[all-commits] [llvm/llvm-project] 0252d3: [SLP]Model single unique value insert + shuffle as...

[Alexey Bataev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0252d338fa9f4f2f1262b5f7d8158e3f5857fcaf
      https://github.com/llvm/llvm-project/commit/0252d338fa9f4f2f1262b5f7d8158e3f5857fcaf
  Author: Alexey Bataev <a.bataev at outlook.com>
  Date:   2025-04-22 (Tue, 22 Apr 2025)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    M llvm/test/Transforms/SLPVectorizer/AArch64/reused-scalar-repeated-in-node.ll
    M llvm/test/Transforms/SLPVectorizer/AArch64/vectorizable-selects-uniform-cmps.ll
    M llvm/test/Transforms/SLPVectorizer/X86/full-match-with-poison-scalar.ll
    M llvm/test/Transforms/SLPVectorizer/X86/full-matched-bv-with-subvectors.ll
    M llvm/test/Transforms/SLPVectorizer/X86/matched-nodes-updated.ll
    M llvm/test/Transforms/SLPVectorizer/X86/memory-runtime-checks.ll
    M llvm/test/Transforms/SLPVectorizer/X86/multi-extracts-bv-combined.ll
    M llvm/test/Transforms/SLPVectorizer/X86/reduced-val-vectorized-in-transform.ll
    M llvm/test/Transforms/SLPVectorizer/icmp-altopcode-after-reordering.ll
    M llvm/test/Transforms/SLPVectorizer/reordering-single-phi.ll

  Log Message:
  -----------
  [SLP]Model single unique value insert + shuffle as splat + select, where profitable

When we have the remaining unique scalar, that should be inserted into
non-poison vector and into non-zero position:
```
%vec1 = insertelement %vec, %v, pos1
%res = shuffle %vec1, poison, <0, 1, 2,..., pos1, pos1 + 1, ..., pos1,
...>
```
better to estimate if it is profitable to model it as is or model it as:
```
%bv = insertelement poison, %v, 0
%splat = shuffle %bv, poison, <poison, ..., 0, ..., 0, ...>
%res = shuffle %vec, %splat, <0, 1, 2,..., pos1 + VF, pos1 + 1, ...>
```

Reviewers: preames, hiraditya, RKSimon

Reviewed By: preames

Pull Request: https://github.com/llvm/llvm-project/pull/136590



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