[all-commits] [llvm/llvm-project] 705e77: [Hexagon] Lower funnel shifts for HVX

[Krzysztof Parzyszek via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 705e77abed0b0fb7c6ab268866d3f841838eaf97
      https://github.com/llvm/llvm-project/commit/705e77abed0b0fb7c6ab268866d3f841838eaf97
  Author: Krzysztof Parzyszek <kparzysz at quicinc.com>
  Date:   2022-10-14 (Fri, 14 Oct 2022)

  Changed paths:
    M llvm/lib/Target/Hexagon/HexagonISelLowering.cpp
    M llvm/lib/Target/Hexagon/HexagonISelLowering.h
    M llvm/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp
    M llvm/lib/Target/Hexagon/HexagonPatterns.td
    M llvm/lib/Target/Hexagon/HexagonPatternsHVX.td
    A llvm/test/CodeGen/Hexagon/autohvx/funnel-128b.ll

  Log Message:
  -----------
  [Hexagon] Lower funnel shifts for HVX

HVX v62+ has bidirectional shifts, which do not mask the shift amount to
the bit width. Instead, the shift amount is sign-extended from the log(BW)
bit value, and a negative value causes a shift in the other direction.
For the shift amount being -log(BW), this reversed shift will shift all
bits out, inserting 0s or sign bits depending on the type and direction.