diff --git a/tests/core/reduc.test b/tests/core/reduc.test
index 1ace7c3c6..ed10c1a6b 100755
--- a/tests/core/reduc.test
+++ b/tests/core/reduc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2009, 2010, 2012, 2015 Laboratoire de Recherche et
+# Copyright (C) 2009, 2010, 2012, 2015, 2016 Laboratoire de Recherche et
 # Développement de l'Epita (LRDE).
 # Copyright (C) 2004, 2005, 2006 Laboratoire d'Informatique de Paris 6
 # (LIP6), département Systèmes Répartis Coopératifs (SRC), Université
@@ -27,21 +27,20 @@
 
 set -e
 
-randltl=randltl
-
-FILE=formulae
-: > $FILE
-# for i in 10 11 12 13 14 15 16 17 18 19 20; do
-for i in 10 12 14 16 18 20; do
-  run 0 $randltl --seed 0   --tree-size $i a b c       -n 100 >> $FILE
-  run 0 $randltl --seed 100 --tree-size $i a b c d e f -n 100 >> $FILE
+# Do the first run through valgrind, and the rest without
+run 0 randltl --seed 0 --tree-size 10 a b c -n 100 > formulas
+randltl --seed 100 --tree-size 10 a b c d e f -n 100 >> formulas
+for i in 12 14 16 18 20; do
+  randltl --seed 0   --tree-size $i a b c       -n 100 >> formulas
+  randltl --seed 100 --tree-size $i a b c d e f -n 100 >> formulas
 done
 
-for opt in 0 1 2 3 7; do
-  run 0 ../reduc -f -h $opt "$FILE"
-done
-# Running the above through valgrind is quite slow already.
-# Don't use valgrind for the next reductions (even slower).
-for opt in 8 9; do
-  ../reduc -f -h $opt "$FILE"
+for opt in 0 1 2 3 7 8 9; do
+    case $opt in
+        # Running valgrind on all these runs would be too slow.  Only
+        # do that for 3 (all basic reductions) and 8 (containment
+        # checks).
+        3|7) run 0 ../reduc -f -h $opt formulas;;
+        *)         ../reduc -f -h $opt formulas;;
+    esac
 done
diff --git a/tests/core/reducpsl.test b/tests/core/reducpsl.test
index ca2e7d243..317cbf4b5 100755
--- a/tests/core/reducpsl.test
+++ b/tests/core/reducpsl.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2011, 2012, 2015 Laboratoire de Recherche et
+# Copyright (C) 2011, 2012, 2015, 2016 Laboratoire de Recherche et
 # Développement de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -24,20 +24,20 @@
 
 set -e
 
-randltl=randltl
-
-FILE=formulae
-: > $FILE
-for i in 10 12 14 16 18 20; do
-  run 0 $randltl --psl --seed 0   --tree-size $i a b c       -n 100 >> $FILE
-  run 0 $randltl --psl --seed 100 --tree-size $i a b c d e f -n 100 >> $FILE
+# Do the first run through valgrind, and the rest without
+run 0 randltl --psl --seed 0 --tree-size 10 a b c -n 100 > formulas
+randltl --psl --seed 100 --tree-size 10 a b c d e f -n 100 >> formulas
+for i in 12 14 16 18 20; do
+  randltl --psl --seed 0   --tree-size $i a b c       -n 100 >> formulas
+  randltl --psl --seed 100 --tree-size $i a b c d e f -n 100 >> formulas
 done
 
-for opt in 0 1 2 3 7; do
-  run 0 ../reduc -f -h $opt "$FILE"
-done
-# Running the above through valgrind is quite slow already.
-# Don't use valgrind for the next reductions (even slower).
-for opt in 8 9; do
-  ../reduc -f -h $opt "$FILE"
+for opt in 0 1 2 3 7 8 9; do
+    case $opt in
+        # Running valgrind on all these runs would be too slow.  Only
+        # do that for 3 (all basic reductions) and 8 (containment
+        # checks).
+        3|7) run 0 ../reduc -f -h $opt formulas;;
+        *)         ../reduc -f -h $opt formulas;;
+    esac
 done