[clang][dataflow] Avoid MaxIterations overflow

unsigned is technically guaranteed to be only 16 bits in which case 1 << 16 would wrap around to zero.

Differential Revision: https://reviews.llvm.org/D117938

clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp

@@ -210,8 +210,8 @@ runTypeErasedDataflowAnalysis(const ControlFlowContext &CFCtx,
   // FIXME: Consider making the maximum number of iterations configurable.
   // FIXME: Set up statistics (see llvm/ADT/Statistic.h) to count average number
   // of iterations, number of functions that time out, etc.
-  unsigned Iterations = 0;
-  static constexpr unsigned MaxIterations = 1 << 16;
+  uint32_t Iterations = 0;
+  static constexpr uint32_t MaxIterations = 1 << 16;
   while (const CFGBlock *Block = Worklist.dequeue()) {
     if (++Iterations > MaxIterations) {
       llvm::errs() << "Maximum number of iterations reached, giving up.\n";