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llvm-mirror/lib/Transforms/Scalar/CMakeLists.txt
Alexey Zhikhartsev 6516543c4b Add jump-threading optimization for deterministic finite automata
The current JumpThreading pass does not jump thread loops since it can
result in irreducible control flow that harms other optimizations. This
prevents switch statements inside a loop from being optimized to use
unconditional branches.

This code pattern occurs in the core_state_transition function of
Coremark. The state machine can be implemented manually with goto
statements resulting in a large runtime improvement, and this transform
makes the switch implementation match the goto version in performance.

This patch specifically targets switch statements inside a loop that
have the opportunity to be threaded. Once it identifies an opportunity,
it creates new paths that branch directly to the correct code block.
For example, the left CFG could be transformed to the right CFG:

```
          sw.bb                        sw.bb
        /   |   \                    /   |   \
   case1  case2  case3          case1  case2  case3
        \   |   /                /       |       \
        latch.bb             latch.2  latch.3  latch.1
         br sw.bb              /         |         \
                           sw.bb.2     sw.bb.3     sw.bb.1
                            br case2    br case3    br case1
```

Co-author: Justin Kreiner @jkreiner
Co-author: Ehsan Amiri @amehsan

Reviewed By: SjoerdMeijer

Differential Revision: https://reviews.llvm.org/D99205
2021-07-27 14:34:04 -04:00

100 lines
2.0 KiB
CMake

add_llvm_component_library(LLVMScalarOpts
ADCE.cpp
AlignmentFromAssumptions.cpp
AnnotationRemarks.cpp
BDCE.cpp
CallSiteSplitting.cpp
ConstantHoisting.cpp
ConstraintElimination.cpp
CorrelatedValuePropagation.cpp
DCE.cpp
DeadStoreElimination.cpp
DFAJumpThreading.cpp
DivRemPairs.cpp
EarlyCSE.cpp
FlattenCFGPass.cpp
Float2Int.cpp
GuardWidening.cpp
GVN.cpp
GVNHoist.cpp
GVNSink.cpp
IVUsersPrinter.cpp
InductiveRangeCheckElimination.cpp
IndVarSimplify.cpp
InferAddressSpaces.cpp
InstSimplifyPass.cpp
JumpThreading.cpp
LICM.cpp
LoopAccessAnalysisPrinter.cpp
LoopBoundSplit.cpp
LoopSink.cpp
LoopDeletion.cpp
LoopDataPrefetch.cpp
LoopDistribute.cpp
LoopFuse.cpp
LoopIdiomRecognize.cpp
LoopInstSimplify.cpp
LoopInterchange.cpp
LoopFlatten.cpp
LoopLoadElimination.cpp
LoopPassManager.cpp
LoopPredication.cpp
LoopRerollPass.cpp
LoopRotation.cpp
LoopSimplifyCFG.cpp
LoopStrengthReduce.cpp
LoopUnrollPass.cpp
LoopUnrollAndJamPass.cpp
LoopUnswitch.cpp
LoopVersioningLICM.cpp
LowerAtomic.cpp
LowerConstantIntrinsics.cpp
LowerExpectIntrinsic.cpp
LowerGuardIntrinsic.cpp
LowerMatrixIntrinsics.cpp
LowerWidenableCondition.cpp
MakeGuardsExplicit.cpp
MemCpyOptimizer.cpp
MergeICmps.cpp
MergedLoadStoreMotion.cpp
NaryReassociate.cpp
NewGVN.cpp
PartiallyInlineLibCalls.cpp
PlaceSafepoints.cpp
Reassociate.cpp
Reg2Mem.cpp
RewriteStatepointsForGC.cpp
SCCP.cpp
SROA.cpp
Scalar.cpp
Scalarizer.cpp
ScalarizeMaskedMemIntrin.cpp
SeparateConstOffsetFromGEP.cpp
SimpleLoopUnswitch.cpp
SimplifyCFGPass.cpp
Sink.cpp
SpeculativeExecution.cpp
StraightLineStrengthReduce.cpp
StructurizeCFG.cpp
TailRecursionElimination.cpp
WarnMissedTransforms.cpp
ADDITIONAL_HEADER_DIRS
${LLVM_MAIN_INCLUDE_DIR}/llvm/Transforms
${LLVM_MAIN_INCLUDE_DIR}/llvm/Transforms/Scalar
DEPENDS
intrinsics_gen
COMPONENT_NAME
Scalar
LINK_COMPONENTS
AggressiveInstCombine
Analysis
Core
InstCombine
Support
TransformUtils
)