[llvm] [AArch64][LV] Cost low-VF interleaved access (PR #205844)

[Graham Hunter via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc -O3 < %s | FileCheck %s
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huntergr-arm wrote:

`deinterleave4_nxv8i16_zext_i64_in_loop` exercises the SVE shuffle opts pass, which requires -O2 or above?

(You could argue that test is redundant given the shuffle opts pass has its own tests in sve-tbl-folding-opts.ll)

https://github.com/llvm/llvm-project/pull/205844