[all-commits] [llvm/llvm-project] 84364b: [CodeGen][AArch64] Bail out in performConcatVector...

[david-arm via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 84364bdaabfca35f083c932ffd3a14f3b9ad4f3a
      https://github.com/llvm/llvm-project/commit/84364bdaabfca35f083c932ffd3a14f3b9ad4f3a
  Author: David Sherwood <david.sherwood at arm.com>
  Date:   2021-11-29 (Mon, 29 Nov 2021)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    M llvm/test/CodeGen/AArch64/concat_vector-truncate-combine.ll

  Log Message:
  -----------
  [CodeGen][AArch64] Bail out in performConcatVectorsCombine for scalable vectors

I tried to exercise the existing combine patterns in performConcatVectorsCombine
for scalable vectors and at the moment it doesn't seem possible. Parts of
the code currently assume we're dealing with fixed-width vectors with calls
to getVectorNumElements(), therefore I've decided to simply bail out early
for scalable vectors.

Added a test here to show that we don't crash when attempting to combine
truncate + concat:

  CodeGen/AArch64/concat_vector-truncate-combine.ll

Differential Revision: https://reviews.llvm.org/D114600