diff --git a/llvm/lib/Fuzzer/FuzzerDriver.cpp b/llvm/lib/Fuzzer/FuzzerDriver.cpp
index 4b9b57f27ea7..b267a9bf039f 100644
--- a/llvm/lib/Fuzzer/FuzzerDriver.cpp
+++ b/llvm/lib/Fuzzer/FuzzerDriver.cpp
@@ -255,7 +255,6 @@ int FuzzerDriver(const std::vector<std::string> &Args,
   Options.ExitOnFirst = Flags.exit_on_first;
   Options.UseCounters = Flags.use_counters;
   Options.UseTraces = Flags.use_traces;
-  Options.UseFullCoverageSet = Flags.use_full_coverage_set;
   Options.PreferSmallDuringInitialShuffle =
       Flags.prefer_small_during_initial_shuffle;
   Options.Tokens = ReadTokensFile(Flags.deprecated_tokens);
diff --git a/llvm/lib/Fuzzer/FuzzerFlags.def b/llvm/lib/Fuzzer/FuzzerFlags.def
index 48ae220dee71..daf0882ce6fe 100644
--- a/llvm/lib/Fuzzer/FuzzerFlags.def
+++ b/llvm/lib/Fuzzer/FuzzerFlags.def
@@ -37,10 +37,6 @@ FUZZER_FLAG_INT(
     "Example: ./fuzzer -save_minimized_corpus=1 NEW_EMPTY_DIR OLD_CORPUS")
 FUZZER_FLAG_INT(use_counters, 1, "Use coverage counters")
 FUZZER_FLAG_INT(use_traces, 0, "Experimental: use instruction traces")
-FUZZER_FLAG_INT(use_full_coverage_set, 0,
-            "Experimental: Maximize the number of different full"
-            " coverage sets as opposed to maximizing the total coverage."
-            " This is potentially MUCH slower, but may discover more paths.")
 FUZZER_FLAG_INT(jobs, 0, "Number of jobs to run. If jobs >= 1 we spawn"
                           " this number of jobs in separate worker processes"
                           " with stdout/stderr redirected to fuzz-JOB.log.")
diff --git a/llvm/lib/Fuzzer/FuzzerInternal.h b/llvm/lib/Fuzzer/FuzzerInternal.h
index 8d4833f1d93c..78e9c2208b6c 100644
--- a/llvm/lib/Fuzzer/FuzzerInternal.h
+++ b/llvm/lib/Fuzzer/FuzzerInternal.h
@@ -125,7 +125,6 @@ class Fuzzer {
   size_t RunOne(const Unit &U);
   void RunOneAndUpdateCorpus(Unit &U);
   size_t RunOneMaximizeTotalCoverage(const Unit &U);
-  size_t RunOneMaximizeFullCoverageSet(const Unit &U);
   size_t RunOneMaximizeCoveragePairs(const Unit &U);
   void WriteToOutputCorpus(const Unit &U);
   void WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix);
@@ -155,7 +154,6 @@ class Fuzzer {
 
   std::vector<Unit> Corpus;
   std::unordered_set<std::string> UnitHashesAddedToCorpus;
-  std::unordered_set<uintptr_t> FullCoverageSets;
 
   // For UseCounters
   std::vector<uint8_t> CounterBitmap;
diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index 6e04868fd40f..62a47bf05815 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -156,11 +156,7 @@ void Fuzzer::ShuffleAndMinimize() {
 size_t Fuzzer::RunOne(const Unit &U) {
   UnitStartTime = system_clock::now();
   TotalNumberOfRuns++;
-  size_t Res = 0;
-  if (Options.UseFullCoverageSet)
-    Res = RunOneMaximizeFullCoverageSet(U);
-  else
-    Res = RunOneMaximizeTotalCoverage(U);
+  size_t Res = RunOneMaximizeTotalCoverage(U);
   auto UnitStopTime = system_clock::now();
   auto TimeOfUnit =
       duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
@@ -183,14 +179,6 @@ void Fuzzer::RunOneAndUpdateCorpus(Unit &U) {
   ReportNewCoverage(RunOne(U), U);
 }
 
-static uintptr_t HashOfArrayOfPCs(uintptr_t *PCs, uintptr_t NumPCs) {
-  uintptr_t Res = 0;
-  for (uintptr_t i = 0; i < NumPCs; i++) {
-    Res = (Res + PCs[i]) * 7;
-  }
-  return Res;
-}
-
 Unit Fuzzer::SubstituteTokens(const Unit &U) const {
   Unit Res;
   for (auto Idx : U) {
@@ -214,22 +202,6 @@ void Fuzzer::ExecuteCallback(const Unit &U) {
   }
 }
 
-// Experimental.
-// Fuly reset the current coverage state, run a single unit,
-// compute a hash function from the full coverage set,
-// return non-zero if the hash value is new.
-// This produces tons of new units and as is it's only suitable for small tests,
-// e.g. test/FullCoverageSetTest.cpp. FIXME: make it scale.
-size_t Fuzzer::RunOneMaximizeFullCoverageSet(const Unit &U) {
-  __sanitizer_reset_coverage();
-  ExecuteCallback(U);
-  uintptr_t *PCs;
-  uintptr_t NumPCs =__sanitizer_get_coverage_guards(&PCs);
-  if (FullCoverageSets.insert(HashOfArrayOfPCs(PCs, NumPCs)).second)
-    return FullCoverageSets.size();
-  return 0;
-}
-
 size_t Fuzzer::RunOneMaximizeTotalCoverage(const Unit &U) {
   size_t NumCounters = __sanitizer_get_number_of_counters();
   if (Options.UseCounters) {
diff --git a/llvm/lib/Fuzzer/test/fuzzer.test b/llvm/lib/Fuzzer/test/fuzzer.test
index 046c377206d9..9bd3c71d3df0 100644
--- a/llvm/lib/Fuzzer/test/fuzzer.test
+++ b/llvm/lib/Fuzzer/test/fuzzer.test
@@ -17,9 +17,9 @@ TimeoutTest: Test unit written to timeout-
 RUN: not LLVMFuzzer-NullDerefTest 2>&1 | FileCheck %s --check-prefix=NullDerefTest
 NullDerefTest: Test unit written to crash-
 
-RUN: not LLVMFuzzer-FullCoverageSetTest -timeout=15 -seed=1 -mutate_depth=2 -use_full_coverage_set=1 2>&1 | FileCheck %s
+#not LLVMFuzzer-FullCoverageSetTest -timeout=15 -seed=1 -mutate_depth=2 -use_full_coverage_set=1 2>&1 | FileCheck %s
 
-RUN: not LLVMFuzzer-FourIndependentBranchesTest -timeout=15 -seed=1 -use_full_coverage_set=1 2>&1 | FileCheck %s
+#not LLVMFuzzer-FourIndependentBranchesTest -timeout=15 -seed=1 -use_traces=1 2>&1 | FileCheck %s
 
 RUN: not LLVMFuzzer-CounterTest -use_counters=1 -max_len=6 -seed=1 -timeout=15 2>&1 | FileCheck %s