llvm-project/llvm/lib/CodeGen
Amara Emerson 93e58d2396 [AArch64][GlobalISel] Enable copy elision in the pre-legalizer combine and fix a crash.
This enables the simple copy combine that already exists in the CombinerHelper.
However, it exposed a bug in the GISelChangeObserver where it wouldn't clear a
set of MIs to process, and so would end up causing a crash when deleted MIs were
being added to the combiner worklist again.

Differential Revision: https://reviews.llvm.org/D60579

llvm-svn: 358318
2019-04-13 00:33:25 +00:00
..
AsmPrinter Revert r358268 "[DebugInfo] DW_OP_deref_size in PrologEpilogInserter." 2019-04-12 12:54:52 +00:00
GlobalISel [AArch64][GlobalISel] Enable copy elision in the pre-legalizer combine and fix a crash. 2019-04-13 00:33:25 +00:00
MIRParser Revert r358268 "[DebugInfo] DW_OP_deref_size in PrologEpilogInserter." 2019-04-12 12:54:52 +00:00
SelectionDAG [DAGCombiner] narrow shuffle of concatenated vectors 2019-04-12 16:31:56 +00:00
AggressiveAntiDepBreaker.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
AggressiveAntiDepBreaker.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
AllocationOrder.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
AllocationOrder.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Analysis.cpp GlobalISel: Move computeValueLLTs 2019-04-10 17:27:56 +00:00
AntiDepBreaker.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
AtomicExpandPass.cpp [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +00:00
BasicTargetTransformInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
BranchFolding.cpp [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +00:00
BranchFolding.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
BranchRelaxation.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
BreakFalseDeps.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
BuiltinGCs.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CFIInstrInserter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CMakeLists.txt Remove an unnecessary file; NFC. 2018-11-26 15:54:36 +00:00
CalcSpillWeights.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CallingConvLower.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CodeGen.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CodeGenPrepare.cpp Include what's used in a few cpp files - these were getting transitive 2019-04-12 06:16:33 +00:00
CriticalAntiDepBreaker.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CriticalAntiDepBreaker.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
DFAPacketizer.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
DeadMachineInstructionElim.cpp Revert LIS handling in MachineDCE 2019-04-09 16:13:53 +00:00
DetectDeadLanes.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
DwarfEHPrepare.cpp Add an optional list of blocks to avoid when looking for a path in isPotentiallyReachable. 2019-04-02 01:05:48 +00:00
EarlyIfConversion.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
EdgeBundles.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ExecutionDomainFix.cpp Use llvm::upper_bound. NFC 2019-04-12 11:31:16 +00:00
ExpandISelPseudos.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ExpandMemCmp.cpp Add options for MaxLoadsPerMemcmp(OptSize). 2019-04-12 15:05:46 +00:00
ExpandPostRAPseudos.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ExpandReductions.cpp Reland "Relax constraints for reduction vectorization" 2019-03-12 01:31:44 +00:00
FEntryInserter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
FaultMaps.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
FuncletLayout.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
GCMetadata.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
GCMetadataPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
GCRootLowering.cpp [opaque pointer types] Pass value type to LoadInst creation. 2019-02-01 20:44:24 +00:00
GCStrategy.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
GlobalMerge.cpp [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +00:00
IfConversion.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ImplicitNullChecks.cpp [ImplicitNullChecks] Support unordered atomic accesses 2019-03-13 03:25:20 +00:00
IndirectBrExpandPass.cpp Implementation of asm-goto support in LLVM 2019-02-08 20:48:56 +00:00
InlineSpiller.cpp [InlineSpiller] Fix a crash due to lack of forward progress from remat (try 2) 2019-02-12 18:33:01 +00:00
InterferenceCache.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
InterferenceCache.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
InterleavedAccessPass.cpp [InterleavedAccessPass] Don't increase the number of bytes loaded. 2019-03-28 20:44:50 +00:00
InterleavedLoadCombinePass.cpp [opaque pointer types] Pass value type to LoadInst creation. 2019-02-01 20:44:24 +00:00
IntrinsicLowering.cpp [opaque pointer types] Pass function types to CallInst creation. 2019-02-01 20:43:25 +00:00
LLVMBuild.txt Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LLVMTargetMachine.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LatencyPriorityQueue.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LazyMachineBlockFrequencyInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LexicalScopes.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveDebugValues.cpp [DEBUGINFO] Reposting r352642: Handle restore instructions in LiveDebugValues 2019-02-04 20:42:45 +00:00
LiveDebugVariables.cpp Include what's used in a few cpp files - these were getting transitive 2019-04-12 06:16:33 +00:00
LiveDebugVariables.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveInterval.cpp Use llvm::upper_bound. NFC 2019-04-12 11:31:16 +00:00
LiveIntervalUnion.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveIntervals.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LivePhysRegs.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveRangeCalc.cpp [LiveRange] Reset the VNIs when splitting subranges 2019-03-26 21:27:15 +00:00
LiveRangeCalc.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveRangeEdit.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveRangeShrink.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveRangeUtils.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveRegMatrix.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveRegUnits.cpp [CodeGen] Don't scavenge non-saved regs in exception throwing functions 2019-02-01 09:23:51 +00:00
LiveStacks.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LiveVariables.cpp [NFC] add/modify wrapper function for findRegisterDefOperand(). 2019-02-20 07:01:04 +00:00
LocalStackSlotAllocation.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LoopTraversal.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LowLevelType.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
LowerEmuTLS.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MIRCanonicalizerPass.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MIRPrinter.cpp MIR: Allow targets to serialize MachineFunctionInfo 2019-03-14 22:54:43 +00:00
MIRPrintingPass.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineBasicBlock.cpp [ADT] Notify ilist traits about in-list transfers 2019-01-23 22:59:52 +00:00
MachineBlockFrequencyInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineBlockPlacement.cpp [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +00:00
MachineBranchProbabilityInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineCSE.cpp [Codegen] Remove dead flags on Physical Defs in machine cse 2019-02-20 10:22:18 +00:00
MachineCombiner.cpp [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +00:00
MachineCopyPropagation.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineDominanceFrontier.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineDominators.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineFrameInfo.cpp Enforce StackID definition in PEI 2019-04-02 09:46:52 +00:00
MachineFunction.cpp Move addFrameInst out of line and remove the MCDwarf.h include. 2019-04-12 06:31:59 +00:00
MachineFunctionPass.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineFunctionPrinterPass.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineInstr.cpp Allow unordered loads to be considered invariant in CodeGen 2019-03-19 18:27:18 +00:00
MachineInstrBundle.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineLICM.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineLoopInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineModuleInfo.cpp Fix emission of _fltused for MSVC. 2019-01-24 18:34:00 +00:00
MachineModuleInfoImpls.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineOperand.cpp Include what's used in a few cpp files - these were getting transitive 2019-04-12 06:16:33 +00:00
MachineOptimizationRemarkEmitter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineOutliner.cpp [MachineOutliner] Replace ostringstream based string concatenation with Twine 2019-04-10 14:52:37 +00:00
MachinePipeliner.cpp [Pipeliner] Fix incorrect loop carried dependence calculation 2019-04-11 21:57:51 +00:00
MachinePostDominators.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineRegionInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineRegisterInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineSSAUpdater.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineScheduler.cpp [ScheduleDAG] Move `Topo` and `addEdge` to base class. 2019-03-29 08:33:05 +00:00
MachineSink.cpp Add skipFunction to PostRA machine sinking pass. 2019-02-21 02:11:06 +00:00
MachineTraceMetrics.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
MachineVerifier.cpp GlobalISel: Verify g_insert 2019-02-19 16:10:16 +00:00
MacroFusion.cpp [ScheduleDAG] Move `Topo` and `addEdge` to base class. 2019-03-29 08:33:05 +00:00
OptimizePHIs.cpp [Codegen] Make sure kill flags are not incorrect from removed machine phi's 2019-02-12 15:02:57 +00:00
PHIElimination.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PHIEliminationUtils.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PHIEliminationUtils.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ParallelCG.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PatchableFunction.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PeepholeOptimizer.cpp [PeepholeOpt] Don't stop simplifying copies on sequence of subregs 2019-03-27 17:27:56 +00:00
PostRAHazardRecognizer.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PostRASchedulerList.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PreISelIntrinsicLowering.cpp [opaque pointer types] Pass value type to LoadInst creation. 2019-02-01 20:44:24 +00:00
ProcessImplicitDefs.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
PrologEpilogInserter.cpp Revert r358268 "[DebugInfo] DW_OP_deref_size in PrologEpilogInserter." 2019-04-12 12:54:52 +00:00
PseudoSourceValue.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
README.txt Test commit: Removed trailing space in .txt file. 2018-12-06 13:20:27 +00:00
ReachingDefAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegAllocBase.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegAllocBase.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegAllocBasic.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegAllocFast.cpp RegAllocFast: Do not allocate registers for undef uses 2019-03-19 19:16:04 +00:00
RegAllocGreedy.cpp Use llvm::lower_bound. NFC 2019-04-12 02:02:06 +00:00
RegAllocPBQP.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegUsageInfoCollector.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegUsageInfoPropagate.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegisterClassInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegisterCoalescer.cpp Use llvm::upper_bound. NFC 2019-04-12 11:31:16 +00:00
RegisterCoalescer.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RegisterPressure.cpp RegPressure: Fix crash on blocks with only dbg_value 2019-03-27 18:14:02 +00:00
RegisterScavenging.cpp RegisterScavenger: Allow fail without spill 2019-02-25 20:29:04 +00:00
RegisterUsageInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
RenameIndependentSubregs.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ResetMachineFunctionPass.cpp [ResetMachineFunctionPass] Add visited functions statistics info 2019-03-14 01:13:15 +00:00
SafeStack.cpp [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +00:00
SafeStackColoring.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SafeStackColoring.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SafeStackLayout.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SafeStackLayout.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ScalarizeMaskedMemIntrin.cpp [ScalarizeMaskedMemIntrin] Add support for scalarizing expandload and compressstore intrinsics. 2019-03-21 17:38:52 +00:00
ScheduleDAG.cpp [ScheduleDAG] Add statistics for maintaining the topological order. 2019-04-10 09:03:03 +00:00
ScheduleDAGInstrs.cpp [ScheduleDAG] Move `Topo` and `addEdge` to base class. 2019-03-29 08:33:05 +00:00
ScheduleDAGPrinter.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ScoreboardHazardRecognizer.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
ShadowStackGCLowering.cpp [opaque pointer types] Pass value type to LoadInst creation. 2019-02-01 20:44:24 +00:00
ShrinkWrap.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SjLjEHPrepare.cpp [opaque pointer types] Pass value type to LoadInst creation. 2019-02-01 20:44:24 +00:00
SlotIndexes.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SpillPlacement.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SpillPlacement.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Spiller.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
SplitKit.cpp [LiveRange] Reset the VNIs when splitting subranges 2019-03-26 21:27:15 +00:00
SplitKit.h Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
StackColoring.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
StackMapLivenessAnalysis.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
StackMaps.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
StackProtector.cpp Change some dyn_cast to more apropriate isa. NFC 2019-04-05 16:16:23 +00:00
StackSlotColoring.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TailDuplication.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TailDuplicator.cpp [IR] Refactor attribute methods in Function class (NFC) 2019-04-04 22:40:06 +00:00
TargetFrameLoweringImpl.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TargetInstrInfo.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TargetLoweringBase.cpp [CodeGen] Refactor the option for the maximum jump table size 2019-03-29 17:28:11 +00:00
TargetLoweringObjectFileImpl.cpp [WebAssembly] Remove uses of ThreadModel 2019-02-28 18:39:08 +00:00
TargetOptionsImpl.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TargetPassConfig.cpp CodeGen: Refactor regallocator command line and target selection 2019-03-19 19:33:12 +00:00
TargetRegisterInfo.cpp [RegAlloc] Avoid compile time regression with multiple copy hints. 2019-03-11 19:00:37 +00:00
TargetSchedule.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
TargetSubtargetInfo.cpp [Subtarget] Merge ProcSched and ProcDesc arrays in MCSubtargetInfo into a single array. 2019-03-05 18:54:38 +00:00
TwoAddressInstructionPass.cpp [TwoAddressInstructionPass] After commuting an instruction and before trying to look for more commutable operands, resample the number of operands. 2019-02-23 21:41:44 +00:00
UnreachableBlockElim.cpp [Utils] Extract EliminateUnreachableBlocks (NFC) 2019-03-11 17:51:57 +00:00
ValueTypes.cpp [CodeGen] Defined MVTs v3i32, v3f32, v5i32, v5f32 2019-03-17 22:56:38 +00:00
VirtRegMap.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
WasmEHPrepare.cpp [WebAssembly] Make rethrow take an except_ref type argument 2019-03-16 05:38:57 +00:00
WinEHPrepare.cpp [opaque pointer types] Pass value type to LoadInst creation. 2019-02-01 20:44:24 +00:00
XRayInstrumentation.cpp Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00

README.txt

//===---------------------------------------------------------------------===//

Common register allocation / spilling problem:

        mul lr, r4, lr
        str lr, [sp, #+52]
        ldr lr, [r1, #+32]
        sxth r3, r3
        ldr r4, [sp, #+52]
        mla r4, r3, lr, r4

can be:

        mul lr, r4, lr
        mov r4, lr
        str lr, [sp, #+52]
        ldr lr, [r1, #+32]
        sxth r3, r3
        mla r4, r3, lr, r4

and then "merge" mul and mov:

        mul r4, r4, lr
        str r4, [sp, #+52]
        ldr lr, [r1, #+32]
        sxth r3, r3
        mla r4, r3, lr, r4

It also increase the likelihood the store may become dead.

//===---------------------------------------------------------------------===//

bb27 ...
        ...
        %reg1037 = ADDri %reg1039, 1
        %reg1038 = ADDrs %reg1032, %reg1039, %noreg, 10
    Successors according to CFG: 0x8b03bf0 (#5)

bb76 (0x8b03bf0, LLVM BB @0x8b032d0, ID#5):
    Predecessors according to CFG: 0x8b0c5f0 (#3) 0x8b0a7c0 (#4)
        %reg1039 = PHI %reg1070, mbb<bb76.outer,0x8b0c5f0>, %reg1037, mbb<bb27,0x8b0a7c0>

Note ADDri is not a two-address instruction. However, its result %reg1037 is an
operand of the PHI node in bb76 and its operand %reg1039 is the result of the
PHI node. We should treat it as a two-address code and make sure the ADDri is
scheduled after any node that reads %reg1039.

//===---------------------------------------------------------------------===//

Use local info (i.e. register scavenger) to assign it a free register to allow
reuse:
        ldr r3, [sp, #+4]
        add r3, r3, #3
        ldr r2, [sp, #+8]
        add r2, r2, #2
        ldr r1, [sp, #+4]  <==
        add r1, r1, #1
        ldr r0, [sp, #+4]
        add r0, r0, #2

//===---------------------------------------------------------------------===//

LLVM aggressively lift CSE out of loop. Sometimes this can be negative side-
effects:

R1 = X + 4
R2 = X + 7
R3 = X + 15

loop:
load [i + R1]
...
load [i + R2]
...
load [i + R3]

Suppose there is high register pressure, R1, R2, R3, can be spilled. We need
to implement proper re-materialization to handle this:

R1 = X + 4
R2 = X + 7
R3 = X + 15

loop:
R1 = X + 4  @ re-materialized
load [i + R1]
...
R2 = X + 7 @ re-materialized
load [i + R2]
...
R3 = X + 15 @ re-materialized
load [i + R3]

Furthermore, with re-association, we can enable sharing:

R1 = X + 4
R2 = X + 7
R3 = X + 15

loop:
T = i + X
load [T + 4]
...
load [T + 7]
...
load [T + 15]
//===---------------------------------------------------------------------===//

It's not always a good idea to choose rematerialization over spilling. If all
the load / store instructions would be folded then spilling is cheaper because
it won't require new live intervals / registers. See 2003-05-31-LongShifts for
an example.

//===---------------------------------------------------------------------===//

With a copying garbage collector, derived pointers must not be retained across
collector safe points; the collector could move the objects and invalidate the
derived pointer. This is bad enough in the first place, but safe points can
crop up unpredictably. Consider:

        %array = load { i32, [0 x %obj] }** %array_addr
        %nth_el = getelementptr { i32, [0 x %obj] }* %array, i32 0, i32 %n
        %old = load %obj** %nth_el
        %z = div i64 %x, %y
        store %obj* %new, %obj** %nth_el

If the i64 division is lowered to a libcall, then a safe point will (must)
appear for the call site. If a collection occurs, %array and %nth_el no longer
point into the correct object.

The fix for this is to copy address calculations so that dependent pointers
are never live across safe point boundaries. But the loads cannot be copied
like this if there was an intervening store, so may be hard to get right.

Only a concurrent mutator can trigger a collection at the libcall safe point.
So single-threaded programs do not have this requirement, even with a copying
collector. Still, LLVM optimizations would probably undo a front-end's careful
work.

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The ocaml frametable structure supports liveness information. It would be good
to support it.

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The FIXME in ComputeCommonTailLength in BranchFolding.cpp needs to be
revisited. The check is there to work around a misuse of directives in inline
assembly.

//===---------------------------------------------------------------------===//

It would be good to detect collector/target compatibility instead of silently
doing the wrong thing.

//===---------------------------------------------------------------------===//

It would be really nice to be able to write patterns in .td files for copies,
which would eliminate a bunch of explicit predicates on them (e.g. no side
effects).  Once this is in place, it would be even better to have tblgen
synthesize the various copy insertion/inspection methods in TargetInstrInfo.

//===---------------------------------------------------------------------===//

Stack coloring improvements:

1. Do proper LiveStacks analysis on all stack objects including those which are
   not spill slots.
2. Reorder objects to fill in gaps between objects.
   e.g. 4, 1, <gap>, 4, 1, 1, 1, <gap>, 4 => 4, 1, 1, 1, 1, 4, 4

//===---------------------------------------------------------------------===//

The scheduler should be able to sort nearby instructions by their address. For
example, in an expanded memset sequence it's not uncommon to see code like this:

  movl $0, 4(%rdi)
  movl $0, 8(%rdi)
  movl $0, 12(%rdi)
  movl $0, 0(%rdi)

Each of the stores is independent, and the scheduler is currently making an
arbitrary decision about the order.

//===---------------------------------------------------------------------===//

Another opportunitiy in this code is that the $0 could be moved to a register:

  movl $0, 4(%rdi)
  movl $0, 8(%rdi)
  movl $0, 12(%rdi)
  movl $0, 0(%rdi)

This would save substantial code size, especially for longer sequences like
this. It would be easy to have a rule telling isel to avoid matching MOV32mi
if the immediate has more than some fixed number of uses. It's more involved
to teach the register allocator how to do late folding to recover from
excessive register pressure.