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

[Florian Hahn via llvm-commits]

================
@@ -1214,6 +1218,47 @@ InstructionCost VPWidenRecipe::computeCost(ElementCount VF,
   }
 }
 
+void VPWidenEVLRecipe::execute(VPTransformState &State) {
+  State.setDebugLocFrom(getDebugLoc());
+  assert(State.UF == 1 && "Expected only UF == 1 when vectorizing with "
+                          "explicit vector length.");
+  VPValue *Op0 = getOperand(0);
+
+  assert(State.get(Op0, 0)->getType()->isVectorTy() &&
+         "VPWidenEVLRecipe should not be used for scalars");
+
+  VPValue *EVL = getEVL();
+  Value *EVLArg = State.get(EVL, 0, /*NeedsScalar=*/true);
+  unsigned Opcode = getOpcode();
+  Instruction *I = getUnderlyingInstr();
----------------
fhahn wrote:

```suggestion
  Instruction *UI = getUnderlyingInstr();
```

to avoid clash with `I` below. 

The underlying instruction is only used by `State.addMetadata`, might be better to use`dyn_cast_or_null<Instruction>(getUnderlyingValue())` to make the underlying instruction optional. (getUnderlyingInstr` uses `cast<Instruction>`, which makes the underlying instruction non-optional)

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