llvm-project

88774913 - [ValueTracking] Support horizontal vector add in computeKnownBits (#174410)

[ValueTracking] Support horizontal vector add in computeKnownBits (#174410) Alive2 proofs: * Leading zeros - [4vi32](https://alive2.llvm.org/ce/z/w--S2D), [16vi8](https://alive2.llvm.org/ce/z/hEdVks) * Leading ones - [4vi16](https://alive2.llvm.org/ce/z/RyPdBS), [16vi8](https://alive2.llvm.org/ce/z/UTFFt9)