[BasicBlockUtils] Fix dbg.value elimination problem in MergeBlockIntoPredecessor

Summary:
In commit d60f34c20a2f31335c8d5626e (llvm-svn 317128,
PR35113) MergeBlockIntoPredecessor was changed into
di

[BasicBlockUtils] Fix dbg.value elimination problem in MergeBlockIntoPredecessor

Summary:
In commit d60f34c20a2f31335c8d5626e (llvm-svn 317128,
PR35113) MergeBlockIntoPredecessor was changed into
discarding some dbg.value intrinsics referring to
PHI values, post-splice due to loop rotation.

That elimination of dbg.value intrinsics did not
consider which dbg.value to keep depending on the
context (e.g. if the variable is changing its value
several times inside the basic block).

In the past that hasn't been such a big problem since
CodeGenPrepare::placeDbgValues has moved the dbg.value
to be next to the PHI node anyway. But after commit
00e238896cd8ad3a7d7 CodeGenPrepare isn't doing that
any longer, so we need to be more careful when avoiding
duplicate dbg.value intrinsics in MergeBlockIntoPredecessor.

This patch replaces the code that tried to avoid duplicate
dbg.values by using the RemoveRedundantDbgInstrs helper.

Reviewers: aprantl, jmorse, vsk

Reviewed By: aprantl, vsk

Subscribers: jholewinski, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71480

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[BasicBlockUtils] Add utility to remove redundant dbg.value instrs

Summary:
Add a RemoveRedundantDbgInstrs to BasicBlockUtils with the
goal to remove redundant dbg intrinsics from a basic block.

Th

[BasicBlockUtils] Add utility to remove redundant dbg.value instrs

Summary:
Add a RemoveRedundantDbgInstrs to BasicBlockUtils with the
goal to remove redundant dbg intrinsics from a basic block.

This can be useful after various transforms, as it might
be simpler to do a filtering of dbg intrinsics after the
transform than during the transform.
One primary use case would be to replace a too aggressive
removal done by MergeBlockIntoPredecessor, seen at loop
rotate (not done in this patch).

The elimination algorithm currently focuses on dbg.value
intrinsics and is doing two iterations over the BB.

First we iterate backward starting at the last instruction
in the BB. Whenever a consecutive sequence of dbg.value
instructions are found we keep the last dbg.value for
each variable found (variable fragments are identified
using the {DILocalVariable, FragmentInfo, inlinedAt}
triple as given by the DebugVariable helper class).

Next we iterate forward starting at the first instruction
in the BB. Whenever we find a dbg.value describing a
DebugVariable (identified by {DILocalVariable, inlinedAt})
we save the {DIValue, DIExpression} that describes that
variables value. But if the variable already was mapped
to the same {DIValue, DIExpression} pair we instead drop
the second dbg.value.

To ease the process of making lit tests for this utility a
new pass is introduced called RedundantDbgInstElimination.
It can be executed by opt using -redundant-dbg-inst-elim.

Reviewers: aprantl, jmorse, vsk

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71478

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[MemorySSA] Update analysis when the terminator is a memory instruction.

Update MemorySSA when moving the terminator instruction, as that may be a memory touching instruction.
Resolves PR44029.

[Utils] Cleanup similar cases to MergeBlockIntoPredecessor.

Summary:
There are two cases where a block is merged into its predecessor and the
MergeBlockIntoPredecessor API is not used. Update the AP

[Utils] Cleanup similar cases to MergeBlockIntoPredecessor.

Summary:
There are two cases where a block is merged into its predecessor and the
MergeBlockIntoPredecessor API is not used. Update the API so it can be
reused in the other cases, in order to avoid code duplication.

Cleanup motivated by D68659.

Reviewers: chandlerc, sanjoy.google, george.burgess.iv

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68670

llvm-svn: 375050

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[MemorySSA] Make the use of moveAllAfterMergeBlocks consistent.

Summary:
The rule for the moveAllAfterMergeBlocks API si for all instructions
from `From` to have been moved to `To`, while keeping th

[MemorySSA] Make the use of moveAllAfterMergeBlocks consistent.

Summary:
The rule for the moveAllAfterMergeBlocks API si for all instructions
from `From` to have been moved to `To`, while keeping the CFG edges (and
block terminators) unchanged.
Update all the callsites for moveAllAfterMergeBlocks to follow this.

Pending follow-up: since the same behavior is needed everytime, merge
all callsites into one. The common denominator may be the call to
`MergeBlockIntoPredecessor`.

Resolves PR43569.

Reviewers: george.burgess.iv

Subscribers: Prazek, sanjoy.google, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68659

llvm-svn: 374177

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[BasicBlockUtils] Add optional BBName argument, in line with BB:splitBasicBlock

Reviewers: spatel, asbirlea, craig.topper

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D675

[BasicBlockUtils] Add optional BBName argument, in line with BB:splitBasicBlock

Reviewers: spatel, asbirlea, craig.topper

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D67521

llvm-svn: 371819

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[MemorySSA] MemorySSA should not model debuginfo, and need not update it.

Reverts the change in r371084, but keeps the test.
After r371565, debuginfo cannot be modelled in MemorySSA, even with a
non

[MemorySSA] MemorySSA should not model debuginfo, and need not update it.

Reverts the change in r371084, but keeps the test.
After r371565, debuginfo cannot be modelled in MemorySSA, even with a
non-standard AA pipeline.

llvm-svn: 371573

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[MemorySSA] Verify MSSAUpdater exists.

llvm-svn: 371087

[MemorySSA] Update MemorySSA when removing debug.value calls.

llvm-svn: 371084

[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized lo

[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

> llvm-svn: 363046

llvm-svn: 363786

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Revert "[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion"

This reverts commit 1a0f7a2077b70c9864faa476e15b048686cf1ca7.
See phabricator thread f

Revert "[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion"

This reverts commit 1a0f7a2077b70c9864faa476e15b048686cf1ca7.
See phabricator thread for D60831.

llvm-svn: 363132

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[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized lo

[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

llvm-svn: 363046

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[DomTreeUpdater] Add all insert before all delete updates to reduce compile time.

Summary:
The cleanup in D62751 introduced a compile-time regression due to the way DT updates are performed.
Add all

[DomTreeUpdater] Add all insert before all delete updates to reduce compile time.

Summary:
The cleanup in D62751 introduced a compile-time regression due to the way DT updates are performed.
Add all insert edges then all delete edges in DTU to match the previous compile time.
Compile time on the test provided by @mstorsjo before and after this patch on my machine:
113.046s vs 35.649s
Repro: clang -target x86_64-w64-mingw32 -c -O3 glew-preproc.c; on https://martin.st/temp/glew-preproc.c.

Reviewers: kuhar, NutshellySima, mstorsjo

Subscribers: jlebar, mstorsjo, dmgreen, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62981

llvm-svn: 362839

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[Utils] Clean another duplicated util method.

Summary:
Following the cleanup in D48202, method foldBlockIntoPredecessor has the
same behavior. Replace its uses with MergeBlockIntoPredecessor.
Remove

[Utils] Clean another duplicated util method.

Summary:
Following the cleanup in D48202, method foldBlockIntoPredecessor has the
same behavior. Replace its uses with MergeBlockIntoPredecessor.
Remove foldBlockIntoPredecessor.

Reviewers: chandlerc, dmgreen

Subscribers: jlebar, javed.absar, zzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62751

llvm-svn: 362538

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revert r360162 as it breaks most of the buildbots

llvm-svn: 360190

[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized lo

[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion

Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel

Reviewed By: hfinkel

Subscribers: bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

llvm-svn: 360162

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[Utils] Extract EliminateUnreachableBlocks (NFC)

Summary:
Extract the functionality of eliminating unreachable basic blocks
within a function, previously encapsulated within the
-unreachableblockeli

[Utils] Extract EliminateUnreachableBlocks (NFC)

Summary:
Extract the functionality of eliminating unreachable basic blocks
within a function, previously encapsulated within the
-unreachableblockelim pass, and make it available as a function within
BlockUtils.h. No functional change intended other than making the logic
reusable.

Exposing this logic makes it easier to implement
https://reviews.llvm.org/D59068, which fixes coroutines bug
https://bugs.llvm.org/show_bug.cgi?id=40979.

Reviewers: mkazantsev, wmi, davidxl, silvas, davide

Reviewed By: davide

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59069

llvm-svn: 355846

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Make MergeBlockIntoPredecessor conformant to the precondition of calling DTU.applyUpdates

Summary:
It is mentioned in the document of DTU that "It is illegal to submit any update that has already be

Make MergeBlockIntoPredecessor conformant to the precondition of calling DTU.applyUpdates

Summary:
It is mentioned in the document of DTU that "It is illegal to submit any update that has already been submitted, i.e., you are supposed not to insert an existent edge or delete a nonexistent edge." It is dangerous to violet this rule because DomTree and PostDomTree occasionally crash on this scenario.

This patch fixes `MergeBlockIntoPredecessor`, making it conformant to this precondition.

Reviewers: kuhar, brzycki, chandlerc

Reviewed By: brzycki

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58444

llvm-svn: 355105

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[DTU] Refine the interface and logic of applyUpdates

Summary:
This patch separates two semantics of `applyUpdates`:
1. User provides an accurate CFG diff and the dominator tree is updated according

[DTU] Refine the interface and logic of applyUpdates

Summary:
This patch separates two semantics of `applyUpdates`:
1. User provides an accurate CFG diff and the dominator tree is updated according to the difference of `the number of edge insertions` and `the number of edge deletions` to infer the status of an edge before and after the update.
2. User provides a sequence of hints. Updates mentioned in this sequence might never happened and even duplicated.

Logic changes:

Previously, removing invalid updates is considered a side-effect of deduplication and is not guaranteed to be reliable. To handle the second semantic, `applyUpdates` does validity checking before deduplication, which can cause updates that have already been applied to be submitted again. Then, different calls to `applyUpdates` might cause unintended consequences, for example,
```
DTU(Lazy) and Edge A->B exists.
1. DTU.applyUpdates({{Delete, A, B}, {Insert, A, B}}) // User expects these 2 updates result in a no-op, but {Insert, A, B} is queued
2. Remove A->B
3. DTU.applyUpdates({{Delete, A, B}}) // DTU cancels this update with {Insert, A, B} mentioned above together (Unintended)
```
But by restricting the precondition that updates of an edge need to be strictly ordered as how CFG changes were made, we can infer the initial status of this edge to resolve this issue.

Interface changes:
The second semantic of `applyUpdates` is separated to `applyUpdatesPermissive`.
These changes enable DTU(Lazy) to use the first semantic if needed, which is quite useful in `transforms/utils`.

Reviewers: kuhar, brzycki, dmgreen, grosser

Reviewed By: brzycki

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58170

llvm-svn: 354669

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[DTU] Deprecate insertEdge*/deleteEdge*

Summary: This patch converts all existing `insertEdge*/deleteEdge*` to `applyUpdates` and marks `insertEdge*/deleteEdge*` as deprecated.

Reviewers: kuhar, br

[DTU] Deprecate insertEdge*/deleteEdge*

Summary: This patch converts all existing `insertEdge*/deleteEdge*` to `applyUpdates` and marks `insertEdge*/deleteEdge*` as deprecated.

Reviewers: kuhar, brzycki

Reviewed By: kuhar, brzycki

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58443

llvm-svn: 354652

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[NFC] Tweak SplitBlockAndInsertIfThen to use existing ThenBlock

llvm-svn: 354107

[NFC] Rename DontDeleteUselessPHIs --> KeepOneInputPHIs

llvm-svn: 353801

[NFC] Add parameter for keeping one-input Phis in DeleteDeadBlock(s)

llvm-svn: 353799

Implementation of asm-goto support in LLVM

This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html

This patch adds a new CallBr IR instruction

Implementation of asm-goto support in LLVM

This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html

This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.

This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.

There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.

Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii

Differential Revision: https://reviews.llvm.org/D53765

llvm-svn: 353563

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[NFC] Factor out detatchment of dead blocks from their erasing

llvm-svn: 353277