a51c2f39f5
…r instruction. Before77a609b556, we always skip in-tree uses of the vectorized scalars in `buildExternalUses()`, that commit handles the case that if the in-tree use is scalar operand in vectorized instruction, we need to generate extract for these in-tree uses. in-tree uses remain as scalar in vectorized instructions can be 3 cases: - The pointer operand of vectorized LoadInst uses an in-tree scalar - The pointer operand of vectorized StoreInst uses an in-tree scalar - The scalar argument of vector form intrinsic uses an in-tree scalar Generating extract for in-tree uses for vectorized instructions are implemented in `BoUpSLP::vectorizeTree()`: - https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp#L11497-L11506 - https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp#L11542-L11551 - https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp#L11657-L11667 However,77a609b556not only generates extract for vectorized instructions, but also generates extract for original scalar instructions. There is no need to generate extract for origin scalar instrutions, as these scalar instructions will be replaced by vector instructions and get erased later. This patch marks there is no exact user for in-tree scalars that remain as scalar in vectorized instructions when building external uses, In this case all uses of this scalar will be automatically replaced by extractelement. and remove - https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp#L11497-L11506 - https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp#L11542-L11551 - https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp#L11657-L11667 extracts.