[llvm] [SLP] NFC. Make InstructionsState more constant. (PR #118609)

[Alexey Bataev via llvm-commits]

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@@ -18969,7 +18983,7 @@ bool SLPVectorizerPass::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R,
   if (!S.getOpcode())
     return false;
 
-  Instruction *I0 = cast<Instruction>(S.OpValue);
+  Instruction *I0 = cast<Instruction>(S.getOpValue());
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alexey-bataev wrote:

`auto *I0 = cast<Instruction>(S.getOpValue());`

https://github.com/llvm/llvm-project/pull/118609