diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index b6c0322..7ec83d2 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -130,8 +130,8 @@
     echo "Usage: $0 [options]"
     printf "  -h|--help\tPrint this help.\n"
     printf "  -m|--memcheck\tCheck memory leaks and errors.\n"
-    printf "  -f|--filter\tOnly matching tests are executed (BRE)\n"
-    printf "  -e|--exclude\tMatching tests are excluded (BRE)\n"
+    printf "  -f|--filter\tOnly matching tests are executed (substring or BRE)\n"
+    printf "  -e|--exclude\tMatching tests are excluded (substring or BRE)\n"
     printf "  -n|--number\tExecute only numbered test (comma-separated, e.g. '245,256')\n"
     printf "  -s|--show-numbers\tShow test numbers in front of test names\n"
     printf "  -p|--preserve-logs\tPreserve logs of successful tests as well\n"
@@ -184,6 +184,14 @@
     done
 }
 
+# Read boolean configuration options from config.h for easy and quick
+# testing. Skip non-boolean options (with something other than spaces
+# and a comment after "#define SYMBOL"). The variable contains a
+# space-separated list of symbols.
+CONFIGS_ENABLED=" $(<"$CONFIG_H" \
+                    sed -n 's!^ *#define  *\([A-Za-z][0-9A-Z_a-z]*\) *\(/*\)*!\1!p' |
+                    tr '\n' ' ')"
+
 # Skip next test; use this macro to skip tests which are legitimate
 # in theory and expected to be re-introduced at some point, but
 # aren't expected to succeed at the moment due to problems outside
@@ -194,16 +202,17 @@
 
 # skip next test if the flag is not enabled in config.h
 requires_config_enabled() {
-    if grep "^#define $1" $CONFIG_H > /dev/null; then :; else
-        SKIP_NEXT="YES"
-    fi
+    case $CONFIGS_ENABLED in
+        *" $1 "*) :;;
+        *) SKIP_NEXT="YES";;
+    esac
 }
 
 # skip next test if the flag is enabled in config.h
 requires_config_disabled() {
-    if grep "^#define $1" $CONFIG_H > /dev/null; then
-        SKIP_NEXT="YES"
-    fi
+    case $CONFIGS_ENABLED in
+        *" $1 "*) SKIP_NEXT="YES";;
+    esac
 }
 
 get_config_value_or_default() {
@@ -422,17 +431,21 @@
 
 # is_polar <cmd_line>
 is_polar() {
-    echo "$1" | grep 'ssl_server2\|ssl_client2' > /dev/null
+    case "$1" in
+        *ssl_client2*) true;;
+        *ssl_server2*) true;;
+        *) false;;
+    esac
 }
 
 # openssl s_server doesn't have -www with DTLS
 check_osrv_dtls() {
-    if echo "$SRV_CMD" | grep 's_server.*-dtls' >/dev/null; then
-        NEEDS_INPUT=1
-        SRV_CMD="$( echo $SRV_CMD | sed s/-www// )"
-    else
-        NEEDS_INPUT=0
-    fi
+    case "$SRV_CMD" in
+        *s_server*-dtls*)
+            NEEDS_INPUT=1
+            SRV_CMD="$( echo $SRV_CMD | sed s/-www// )";;
+        *) NEEDS_INPUT=0;;
+    esac
 }
 
 # provide input to commands that need it
@@ -548,11 +561,10 @@
 
 # check if the given command uses dtls and sets global variable DTLS
 detect_dtls() {
-    if echo "$1" | grep 'dtls=1\|-dtls1\|-u' >/dev/null; then
-        DTLS=1
-    else
-        DTLS=0
-    fi
+    case "$1" in
+        *dtls=1*|-dtls|-u) DTLS=1;;
+        *) DTLS=0;;
+    esac
 }
 
 # Usage: run_test name [-p proxy_cmd] srv_cmd cli_cmd cli_exit [option [...]]
@@ -568,8 +580,7 @@
     NAME="$1"
     shift 1
 
-    if echo "$NAME" | grep "$FILTER" | grep -v "$EXCLUDE" >/dev/null; then :
-    else
+    if is_excluded "$NAME"; then
         SKIP_NEXT="NO"
         return
     fi
@@ -577,10 +588,11 @@
     print_name "$NAME"
 
     # Do we only run numbered tests?
-    if [ "X$RUN_TEST_NUMBER" = "X" ]; then :
-    elif echo ",$RUN_TEST_NUMBER," | grep ",$TESTS," >/dev/null; then :
-    else
-        SKIP_NEXT="YES"
+    if [ -n "$RUN_TEST_NUMBER" ]; then
+        case ",$RUN_TEST_NUMBER," in
+            *",$TESTS,"*) :;;
+            *) SKIP_NEXT="YES";;
+        esac
     fi
 
     # should we skip?
@@ -606,10 +618,10 @@
     shift 3
 
     # Check if test uses files
-    TEST_USES_FILES=$(echo "$SRV_CMD $CLI_CMD" | grep "\.\(key\|crt\|pem\)" )
-    if [ ! -z "$TEST_USES_FILES" ]; then
-       requires_config_enabled MBEDTLS_FS_IO
-    fi
+    case "$SRV_CMD $CLI_CMD" in
+        *data_files/*)
+            requires_config_enabled MBEDTLS_FS_IO;;
+    esac
 
     # should we skip?
     if [ "X$SKIP_NEXT" = "XYES" ]; then
@@ -840,6 +852,46 @@
 
 get_options "$@"
 
+# Optimize filters: if $FILTER and $EXCLUDE can be expressed as shell
+# patterns rather than regular expressions, use a case statement instead
+# of calling grep. To keep the optimizer simple, it is incomplete and only
+# detects simple cases: plain substring, everything, nothing.
+#
+# As an exception, the character '.' is treated as an ordinary character
+# if it is the only special character in the string. This is because it's
+# rare to need "any one character", but needing a literal '.' is common
+# (e.g. '-f "DTLS 1.2"').
+need_grep=
+case "$FILTER" in
+    '^$') simple_filter=;;
+    '.*') simple_filter='*';;
+    *[][$+*?\\^{\|}]*) # Regexp special characters (other than .), we need grep
+        need_grep=1;;
+    *) # No regexp or shell-pattern special character
+        simple_filter="*$FILTER*";;
+esac
+case "$EXCLUDE" in
+    '^$') simple_exclude=;;
+    '.*') simple_exclude='*';;
+    *[][$+*?\\^{\|}]*) # Regexp special characters (other than .), we need grep
+        need_grep=1;;
+    *) # No regexp or shell-pattern special character
+        simple_exclude="*$EXCLUDE*";;
+esac
+if [ -n "$need_grep" ]; then
+    is_excluded () {
+        ! echo "$1" | grep "$FILTER" | grep -q -v "$EXCLUDE"
+    }
+else
+    is_excluded () {
+        case "$1" in
+            $simple_exclude) true;;
+            $simple_filter) false;;
+            *) true;;
+        esac
+    }
+fi
+
 # sanity checks, avoid an avalanche of errors
 P_SRV_BIN="${P_SRV%%[  ]*}"
 P_CLI_BIN="${P_CLI%%[  ]*}"