[PATCH] D119285: [SVE] Bail out of constructDup(...) optimization for fixed width vectors > 128 bits

[Cameron McInally via Phabricator via llvm-commits]

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The `getScaledOffsetDup` optimization in `constructDup(...)` expects the EXTRACT_VECTOR's source to be a NEON sized vector. Since the DUPLANE* patterns won't match a larger fixed width vector, bail out of that optimization early when a large vector is seen.

Two notes on the test case:

1. I bumped the -aarch64-sve-vector-bits-min option to 512b so that the new DUPLANE* test can live in this file. I've confirmed that the 2 existing test cases also show their original failure at this new width, so there is no change in coverage.

2. The new test case generates a ton of instructions. I wasn't sure if we should continue using the `update_llc_test_checks.py` script to generate the CHECK lines or not. Or maybe something else? Any preferences?


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D119285

Files:
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/test/CodeGen/AArch64/sve-fixed-length-limit-duplane.ll

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