[llvm] [LV] Support binary and unary operations with EVL-vectorization (PR #93854)

[Kolya Panchenko via llvm-commits]

================
@@ -1405,11 +1407,16 @@ class VPInstruction : public VPRecipeWithIRFlags {
 class VPWidenRecipe : public VPRecipeWithIRFlags {
   unsigned Opcode;
 
+protected:
+  template <typename IterT>
+  VPWidenRecipe(unsigned VPDefOpcode, Instruction &I,
+                iterator_range<IterT> Operands)
+      : VPRecipeWithIRFlags(VPDefOpcode, Operands, I), Opcode(I.getOpcode()) {}
+
 public:
   template <typename IterT>
   VPWidenRecipe(Instruction &I, iterator_range<IterT> Operands)
-      : VPRecipeWithIRFlags(VPDef::VPWidenSC, Operands, I),
-        Opcode(I.getOpcode()) {}
+      : VPWidenRecipe(VPDef::VPWidenSC, I, Operands) {}
----------------
nikolaypanchenko wrote:

I assume than you really meant to introduce base class for `VPWidenRecipe` and `VPWidenEVLRecipe` that will return true for both of them, right ? In this case class hierarchy will be similar to `VPWiden[Load|Store][|EVL]`.
If so, same should go to all future EVL-recipes:
```
           VPSomeRecipeBase
           /             \
VPSomeRecipe          VPSomeEVLRecipe
```

```
VPSomeRecipeBase::classof(...) { return Opcode == VPSomeRecipeSC || Opcode == VPSomeEVLRecipeSC; }
```

https://github.com/llvm/llvm-project/pull/93854