diff --git a/src/test/mir-opt/lower_128bit_debug_test.rs b/src/test/mir-opt/lower_128bit_debug_test.rs
index 3280c8db7f223..1de5e151220fa 100644
--- a/src/test/mir-opt/lower_128bit_debug_test.rs
+++ b/src/test/mir-opt/lower_128bit_debug_test.rs
@@ -74,31 +74,65 @@ fn main() {
 // START rustc.test_signed.Lower128Bit.after.mir
 //     _2 = const i128_addo(_1, const 1i128) -> bb10;
 //     ...
+//     _1 = (_2.0: i128);
 //     _3 = const i128_subo(_1, const 2i128) -> bb11;
 //     ...
+//     _1 = (_3.0: i128);
 //     _4 = const i128_mulo(_1, const 3i128) -> bb12;
 //     ...
+//     _1 = (_4.0: i128);
+//     ...
 //     _1 = const i128_div(_1, const 4i128) -> bb13;
 //     ...
 //     _1 = const i128_rem(_1, const 5i128) -> bb15;
 //     ...
+//     _1 = (_13.0: i128);
 //     _14 = const i128_shro(_1, const 7i32) -> bb16;
 //     ...
+//     _1 = (_14.0: i128);
+//     ...
+//     assert(!(_2.1: bool), "attempt to add with overflow") -> bb1;
+//     ...
+//     assert(!(_3.1: bool), "attempt to subtract with overflow") -> bb2;
+//     ...
+//     assert(!(_4.1: bool), "attempt to multiply with overflow") -> bb3;
+//     ...
+//     assert(!(_13.1: bool), "attempt to shift left with overflow") -> bb8;
+//     ...
 //     _13 = const i128_shlo(_1, const 6i32) -> bb14;
+//     ...
+//     assert(!(_14.1: bool), "attempt to shift right with overflow") -> bb9;
 // END rustc.test_signed.Lower128Bit.after.mir
 
 // START rustc.test_unsigned.Lower128Bit.after.mir
 //     _2 = const u128_addo(_1, const 1u128) -> bb8;
 //     ...
+//     _1 = (_2.0: u128);
 //     _3 = const u128_subo(_1, const 2u128) -> bb9;
 //     ...
+//     _1 = (_3.0: u128);
 //     _4 = const u128_mulo(_1, const 3u128) -> bb10;
 //     ...
+//     _1 = (_4.0: u128);
+//     ...
 //     _1 = const u128_div(_1, const 4u128) -> bb11;
 //     ...
 //     _1 = const u128_rem(_1, const 5u128) -> bb13;
 //     ...
+//     _1 = (_7.0: u128);
 //     _8 = const u128_shro(_1, const 7i32) -> bb14;
 //     ...
+//     _1 = (_8.0: u128);
+//     ...
+//     assert(!(_2.1: bool), "attempt to add with overflow") -> bb1;
+//     ...
+//     assert(!(_3.1: bool), "attempt to subtract with overflow") -> bb2;
+//     ...
+//     assert(!(_4.1: bool), "attempt to multiply with overflow") -> bb3;
+//     ...
+//     assert(!(_7.1: bool), "attempt to shift left with overflow") -> bb6;
+//     ...
 //     _7 = const i128_shlo(_1, const 6i32) -> bb12;
+//     ...
+//     assert(!(_8.1: bool), "attempt to shift right with overflow") -> bb7;
 // END rustc.test_unsigned.Lower128Bit.after.mir