diff --git a/src/test/run-pass/simd-generics.rs b/src/test/run-pass/simd-generics.rs
index 9b48387789dd..900d2befea43 100644
--- a/src/test/run-pass/simd-generics.rs
+++ b/src/test/run-pass/simd-generics.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// xfail-fast
+
 #[feature(simd)];
 
 use std::ops;
diff --git a/src/test/run-pass/simd-issue-10604.rs b/src/test/run-pass/simd-issue-10604.rs
index cf0f020f4396..4132ec0059ff 100644
--- a/src/test/run-pass/simd-issue-10604.rs
+++ b/src/test/run-pass/simd-issue-10604.rs
@@ -7,6 +7,9 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
+
+// xfail-fast
+
 #[allow(experimental)];
 #[feature(simd)];