diff --git a/src/cmd/compile/internal/gc/fmt.go b/src/cmd/compile/internal/gc/fmt.go
index 5c55036..19f1090 100644
--- a/src/cmd/compile/internal/gc/fmt.go
+++ b/src/cmd/compile/internal/gc/fmt.go
@@ -737,6 +737,9 @@
 			Fatalf("cannot use TDDDFIELD with old exporter")
 		}
 		return fmt.Sprintf("%v <%v> %v", Econv(t.Etype), t.Sym, t.DDDField())
+
+	case Txxx:
+		return "Txxx"
 	}
 
 	if fmtmode == FExp {
diff --git a/src/cmd/compile/internal/gc/racewalk.go b/src/cmd/compile/internal/gc/racewalk.go
index 09889a4..f6e6514 100644
--- a/src/cmd/compile/internal/gc/racewalk.go
+++ b/src/cmd/compile/internal/gc/racewalk.go
@@ -164,7 +164,13 @@
 				var outn Nodes
 				outn.Set(out)
 				instrumentnode(&ls[i], &outn, 0, 0)
-				out = append(outn.Slice(), ls[i])
+				if ls[i].Op != OAS || ls[i].Ninit.Len() == 0 {
+					out = append(outn.Slice(), ls[i])
+				} else {
+					// Splice outn onto end of ls[i].Ninit
+					ls[i].Ninit.AppendNodes(&outn)
+					out = append(out, ls[i])
+				}
 			}
 		}
 		n.List.Set(out)
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 90c4d4e..7c5f906 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -3699,6 +3699,10 @@
 	if b == s.f.Entry {
 		// Live variable at start of function.
 		if s.canSSA(name) {
+			if strings.HasPrefix(name.Sym.Name, "autotmp_") {
+				// It's likely that this is an uninitialized variable in the entry block.
+				s.Fatalf("Treating auto as if it were arg, func %s, node %v, value %v", b.Func.Name, name, v)
+			}
 			v.Op = ssa.OpArg
 			v.Aux = name
 			return