llvm-project

bbca78fb - [PowerPC] vector shift word/double by element size - 1 use all ones (#139794)

[PowerPC] vector shift word/double by element size - 1 use all ones (#139794) Vector shift word or double requires a shift amount vector of 31 or 63 which is too big for splat immediate and requires a multi-instruction sequence. However the PPC instructions only use 5 or 6 bits of the shift amount vector elements so an all ones mask, which we can generate efficiently, works.