[dev.ssa] Merge remote-tracking branch 'origin/master' into mergebranch

Semi-regular merge from tip to dev.ssa.

Change-Id: If7d2269f267bcbc0ecd3a483d349951044470e3f
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 19fda37..13d8663 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -561,7 +561,7 @@
 
 	case OAS2DOTTYPE:
 		res, resok := s.dottype(n.Rlist.N, true)
-		s.assign(n.List.N, res, false, false, n.Lineno)
+		s.assign(n.List.N, res, needwritebarrier(n.List.N, n.Rlist.N), false, n.Lineno)
 		s.assign(n.List.Next.N, resok, false, false, n.Lineno)
 		return