llvm-project

ad554651 - Reapply "[VPlan] Extract reverse mask from reverse accesses" (#189930)

Reapply "[VPlan] Extract reverse mask from reverse accesses" (#189930) Following https://github.com/llvm/llvm-project/pull/146525, separate the reverse mask from reverse access recipes. At the same time, remove the unused member variable Reverse from VPWidenMemoryRecipe. This will help to reduce redundant reverse mask computations by VPlan-based common subexpression elimination. The previous revert was due to an over-aggressive assertion that incorrectly flagged a reverse load followed by a scatter store as illegal. This version relaxes the assertion to check the mask only. Re-land #155579 Base on pre-commit #189928