1 files changed, 16 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/ssagen/pgen.go b/src/cmd/compile/internal/ssagen/pgen.go
index 93157bfa11..0ddf11b426 100644
--- a/src/cmd/compile/internal/ssagen/pgen.go
+++ b/src/cmd/compile/internal/ssagen/pgen.go
@@ -75,7 +75,22 @@ func (s byStackVar) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
 // allocate space. In particular, it excludes arguments and results, which are in
 // the callers frame.
 func needAlloc(n *ir.Name) bool {
-	return n.Class == ir.PAUTO || n.Class == ir.PPARAMOUT && n.IsOutputParamInRegisters()
+	if n.Op() != ir.ONAME {
+		base.FatalfAt(n.Pos(), "%v has unexpected Op %v", n, n.Op())
+	}
+
+	switch n.Class {
+	case ir.PAUTO:
+		return true
+	case ir.PPARAM:
+		return false
+	case ir.PPARAMOUT:
+		return n.IsOutputParamInRegisters()
+
+	default:
+		base.FatalfAt(n.Pos(), "%v has unexpected Class %v", n, n.Class)
+		return false
+	}
 }
 
 func (s *ssafn) AllocFrame(f *ssa.Func) {