bench: Add FeefracMultipication benchmark

src/Makefile.bench.include

@@ -32,6 +32,7 @@ bench_bench_bitcoin_SOURCES = \
   bench/duplicate_inputs.cpp \
   bench/ellswift.cpp \
   bench/examples.cpp \
+  bench/feefrac_mul.cpp \
   bench/gcs_filter.cpp \
   bench/hashpadding.cpp \
   bench/index_blockfilter.cpp \

src/bench/feefrac_mul.cpp

@@ -0,0 +1,26 @@
+// Copyright (c) 2024-present The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or https://www.opensource.org/licenses/mit-license.php.
+
+#include <bench/bench.h>
+#include <random.h>
+#include <util/feefrac.h>
+
+#include <bit>
+#include <cstdint>
+
+static void FeefracMultipication(benchmark::Bench& bench)
+{
+    FastRandomContext rnd;
+    uint64_t a64 = rnd.rand64();
+    uint32_t b32 = rnd.rand32();
+    uint64_t c64 = rnd.rand64();
+    uint32_t d32 = rnd.rand32();
+    bench.minEpochIterations(10000000).run([&] {
+        FeeRateCompare(
+            FeeFrac(std::bit_cast<std::int64_t>(a64++), std::bit_cast<std::int32_t>(b32++)),
+            FeeFrac(std::bit_cast<std::int64_t>(c64++), std::bit_cast<std::int32_t>(d32++)));
+    });
+}
+
+BENCHMARK(FeefracMultipication, benchmark::PriorityLevel::HIGH);