[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:

Not sure I understand added hierarchy then. If the goal is to allow reuse of existing code, then what is different in `VPWidenStoreEVL` or `VPWidenLoadEVL` as they won't be treated as `VPWidenStore` or `VPWidenLoad` respectively: 
```
isa<VPWidenMemoryRecipe>(EVLStore) => true
isa<VPWidenStoreEVLRecipe>(EVLStore) => true
isa<VPWidenStoreRecipe>(EVLStore) => false
```
Anyway, I'm _ok_ to extend classof for now

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