[llvm] [SLP] Make getSameOpcode support interchangeable instructions. (PR #133888)

[Gaëtan Bossu via llvm-commits]

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@@ -955,6 +1259,17 @@ static InstructionsState getSameOpcode(ArrayRef<Value *> VL,
       (VL.size() == 2 && InstCnt < 2))
     return InstructionsState::invalid();
 
+  auto FindInstructionWithOpcode = [&](unsigned Opcode) {
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gbossu wrote:

Nit: I guess it could be made into a `unsigned findInstructionWithOpcode(unsigned Opcode, ArrayRef<Value*> VL)` free function just like you created above for `convertTo`.

https://github.com/llvm/llvm-project/pull/133888