llvm-svn: 353273

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

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

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

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

`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

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

Summary:
Extend BasicBlocksUtils to update MemorySSA.

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

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

llvm-svn: 340365

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

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

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

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

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

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

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

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

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

llvm-svn: 323928

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

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

llvm-svn: 321832

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

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

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

llvm-svn: 321585

Stage 2 bootstrap failed:
http://lab.llvm.org:8011/builders/clang-x86_64-linux-selfhost-modules-2/builds/14434

llvm-svn: 320641

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: 320612

Fixes part of PR35113.

This reapplies r317105 with an additional check for isa<Instruction>
as found by the bots.

llvm-svn: 317120

llvm-svn: 317110

Fixes part of PR35113.

llvm-svn: 317105

[Transforms] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).

llvm-svn: 316724

This relands r301424.

llvm-svn: 301812

Commits were:

"Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts"
"Add a new WeakVH value handle; NFC"
"Rename WeakVH to WeakTrackingVH; NFC"

The changes assumed pointers are 8 byte aligned on all architectures.

llvm-svn: 301429

Summary:
I plan to use WeakVH to mean "nulls itself out on deletion, but does
not track RAUW" in a subsequent commit.

Reviewers: dblaikie, davide

Reviewed By: davide

Subscribers: arsenm, mehdi_amini, mcrosier, mzolotukhin, jfb, llvm-commits, nhaehnle

Differential Revision: https://reviews.llvm.org/D32266

llvm-svn: 301424

LoopInfo::getLoopFor returns nullptr if a BB is not in a loop and only
then can the loop be updated to contain the newly created BBs. Add the
missing nullptr check to SplitBlockAndInsertIfThen.

Within LLVM, the only user of this function that also passes a LoopInfo
to be updated is InnerLoopVectorizer::predicateInstructions().
As the method's name implies, the BB operataten on will always be within
a loop, but out-of-tree users may also use it differently (here: Polly).

All other uses of LoopInfo::getLoopFor in the file properly check its
return value for nullptr.

llvm-svn: 297016

[BasicBlockUtils] Use getFirstNonPHIOrDbg to set debugloc for instructions created in SplitBlockPredecessors

Summary:
When setting debugloc for instructions created in SplitBlockPredecessors, current implementation copies debugloc from the first-non-phi instruction of the original basic block. However, if the first-non-phi instruction is a call for @llvm.dbg.value, the debugloc of the instruction may point the location outside of the block itself. For the example code of

```
  1 typedef struct _node_t {
  2   struct _node_t *next;
  3 } node_t;
  4
  5 extern node_t *root;
  6
  7 int foo() {
  8   node_t *node, *tmp;
  9   int ret = 0;
 10
 11   node = tmp = root->next;
 12   while (node != root) {
 13     while (node) {
 14       tmp = node;
 15       node = node->next;
 16       ret++;
 17     }
 18   }
 19
 20   return ret;
 21 }
```

, below is the basicblock corresponding to line 12 after Reassociate expressions pass:

```
while.cond:                                       ; preds = %while.cond2, %entry
  %node.0 = phi %struct._node_t* [ %1, %entry ], [ null, %while.cond2 ]
  %ret.0 = phi i32 [ 0, %entry ], [ %ret.1, %while.cond2 ]
  tail call void @llvm.dbg.value(metadata i32 %ret.0, i64 0, metadata !19, metadata !20), !dbg !21
  tail call void @llvm.dbg.value(metadata %struct._node_t* %node.0, i64 0, metadata !11, metadata !20), !dbg !31
  %cmp = icmp eq %struct._node_t* %node.0, %0, !dbg !33
  br i1 %cmp, label %while.end5, label %while.cond2, !dbg !35
```

As you can see, the first-non-phi instruction is a call for @llvm.dbg.value, and the debugloc is

```
!21 = !DILocation(line: 9, column: 7, scope: !6)
```

, which is a definition of 'ret' variable and outside of the scope of the basicblock itself. However, current implementation picks up this debugloc for the instructions created in SplitBlockPredecessors. This patch addresses this problem by picking up debugloc from the first-non-phi-non-dbg instruction.

Reviewers: dblaikie, samsonov, eugenis

Reviewed By: eugenis

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29867

llvm-svn: 295106

Only minor manual fixes. No functionality change intended.

llvm-svn: 273808

llvm-svn: 267292

This was a latent bug that got exposed by the change to add LoopSimplify
as a dependence to LoopLoadElimination.  Since LoopInfo was corrupted
after LV, LoopSimplify mis-compiled nbench in the test-suite (more
details in the PR).

The problem was that when we create the blocks for predicated stores we
didn't add those to any loops.

The original testcase for store predication provides coverage for this
assuming we verify LI on the way out of LV.

Fixes PR26952.

llvm-svn: 263565

This is a fairly straightforward port to the new pass manager with one
exception. It removes a very questionable use of releaseMemory() in
the old pass to invalidate its caches between runs on a function.
I don't think this is really guaranteed to be safe. I've just used the
more direct port to the new PM to address this by nuking the results
object each time the pass runs. While this could cause some minor malloc
traffic increase, I don't expect the compile time performance hit to be
noticable, and it makes the correctness and other aspects of the pass
much easier to reason about. In some cases, it may make things faster by
making the sets and maps smaller with better locality. Indeed, the
measurements collected by Bruno (thanks!!!) show mostly compile time
improvements.

There is sadly very limited testing at this point as there are only two
tests of memdep, and both rely on GVN. I'll be porting GVN next and that
will exercise this heavily though.

Differential Revision: http://reviews.llvm.org/D17962

llvm-svn: 263082

Summary: This patch adds a check in SplitLandingPadPredecessors to see if the original landingpad instruction has any uses. If not, we don't need to create a PHINode for it in the joint block since it's gonna be a dead code anyway. The motivation for this patch is that we found a bug that SplitLandingPadPredecessors created a PHINode of token type landingpad, which failed the verifier since PHINode can not be token type. However, the created PHINode will never be used in our code pattern. This patch will workaround this bug, and we might add supports in SplitLandingPadPredecessors to handle token type landingpad with uses in the future.

Reviewers: reames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D15835

llvm-svn: 256972

Continuing the work from last week to remove implicit ilist iterator
conversions.  First related commit was probably r249767, with some more
motivation in r249925.  This edition gets LLVMTransformUtils compiling
without the implicit conversions.

No functional change intended.

llvm-svn: 250142