diff --git a/qemu/tcg/tcg.h b/qemu/tcg/tcg.h
index bcc8ea22..d883de22 100644
--- a/qemu/tcg/tcg.h
+++ b/qemu/tcg/tcg.h
@@ -989,7 +989,7 @@ struct TCGContext {
 
 static inline TCGTemp *arg_temp(TCGContext *tcg_ctx, TCGArg a)
 {
-    return &tcg_ctx->temps[a];
+    return a == TCG_CALL_DUMMY_ARG ? NULL : &tcg_ctx->temps[a];
 }
 
 static inline void tcg_set_insn_param(TCGContext *tcg_ctx, int op_idx, int arg, TCGArg v)