[all-commits] [llvm/llvm-project] b14f6e: [RISCV] Fix crash when lowering fixed length inser...

[Luke Lau via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b14f6eebc9e2c56c325fe72aa29a1f042bb9e9b3
      https://github.com/llvm/llvm-project/commit/b14f6eebc9e2c56c325fe72aa29a1f042bb9e9b3
  Author: Luke Lau <luke at igalia.com>
  Date:   2023-09-28 (Thu, 28 Sep 2023)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-insert-subvector.ll

  Log Message:
  -----------
  [RISCV] Fix crash when lowering fixed length insert_subvector into undef at 0 (#67535)

This fixes a crash seen in https://github.com/openxla/iree/issues/15038
and
elsewhere. We were reducing the LMUL for inserts into undef at 0 without
inserting it back into the original LMUL at the end. But we don't
actually
perform the slidedown in this path, so we can just skip reducing LMUL
here.