[all-commits] [llvm/llvm-project] 9f3798: [AArch64][SVE] Fold insert(zero, extract(X, 0), 0)...

[Bradley Smith via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9f37980d45c7ea05c16851b1d672ab41907a38b7
      https://github.com/llvm/llvm-project/commit/9f37980d45c7ea05c16851b1d672ab41907a38b7
  Author: Bradley Smith <bradley.smith at arm.com>
  Date:   2021-05-04 (Tue, 04 May 2021)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    A llvm/test/CodeGen/AArch64/sve-implicit-zero-filling.ll

  Log Message:
  -----------
  [AArch64][SVE] Fold insert(zero, extract(X, 0), 0) -> X, when X is known to zero lanes 1-N

Specifically, this allow us to rely on the lane zero'ing behaviour of
SVE reduce instructions.

Co-authored-by: Paul Walker <paul.walker at arm.com>

Differential Revision: https://reviews.llvm.org/D101369