diff --git a/build_sysroot/Cargo.lock b/build_sysroot/Cargo.lock
index 61c03378aae..63909f92952 100644
--- a/build_sysroot/Cargo.lock
+++ b/build_sysroot/Cargo.lock
@@ -76,9 +76,9 @@ version = "0.0.0"
 
 [[package]]
 name = "dlmalloc"
-version = "0.1.4"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "35055b1021724f4eb5262eb49130eebff23fc59fc5a14160e05faad8eeb36673"
+checksum = "332570860c2edf2d57914987bf9e24835425f75825086b6ba7d1e6a3e4f1f254"
 dependencies = [
  "compiler_builtins",
  "libc",
diff --git a/example/std_example.rs b/example/std_example.rs
index cb512a4aa33..b38e25328a4 100644
--- a/example/std_example.rs
+++ b/example/std_example.rs
@@ -53,6 +53,7 @@ fn main() {
 
     assert_eq!(0b0000000000000000000000000010000010000000000000000000000000000000_0000000000100000000000000000000000001000000000000100000000000000u128.leading_zeros(), 26);
     assert_eq!(0b0000000000000000000000000010000000000000000000000000000000000000_0000000000000000000000000000000000001000000000000000000010000000u128.trailing_zeros(), 7);
+    assert_eq!(core::intrinsics::saturating_sub(0, -170141183460469231731687303715884105728i128), 170141183460469231731687303715884105727i128);
 
     let _d = 0i128.checked_div(2i128);
     let _d = 0u128.checked_div(2u128);
diff --git a/patches/0022-core-Disable-not-compiling-tests.patch b/patches/0022-core-Disable-not-compiling-tests.patch
index ee8548783de..8cfffe580a1 100644
--- a/patches/0022-core-Disable-not-compiling-tests.patch
+++ b/patches/0022-core-Disable-not-compiling-tests.patch
@@ -52,8 +52,8 @@ index 0475aeb..9558198 100644
              fn test_rotate() {
                  assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
 @@ -112,6 +113,7 @@ mod tests {
-                 assert_eq!(B.rotate_left(64), B);
-                 assert_eq!(C.rotate_left(64), C);
+                 assert_eq!(B.rotate_left(128), B);
+                 assert_eq!(C.rotate_left(128), C);
              }
 +            */
  
@@ -72,8 +72,8 @@ index 04ed14f..a6e372e 100644
              fn test_rotate() {
                  assert_eq!(A.rotate_left(6).rotate_right(2).rotate_right(4), A);
 @@ -76,6 +77,7 @@ mod tests {
-                 assert_eq!(B.rotate_left(64), B);
-                 assert_eq!(C.rotate_left(64), C);
+                 assert_eq!(B.rotate_left(128), B);
+                 assert_eq!(C.rotate_left(128), C);
              }
 +            */
  
diff --git a/rust-toolchain b/rust-toolchain
index f12267a68fb..6ad89abbc06 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2020-11-13
+nightly-2020-11-21
diff --git a/src/common.rs b/src/common.rs
index dfb61dcea8a..1485d4451b8 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -233,7 +233,7 @@ pub(crate) fn type_min_max_value(
             let min_msb = bcx.ins().iconst(types::I64, (min >> 64) as u64 as i64);
             let min = bcx.ins().iconcat(min_lsb, min_msb);
 
-            let max = i128::MIN as u128;
+            let max = i128::MAX as u128;
             let max_lsb = bcx.ins().iconst(types::I64, max as u64 as i64);
             let max_msb = bcx.ins().iconst(types::I64, (max >> 64) as u64 as i64);
             let max = bcx.ins().iconcat(max_lsb, max_msb);