Merge #16073: refactor: Improve CRollingBloomFilter::reset by using std::fill

df9e15f refactor: Improve CRollingBloomFilter::reset by using std::fill (João Barbosa)
d2dbc7d bench: Add benchmark for CRollingBloomFilter::reset (João Barbosa)

Pull request description:

  Cleaner code. Also improves performance with `--enable-debug` (which is meaningless to non-developers).

  Before:
  ```
  # Benchmark, evals, iterations, total, min, max, median
  RollingBloomReset, 5, 150, 19.3008, 0.0254917, 0.0259195, 0.0257395
  ```
  After:
  ```
  # Benchmark, evals, iterations, total, min, max, median
  RollingBloomReset, 5, 150, 5.43269, 0.00720651, 0.00729697, 0.00724854
  ```

ACKs for commit df9e15:
  MarcoFalke:
    re-utACK df9e15f
  jamesob:
    re-utACK bitcoin/bitcoin@df9e15f

Tree-SHA512: 22038411dfd41afad77b17a3da9ee04476ffbd4d215dcf47bdd9f14588759bc328a55d958dcebc2036b52ce4c56f79b1284eae11e56ddfaf21f0b2ee1c6a914a

Author: laanwj

src/bench/rollingbloom.cpp

@@ -28,4 +28,13 @@ static void RollingBloom(benchmark::State& state)
     }
 }
 
+static void RollingBloomReset(benchmark::State& state)
+{
+    CRollingBloomFilter filter(120000, 0.000001);
+    while (state.KeepRunning()) {
+        filter.reset();
+    }
+}
+
 BENCHMARK(RollingBloom, 1500 * 1000);
+BENCHMARK(RollingBloomReset, 20000);

src/bloom.cpp

@@ -14,6 +14,7 @@
 #include <math.h>
 #include <stdlib.h>
 
+#include <algorithm>
 
 #define LN2SQUARED 0.4804530139182014246671025263266649717305529515945455
 #define LN2 0.6931471805599453094172321214581765680755001343602552
@@ -304,7 +305,5 @@ void CRollingBloomFilter::reset()
     nTweak = GetRand(std::numeric_limits<unsigned int>::max());
     nEntriesThisGeneration = 0;
     nGeneration = 1;
-    for (std::vector<uint64_t>::iterator it = data.begin(); it != data.end(); it++) {
-        *it = 0;
-    }
+    std::fill(data.begin(), data.end(), 0);
 }