[llvm] [SLP][NFC] Refactor duplicate code into `getVectorizedValue` (PR #156277)

[Alexey Bataev via llvm-commits]

================
@@ -17848,6 +17848,17 @@ class BoUpSLP::ShuffleInstructionBuilder final : public BaseShuffleAnalysis {
         IsSigned.value_or(!isKnownNonNegative(V, SimplifyQuery(*R.DL))));
   }
 
+  Value *getVectorizedValue(const TreeEntry &E1) {
+    Value *V1 = E1.VectorizedValue;
+    if (!V1->getType()->isIntOrIntVectorTy())
+      return V1;
+    return castToScalarTyElem(V1, any_of(E1.Scalars, [&](Value *V) {
+                                return !isa<PoisonValue>(V) &&
+                                       !isKnownNonNegative(
+                                           V, SimplifyQuery(*R.DL));
+                              }));
+  }
----------------
alexey-bataev wrote:

```suggestion
  Value *getVectorizedValue(const TreeEntry &E) {
    Value *Vec = E.VectorizedValue;
    if (!Vec->getType()->isIntOrIntVectorTy())
      return Vec;
    return castToScalarTyElem(Vec, any_of(E.Scalars, [&](Value *V) {
                                return !isa<PoisonValue>(V) &&
                                       !isKnownNonNegative(
                                           V, SimplifyQuery(*R.DL));
                              }));
  }
```

https://github.com/llvm/llvm-project/pull/156277