Revision: https://reviews.llvm.org/D47467

llvm-svn: 340698

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Update MemorySSA in BasicBlockUtils.

Summary:
Extend BasicBlocksUtils to update MemorySSA.

Subscribers: sanjoy, arsenm, nhaehnle, jlebar, Prazek, llvm-commits

Differential Revision: https://review

Update MemorySSA in BasicBlockUtils.

Summary:
Extend BasicBlocksUtils to update MemorySSA.

Subscribers: sanjoy, arsenm, nhaehnle, jlebar, Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D45300

llvm-svn: 340365

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[TailCallElim] Preserve DT and PDT

Summary:
Previously, in the NewPM pipeline, TailCallElim recalculates the DomTree when it modifies any instruction in the Function.
For example,
```
CallInst *CI =

[TailCallElim] Preserve DT and PDT

Summary:
Previously, in the NewPM pipeline, TailCallElim recalculates the DomTree when it modifies any instruction in the Function.
For example,
```
CallInst *CI = dyn_cast<CallInst>(&I);
...
CI->setTailCall();
Modified = true;
...
if (!Modified || ...)
return PreservedAnalyses::all();
```
After applying this patch, the DomTree only recalculates if needed (plus an extra insertEdge() + an extra deleteEdge() call).

When optimizing SQLite with `-passes="default<O3>"` pipeline of the newPM, the number of DomTree recalculation decreases by 6.2%, the number of nodes visited by DFS decreases by 2.9%. The time used by DomTree will decrease approximately 1%~2.5% after applying the patch.

Statistics:
```
Before the patch:
23010 dom-tree-stats - Number of DomTree recalculations
489264 dom-tree-stats - Number of nodes visited by DFS -- DomTree
After the patch:
21581 dom-tree-stats - Number of DomTree recalculations
475088 dom-tree-stats - Number of nodes visited by DFS -- DomTree
```

Reviewers: kuhar, dmgreen, brzycki, grosser, davide

Reviewed By: kuhar, brzycki

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D49982

llvm-svn: 338954

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[Dominators] Convert existing passes and utils to use the DomTreeUpdater class

Summary:
This patch is the second in a series of patches related to the [[ http://lists.llvm.org/pipermail/llvm-dev/201

[Dominators] Convert existing passes and utils to use the DomTreeUpdater class

Summary:
This patch is the second in a series of patches related to the [[ http://lists.llvm.org/pipermail/llvm-dev/2018-June/123883.html | RFC - A new dominator tree updater for LLVM ]].

It converts passes (e.g. adce/jump-threading) and various functions which currently accept DDT in local.cpp and BasicBlockUtils.cpp to use the new DomTreeUpdater class.
These converted functions in utils can accept DomTreeUpdater with either UpdateStrategy and can deal with both DT and PDT held by the DomTreeUpdater.

Reviewers: brzycki, kuhar, dmgreen, grosser, davide

Reviewed By: brzycki

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D48967

llvm-svn: 338814

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Generalize MergeBlockIntoPredecessor. Replace uses of MergeBasicBlockIntoOnlyPred.

Summary:
Two utils methods have essentially the same functionality. This is an attempt to merge them into one.
1. l

Generalize MergeBlockIntoPredecessor. Replace uses of MergeBasicBlockIntoOnlyPred.

Summary:
Two utils methods have essentially the same functionality. This is an attempt to merge them into one.
1. lib/Transforms/Utils/Local.cpp : MergeBasicBlockIntoOnlyPred
2. lib/Transforms/Utils/BasicBlockUtils.cpp : MergeBlockIntoPredecessor

Prior to the patch:
1. MergeBasicBlockIntoOnlyPred
Updates either DomTree or DeferredDominance
Moves all instructions from Pred to BB, deletes Pred
Asserts BB has single predecessor
If address was taken, replace the block address with constant 1 (?)

2. MergeBlockIntoPredecessor
Updates DomTree, LoopInfo and MemoryDependenceResults
Moves all instruction from BB to Pred, deletes BB
Returns if doesn't have a single predecessor
Returns if BB's address was taken

After the patch:
Method 2. MergeBlockIntoPredecessor is attempting to become the new default:
Updates DomTree or DeferredDominance, and LoopInfo and MemoryDependenceResults
Moves all instruction from BB to Pred, deletes BB
Returns if doesn't have a single predecessor
Returns if BB's address was taken

Uses of MergeBasicBlockIntoOnlyPred that need to be replaced:

1. lib/Transforms/Scalar/LoopSimplifyCFG.cpp
Updated in this patch. No challenges.

2. lib/CodeGen/CodeGenPrepare.cpp
Updated in this patch.
i. eliminateFallThrough is straightforward, but I added using a temporary array to avoid the iterator invalidation.
ii. eliminateMostlyEmptyBlock(s) methods also now use a temporary array for blocks
Some interesting aspects:
- Since Pred is not deleted (BB is), the entry block does not need updating.
- The entry block was being updated with the deleted block in eliminateMostlyEmptyBlock. Added assert to make obvious that BB=SinglePred.
- isMergingEmptyBlockProfitable assumes BB is the one to be deleted.
- eliminateMostlyEmptyBlock(BB) does not delete BB on one path, it deletes its unique predecessor instead.
- adding some test owner as subscribers for the interesting tests modified:
test/CodeGen/X86/avx-cmp.ll
test/CodeGen/AMDGPU/nested-loop-conditions.ll
test/CodeGen/AMDGPU/si-annotate-cf.ll
test/CodeGen/X86/hoist-spill.ll
test/CodeGen/X86/2006-11-17-IllegalMove.ll

3. lib/Transforms/Scalar/JumpThreading.cpp
Not covered in this patch. It is the only use case using the DeferredDominance.
I would defer to Brian Rzycki to make this replacement.

Reviewers: chandlerc, spatel, davide, brzycki, bkramer, javed.absar

Subscribers: qcolombet, sanjoy, nemanjai, nhaehnle, jlebar, tpr, kbarton, RKSimon, wmi, arsenm, llvm-commits

Differential Revision: https://reviews.llvm.org/D48202

llvm-svn: 335183

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Revert "Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor"

This reverts commit f976cf4cca0794267f28b54e468007fd476d37d9.

I am reverting this because it causes break in a few

Revert "Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor"

This reverts commit f976cf4cca0794267f28b54e468007fd476d37d9.

I am reverting this because it causes break in a few bots and its going
to take me sometime to look at this.

llvm-svn: 334993

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Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor

Summary:
Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor

This is a missing small optimization in

Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor

Summary:
Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor

This is a missing small optimization in MergeBlockIntoPredecessor.

This helps with one simplifycfg test which expects this case to be handled.

Reviewers: davide, spatel, brzycki, asbirlea

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D48284

llvm-svn: 334992

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Move Analysis/Utils/Local.h back to Transforms

Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change onl

Move Analysis/Utils/Local.h back to Transforms

Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)

llvm-svn: 333954

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[SimplifyCFG] Fix a crash when folding PHIs.

We enter MergeBlockIntoPredecessor with a block looking like this:

for.inc.us-lcssa: ; preds = %cond.end
%k.1.lcssa.ph

[SimplifyCFG] Fix a crash when folding PHIs.

We enter MergeBlockIntoPredecessor with a block looking like this:

for.inc.us-lcssa: ; preds = %cond.end
%k.1.lcssa.ph = phi i32 [ %conv15, %cond.end ]
%t.3.lcssa.ph = phi i32 [ %k.1.lcssa.ph, %cond.end ]
br label %for.inc, !dbg !66

[note the first arg of the PHI being a PHI].
FoldSingleEntryPHINodes gets rid of both PHIs (calling, eraseFromParent).
But right before we call the function, we push into IncomingValues the
only argument of the PHIs, and shortly after we try to iterate over
something which has been invalidated before :(

The fix its not trying to remove PHIs which have an incoming value
coming from the same BB we're looking at.

Fixes PR37300 and rdar://problem/39910460

Differential Revision: https://reviews.llvm.org/D46568

llvm-svn: 331824

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Fix a couple of layering violations in Transforms

Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.

Transforms depends on Transforms/Utils, not the other way around. So
r

Fix a couple of layering violations in Transforms

Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.

Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.

Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.

llvm-svn: 328165

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Utils: Fix DomTree update for entry block

If SplitBlockPredecessors was used on a function entry block,
it wouldn't update the dominator tree.

llvm-svn: 323928

[JumpThreading] Preservation of DT and LVI across the pass

Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.

Preserves dominance in a deferred manner usin

[JumpThreading] Preservation of DT and LVI across the pass

Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.

Preserves dominance in a deferred manner using a new class
DeferredDominance. This reduces the performance impact of
updating the DominatorTree at every edge insertion and
deletion. A user may call DDT->flush() within JumpThreading
for an up-to-date DT. This patch currently has one flush()
at the end of runImpl() to ensure DT is preserved across
the pass.

LVI is also preserved to help subsequent passes such as
CorrelatedValuePropagation. LVI is simpler to maintain and
is done immediately (not deferred). The code to perform the
preversation was minimally altered and simply marked as
preserved for the PassManager to be informed.

This extends the analysis available to JumpThreading for
future enhancements such as threading across loop headers.

Reviewers: dberlin, kuhar, sebpop

Reviewed By: kuhar, sebpop

Subscribers: mgorny, dmgreen, kuba, rnk, rsmith, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D40146

llvm-svn: 322401

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Revert "[JumpThreading] Preservation of DT and LVI across the pass"

This reverts r321825, it causes crashes in Chromium. Reproducer
forthcoming.

llvm-svn: 321832

[JumpThreading] Preservation of DT and LVI across the pass

Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.

Preserves dominance in a deferred manner usin

[JumpThreading] Preservation of DT and LVI across the pass

Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.

Preserves dominance in a deferred manner using a new class
DeferredDominance. This reduces the performance impact of
updating the DominatorTree at every edge insertion and
deletion. A user may call DDT->flush() within JumpThreading
for an up-to-date DT. This patch currently has one flush()
at the end of runImpl() to ensure DT is preserved across
the pass.

LVI is also preserved to help subsequent passes such as
CorrelatedValuePropagation. LVI is simpler to maintain and
is done immediately (not deferred). The code to perfom the
preversation was minimally altered and was simply marked
as preserved for the PassManager to be informed.

This extends the analysis available to JumpThreading for
future enhancements. One example is loop boundary threading.

Reviewers: dberlin, kuhar, sebpop

Reviewed By: kuhar, sebpop

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D40146

llvm-svn: 321825

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Add assertion on DT availability during LI update in UpdateAnalysisInformation

This came up during discussions in llvm-commits for
rL321653: Check for unreachable preds before updating LI in
UpdateA

Add assertion on DT availability during LI update in UpdateAnalysisInformation

This came up during discussions in llvm-commits for
rL321653: Check for unreachable preds before updating LI in
UpdateAnalysisInformation

The assert provides hints to passes to require both DT and LI if we plan on
updating LI through this function.

Tests run: make check

llvm-svn: 321805

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[BasicBlockUtils] Check for unreachable preds before updating LI in UpdateAnalysisInformation

Summary:
We are incorrectly updating the LI when loop-simplify generates
dedicated exit blocks for a loo

[BasicBlockUtils] Check for unreachable preds before updating LI in UpdateAnalysisInformation

Summary:
We are incorrectly updating the LI when loop-simplify generates
dedicated exit blocks for a loop. The issue is that there's an implicit
assumption that the Preds passed into UpdateAnalysisInformation are
reachable. However, this is not true and breaks LI by incorrectly
updating the header of a loop.

One such case is when we generate dedicated exits when the exit block is
a landing pad (through SplitLandingPadPredecessors). There maybe other
cases as well, since we do not guarantee that Preds passed in are
reachable basic blocks.

The added test case shows how loop-simplify breaks LI for the outer loop (and DT in turn)
after we try to generate the LoopSimplifyForm.

Reviewers: davide, chandlerc, sanjoy

Reviewed By: davide

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D41519

llvm-svn: 321653

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Use phi ranges to simplify code. No functionality change intended.

llvm-svn: 321585