[llvm] [AArch64][GlobalISel] Combine G_EXTRACT_VECTOR_ELT and G_BUILD_VECTOR sequences into G_SHUFFLE_VECTOR (PR #110545)

[via llvm-commits]

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@@ -4205,6 +4207,97 @@ void CombinerHelper::applyExtractVecEltBuildVec(MachineInstr &MI,
   replaceSingleDefInstWithReg(MI, Reg);
 }
 
+bool CombinerHelper::matchCombineExtractToShuffle(
+    MachineInstr &MI, SmallVectorImpl<std::pair<Register, int>> &VecIndexPair,
+    std::pair<Register, Register> &VectorRegisters) {
+  assert(MI.getOpcode() == TargetOpcode::G_BUILD_VECTOR);
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ValentijnvdBeek wrote:

Replaced in a fixup commit (to be squashed before merging)

https://github.com/llvm/llvm-project/pull/110545