forked from OSchip/llvm-project
0c1c70aef4
By enhancing value tracking, we allow an existing min/max canonicalization to kick in and improve codegen for several targets that have min/max instructions. Unfortunately, recognizing min/max in value tracking may cause us to hit a hack in InstCombiner::visitICmpInst() more often: http://lists.llvm.org/pipermail/llvm-dev/2017-January/109340.html ...but I'm hoping we can remove that soon. Correctness proofs based on Alive: Name: smaxmin Pre: C1 < C2 %cmp2 = icmp slt i8 %x, C2 %min = select i1 %cmp2, i8 %x, i8 C2 %cmp3 = icmp slt i8 %x, C1 %r = select i1 %cmp3, i8 C1, i8 %min => %cmp2 = icmp slt i8 %x, C2 %min = select i1 %cmp2, i8 %x, i8 C2 %cmp1 = icmp sgt i8 %min, C1 %r = select i1 %cmp1, i8 %min, i8 C1 Name: sminmax Pre: C1 > C2 %cmp2 = icmp sgt i8 %x, C2 %max = select i1 %cmp2, i8 %x, i8 C2 %cmp3 = icmp sgt i8 %x, C1 %r = select i1 %cmp3, i8 C1, i8 %max => %cmp2 = icmp sgt i8 %x, C2 %max = select i1 %cmp2, i8 %x, i8 C2 %cmp1 = icmp slt i8 %max, C1 %r = select i1 %cmp1, i8 %max, i8 C1 ---------------------------------------- Optimization: smaxmin Done: 1 Optimization is correct! ---------------------------------------- Optimization: sminmax Done: 1 Optimization is correct! Name: umaxmin Pre: C1 u< C2 %cmp2 = icmp ult i8 %x, C2 %min = select i1 %cmp2, i8 %x, i8 C2 %cmp3 = icmp ult i8 %x, C1 %r = select i1 %cmp3, i8 C1, i8 %min => %cmp2 = icmp ult i8 %x, C2 %min = select i1 %cmp2, i8 %x, i8 C2 %cmp1 = icmp ugt i8 %min, C1 %r = select i1 %cmp1, i8 %min, i8 C1 Name: uminmax Pre: C1 u> C2 %cmp2 = icmp ugt i8 %x, C2 %max = select i1 %cmp2, i8 %x, i8 C2 %cmp3 = icmp ugt i8 %x, C1 %r = select i1 %cmp3, i8 C1, i8 %max => %cmp2 = icmp ugt i8 %x, C2 %max = select i1 %cmp2, i8 %x, i8 C2 %cmp1 = icmp ult i8 %max, C1 %r = select i1 %cmp1, i8 %max, i8 C1 ---------------------------------------- Optimization: umaxmin Done: 1 Optimization is correct! ---------------------------------------- Optimization: uminmax Done: 1 Optimization is correct! llvm-svn: 292660 |
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| .. | ||
| ADCE | ||
| AddDiscriminators | ||
| AlignmentFromAssumptions | ||
| ArgumentPromotion | ||
| AtomicExpand | ||
| BBVectorize | ||
| BDCE | ||
| BranchFolding | ||
| CodeExtractor | ||
| CodeGenPrepare | ||
| ConstProp | ||
| ConstantHoisting | ||
| ConstantMerge | ||
| Coroutines | ||
| CorrelatedValuePropagation | ||
| CountingFunctionInserter | ||
| CrossDSOCFI | ||
| DCE | ||
| DeadArgElim | ||
| DeadStoreElimination | ||
| EarlyCSE | ||
| EliminateAvailableExternally | ||
| Float2Int | ||
| ForcedFunctionAttrs | ||
| FunctionAttrs | ||
| FunctionImport | ||
| GCOVProfiling | ||
| GVN | ||
| GVNHoist | ||
| GlobalDCE | ||
| GlobalMerge | ||
| GlobalOpt | ||
| GlobalSplit | ||
| GuardWidening | ||
| IPConstantProp | ||
| IRCE | ||
| IndVarSimplify | ||
| InferFunctionAttrs | ||
| Inline | ||
| InstCombine | ||
| InstMerge | ||
| InstSimplify | ||
| InterleavedAccess/X86 | ||
| Internalize | ||
| JumpThreading | ||
| LCSSA | ||
| LICM | ||
| LoadCombine | ||
| LoadStoreVectorizer | ||
| LoopDataPrefetch | ||
| LoopDeletion | ||
| LoopDistribute | ||
| LoopIdiom | ||
| LoopInterchange | ||
| LoopLoadElim | ||
| LoopReroll | ||
| LoopRotate | ||
| LoopSimplify | ||
| LoopSimplifyCFG | ||
| LoopStrengthReduce | ||
| LoopUnroll | ||
| LoopUnswitch | ||
| LoopVectorize | ||
| LoopVersioning | ||
| LoopVersioningLICM | ||
| LowerAtomic | ||
| LowerExpectIntrinsic | ||
| LowerGuardIntrinsic | ||
| LowerInvoke | ||
| LowerSwitch | ||
| LowerTypeTests | ||
| Mem2Reg | ||
| MemCpyOpt | ||
| MergeFunc | ||
| MetaRenamer | ||
| NameAnonGlobals | ||
| NaryReassociate | ||
| NewGVN | ||
| ObjCARC | ||
| PGOProfile | ||
| PartiallyInlineLibCalls | ||
| PhaseOrdering | ||
| PlaceSafepoints | ||
| PreISelIntrinsicLowering | ||
| PruneEH | ||
| Reassociate | ||
| Reg2Mem | ||
| RewriteStatepointsForGC | ||
| SCCP | ||
| SLPVectorizer | ||
| SROA | ||
| SafeStack | ||
| SampleProfile | ||
| Scalarizer | ||
| SeparateConstOffsetFromGEP | ||
| SimplifyCFG | ||
| Sink | ||
| SpeculativeExecution | ||
| StraightLineStrengthReduce | ||
| StripDeadPrototypes | ||
| StripSymbols | ||
| StructurizeCFG | ||
| TailCallElim | ||
| ThinLTOBitcodeWriter | ||
| Util | ||
| WholeProgramDevirt | ||