diff --git a/Makefile b/Makefile
index 3a59b04..989281c 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,7 @@ VLEN = 256
 XLEN = 64
 SPLIT = 10000
 INTEGER = 0
+PATTERN = '.*'
 SPIKE_INSTALL = $(RISCV)
 OUTPUT = out/v$(VLEN)x$(XLEN)$(MODE)
 OUTPUT_STAGE1 = $(OUTPUT)/tests/stage1/
@@ -62,7 +63,7 @@ unittest:
 
 generate-stage1: clean-out build
 	@mkdir -p ${OUTPUT_STAGE1}
-	build/generator -VLEN ${VLEN} -XLEN ${XLEN} -split=${SPLIT} -integer=${INTEGER} -stage1output ${OUTPUT_STAGE1} -configs ${CONFIGS}
+	build/generator -VLEN ${VLEN} -XLEN ${XLEN} -split=${SPLIT} -integer=${INTEGER} -pattern='${PATTERN}' -stage1output ${OUTPUT_STAGE1} -configs ${CONFIGS}
 
 include Makefrag
 
diff --git a/README.md b/README.md
index 98dc53d..8d838a2 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,7 @@ Options:
 - `XLEN`, default is 64, we do not support specifying ELEN yet, ELEN is consistent with XLEN
 - `MODE`, default is `machine`, can be `machine`, `virtual` or `user`
 - `INTEGER`, default is 0, set to 1 if you don't want float tests (i.e. for Zve32x or Zve64x)
+- `PATTERN`, default is `.*`, set to a valid regex to generate the tests of your interests (e.g. `PATTERN='^v[ls].+\.v$'` to generate load/store tests)
 
 For example, to generate `isa=rv32gcv varch=vlen:128,elen:32 mode=machine` tests, use `make -e VLEN=128 XLEN=32 MODE=machine -j$(nproc)`.
 
diff --git a/main.go b/main.go
index 8904b46..d7e3e83 100644
--- a/main.go
+++ b/main.go
@@ -7,6 +7,7 @@ import (
 	"github.com/ksco/riscv-vector-tests/generator"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -22,15 +23,19 @@ func fatalIf(err error) {
 }
 
 var vlenF = flag.Int("VLEN", 256, "")
-var xlenF = flag.Int("XLEN", 64, "")
-var splitF = flag.Int("split", 10000, "")
-var integer = flag.Bool("integer", false, "")
+var xlenF = flag.Int("XLEN", 64, "we do not support specifying ELEN yet, ELEN is consistent with XLEN.")
+var splitF = flag.Int("split", 10000, "split per lines.")
+var integerF = flag.Bool("integer", false, "only generate integer tests.")
+var patternF = flag.String("pattern", ".*", "regex to filter out tests.")
 var stage1OutputDirF = flag.String("stage1output", "", "stage1 output directory.")
 var configsDirF = flag.String("configs", "configs/", "config files directory.")
 
 func main() {
 	flag.Parse()
 
+	pattern, err := regexp.Compile(*patternF)
+	fatalIf(err)
+
 	if stage1OutputDirF == nil || *stage1OutputDirF == "" {
 		fatalIf(errors.New("-stage1output is required"))
 	}
@@ -49,7 +54,11 @@ func main() {
 	lk := sync.Mutex{}
 	wg := sync.WaitGroup{}
 	for _, file := range files {
-		if *integer && strings.HasPrefix(file.Name(), "vf") {
+		if *integerF && strings.HasPrefix(file.Name(), "vf") {
+			continue
+		}
+
+		if !pattern.MatchString(strings.TrimSuffix(file.Name(), ".toml")) {
 			continue
 		}