diff --git a/src/testing/benchmark.go b/src/testing/benchmark.go
index c293e37d..8a409382 100644
--- a/src/testing/benchmark.go
+++ b/src/testing/benchmark.go
@@ -329,7 +329,7 @@ func (b *B) processBench(ctx *benchContext) {
 // least once will not be measured itself and will be called once with N=1.
 func (b *B) Run(name string, f func(b *B)) bool {
 	if b.level > 0 {
-		name = b.name + "/" + name
+		name = b.name + "/" + rewrite(name)
 	}
 	b.hasSub = true
 	sub := &B{
diff --git a/src/testing/match.go b/src/testing/match.go
new file mode 100644
index 00000000..26b1f904
--- /dev/null
+++ b/src/testing/match.go
@@ -0,0 +1,46 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package testing
+
+import (
+	"strconv"
+)
+
+// rewrite rewrites a subname to having only printable characters and no white
+// space.
+func rewrite(s string) string {
+	b := []byte{}
+	for _, r := range s {
+		switch {
+		case isSpace(r):
+			b = append(b, '_')
+		case !strconv.IsPrint(r):
+			s := strconv.QuoteRune(r)
+			b = append(b, s[1:len(s)-1]...)
+		default:
+			b = append(b, string(r)...)
+		}
+	}
+	return string(b)
+}
+
+func isSpace(r rune) bool {
+	if r < 0x2000 {
+		switch r {
+		// Note: not the same as Unicode Z class.
+		case '\t', '\n', '\v', '\f', '\r', ' ', 0x85, 0xA0, 0x1680:
+			return true
+		}
+	} else {
+		if r <= 0x200a {
+			return true
+		}
+		switch r {
+		case 0x2028, 0x2029, 0x202f, 0x205f, 0x3000:
+			return true
+		}
+	}
+	return false
+}
diff --git a/src/testing/testing.go b/src/testing/testing.go
index 3eac03dd..fbf4cc92 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -211,7 +211,7 @@ func (t *T) Run(name string, f func(t *T)) bool {
 	// Create a subtest.
 	sub := T{
 		common: common{
-			name:   t.name + "/" + name,
+			name:   t.name + "/" + rewrite(name),
 			indent: t.indent + "    ",
 		},
 	}