[all-commits] [llvm/llvm-project] 4325fd: [AArch64ISelLowering] Don't look through scalable ...

[paulwalker-arm via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4325fd7402bf41bbe6c944cfb84da95c4d8e875d
      https://github.com/llvm/llvm-project/commit/4325fd7402bf41bbe6c944cfb84da95c4d8e875d
  Author: Paul Walker <paul.walker at arm.com>
  Date:   2022-01-05 (Wed, 05 Jan 2022)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    M llvm/test/CodeGen/AArch64/sve-fixed-length-limit-duplane.ll

  Log Message:
  -----------
  [AArch64ISelLowering] Don't look through scalable extract_subvector when optimising DUPLANE.

When constructDup is passed an extract_subvector it tries to use
extract_subvector's operand directly when creating the DUPLANE.
This is invalid when extracting from a scalable vector because the
necessary DUPLANE ISel patterns do not exist.

NOTE: This patch is an update to https://reviews.llvm.org/D110524
that originally fixed this but introduced a bug when the result
VT is 64bits. I've restructured the code so the critial final
else block is entered when necessary.

Differential Revision: https://reviews.llvm.org/D116442