Why should I know this?

1. 정의 2. 주요 기능 3. 활용 예제 1. ConstantRange 는 ConstantRange.h 에 선언되어 있다. /// This class represents a range of values. 생성자 셋 ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) : Lower(Full ? APInt::getMaxValue(BitWidth) : APInt::getMinValue(BitWidth)), Upper(Lower) {} ConstantRange::ConstantRange(APInt V) : Lower(std::move(V)), Upper(Lower + 1) {} ConstantRange::ConstantRange(APInt L, APInt ..

1. 기능 설명 2. 내부 함수 설명 3. 활용 설명 https://github.com/ParkHanbum/llvm-project/commit/d77067d08a3f56dc2d0e6c95bd2852c943df743a [ValueTracking] Add dominating condition support in computeKnownBits(… · ParkHanbum/llvm-project@d77067d …) (#73662) This adds support for using dominating conditions in computeKnownBits() when called from InstCombine. The implementation uses a DomConditionCache, which stores ..

LLVM 에는 최적화를 위한 부가 데이터가 있다. value.h protected: /// Hold subclass data that can be dropped. /// /// This member is similar to SubclassData, however it is for holding /// information which may be used to aid optimization, but which may be /// cleared to zero without affecting conservative interpretation. unsigned char SubclassOptionalData : 7; SubClassOptionalData or disjoint disjoint는 or 최적화를 위한 ..

computeKnownBits https://llvm.org/doxygen/ValueTracking_8cpp.html#a903bd19e9d31beff55b22fe86111639e Determine which bits of V are known to be either zero or one and return them. void computeKnownBits (const Value *V, KnownBits &Known, const DataLayout &DL, unsigned Depth=0, AssumptionCache *AC=nullptr, const Instruction *CxtI=nullptr, const DominatorTree *DT=nullptr, bool UseInstrInfo=true) Dete..

* 다른 이슈 스터디 차원에서 먼저 일부 GVN 로직을 다룹니다. ;*** IR Dump After MergedLoadStoreMotionPass on test1 *** ; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone uwtable willreturn define dso_local zeroext i1 @test1(i1 noundef zeroext %a, i1 noundef zeroext %b) local_unnamed_addr #0 { entry: %or5 = or i1 %a, %b br i1 %or5, label %cond.true, label %cond.false cond.true: ; preds = %entry %xo..

이번에 살펴볼 이슈는 이겁니다. https://github.com/llvm/llvm-project/issues/71792 Simplification Comparison for `(a | b) ? (a ^ b) : (a & b)` etc. (Clang13 vs Clang trunk) · Issue #71792 · llvm/llvm-project Consider the following six functions. https://godbolt.org/z/cTsd43jhh bool test1(bool a, bool b) { return (a | b) ? (a ^ b) : (a & b); } bool test2(bool a, bool b) { return (a | b) ? (a & b) : (a ^... gith..

패치 링크 : https://github.com/llvm/llvm-project/issues/70578 [MemCpyOpt] The store instruction should not be removed by DSE. · Issue #70578 · llvm/llvm-project This IR is reduced from rust-lang/rust#116976. declare void @f_byval(ptr byval(i32)) declare void @llvm.memcpy.p0.p0.i64(ptr, ptr, i64, i1) define void @byval_param_noalias_metadata(ptr align 4 byv... github.com 문제 IR https://llvm.godbolt.or..

https://discourse.llvm.org/t/how-does-byval-work/62397/3 How does byval work? Yeah I’m actually looking for the behavior as it is now. I’m not implementing a new backend, I’m trying to see if byval passes it on the stack on all platforms (arm, aarch64, x86_64, i386, etc), so I was wondering if there is a default behavior here discourse.llvm.org

(gdb) bt #0 0x00005555562eebc6 in llvm::BatchAAResults::getModRefInfo (this=0x7fffffffb980, I=0x55555ceb46a0, OptLoc=std::optional [no contained value]) at /home/m/llvm-project/llvm/include/llvm/Analysis/AliasAnalysis.h:641 #1 0x000055555657a3de in llvm::MemorySSA::createNewAccess (this=0x55555ce56230, I=0x55555ceb46a0, AAP=0x7fffffffb980, Template=0x0) at /home/m/llvm-project/llvm/lib/Analysis/..

https://llvm.org/devmtg/2016-11/Slides/Finkel-IntrinsicsMetadataAttributes.pdf