7 files changed, 8 insertions, 20 deletions
diff --git a/llvm/lib/Fuzzer/FuzzerDriver.cpp b/llvm/lib/Fuzzer/FuzzerDriver.cpp
index f2452dc95f2..484d8901525 100644
--- a/llvm/lib/Fuzzer/FuzzerDriver.cpp
+++ b/llvm/lib/Fuzzer/FuzzerDriver.cpp
@@ -427,7 +427,6 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
   Options.PrintFinalStats = Flags.print_final_stats;
   Options.PrintCorpusStats = Flags.print_corpus_stats;
   Options.PrintCoverage = Flags.print_coverage;
-  Options.PruneCorpus = Flags.prune_corpus;
   if (Flags.exit_on_src_pos)
     Options.ExitOnSrcPos = Flags.exit_on_src_pos;
 
diff --git a/llvm/lib/Fuzzer/FuzzerFlags.def b/llvm/lib/Fuzzer/FuzzerFlags.def
index 1d62e429b30..230ad579955 100644
--- a/llvm/lib/Fuzzer/FuzzerFlags.def
+++ b/llvm/lib/Fuzzer/FuzzerFlags.def
@@ -92,8 +92,6 @@ FUZZER_FLAG_INT(detect_leaks, 1, "If 1, and if LeakSanitizer is enabled "
     "try to detect memory leaks during fuzzing (i.e. not only at shut down).")
 FUZZER_FLAG_INT(rss_limit_mb, 2048, "If non-zero, the fuzzer will exit upon"
     "reaching this limit of RSS memory usage.")
-FUZZER_FLAG_INT(prune_corpus, 1, "Prune corpus items without new coverage when "
-                                 "loading corpus.")
 FUZZER_FLAG_STRING(exit_on_src_pos, "Exit if a newly found PC originates"
     " from the given source location. Example: -exit_on_src_pos=foo.cc:123. "
     "Used primarily for testing libFuzzer itself.")
diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index f7d0b156a5b..e0deab3c42e 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -413,8 +413,7 @@ void Fuzzer::ShuffleAndMinimize(UnitVector *InitialCorpus) {
     ShuffleCorpus(InitialCorpus);
 
   for (const auto &U : *InitialCorpus) {
-    bool NewCoverage = RunOne(U);
-    if (!Options.PruneCorpus || NewCoverage) {
+    if (RunOne(U)) {
       AddToCorpusAndMaybeRerun(U);
       if (Options.Verbosity >= 2)
         Printf("NEW0: %zd L %zd\n", MaxCoverage.BlockCoverage, U.size());
diff --git a/llvm/lib/Fuzzer/FuzzerOptions.h b/llvm/lib/Fuzzer/FuzzerOptions.h
index 56c35aa5253..09b2cdec945 100644
--- a/llvm/lib/Fuzzer/FuzzerOptions.h
+++ b/llvm/lib/Fuzzer/FuzzerOptions.h
@@ -49,7 +49,6 @@ struct FuzzingOptions {
   bool PrintCorpusStats = false;
   bool PrintCoverage = false;
   bool DetectLeaks = true;
-  bool PruneCorpus = true;
 };
 
 }  // namespace fuzzer
diff --git a/llvm/lib/Fuzzer/test/CustomCrossOverTest.cpp b/llvm/lib/Fuzzer/test/CustomCrossOverTest.cpp
index 2ab5781155f..b624088b902 100644
--- a/llvm/lib/Fuzzer/test/CustomCrossOverTest.cpp
+++ b/llvm/lib/Fuzzer/test/CustomCrossOverTest.cpp
@@ -15,10 +15,16 @@
 static const char *Separator = "-_^_-";
 static const char *Target = "012-_^_-abc";
 
+static volatile int sink;
+
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
   assert(Data);
   std::string Str(reinterpret_cast<const char *>(Data), Size);
 
+  // Ensure that two different elements exist in the corpus.
+  if (Size && Data[0] == '0') sink++;
+  if (Size && Data[0] == 'a') sink--;
+
   if (Str.find(Target) != std::string::npos) {
     std::cout << "BINGO; Found the target, exiting\n";
     exit(1);
diff --git a/llvm/lib/Fuzzer/test/fuzzer-customcrossover.test b/llvm/lib/Fuzzer/test/fuzzer-customcrossover.test
index 4be54d3f799..28d39ce31de 100644
--- a/llvm/lib/Fuzzer/test/fuzzer-customcrossover.test
+++ b/llvm/lib/Fuzzer/test/fuzzer-customcrossover.test
@@ -2,7 +2,7 @@ RUN: rm -rf %t/CustomCrossover
 RUN: mkdir -p %t/CustomCrossover
 RUN: echo "0123456789" > %t/CustomCrossover/digits
 RUN: echo "abcdefghij" > %t/CustomCrossover/chars
-RUN: not LLVMFuzzer-CustomCrossOverTest -seed=1 -use_memcmp=0 -runs=100000 -prune_corpus=0 %t/CustomCrossover 2>&1 | FileCheck %s --check-prefix=LLVMFuzzerCustomCrossover
+RUN: not LLVMFuzzer-CustomCrossOverTest -seed=1 -use_memcmp=0 -runs=100000 %t/CustomCrossover 2>&1 | FileCheck %s --check-prefix=LLVMFuzzerCustomCrossover
 RUN: rm -rf %t/CustomCrossover
 
 LLVMFuzzerCustomCrossover: In LLVMFuzzerCustomCrossover
diff --git a/llvm/lib/Fuzzer/test/fuzzer-prunecorpus.test b/llvm/lib/Fuzzer/test/fuzzer-prunecorpus.test
deleted file mode 100644
index a8a660e91b9..00000000000
--- a/llvm/lib/Fuzzer/test/fuzzer-prunecorpus.test
+++ /dev/null
@@ -1,13 +0,0 @@
-RUN: rm -rf %t/PruneCorpus
-RUN: mkdir -p %t/PruneCorpus
-RUN: echo a > %t/PruneCorpus/a
-RUN: echo b > %t/PruneCorpus/b
-RUN: LLVMFuzzer-EmptyTest %t/PruneCorpus -prune_corpus=1 -runs=0 2>&1 | FileCheck %s --check-prefix=PRUNE
-RUN: LLVMFuzzer-EmptyTest %t/PruneCorpus -prune_corpus=0 -runs=0 2>&1 | FileCheck %s --check-prefix=NOPRUNE
-RUN: rm -rf %t/PruneCorpus
-
-PRUNE: READ units: 2
-PRUNE: INITED{{.*}}units: 1
-NOPRUNE: READ units: 2
-NOPRUNE: INITED{{.*}}units: 2
-