diff --git a/src/comp/back/abi.rs b/src/comp/back/abi.rs
index 106aba39be6f..6e7decbb405f 100644
--- a/src/comp/back/abi.rs
+++ b/src/comp/back/abi.rs
@@ -66,7 +66,7 @@ const int closure_elt_target = 1;
 const int closure_elt_bindings = 2;
 const int closure_elt_ty_params = 3;
 
-const uint ivec_default_size = 16u;
+const uint ivec_default_size = 64u;
 
 const uint ivec_elt_len = 0u;
 const uint ivec_elt_alen = 1u;