[all-commits] [llvm/llvm-project] fbc329: [AArch64] Add S/UQXTRN tablegen patterns.

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: fbc329efbdba3edad78a1651148b340bcc7bf032
      https://github.com/llvm/llvm-project/commit/fbc329efbdba3edad78a1651148b340bcc7bf032
  Author: David Green <david.green at arm.com>
  Date:   2021-07-03 (Sat, 03 Jul 2021)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64InstrInfo.td
    M llvm/test/CodeGen/AArch64/qmovn.ll

  Log Message:
  -----------
  [AArch64] Add S/UQXTRN tablegen patterns.

This adds simple patterns for signed and unsigned saturating extract
narrow instructions. They combine a min/max/truncate into a single
instruction, providing that the immediates on the min/max are correct
for the saturation type. This is just handled in tablegen with some
extra patterns.

v2i64->v2i32 is not handled here as the min/max nodes are not legal,
making the lowering quite different.

Differential Revision: https://reviews.llvm.org/D103263