diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 6d136f6..3b36457 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -2146,6 +2146,13 @@
 		return false
 	}
 
+	// No write barrier for writing a sliced slice back to its
+	// original location.
+	if (r.Op == OSLICE || r.Op == OSLICE3 || r.Op == OSLICESTR) &&
+		samesafeexpr(r.Left, l) {
+		return false
+	}
+
 	// Otherwise, be conservative and use write barrier.
 	return true
 }