diff --git a/find_bisect_testcases.sh b/find_bisect_testcases.sh
new file mode 100755
index 00000000000000..d1cee54022e479
--- /dev/null
+++ b/find_bisect_testcases.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+#
+# Find test cases candidates when bisect goes through
+# many merge cases
+
+NB_COMMITS="$1"
+
+COUNT_LOG="my_count_log.txt"
+SCRIPT_DIR="$(pwd)"
+
+touch "$COUNT_LOG"
+
+while :
+do
+  randnum=$(eval "shuf -i 1-$NB_COMMITS -n 2")
+  commit1="$(echo "$randnum" | tail -1)"
+  commit2="$(echo "$randnum" | head -1)"
+  hash1=$(eval "git rev-list master -$NB_COMMITS | sed -n $commit1""p")
+  hash2=$(eval "git rev-list master -$NB_COMMITS | sed -n $commit2""p")
+
+  mb_num=$("$SCRIPT_DIR/merge_bases_count.sh" "$hash1" "$hash2")
+  if test "$mb_num" -gt 2 
+  then
+    echo "$hash1 $hash2 : $mb_num" >> "$COUNT_LOG"
+  fi
+done
diff --git a/merge_bases_count.sh b/merge_bases_count.sh
index 8852675d7a3808..46d3d438d968f6 100755
--- a/merge_bases_count.sh
+++ b/merge_bases_count.sh
@@ -2,23 +2,27 @@
 #
 # Count merge bases with bisect
 
-BISECT_LOG="my_bisect_log.txt"
-# export LC_ALL=C
-touch $BISECT_LOG
+trap "git bisect reset" INT
+
+hash1="$1"
+hash2="$2"
 
-hash1=$1
-hash2=$2
+BISECT_LOG="my_bisect_log.txt"
 
-git bisect start $hash1 $hash2 > $BISECT_LOG
+git bisect start "$hash1" "$hash2" --no-checkout > "$BISECT_LOG"
 count=0
 
-while grep -q "merge base must be tested" $BISECT_LOG
+if grep -q "Some good revs are not ancestors of the bad rev" "$BISECT_LOG"
+then
+  return 0
+fi
+
+while grep -q "merge base must be tested" "$BISECT_LOG"
 do
-  git bisect good > $BISECT_LOG
+  git bisect good > "$BISECT_LOG"
   count=$(($count + 1))
 done
 
-echo "Merge bases: $count"
+echo "$count"
 
-git bisect reset
-rm $BISECT_LOG
+rm "$BISECT_LOG"
diff --git a/remove_many_parents.sh b/remove_many_parents.sh
index f778d09f16a54f..131de7b6588ae0 100755
--- a/remove_many_parents.sh
+++ b/remove_many_parents.sh
@@ -16,7 +16,8 @@ while read -r commit
 do
 	echo "Processing $commit"
 	GIT_EDITOR="$SCRIPT_DIR/remove_parent.sh" git replace --edit "$commit"
-	test $("$SCRIPT_DIR/merge_bases_count.sh" "$hash1" "$hash2") -eq "$nb_mb" ||
+	mb_counts=$("$SCRIPT_DIR/merge_bases_count.sh" "$hash1" "$hash2")
+	test "$mb_counts" = "$nb_mb" ||
 		git replace -d "$commit"
 done <"$TMP_MERGE_COMMITS"