1 files changed, 78 insertions, 0 deletions
diff --git a/libgo/go/runtime/slice_test.go b/libgo/go/runtime/slice_test.go
index 0463fc7..e963a43 100644
--- a/libgo/go/runtime/slice_test.go
+++ b/libgo/go/runtime/slice_test.go
@@ -10,6 +10,84 @@ import (
 
 const N = 20
 
+func BenchmarkMakeSliceCopy(b *testing.B) {
+	const length = 32
+	var bytes = make([]byte, 8*length)
+	var ints = make([]int, length)
+	var ptrs = make([]*byte, length)
+	b.Run("mallocmove", func(b *testing.B) {
+		b.Run("Byte", func(b *testing.B) {
+			var x []byte
+			for i := 0; i < b.N; i++ {
+				x = make([]byte, len(bytes))
+				copy(x, bytes)
+			}
+		})
+		b.Run("Int", func(b *testing.B) {
+			var x []int
+			for i := 0; i < b.N; i++ {
+				x = make([]int, len(ints))
+				copy(x, ints)
+			}
+		})
+		b.Run("Ptr", func(b *testing.B) {
+			var x []*byte
+			for i := 0; i < b.N; i++ {
+				x = make([]*byte, len(ptrs))
+				copy(x, ptrs)
+			}
+
+		})
+	})
+	b.Run("makecopy", func(b *testing.B) {
+		b.Run("Byte", func(b *testing.B) {
+			var x []byte
+			for i := 0; i < b.N; i++ {
+				x = make([]byte, 8*length)
+				copy(x, bytes)
+			}
+		})
+		b.Run("Int", func(b *testing.B) {
+			var x []int
+			for i := 0; i < b.N; i++ {
+				x = make([]int, length)
+				copy(x, ints)
+			}
+		})
+		b.Run("Ptr", func(b *testing.B) {
+			var x []*byte
+			for i := 0; i < b.N; i++ {
+				x = make([]*byte, length)
+				copy(x, ptrs)
+			}
+
+		})
+	})
+	b.Run("nilappend", func(b *testing.B) {
+		b.Run("Byte", func(b *testing.B) {
+			var x []byte
+			for i := 0; i < b.N; i++ {
+				x = append([]byte(nil), bytes...)
+				_ = x
+			}
+		})
+		b.Run("Int", func(b *testing.B) {
+			var x []int
+			for i := 0; i < b.N; i++ {
+				x = append([]int(nil), ints...)
+				_ = x
+			}
+		})
+		b.Run("Ptr", func(b *testing.B) {
+			var x []*byte
+			for i := 0; i < b.N; i++ {
+				x = append([]*byte(nil), ptrs...)
+				_ = x
+			}
+		})
+	})
+}
+
 type (
 	struct24 struct{ a, b, c int64 }
 	struct32 struct{ a, b, c, d int64 }