Summary:
This patch makes LoopUnswitch use new incremental API for updating dominators.
It also updates SplitCriticalEdge, as it is called in LoopUnswitch.

There doesn't seem to be any noticeable performance difference when bootstrapping clang with this patch.

Reviewers: dberlin, davide, sanjoy, grosser, chandlerc

Reviewed By: davide, grosser

Subscribers: mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D35528

llvm-svn: 311093

Summary: When we move then-else code to if, we need to merge its debug info, otherwise the hoisted instruction may have inaccurate debug info attached.

Reviewers: aprantl, probinson, dblaikie, echristo, loladiro

Reviewed By: aprantl

Subscribers: sanjoy, llvm-commits

Differential Revision: https://reviews.llvm.org/D36778

llvm-svn: 310985

Two minor savings: avoid copying the SinkAfter map and avoid moving a cast if it
is not needed.

Differential Revision: https://reviews.llvm.org/D36408

llvm-svn: 310910

Recommit r310869, "[InstSimplify][InstCombine] Modify the interface of decomposeBitTestICmp and use it in the InstSimplify"

This recommits r310869, with the moved files and no extra changes.

Original commit message:

This addresses a fixme in InstSimplify about using decomposeBitTest. This also fixes InstSimplify to handle ugt and ult compares too.

I've modified the interface a little to return only the APInt version of the mask that InstSimplify needs. InstCombine now has a small wrapper routine to create a Constant out of it. I've also dropped the returning of 0 since InstSimplify doesn't need that. So InstCombine creates a zero constant itself.

I also had to make decomposeBitTest support vectors since InstSimplify needs that.

As InstSimplify can't use something from the Transforms library, I've moved the CmpInstAnalysis code to the Analysis library.

Differential Revision: https://reviews.llvm.org/D36593

llvm-svn: 310889

Differential Revision: https://reviews.llvm.org/D34163

llvm-svn: 310885

Revert r310869 "[InstSimplify][InstCombine] Modify the interface of decomposeBitTestICmp and use it in the InstSimplify"

Failed to add the two files that moved. And then added an extra change I didn't mean to while trying to fix that. Reverting everything.

llvm-svn: 310873

[InstSimplify][InstCombine] Modify the interface of decomposeBitTestICmp and use it in the InstSimplify

This addresses a fixme in InstSimplify about using decomposeBitTest. This also fixes InstSimplify to handle ugt and ult compares too.

I've modified the interface a little to return only the APInt version of the mask that InstSimplify needs. InstCombine now has a small wrapper routine to create a Constant out of it. I've also dropped the returning of 0 since InstSimplify doesn't need that. So InstCombine creates a zero constant itself.

I also had to make decomposeBitTest support vectors since InstSimplify needs that.

As InstSimplify can't use something from the Transforms library, I've moved the CmpInstAnalysis code to the Analysis library.

Differential Revision: https://reviews.llvm.org/D36593

llvm-svn: 310869

On some targets, the penalty of executing runtime unrolling checks
and then not the unrolled loop can be significantly detrimental to
performance. This results in the need to be more conservative with
the unroll count, keeping a trip count of 2 reduces the overhead as
well as increasing the chance of the unrolled body being executed. But
being conservative leaves performance gains on the table.

This patch enables the unrolling of the remainder loop introduced by
runtime unrolling. This can help reduce the overhead of misunrolled
loops because the cost of non-taken branches is much less than the
cost of the backedge that would normally be executed in the remainder
loop. This allows larger unroll factors to be used without suffering
performance loses with smaller iteration counts.

Differential Revision: https://reviews.llvm.org/D36309

llvm-svn: 310824

[DebugCounter] Move the semicolon out of the DEBUG_COUNTER macro and require it to be placed at the end of each use.

This make it consistent with STATISTIC which it will often appears near.

While there move one DEBUG_COUNTER instance out of an anonymous namespace. It's already declaring a static variable so the namespace is unnecessary.

llvm-svn: 310637

Duplicating the distinct Subprogram and CU metadata nodes seems like the incorrect thing to do in CloneModule for GlobalVariable debug info. As it results in the scope of the GlobalVariable DI no longer being consistent with the rest of the module, and the new CU is absent from llvm.dbg.cu.

Fixed by adding RF_MoveDistinctMDs to MapMetadata flags for GlobalVariables.

Current unit test IR after clone:
```
@gv = global i32 1, comdat($comdat), !dbg !0, !type !5

define private void @f() comdat($comdat) personality void ()* @persfn !dbg !14 {

!llvm.dbg.cu = !{!10}

!0 = !DIGlobalVariableExpression(var: !1)
!1 = distinct !DIGlobalVariable(name: "gv", linkageName: "gv", scope: !2, file: !3, line: 1, type: !9, isLocal: false, isDefinition: true)
!2 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !3, line: 4, type: !4, isLocal: true, isDefinition: true, scopeLine: 3, isOptimized: false, unit: !6, variables: !5)
!3 = !DIFile(filename: "filename.c", directory: "/file/dir/")
!4 = !DISubroutineType(types: !5)
!5 = !{}
!6 = distinct !DICompileUnit(language: DW_LANG_C99, file: !7, producer: "CloneModule", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, globals: !8)
!7 = !DIFile(filename: "filename.c", directory: "/file/dir")
!8 = !{!0}
!9 = !DIBasicType(tag: DW_TAG_unspecified_type, name: "decltype(nullptr)")
!10 = distinct !DICompileUnit(language: DW_LANG_C99, file: !7, producer: "CloneModule", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, globals: !11)
!11 = !{!12}
!12 = !DIGlobalVariableExpression(var: !13)
!13 = distinct !DIGlobalVariable(name: "gv", linkageName: "gv", scope: !14, file: !3, line: 1, type: !9, isLocal: false, isDefinition: true)
!14 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !3, line: 4, type: !4, isLocal: true, isDefinition: true, scopeLine: 3, isOptimized: false, unit: !10, variables: !5)
```

Patched IR after clone:
```
@gv = global i32 1, comdat($comdat), !dbg !0, !type !5

define private void @f() comdat($comdat) personality void ()* @persfn !dbg !2 {

!llvm.dbg.cu = !{!6}

!0 = !DIGlobalVariableExpression(var: !1)
!1 = distinct !DIGlobalVariable(name: "gv", linkageName: "gv", scope: !2, file: !3, line: 1, type: !9, isLocal: false, isDefinition: true)
!2 = distinct !DISubprogram(name: "f", linkageName: "f", scope: null, file: !3, line: 4, type: !4, isLocal: true, isDefinition: true, scopeLine: 3, isOptimized: false, unit: !6, variables: !5)
!3 = !DIFile(filename: "filename.c", directory: "/file/dir/")
!4 = !DISubroutineType(types: !5)
!5 = !{}
!6 = distinct !DICompileUnit(language: DW_LANG_C99, file: !7, producer: "CloneModule", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, globals: !8)
!7 = !DIFile(filename: "filename.c", directory: "/file/dir")
!8 = !{!0}
!9 = !DIBasicType(tag: DW_TAG_unspecified_type, name: "decltype(nullptr)")
```

Reviewers: aprantl, probinson, dblaikie, echristo, loladiro
Reviewed By: aprantl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D36082

llvm-svn: 309928

llvm-svn: 309785

IMHO this is a bit more readable.

llvm-svn: 309739

To the best of my knowledge -metarenamer is used in two cases:
1) obfuscate names, when e.g. they contain informations that
can't be shared.
2) Improve clarity of the textual IR for testcases.

One of the usecases if getting the output of `opt` and passing it
to the lli interpreter to run the test. If metarenamer renames
@main, lli can't find an entry point.

llvm-svn: 309657

Differential Revision: https://reviews.llvm.org/D35579

llvm-svn: 309444

There is no situation where this rarely-used argument cannot be
substituted with a DIExpression and removing it allows us to simplify
the DWARF backend. Note that this patch does not yet remove any of
the newly dead code.

rdar://problem/33580047
Differential Revision: https://reviews.llvm.org/D35951

llvm-svn: 309426

Summary:
It is possible for some passes to materialize a call to a libcall (ex: ldexp, exp2, etc),
but these passes will not mark the call as a gc-leaf-function. All libcalls are
actually gc-leaf-functions, so we change llvm::callsGCLeafFunction() to tell us that
available libcalls are equivalent to gc-leaf-function calls.

Reviewers: sanjoy, anna, reames

Reviewed By: anna

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D35840

llvm-svn: 309291

llvm-svn: 309281

Summary:
Until a more advanced version of importing can be implemented for
aliases (one that imports an alias as an available_externally definition
of the aliasee), skip the narrow subset of cases that was possible but
came at a cost: aliases of linkonce_odr functions could be imported
because the linkonce_odr function could be safely duplicated from the
source module. This came/comes at the cost of not being able to 'home'
imported linkonce functions (they had to be emitted linkonce_odr in all
the destination modules (even if they weren't used by an alias) rather
than as available_externally - causing extra object size).

Tangentially, this also was the only reason ThinLTO would emit multiple
CUs in to the resulting DWARF - which happens to be a problem for
Fission (there's a fix for this in GDB but not released yet, etc).
(actually it's not the only reason - but I'm sending a patch to fix the
other reason shortly)

There's no reason to believe this particularly narrow alias importing
was especially/meaningfully important, only that it was /possible/ to
implement in this way. When a more general solution is done, it should
still satisfy the DWARF concerns above, since the import will still be
available_externally, and thus not create extra CUs.

Since now all aliases are treated the same, I removed/simplified some
test cases since they were testing corner cases where there are no
longer any corners.

Reviewers: tejohnson, mehdi_amini

Differential Revision: https://reviews.llvm.org/D35875

llvm-svn: 309278

Summary:
This changes SimplifyLibCalls to use the new OptimizationRemarkEmitter
API.

In fact, as SimplifyLibCalls is only ever called via InstCombine,
(as far as I can tell) the OptimizationRemarkEmitter is added there,
and then passed through to SimplifyLibCalls later.

I have avoided changing any remark text.

This closes PR33787

Patch by Sam Elliott!

Reviewers: anemet, davide

Reviewed By: anemet

Subscribers: davide, mehdi_amini, eraman, fhahn, llvm-commits

Differential Revision: https://reviews.llvm.org/D35608

llvm-svn: 309158

Separated out the profitability from the safety analysis for multiexit
loop unrolling. Currently, this is an NFC because profitability is true
only if the unroll-runtime-multi-exit is set to true (off-by-default).

This is to ease adding the profitability heuristic up for review at
D35380.

llvm-svn: 308753

If OpValue is non-null, we only consider operations similar to OpValue
when intersecting.

Differential Revision: https://reviews.llvm.org/D35292

llvm-svn: 308428

[SimplifyCFG] Defer folding unconditional branches to LateSimplifyCFG if it can destroy canonical loop structure.

Summary:
When simplifying unconditional branches from empty blocks, we pre-test if the
BB belongs to a set of loop headers and keep the block to prevent passes from
destroying canonical loop structure. However, the current algorithm fails if
the destination of the branch is a loop header. Especially when such a loop's
latch block is folded into loop header it results in additional backedges and
LoopSimplify turns it into a nested loop which prevent later optimizations
from being applied (e.g., loop  unrolling and loop interleaving).

This patch augments the existing algorithm by further checking if the
destination of the branch belongs to a set of loop headers and defer
eliminating it if yes to LateSimplifyCFG.

Fixes PR33605: https://bugs.llvm.org/show_bug.cgi?id=33605

Reviewers: efriedma, mcrosier, pacxx, hsung, davidxl

Reviewed By: efriedma

Subscribers: ashutosh.nema, gberry, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D35411

llvm-svn: 308422

llvm-svn: 307929

Summary:
When we runtime unroll with multiple exit blocks, we also need to update the
immediate dominators of the immediate successors of the exit blocks.

Reviewers: reames, mkuper, mzolotukhin, apilipenko

Reviewed by: mzolotukhin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D35304

llvm-svn: 307909

Refactored the code and separated out a function
`canSafelyUnrollMultiExitLoop` to reduce redundant checks and make it
easier to add profitability heuristics later.
Added tests to runtime unrolling to make sure that unrolling for
multi-exit loops is not done unless the option
-unroll-runtime-multi-exit is true.

llvm-svn: 307843

  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

llvm-svn: 307705

The loop structure for the outer loop does not contain the epilog
preheader when we try to unroll inner loop with multiple exits and
epilog code is generated. For now, we just bail out in such cases.
Added a test case that shows the problem. Without this bailout, we would
trip on assert saying LCSSA form is incorrect for outer loop.

llvm-svn: 307676

Summary:
As metioned in https://reviews.llvm.org/D34576, checkings in
`collectConstantCandidates` can be replaced by using
`llvm::canReplaceOperandWithVariable`.

The only special case is that `collectConstantCandidates` return false for
all `IntrinsicInst` but it is safe for us to collect constant candidates from
`IntrinsicInst`.

Reviewers: pirama, efriedma, srhines

Reviewed By: efriedma

Subscribers: llvm-commits, javed.absar

Differential Revision: https://reviews.llvm.org/D34921

llvm-svn: 307587

When unrolling under multiple exits which is under off-by-default option,
the assert that checks for VMap entry in loop exit values is too strong.
(assert if VMap entry did not exist, the value should be a
constant). However, values derived from
constants or from values outside loop, does not have a VMap entry too.

Removed the assert and added a testcase showcasing the property for
non-constant values.

llvm-svn: 307542

llvm-svn: 307491

The patch was reverted due to a bug. The bug was that if the IV is the 2nd operand of the icmp
instruction, then the "Pred" variable gets swapped and differs from the instruction's predicate.
In this patch we use the original predicate to do the transformation.

Also added a test case that exercises this situation.

Differentian Revision: https://reviews.llvm.org/D35107

llvm-svn: 307477

With the NFC refactoring in rL307417 (git SHA 987dd01), all the logic
is in place to support multiple exit/exiting blocks when prolog
remainder is generated.
This patch removed the assert that multiple exit blocks unrolling is only
supported when epilog remainder is generated.

Also, added test runs and checks with PROLOG prefix in
runtime-loop-multiple-exits.ll test cases.

llvm-svn: 307435

It referenced a wrong function name, and didn't mention what the
second argument did. This should be slightly more accurate now.

llvm-svn: 307425

Summary:
This is an addon to the change rl304488 cloning fixes. (Originally rl304226 reverted rl304228 and reapplied rl304488 https://reviews.llvm.org/D33655)

rl304488 works great when DILocalVariables that comes from the inlined function has a 'unique-ed' type, but,
in the case when the variable type is distinct we will create a second DILocalVariable in the scope of the original function that was inlined.

Consider cloning of the following function:
```
define private void @f() !dbg !5 {
  %1 = alloca i32, !dbg !11
  call void @llvm.dbg.declare(metadata i32* %1, metadata !14, metadata !12), !dbg !18
  ret void, !dbg !18
}

!14 = !DILocalVariable(name: "inlined", scope: !15, file: !6, line: 5, type: !17) ; came from an inlined function
!15 = distinct !DISubprogram(name: "inlined", linkageName: "inlined", scope: null, file: !6, line: 8, type: !7, isLocal: true, isDefinition: true, scopeLine: 9, isOptimized: false, unit: !0, variables: !16)
!16 = !{!14}
!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "some_struct", size: 32, align: 32)
```

Without this fix, when function 'f' is cloned, we will create another DILocalVariable for "inlined", due to its type being distinct.

```
define private void @f.1() !dbg !23 {
  %1 = alloca i32, !dbg !26
  call void @llvm.dbg.declare(metadata i32* %1, metadata !28, metadata !12), !dbg !30
  ret void, !dbg !30
}

!14 = !DILocalVariable(name: "inlined", scope: !15, file: !6, line: 5, type: !17)
!15 = distinct !DISubprogram(name: "inlined", linkageName: "inlined", scope: null, file: !6, line: 8, type: !7, isLocal: true, isDefinition: true, scopeLine: 9, isOptimized: false, unit: !0, variables: !16)
!16 = !{!14}
!17 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "some_struct", size: 32, align: 32)
 ;
!28 = !DILocalVariable(name: "inlined", scope: !15, file: !6, line: 5, type: !29) ; OOPS second DILocalVariable
!29 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "some_struct", size: 32, align: 32)
```

Now we have two DILocalVariable for "inlined" within the same scope. This result in assert in AsmPrinter/DwarfDebug.h:131: void llvm::DbgVariable::addMMIEntry(const llvm::DbgVariable &): Assertion `V.Var == Var && "conflicting variable"' failed.
(Full example: See: https://bugs.llvm.org/show_bug.cgi?id=33492)

In this change we prevent duplication of types so that when a metadata for DILocalVariable is cloned it will get uniqued to the same metadate node as an original variable.

Reviewers: loladiro, dblaikie, aprantl, echristo

Reviewed By: loladiro

Subscribers: EricWF, llvm-commits

Differential Revision: https://reviews.llvm.org/D35106

llvm-svn: 307418

Minor refactoring to use the preexisting loop exit that's already
calculated. We do not need to recompute the loop exit in ConnectProlog.
Apart from avoiding redundant computation, this is required for
supporting multiple loop exits when Prolog remainder loops are generated.

llvm-svn: 307417

Adds loop expansions for known-size and unknown-sized memcpy calls, allowing the
target to provide the operand types through TTI callbacks. The default values
for the TTI callbacks use int8 operand types and matches the existing behaviour
if they aren't overridden by the target.

Differential revision: https://reviews.llvm.org/D32536

llvm-svn: 307346

Summary:
`Instruction::Switch`: only first operand can be set to a non-constant value.
`Instruction::InsertValue` both the first and the second operand can be set to a non-constant value.
`Instruction::Alloca` return true for non-static allocation.

Reviewers: efriedma

Reviewed By: efriedma

Subscribers: srhines, pirama, llvm-commits

Differential Revision: https://reviews.llvm.org/D34905

llvm-svn: 307294

[Constants] If we already have a ConstantInt*, prefer to use isZero/isOne/isMinusOne instead of isNullValue/isOneValue/isAllOnesValue inherited from Constant. NFCI

Going through the Constant methods requires redetermining that the Constant is a ConstantInt and then calling isZero/isOne/isMinusOne.

llvm-svn: 307292

Currently, we do not support multiple exiting blocks to the
latch exit block. However, this bailout wasn't triggered when we had a
unique exit block (which is the latch exit), with multiple exiting
blocks to that unique exit.

Moved the bailout so that it's triggered in both cases and added
testcase.

llvm-svn: 307291