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
..
ADCE.cpp	[IR] Consider non-willreturn as side effect (PR50511)	2021-07-26 16:35:14 +02:00
AlignmentFromAssumptions.cpp	Recommit [ScalarEvolution] Make getMinusSCEV() fail for unrelated pointers.	2021-07-06 12:16:05 -07:00
AnnotationRemarks.cpp
BDCE.cpp
CallSiteSplitting.cpp
CMakeLists.txt	Add jump-threading optimization for deterministic finite automata	2021-07-27 14:34:04 -04:00
ConstantHoisting.cpp
ConstraintElimination.cpp
CorrelatedValuePropagation.cpp	[CVP] Guard against poison in common phi value transform (PR50399)	2021-05-25 20:47:17 +02:00
DCE.cpp
DeadStoreElimination.cpp	Revert "[DSE] Transform memset + malloc --> calloc (PR25892)"	2021-07-23 11:51:59 +02:00
DFAJumpThreading.cpp	Add jump-threading optimization for deterministic finite automata	2021-07-27 14:34:04 -04:00
DivRemPairs.cpp	[DivRemPairs] Add an initial case for hoisting to a common predecessor.	2021-07-11 10:03:07 -07:00
EarlyCSE.cpp
FlattenCFGPass.cpp
Float2Int.cpp	[NFCI] Move DEBUG_TYPE definition below #includes	2021-05-30 17:31:01 +08:00
GuardWidening.cpp
GVN.cpp	GVN.cpp - remove unused <vector> include. NFCI.	2021-06-13 14:06:32 +01:00
GVNHoist.cpp
GVNSink.cpp
InductiveRangeCheckElimination.cpp
IndVarSimplify.cpp
InferAddressSpaces.cpp	[infer-address-spaces] Handle complex non-pointer constexpr arguments.	2021-07-19 12:15:52 -07:00
InstSimplifyPass.cpp
IVUsersPrinter.cpp
JumpThreading.cpp	[CSSPGO] Undoing the concept of dangling pseudo probe	2021-06-18 15:14:11 -07:00
LICM.cpp	Strip undef implying attributes when moving calls	2021-07-27 10:57:05 -04:00
LoopAccessAnalysisPrinter.cpp
LoopBoundSplit.cpp	[LoopBoundSplit] Ignore phi node which is not scevable	2021-06-09 09:44:36 +01:00
LoopDataPrefetch.cpp	[NFCI] Move DEBUG_TYPE definition below #includes	2021-05-30 17:31:01 +08:00
LoopDeletion.cpp	[LoopDeletion] Handle switch in proving that loop exits on first iteration	2021-07-09 18:03:34 +07:00
LoopDistribute.cpp
LoopFlatten.cpp	[LoopFlatten] Use SCEV and Loop APIs to identify increment and trip count	2021-07-27 08:42:59 +01:00
LoopFuse.cpp
LoopIdiomRecognize.cpp	[LoopIdiom] Transform memmove-like loop into memmove (PR46179)	2021-07-22 13:05:43 +02:00
LoopInstSimplify.cpp
LoopInterchange.cpp	[LoopInterchange] Check lcssa phis in the inner latch in scenarios of multi-level nested loops	2021-07-16 11:59:20 -04:00
LoopLoadElimination.cpp	[NFC] Inline variable to prevent unused variable warning	2021-07-13 09:57:59 -07:00
LoopPassManager.cpp
LoopPredication.cpp
LoopRerollPass.cpp	[LoopReroll] Add an extra defensive check to avoid SCEV assertion.	2021-07-13 12:17:09 -07:00
LoopRotation.cpp
LoopSimplifyCFG.cpp
LoopSink.cpp
LoopStrengthReduce.cpp	Handle unused variable when assertions are disabled	2021-07-27 15:43:06 +02:00
LoopUnrollAndJamPass.cpp	LoopUnrollAndJamPass.cpp - remove unused <vector> include. NFCI.	2021-06-13 14:06:32 +01:00
LoopUnrollPass.cpp	[LoopUnroll] Don't modify TripCount/TripMultiple in computeUnrollCount() (NFCI)	2021-06-21 21:34:17 +02:00
LoopUnswitch.cpp
LoopVersioningLICM.cpp
LowerAtomic.cpp
LowerConstantIntrinsics.cpp
LowerExpectIntrinsic.cpp
LowerGuardIntrinsic.cpp
LowerMatrixIntrinsics.cpp	[Matrix] Fix -Wunused-variable in -DLLVM_ENABLE_ASSERTIONS=off build after D106457. NFC	2021-07-22 11:33:02 -07:00
LowerWidenableCondition.cpp
MakeGuardsExplicit.cpp
MemCpyOptimizer.cpp	Revert "[MemCpyOpt] Enable memcpy optimizations unconditionally."	2021-07-19 14:27:41 -07:00
MergedLoadStoreMotion.cpp
MergeICmps.cpp	[MergeICmps] Collect block instructions once (NFC)	2021-07-26 18:07:20 +02:00
NaryReassociate.cpp
NewGVN.cpp
PartiallyInlineLibCalls.cpp	[PartiallyInlineLibCalls] Disable sqrt expansion for strictfp.	2021-06-17 14:15:12 -07:00
PlaceSafepoints.cpp
Reassociate.cpp
Reg2Mem.cpp
RewriteStatepointsForGC.cpp	[RS4GC] Use one DVCache for both inlineGetBaseAndOffset() and insertParsePoints()	2021-07-12 18:13:00 +07:00
Scalar.cpp	Add jump-threading optimization for deterministic finite automata	2021-07-27 14:34:04 -04:00
ScalarizeMaskedMemIntrin.cpp	[ScalarizeMaskedMemIntrin][SelectionDAGBuilder] Use the element type to calculate alignment for gather/scatter when alignment operand is 0.	2021-07-01 19:08:47 -07:00
Scalarizer.cpp	Update @llvm.powi to handle different int sizes for the exponent	2021-06-17 09:38:28 +02:00
SCCP.cpp	[Local] Do not introduce a new llvm.trap before unreachable	2021-07-26 23:33:36 -05:00
SeparateConstOffsetFromGEP.cpp
SimpleLoopUnswitch.cpp	[SimpleLoopUnswitch] Don't non-trivially unswitch loops with catchswitch exits	2021-07-14 14:07:28 -07:00
SimplifyCFGPass.cpp	[SimplifyCFG] Tail-merging all blocks with resume terminator	2021-06-24 21:25:06 +03:00
Sink.cpp
SpeculativeExecution.cpp
SROA.cpp	[SROA] avoid crash on memset with constant expression length	2021-07-21 15:20:28 -04:00
StraightLineStrengthReduce.cpp
StructurizeCFG.cpp
TailRecursionElimination.cpp
WarnMissedTransforms.cpp