diff --git a/tests/playground/Makefile b/tests/playground/Makefile
index e1b98ccc98..edd295622b 100644
--- a/tests/playground/Makefile
+++ b/tests/playground/Makefile
@@ -1,11 +1,14 @@
 ## CONFIG
 
+LEAN_BENCHES = binarytrees deriv expr_const_folding qsort rbmap rbmap_checkpoint_10 rbmap_shared unionfind1 unionfind2
 CROSS_BENCHES = binarytrees deriv expr_const_folding qsort rbmap rbmap_checkpoint_10 rbmap_shared
 
+LEAN_CATS = .lean .no_reuse.lean .no_borrow.lean .no_st.lean
 CROSS_CATS = .lean .gc.lean .lean.perf .hs .gc.hs .hs.perf .ml .gc.ml .ml.perf .mlton .gc.mlton .mlton.perf .mlkit .gc.mlkit .mlkit.perf
 TIME_CATS = .lean .hs .ml .mlton .mlkit
 RETIRED_CATS = .gcc.lean .llvm.hs .flambda.ml
 
+LEAN_FLAGS =
 LEANC_FLAGS = -O3
 GHC_FLAGS = -O3
 OCAML_FLAGS = -O3
@@ -21,27 +24,36 @@ MLKIT ?= mlkit
 
 ## IMPLEMENTATION
 
+LEAN_INPUTS = $(foreach bench,$(LEAN_BENCHES), $(foreach cat, $(LEAN_CATS), $(bench)$(cat)))
 CROSS_INPUTS = $(foreach bench,$(CROSS_BENCHES), $(foreach cat, $(CROSS_CATS), $(bench)$(cat)))
 
-.SECONDARY: $(CROSS_INPUTS:%=%.out) $(CROSS_INPUTS:%=bench/%.bench)
+.SECONDARY: $(LEAN_INPUTS:%=%.out) $(LEAN_INPUTS:%=bench/%.bench) $(CROSS_INPUTS:%=%.out) $(CROSS_INPUTS:%=bench/%.bench)
 .DELETE_ON_ERROR:
 
-all: reports report_cross.csv
+all: reports report_lean.csv report_cross.csv
 
 # disable some built-in rules
 %.lean:
 %.out: %
 
 %.lean.cpp: %.lean
-	$(LEAN_BIN)/lean --cpp=$@ $<
+	$(LEAN_BIN)/lean --cpp=$@ $(LEAN_FLAGS) $<
 %.lean.out: %.lean.cpp
 	$(LEAN_BIN)/leanc $(LEANC_FLAGS) -o $@ $<
+frontend%lean.out:
+	ln -f $(LEAN_BIN)/lean
 # Binaries x.lean.out and x.gcc.lean.out etc. are produced by the
 # same rules and x.lean source file by copying the latter to
 # x.gcc.lean. This also avoids conflicts between intermediate
 # files of the two binaries.
 %.gcc.lean.out: LEAN_BIN = $(LEAN_GCC_BIN)
 %.gcc.lean: %.lean; ln -f $< $@
+%.no_reuse.lean.out: LEAN_BIN = $(LEAN_NO_REUSE_BIN)
+%.no_reuse.lean: %.lean; ln -f $< $@
+%.no_borrow.lean.out: LEAN_BIN = $(LEAN_NO_BORROW_BIN)
+%.no_borrow.lean: %.lean; ln -f $< $@
+%.no_st.lean.out: LEAN_BIN = $(LEAN_NO_ST_BIN)
+%.no_st.lean: %.lean; ln -f $< $@
 
 %.hs.out: %.hs
 	$(GHC) $(GHC_FLAGS) -rtsopts $< -o $@
@@ -76,6 +88,8 @@ bench:
 bench/%.bench: %.out | bench
 	ulimit -s unlimited && $(TEMCI) short exec -d $< "./$< $(BENCH_PARAMS)" --out $@
 
+bench/frontend.%.bench: BENCH_PARAMS = --new-frontend ../../library/init/core.lean
+
 bench/binarytrees.%.bench: BENCH_PARAMS = 21
 
 bench/qsort.%.bench: BENCH_PARAMS = 250
@@ -88,6 +102,9 @@ bench/rbmap_shared.%.bench: BENCH_PARAMS = 500000 1
 rbmap_checkpoint_10.%.out: rbmap_checkpoint.%.out; ln -f $< $@
 bench/rbmap_checkpoint_10.%.bench: BENCH_PARAMS = 2000000 10
 
+bench/unionfind1.%.bench: BENCH_PARAMS = 3000000
+bench/unionfind2.%.bench: BENCH_PARAMS = 3000000
+
 bench/%gc.lean.bench: %lean.out | bench
 	ulimit -s unlimited && $(TEMCI) short exec\
     -d $< "perf record -o $@.tmp ./$< $(BENCH_PARAMS) >/dev/null && perf report -i $@.tmp -t ';' --stdio -S 'lean::del,lean::dealloc' | ./lean-gc.py"\
@@ -127,6 +144,7 @@ bench/binarytrees%mlton.perf.bench: ; touch $@
 bench/binarytrees%mlkit.bench: ; touch $@
 bench/binarytrees%mlkit.perf.bench: ; touch $@
 
+bench_lean: $(LEAN_INPUTS:%=bench/%.bench)
 bench_cross: $(CROSS_INPUTS:%=bench/%.bench)
 
 report:
@@ -147,6 +165,9 @@ reports: $(foreach bench, $(CROSS_BENCHES), report/$(bench)) report/index.html
 # yes.
 space = $() $()
 
+report_lean.csv: $(LEAN_INPUTS:%=bench/%.bench) report.py temci.yaml
+	BENCHES=$(subst $(space),:,$(LEAN_BENCHES)) CATS=$(subst $(space),:,$(LEAN_CATS)) ./report.py > $@
+
 report_cross.csv: $(CROSS_INPUTS:%=bench/%.bench) report.py temci.yaml
 	BENCHES=$(subst $(space),:,$(CROSS_BENCHES)) CATS=$(subst $(space),:,$(CROSS_CATS)) ./report.py > $@
 
diff --git a/tests/playground/bench.nix b/tests/playground/bench.nix
index 2223514398..2550d87ba4 100644
--- a/tests/playground/bench.nix
+++ b/tests/playground/bench.nix
@@ -1,12 +1,11 @@
 { pkgs ? import ./nixpkgs.nix }:
 
 let
-  lean = { cmakeFlags ? "", stdenv ? pkgs.llvmPackages_7.stdenv }:
+  lean = { stdenv ? pkgs.llvmPackages_7.stdenv }:
     (pkgs.callPackage ../../default.nix { inherit stdenv; }).overrideAttrs (attrs: {
-      inherit cmakeFlags;
      # pin Lean commit to avoid rebuilds
-     # 2019-05-24
-     src = builtins.fetchGit { url = ../../.; rev = "074002eb847b6f4fbaf2484c928c86baadf66a42"; };
+     # 2019-05-27
+     src = builtins.fetchGit { url = ../../.; rev = "0e8abd81bba1b9c06ea7eab23001bbf08ff267dc"; };
     });
   # for binarytrees.hs
   ghcPackages = p: [ p.parallel ];
@@ -39,6 +38,15 @@ in pkgs.stdenv.mkDerivation rec {
   src = pkgs.lib.sourceFilesBySuffices ./. ["Makefile" "leanpkg.path" "temci.yaml" ".py" ".lean" ".hs" ".ml"];
   LEAN_BIN = "${lean {}}/bin";
   LEAN_GCC_BIN = "${lean { stdenv = pkgs.gcc9Stdenv; }}/bin";
+  LEAN_NO_REUSE_BIN = "${(lean {}).overrideAttrs (attrs: { prePatch = ''
+    substituteInPlace library/init/lean/compiler/ir/default.lean --replace "decls.map Decl.insertResetReuse" "decls"
+  ''; })}/bin";
+  LEAN_NO_BORROW_BIN = "${(lean {}).overrideAttrs (attrs: { prePatch = ''
+    substituteInPlace library/init/lean/compiler/ir/default.lean --replace "decls.map Decl.inferBorrow" "decls"
+  ''; })}/bin";
+  LEAN_NO_ST_BIN = "${(lean {}).overrideAttrs (attrs: { prePatch = ''
+    substituteInPlace src/runtime/object.h --replace "c_init_mem_kind = object_memory_kind::STHeap" "c_init_mem_kind = object_memory_kind::MTHeap"
+  ''; })}/bin";
   GHC = "${ghc}/bin/ghc";
   OCAML = "${ocaml}/bin/ocamlopt.opt";
   OCAML_FLAMBDA = "${ocamlFlambda}/bin/ocamlopt.opt";
diff --git a/tests/playground/report.py b/tests/playground/report.py
index 34692524b2..7d3c5b4ade 100755
--- a/tests/playground/report.py
+++ b/tests/playground/report.py
@@ -31,8 +31,7 @@ def pp(bench, cat, prop, norm):
     norm = norm if prop == 'etime' else 1
     mean_by_cat[cat].append(s.mean() / norm)
     stddev_by_cat[cat].append(s.std_dev() / norm)
-    return number.fnumber(s.mean() / norm, abs_deviation=s.std_dev() / norm,
-            min_decimal_places = 0 if cat in ['del', 'gc'] else None)
+    return number.fnumber(s.mean() / norm, abs_deviation=s.std_dev() / norm)
 
 def gmean(cat):
     mean = st.gmean(mean_by_cat[cat])
@@ -41,6 +40,9 @@ def gmean(cat):
 
 CATBAG = {
     '.lean': ("Lean [s]", "etime"),
+    '.no_reuse.lean': ("-reuse", "etime"),
+    '.no_borrow.lean': ("-borrow", "etime"),
+    '.no_st.lean': ("-ST", "etime"),
     '.gcc.lean': ("Lean+GCC9", "etime"),
     '.gc.lean': ("del [%]", "gc"),
     '.lean.perf': ("cache misses (CM) [1M/s]", "cache-misses"),