[llvm] [SLP] SLP's copyable elements based upon Main/Alt operations. (PR #124242)

[Alexey Bataev via llvm-commits]

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@@ -7697,6 +7993,8 @@ bool BoUpSLP::areAltOperandsProfitable(const InstructionsState &S,
                            Opcode0, Opcode1, OpcodeMask))
     return true;
   SmallVector<ValueList> Operands;
+  if (S.getMainOp()->getNumOperands() != S.getAltOp()->getNumOperands())
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alexey-bataev wrote:

Why?

https://github.com/llvm/llvm-project/pull/124242