forked from OSchip/llvm-project
dfd14adeb0
Summary:
Two utils methods have essentially the same functionality. This is an attempt to merge them into one.
1. lib/Transforms/Utils/Local.cpp : MergeBasicBlockIntoOnlyPred
2. lib/Transforms/Utils/BasicBlockUtils.cpp : MergeBlockIntoPredecessor
Prior to the patch:
1. MergeBasicBlockIntoOnlyPred
Updates either DomTree or DeferredDominance
Moves all instructions from Pred to BB, deletes Pred
Asserts BB has single predecessor
If address was taken, replace the block address with constant 1 (?)
2. MergeBlockIntoPredecessor
Updates DomTree, LoopInfo and MemoryDependenceResults
Moves all instruction from BB to Pred, deletes BB
Returns if doesn't have a single predecessor
Returns if BB's address was taken
After the patch:
Method 2. MergeBlockIntoPredecessor is attempting to become the new default:
Updates DomTree or DeferredDominance, and LoopInfo and MemoryDependenceResults
Moves all instruction from BB to Pred, deletes BB
Returns if doesn't have a single predecessor
Returns if BB's address was taken
Uses of MergeBasicBlockIntoOnlyPred that need to be replaced:
1. lib/Transforms/Scalar/LoopSimplifyCFG.cpp
Updated in this patch. No challenges.
2. lib/CodeGen/CodeGenPrepare.cpp
Updated in this patch.
i. eliminateFallThrough is straightforward, but I added using a temporary array to avoid the iterator invalidation.
ii. eliminateMostlyEmptyBlock(s) methods also now use a temporary array for blocks
Some interesting aspects:
- Since Pred is not deleted (BB is), the entry block does not need updating.
- The entry block was being updated with the deleted block in eliminateMostlyEmptyBlock. Added assert to make obvious that BB=SinglePred.
- isMergingEmptyBlockProfitable assumes BB is the one to be deleted.
- eliminateMostlyEmptyBlock(BB) does not delete BB on one path, it deletes its unique predecessor instead.
- adding some test owner as subscribers for the interesting tests modified:
test/CodeGen/X86/avx-cmp.ll
test/CodeGen/AMDGPU/nested-loop-conditions.ll
test/CodeGen/AMDGPU/si-annotate-cf.ll
test/CodeGen/X86/hoist-spill.ll
test/CodeGen/X86/2006-11-17-IllegalMove.ll
3. lib/Transforms/Scalar/JumpThreading.cpp
Not covered in this patch. It is the only use case using the DeferredDominance.
I would defer to Brian Rzycki to make this replacement.
Reviewers: chandlerc, spatel, davide, brzycki, bkramer, javed.absar
Subscribers: qcolombet, sanjoy, nemanjai, nhaehnle, jlebar, tpr, kbarton, RKSimon, wmi, arsenm, llvm-commits
Differential Revision: https://reviews.llvm.org/D48202
llvm-svn: 335183
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| .. | ||
| ASanStackFrameLayout.cpp | ||
| AddDiscriminators.cpp | ||
| BasicBlockUtils.cpp | ||
| BreakCriticalEdges.cpp | ||
| BuildLibCalls.cpp | ||
| BypassSlowDivision.cpp | ||
| CMakeLists.txt | ||
| CallPromotionUtils.cpp | ||
| CloneFunction.cpp | ||
| CloneModule.cpp | ||
| CodeExtractor.cpp | ||
| CtorUtils.cpp | ||
| DemoteRegToStack.cpp | ||
| EntryExitInstrumenter.cpp | ||
| EscapeEnumerator.cpp | ||
| Evaluator.cpp | ||
| FlattenCFG.cpp | ||
| FunctionComparator.cpp | ||
| FunctionImportUtils.cpp | ||
| GlobalStatus.cpp | ||
| ImportedFunctionsInliningStatistics.cpp | ||
| InlineFunction.cpp | ||
| InstructionNamer.cpp | ||
| IntegerDivision.cpp | ||
| LCSSA.cpp | ||
| LLVMBuild.txt | ||
| LibCallsShrinkWrap.cpp | ||
| Local.cpp | ||
| LoopRotationUtils.cpp | ||
| LoopSimplify.cpp | ||
| LoopUnroll.cpp | ||
| LoopUnrollPeel.cpp | ||
| LoopUnrollRuntime.cpp | ||
| LoopUtils.cpp | ||
| LoopVersioning.cpp | ||
| LowerInvoke.cpp | ||
| LowerMemIntrinsics.cpp | ||
| LowerSwitch.cpp | ||
| Mem2Reg.cpp | ||
| MetaRenamer.cpp | ||
| ModuleUtils.cpp | ||
| NameAnonGlobals.cpp | ||
| OrderedInstructions.cpp | ||
| PredicateInfo.cpp | ||
| PromoteMemoryToRegister.cpp | ||
| SSAUpdater.cpp | ||
| SSAUpdaterBulk.cpp | ||
| SanitizerStats.cpp | ||
| SimplifyCFG.cpp | ||
| SimplifyIndVar.cpp | ||
| SimplifyInstructions.cpp | ||
| SimplifyLibCalls.cpp | ||
| SplitModule.cpp | ||
| StripGCRelocates.cpp | ||
| StripNonLineTableDebugInfo.cpp | ||
| SymbolRewriter.cpp | ||
| UnifyFunctionExitNodes.cpp | ||
| Utils.cpp | ||
| VNCoercion.cpp | ||
| ValueMapper.cpp | ||