[llvm] [Transform] Clean up strlen loop idiom (PR #132421)

[Nikita Popov via llvm-commits]

================
@@ -1540,7 +1530,8 @@ static Value *matchCondition(BranchInst *BI, BasicBlock *LoopEntry,
   if (!Cond)
     return nullptr;
 
-  if (!isZeroConstant(Cond->getOperand(1)))
+  const ConstantInt *CmpZero = dyn_cast<ConstantInt>(Cond->getOperand(1));
----------------
nikic wrote:

```suggestion
  auto *CmpZero = dyn_cast<ConstantInt>(Cond->getOperand(1));
```
Prefer auto with dyn_cast.

https://github.com/llvm/llvm-project/pull/132421