diff --git a/tools/cmd/diff/collect.go b/tools/cmd/diff/collect.go
index 171f424dc..cf52ffc9e 100644
--- a/tools/cmd/diff/collect.go
+++ b/tools/cmd/diff/collect.go
@@ -104,7 +104,9 @@ func hash_for_path(path string) (string, error) {
 }
 
 func sanitize_control_codes(x string) string {
-	return utils.SanitizeControlCodes(x, "░")
+	// exclude newlines, carriage returns and tabs
+	pat := utils.MustCompile("[\x00-\x08\x0b\x0c\x0e-\x1f\x7f\u0080-\u009f]")
+	return pat.ReplaceAllLiteralString(x, "░")
 }
 
 func sanitize_tabs_and_carriage_returns(x string) string {
diff --git a/tools/utils/misc.go b/tools/utils/misc.go
index 8d11c0248..6e523cb0b 100644
--- a/tools/utils/misc.go
+++ b/tools/utils/misc.go
@@ -4,7 +4,6 @@ package utils
 
 import (
 	"fmt"
-	"regexp"
 	"sort"
 
 	"golang.org/x/exp/constraints"
@@ -152,15 +151,3 @@ func Memset[T any](dest []T, pattern ...T) []T {
 	}
 	return dest
 }
-
-var ControlCodesPat = (&Once[*regexp.Regexp]{Run: func() *regexp.Regexp {
-	return regexp.MustCompile("[\x00-\x09\x0b-\x1f\x7f\u0080-\u009f]")
-}}).Get
-
-func SanitizeControlCodes(raw string, replace_with ...string) string {
-	r := ""
-	if len(replace_with) > 0 {
-		r = replace_with[0]
-	}
-	return ControlCodesPat().ReplaceAllLiteralString(raw, r)
-}