[all-commits] [llvm/llvm-project] 3e65ad: [AArch64] Combine Trunc(DUP) -> DUP

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3e65ad7482e9e612abcc115f8fb2ed379fcad612
      https://github.com/llvm/llvm-project/commit/3e65ad7482e9e612abcc115f8fb2ed379fcad612
  Author: David Green <david.green at arm.com>
  Date:   2022-12-21 (Wed, 21 Dec 2022)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    M llvm/test/CodeGen/AArch64/aarch64-dup-ext.ll
    M llvm/test/CodeGen/AArch64/aarch64-smull.ll
    M llvm/test/CodeGen/AArch64/dag-combine-trunc-build-vec.ll

  Log Message:
  -----------
  [AArch64] Combine Trunc(DUP) -> DUP

This adds a simple fold of TRUNCATE(AArch64ISD::DUP) -> AArch64ISD::DUP,
which can help generate more optimal UMULL sequences, and seems useful
in general.

Differential Revision: https://reviews.llvm.org/D140289