[llvm] [Knowbits] Make nuw and nsw support in computeForAddSub optimal (PR #83382)

[Matt Arsenault via llvm-commits]

================
@@ -1689,15 +1692,15 @@ static void computeKnownBitsFromOperator(const Operator *I,
         default: break;
         case Intrinsic::uadd_with_overflow:
         case Intrinsic::sadd_with_overflow:
-          computeKnownBitsAddSub(true, II->getArgOperand(0),
-                                 II->getArgOperand(1), false, DemandedElts,
-                                 Known, Known2, Depth, Q);
+          computeKnownBitsAddSub(
+              true, II->getArgOperand(0), II->getArgOperand(1), /*NSW*/ false,
+              /* NUW*/ false, DemandedElts, Known, Known2, Depth, Q);
           break;
         case Intrinsic::usub_with_overflow:
         case Intrinsic::ssub_with_overflow:
-          computeKnownBitsAddSub(false, II->getArgOperand(0),
-                                 II->getArgOperand(1), false, DemandedElts,
-                                 Known, Known2, Depth, Q);
+          computeKnownBitsAddSub(
+              false, II->getArgOperand(0), II->getArgOperand(1), /*NSW*/ false,
+              /* NUW*/ false, DemandedElts, Known, Known2, Depth, Q);
----------------
arsenm wrote:

```suggestion
              false, II->getArgOperand(0), II->getArgOperand(1), /*NSW=*/ false,
              /* NUW=*/ false, DemandedElts, Known, Known2, Depth, Q);
```

https://github.com/llvm/llvm-project/pull/83382