[llvm] [ConstantFolding] Support ptrtoaddr in cast folds (PR #162480)

[Hongyu Chen via llvm-commits]

================
@@ -1495,17 +1495,17 @@ Constant *llvm::ConstantFoldCastOperand(unsigned Opcode, Constant *C,
   default:
     llvm_unreachable("Missing case");
   case Instruction::PtrToAddr:
-    // TODO: Add some of the ptrtoint folds here as well.
-    break;
   case Instruction::PtrToInt:
     if (auto *CE = dyn_cast<ConstantExpr>(C)) {
       Constant *FoldedValue = nullptr;
       // If the input is a inttoptr, eliminate the pair.  This requires knowing
----------------
XChy wrote:

```suggestion
      // If the input is an inttoptr, eliminate the pair.  This requires knowing
```

https://github.com/llvm/llvm-project/pull/162480