[all-commits] [llvm/llvm-project] 37aa07: [RISCV] Move narrowIndex to be a DAG combine over ...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 37aa07ad312f58bd2ca59ea712a72544f753f5d3
      https://github.com/llvm/llvm-project/commit/37aa07ad312f58bd2ca59ea712a72544f753f5d3
  Author: Philip Reames <preames at rivosinc.com>
  Date:   2023-09-15 (Fri, 15 Sep 2023)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-gather.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-scatter.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpgather.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpscatter.ll
    M llvm/test/CodeGen/RISCV/rvv/narrow-shift-extend.ll
    M llvm/test/CodeGen/RISCV/rvv/vpgather-sdnode.ll
    M llvm/test/CodeGen/RISCV/rvv/vpscatter-sdnode.ll

  Log Message:
  -----------
  [RISCV] Move narrowIndex to be a DAG combine over target independent nodes

In D154687, we added a transform to narrow indexed load/store indices of the
form (shl (zext), C).  We can move this into a generic transform over the
target independent nodes instead, and pick up the fixed vector cases with no
additional work required.  This is an alternative to D158163.

Performing this transform points out that we weren't eliminating zero_extends
via the the generic DAG combine.  Adjust the (existing) callbacks so that we
do.

This change *removes* the existing transform on the target specific intrinsic
nodes.  If anyone has a use case this impacts, please speak up.

Note: Reviewed as part of a stack of changes in PR# 66405.