4 files changed, 7 insertions, 11 deletions
diff --git a/lib/fuzzer/FuzzerInternal.h b/lib/fuzzer/FuzzerInternal.h
index 5ae9e2b8f..2b2638f1f 100644
--- a/lib/fuzzer/FuzzerInternal.h
+++ b/lib/fuzzer/FuzzerInternal.h
@@ -124,8 +124,6 @@ private:
   size_t NumberOfNewUnitsAdded = 0;
 
   size_t LastCorpusUpdateRun = 0;
-  system_clock::time_point LastCorpusUpdateTime = system_clock::now();
-
 
   bool HasMoreMallocsThanFrees = false;
   size_t NumberOfLeakDetectionAttempts = 0;
diff --git a/lib/fuzzer/FuzzerLoop.cpp b/lib/fuzzer/FuzzerLoop.cpp
index 6ed48e08b..5b451ca12 100644
--- a/lib/fuzzer/FuzzerLoop.cpp
+++ b/lib/fuzzer/FuzzerLoop.cpp
@@ -567,7 +567,6 @@ void Fuzzer::ReportNewCoverage(InputInfo *II, const Unit &U) {
   NumberOfNewUnitsAdded++;
   CheckExitOnSrcPosOrItem(); // Check only after the unit is saved to corpus.
   LastCorpusUpdateRun = TotalNumberOfRuns;
-  LastCorpusUpdateTime = system_clock::now();
 }
 
 // Tries detecting a memory leak on the particular input that we have just
@@ -758,18 +757,15 @@ void Fuzzer::Loop(const Vector<std::string> &CorpusDirs) {
     // Update TmpMaxMutationLen
     if (Options.ExperimentalLenControl) {
       if (TmpMaxMutationLen < MaxMutationLen &&
-          (TotalNumberOfRuns - LastCorpusUpdateRun >
-               Options.ExperimentalLenControl &&
-           duration_cast<seconds>(Now - LastCorpusUpdateTime).count() >= 1)) {
-        LastCorpusUpdateRun = TotalNumberOfRuns;
-        LastCorpusUpdateTime = Now;
+          TotalNumberOfRuns - LastCorpusUpdateRun >
+              Options.ExperimentalLenControl * Log(TmpMaxMutationLen)) {
         TmpMaxMutationLen =
-            Min(MaxMutationLen,
-                TmpMaxMutationLen + Max(size_t(4), TmpMaxMutationLen / 8));
+            Min(MaxMutationLen, TmpMaxMutationLen + Log(TmpMaxMutationLen));
         if (TmpMaxMutationLen <= MaxMutationLen)
           Printf("#%zd\tTEMP_MAX_LEN: %zd (%zd %zd)\n", TotalNumberOfRuns,
                  TmpMaxMutationLen, Options.ExperimentalLenControl,
                  LastCorpusUpdateRun);
+        LastCorpusUpdateRun = TotalNumberOfRuns;
       }
     } else {
       TmpMaxMutationLen = MaxMutationLen;
diff --git a/lib/fuzzer/FuzzerTracePC.h b/lib/fuzzer/FuzzerTracePC.h
index 300e5db38..dc65cd720 100644
--- a/lib/fuzzer/FuzzerTracePC.h
+++ b/lib/fuzzer/FuzzerTracePC.h
@@ -276,7 +276,7 @@ void TracePC::CollectFeatures(Callback HandleFeature) const {
 
   // Step function, grows similar to 8 * Log_2(A).
   auto StackDepthStepFunction = [](uint32_t A) -> uint32_t {
-    uint32_t Log2 = 32 - __builtin_clz(A) - 1;
+    uint32_t Log2 = Log(A);
     if (Log2 < 3) return A;
     Log2 -= 3;
     return (Log2 + 1) * 8 + ((A >> Log2) & 7);
diff --git a/lib/fuzzer/FuzzerUtil.h b/lib/fuzzer/FuzzerUtil.h
index 9a6227ea7..f2ed028ce 100644
--- a/lib/fuzzer/FuzzerUtil.h
+++ b/lib/fuzzer/FuzzerUtil.h
@@ -80,6 +80,8 @@ std::string SearchRegexCmd(const std::string &Regex);
 
 size_t SimpleFastHash(const uint8_t *Data, size_t Size);
 
+inline uint32_t Log(uint32_t X) { return 32 - __builtin_clz(X) - 1; }
+
 }  // namespace fuzzer
 
 #endif  // LLVM_FUZZER_UTIL_H