Add longestCommonPrefix bench

ConflictSet.cpp

@@ -3979,6 +3979,17 @@ template <int kN> void benchScan2() {
   });
 }
 
+void benchLCP(int len) {
+  ankerl::nanobench::Bench bench;
+  std::vector<uint8_t> lhs(len);
+  std::vector<uint8_t> rhs(len);
+  bench.run("lcp " + std::to_string(len), [&]() {
+    bench.doNotOptimizeAway(lhs);
+    bench.doNotOptimizeAway(rhs);
+    bench.doNotOptimizeAway(longestCommonPrefix(lhs.data(), rhs.data(), len));
+  });
+}
+
 void printTree() {
   int64_t writeVersion = 0;
   ConflictSet::Impl cs{writeVersion};
@@ -4000,7 +4011,11 @@ void printTree() {
   debugPrintDot(stdout, cs.root, &cs);
 }
 
-int main(void) { benchScan1<16>(); }
+int main(void) {
+  for (int i = 0; i < 256; ++i) {
+    benchLCP(i);
+  }
+}
 #endif
 
 #ifdef ENABLE_FUZZ