Auto merge of #3469 - rust-lang:rustup-2024-04-16, r=RalfJung

Automatic Rustup

8 files changed, 80 insertions, 143 deletions

diff --git a/compiler/rustc_data_structures/src/graph/iterate/mod.rs b/compiler/rustc_data_structures/src/graph/iterate/mod.rs
index 9eb4b5278c0..7a77f2c0dbb 100644
--- a/compiler/rustc_data_structures/src/graph/iterate/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/iterate/mod.rs
@@ -1,4 +1,4 @@
-use super::{DirectedGraph, WithNumNodes, WithStartNode, WithSuccessors};
+use super::{DirectedGraph, StartNode, Successors};
 use rustc_index::bit_set::BitSet;
 use rustc_index::{IndexSlice, IndexVec};
 use std::ops::ControlFlow;
@@ -6,14 +6,14 @@ use std::ops::ControlFlow;
 #[cfg(test)]
 mod tests;
 
-pub fn post_order_from<G: DirectedGraph + WithSuccessors + WithNumNodes>(
+pub fn post_order_from<G: DirectedGraph + Successors>(
     graph: &G,
     start_node: G::Node,
 ) -> Vec<G::Node> {
     post_order_from_to(graph, start_node, None)
 }
 
-pub fn post_order_from_to<G: DirectedGraph + WithSuccessors + WithNumNodes>(
+pub fn post_order_from_to<G: DirectedGraph + Successors>(
     graph: &G,
     start_node: G::Node,
     end_node: Option<G::Node>,
@@ -27,7 +27,7 @@ pub fn post_order_from_to<G: DirectedGraph + WithSuccessors + WithNumNodes>(
     result
 }
 
-fn post_order_walk<G: DirectedGraph + WithSuccessors + WithNumNodes>(
+fn post_order_walk<G: DirectedGraph + Successors>(
     graph: &G,
     node: G::Node,
     result: &mut Vec<G::Node>,
@@ -60,7 +60,7 @@ fn post_order_walk<G: DirectedGraph + WithSuccessors + WithNumNodes>(
     }
 }
 
-pub fn reverse_post_order<G: DirectedGraph + WithSuccessors + WithNumNodes>(
+pub fn reverse_post_order<G: DirectedGraph + Successors>(
     graph: &G,
     start_node: G::Node,
 ) -> Vec<G::Node> {
@@ -72,7 +72,7 @@ pub fn reverse_post_order<G: DirectedGraph + WithSuccessors + WithNumNodes>(
 /// A "depth-first search" iterator for a directed graph.
 pub struct DepthFirstSearch<'graph, G>
 where
-    G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
+    G: ?Sized + DirectedGraph + Successors,
 {
     graph: &'graph G,
     stack: Vec<G::Node>,
@@ -81,7 +81,7 @@ where
 
 impl<'graph, G> DepthFirstSearch<'graph, G>
 where
-    G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
+    G: ?Sized + DirectedGraph + Successors,
 {
     pub fn new(graph: &'graph G) -> Self {
         Self { graph, stack: vec![], visited: BitSet::new_empty(graph.num_nodes()) }
@@ -127,7 +127,7 @@ where
 
 impl<G> std::fmt::Debug for DepthFirstSearch<'_, G>
 where
-    G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
+    G: ?Sized + DirectedGraph + Successors,
 {
     fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let mut f = fmt.debug_set();
@@ -140,7 +140,7 @@ where
 
 impl<G> Iterator for DepthFirstSearch<'_, G>
 where
-    G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
+    G: ?Sized + DirectedGraph + Successors,
 {
     type Item = G::Node;
 
@@ -201,7 +201,7 @@ struct Event<N> {
 /// [CLR]: https://en.wikipedia.org/wiki/Introduction_to_Algorithms
 pub struct TriColorDepthFirstSearch<'graph, G>
 where
-    G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
+    G: ?Sized + DirectedGraph + Successors,
 {
     graph: &'graph G,
     stack: Vec<Event<G::Node>>,
@@ -211,7 +211,7 @@ where
 
 impl<'graph, G> TriColorDepthFirstSearch<'graph, G>
 where
-    G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors,
+    G: ?Sized + DirectedGraph + Successors,
 {
     pub fn new(graph: &'graph G) -> Self {
         TriColorDepthFirstSearch {
@@ -278,7 +278,7 @@ where
 
 impl<G> TriColorDepthFirstSearch<'_, G>
 where
-    G: ?Sized + DirectedGraph + WithNumNodes + WithSuccessors + WithStartNode,
+    G: ?Sized + DirectedGraph + Successors + StartNode,
 {
     /// Performs a depth-first search, starting from `G::start_node()`.
     ///
diff --git a/compiler/rustc_data_structures/src/graph/mod.rs b/compiler/rustc_data_structures/src/graph/mod.rs
index e06ab2fe36b..3ae3023a91b 100644
--- a/compiler/rustc_data_structures/src/graph/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/mod.rs
@@ -12,70 +12,43 @@ mod tests;
 
 pub trait DirectedGraph {
     type Node: Idx;
-}
 
-pub trait WithNumNodes: DirectedGraph {
     fn num_nodes(&self) -> usize;
 }
 
-pub trait WithNumEdges: DirectedGraph {
+pub trait NumEdges: DirectedGraph {
     fn num_edges(&self) -> usize;
 }
 
-pub trait WithSuccessors: DirectedGraph
-where
-    Self: for<'graph> GraphSuccessors<'graph, Item = <Self as DirectedGraph>::Node>,
-{
-    fn successors(&self, node: Self::Node) -> <Self as GraphSuccessors<'_>>::Iter;
-
-    fn depth_first_search(&self, from: Self::Node) -> iterate::DepthFirstSearch<'_, Self>
-    where
-        Self: WithNumNodes,
-    {
-        iterate::DepthFirstSearch::new(self).with_start_node(from)
-    }
-}
-
-#[allow(unused_lifetimes)]
-pub trait GraphSuccessors<'graph> {
-    type Item;
-    type Iter: Iterator<Item = Self::Item>;
-}
-
-pub trait WithPredecessors: DirectedGraph
-where
-    Self: for<'graph> GraphPredecessors<'graph, Item = <Self as DirectedGraph>::Node>,
-{
-    fn predecessors(&self, node: Self::Node) -> <Self as GraphPredecessors<'_>>::Iter;
-}
-
-#[allow(unused_lifetimes)]
-pub trait GraphPredecessors<'graph> {
-    type Item;
-    type Iter: Iterator<Item = Self::Item>;
-}
-
-pub trait WithStartNode: DirectedGraph {
+pub trait StartNode: DirectedGraph {
     fn start_node(&self) -> Self::Node;
 }
 
-pub trait ControlFlowGraph:
-    DirectedGraph + WithStartNode + WithPredecessors + WithSuccessors + WithNumNodes
-{
-    // convenient trait
+pub trait Successors: DirectedGraph {
+    fn successors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node>;
 }
 
-impl<T> ControlFlowGraph for T where
-    T: DirectedGraph + WithStartNode + WithPredecessors + WithSuccessors + WithNumNodes
-{
+pub trait Predecessors: DirectedGraph {
+    fn predecessors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node>;
 }
 
+/// Alias for [`DirectedGraph`] + [`StartNode`] + [`Predecessors`] + [`Successors`].
+pub trait ControlFlowGraph: DirectedGraph + StartNode + Predecessors + Successors {}
+impl<T> ControlFlowGraph for T where T: DirectedGraph + StartNode + Predecessors + Successors {}
+
 /// Returns `true` if the graph has a cycle that is reachable from the start node.
 pub fn is_cyclic<G>(graph: &G) -> bool
 where
-    G: ?Sized + DirectedGraph + WithStartNode + WithSuccessors + WithNumNodes,
+    G: ?Sized + DirectedGraph + StartNode + Successors,
 {
     iterate::TriColorDepthFirstSearch::new(graph)
         .run_from_start(&mut iterate::CycleDetector)
         .is_some()
 }
+
+pub fn depth_first_search<G>(graph: &G, from: G::Node) -> iterate::DepthFirstSearch<'_, G>
+where
+    G: ?Sized + Successors,
+{
+    iterate::DepthFirstSearch::new(graph).with_start_node(from)
+}
diff --git a/compiler/rustc_data_structures/src/graph/reference.rs b/compiler/rustc_data_structures/src/graph/reference.rs
index c259fe56c15..7a487552f53 100644
--- a/compiler/rustc_data_structures/src/graph/reference.rs
+++ b/compiler/rustc_data_structures/src/graph/reference.rs
@@ -2,38 +2,26 @@ use super::*;
 
 impl<'graph, G: DirectedGraph> DirectedGraph for &'graph G {
     type Node = G::Node;
-}
 
-impl<'graph, G: WithNumNodes> WithNumNodes for &'graph G {
     fn num_nodes(&self) -> usize {
         (**self).num_nodes()
     }
 }
 
-impl<'graph, G: WithStartNode> WithStartNode for &'graph G {
+impl<'graph, G: StartNode> StartNode for &'graph G {
     fn start_node(&self) -> Self::Node {
         (**self).start_node()
     }
 }
 
-impl<'graph, G: WithSuccessors> WithSuccessors for &'graph G {
-    fn successors(&self, node: Self::Node) -> <Self as GraphSuccessors<'_>>::Iter {
+impl<'graph, G: Successors> Successors for &'graph G {
+    fn successors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node> {
         (**self).successors(node)
     }
 }
 
-impl<'graph, G: WithPredecessors> WithPredecessors for &'graph G {
-    fn predecessors(&self, node: Self::Node) -> <Self as GraphPredecessors<'_>>::Iter {
+impl<'graph, G: Predecessors> Predecessors for &'graph G {
+    fn predecessors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node> {
         (**self).predecessors(node)
     }
 }
-
-impl<'iter, 'graph, G: WithPredecessors> GraphPredecessors<'iter> for &'graph G {
-    type Item = G::Node;
-    type Iter = <G as GraphPredecessors<'iter>>::Iter;
-}
-
-impl<'iter, 'graph, G: WithSuccessors> GraphSuccessors<'iter> for &'graph G {
-    type Item = G::Node;
-    type Iter = <G as GraphSuccessors<'iter>>::Iter;
-}
diff --git a/compiler/rustc_data_structures/src/graph/scc/mod.rs b/compiler/rustc_data_structures/src/graph/scc/mod.rs
index b54d75f7ed7..5021e5e8fc0 100644
--- a/compiler/rustc_data_structures/src/graph/scc/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/scc/mod.rs
@@ -7,7 +7,7 @@
 
 use crate::fx::FxHashSet;
 use crate::graph::vec_graph::VecGraph;
-use crate::graph::{DirectedGraph, GraphSuccessors, WithNumEdges, WithNumNodes, WithSuccessors};
+use crate::graph::{DirectedGraph, NumEdges, Successors};
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use std::ops::Range;
 
@@ -39,7 +39,7 @@ pub struct SccData<S: Idx> {
 }
 
 impl<N: Idx, S: Idx + Ord> Sccs<N, S> {
-    pub fn new(graph: &(impl DirectedGraph<Node = N> + WithNumNodes + WithSuccessors)) -> Self {
+    pub fn new(graph: &(impl DirectedGraph<Node = N> + Successors)) -> Self {
         SccsConstruction::construct(graph)
     }
 
@@ -89,30 +89,22 @@ impl<N: Idx, S: Idx + Ord> Sccs<N, S> {
     }
 }
 
-impl<N: Idx, S: Idx> DirectedGraph for Sccs<N, S> {
+impl<N: Idx, S: Idx + Ord> DirectedGraph for Sccs<N, S> {
     type Node = S;
-}
 
-impl<N: Idx, S: Idx + Ord> WithNumNodes for Sccs<N, S> {
     fn num_nodes(&self) -> usize {
         self.num_sccs()
     }
 }
 
-impl<N: Idx, S: Idx> WithNumEdges for Sccs<N, S> {
+impl<N: Idx, S: Idx + Ord> NumEdges for Sccs<N, S> {
     fn num_edges(&self) -> usize {
         self.scc_data.all_successors.len()
     }
 }
 
-impl<'graph, N: Idx, S: Idx> GraphSuccessors<'graph> for Sccs<N, S> {
-    type Item = S;
-
-    type Iter = std::iter::Cloned<std::slice::Iter<'graph, S>>;
-}
-
-impl<N: Idx, S: Idx + Ord> WithSuccessors for Sccs<N, S> {
-    fn successors(&self, node: S) -> <Self as GraphSuccessors<'_>>::Iter {
+impl<N: Idx, S: Idx + Ord> Successors for Sccs<N, S> {
+    fn successors(&self, node: S) -> impl Iterator<Item = Self::Node> {
         self.successors(node).iter().cloned()
     }
 }
@@ -158,7 +150,7 @@ impl<S: Idx> SccData<S> {
     }
 }
 
-struct SccsConstruction<'c, G: DirectedGraph + WithNumNodes + WithSuccessors, S: Idx> {
+struct SccsConstruction<'c, G: DirectedGraph + Successors, S: Idx> {
     graph: &'c G,
 
     /// The state of each node; used during walk to record the stack
@@ -218,7 +210,7 @@ enum WalkReturn<S> {
 
 impl<'c, G, S> SccsConstruction<'c, G, S>
 where
-    G: DirectedGraph + WithNumNodes + WithSuccessors,
+    G: DirectedGraph + Successors,
     S: Idx,
 {
     /// Identifies SCCs in the graph `G` and computes the resulting
diff --git a/compiler/rustc_data_structures/src/graph/tests.rs b/compiler/rustc_data_structures/src/graph/tests.rs
index 7f4ef906b36..85c2703cc25 100644
--- a/compiler/rustc_data_structures/src/graph/tests.rs
+++ b/compiler/rustc_data_structures/src/graph/tests.rs
@@ -1,7 +1,5 @@
 use crate::fx::FxHashMap;
 use std::cmp::max;
-use std::iter;
-use std::slice;
 
 use super::*;
 
@@ -36,38 +34,26 @@ impl TestGraph {
 
 impl DirectedGraph for TestGraph {
     type Node = usize;
-}
 
-impl WithStartNode for TestGraph {
-    fn start_node(&self) -> usize {
-        self.start_node
+    fn num_nodes(&self) -> usize {
+        self.num_nodes
     }
 }
 
-impl WithNumNodes for TestGraph {
-    fn num_nodes(&self) -> usize {
-        self.num_nodes
+impl StartNode for TestGraph {
+    fn start_node(&self) -> usize {
+        self.start_node
     }
 }
 
-impl WithPredecessors for TestGraph {
-    fn predecessors(&self, node: usize) -> <Self as GraphPredecessors<'_>>::Iter {
+impl Predecessors for TestGraph {
+    fn predecessors(&self, node: usize) -> impl Iterator<Item = Self::Node> {
         self.predecessors[&node].iter().cloned()
     }
 }
 
-impl WithSuccessors for TestGraph {
-    fn successors(&self, node: usize) -> <Self as GraphSuccessors<'_>>::Iter {
+impl Successors for TestGraph {
+    fn successors(&self, node: usize) -> impl Iterator<Item = Self::Node> {
         self.successors[&node].iter().cloned()
     }
 }
-
-impl<'graph> GraphPredecessors<'graph> for TestGraph {
-    type Item = usize;
-    type Iter = iter::Cloned<slice::Iter<'graph, usize>>;
-}
-
-impl<'graph> GraphSuccessors<'graph> for TestGraph {
-    type Item = usize;
-    type Iter = iter::Cloned<slice::Iter<'graph, usize>>;
-}
diff --git a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
index 00f6266ce1d..26c86469fad 100644
--- a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
@@ -1,4 +1,4 @@
-use crate::graph::{DirectedGraph, GraphSuccessors, WithNumEdges, WithNumNodes, WithSuccessors};
+use crate::graph::{DirectedGraph, NumEdges, Successors};
 use rustc_index::{Idx, IndexVec};
 
 #[cfg(test)]
@@ -80,28 +80,20 @@ impl<N: Idx + Ord> VecGraph<N> {
 
 impl<N: Idx> DirectedGraph for VecGraph<N> {
     type Node = N;
-}
 
-impl<N: Idx> WithNumNodes for VecGraph<N> {
     fn num_nodes(&self) -> usize {
         self.node_starts.len() - 1
     }
 }
 
-impl<N: Idx> WithNumEdges for VecGraph<N> {
+impl<N: Idx> NumEdges for VecGraph<N> {
     fn num_edges(&self) -> usize {
         self.edge_targets.len()
     }
 }
 
-impl<'graph, N: Idx> GraphSuccessors<'graph> for VecGraph<N> {
-    type Item = N;
-
-    type Iter = std::iter::Cloned<std::slice::Iter<'graph, N>>;
-}
-
-impl<N: Idx + Ord> WithSuccessors for VecGraph<N> {
-    fn successors(&self, node: N) -> <Self as GraphSuccessors<'_>>::Iter {
+impl<N: Idx + Ord> Successors for VecGraph<N> {
+    fn successors(&self, node: N) -> impl Iterator<Item = Self::Node> {
         self.successors(node).iter().cloned()
     }
 }
diff --git a/compiler/rustc_data_structures/src/graph/vec_graph/tests.rs b/compiler/rustc_data_structures/src/graph/vec_graph/tests.rs
index 7c866da6009..87c8d25f094 100644
--- a/compiler/rustc_data_structures/src/graph/vec_graph/tests.rs
+++ b/compiler/rustc_data_structures/src/graph/vec_graph/tests.rs
@@ -1,3 +1,5 @@
+use crate::graph;
+
 use super::*;
 
 fn create_graph() -> VecGraph<usize> {
@@ -37,6 +39,6 @@ fn successors() {
 #[test]
 fn dfs() {
     let graph = create_graph();
-    let dfs: Vec<_> = graph.depth_first_search(0).collect();
+    let dfs: Vec<_> = graph::depth_first_search(&graph, 0).collect();
     assert_eq!(dfs, vec![0, 1, 3, 4, 2]);
 }
diff --git a/compiler/rustc_data_structures/src/sip128.rs b/compiler/rustc_data_structures/src/sip128.rs
index 4a0ed87f77c..4c9acfe0f71 100644
--- a/compiler/rustc_data_structures/src/sip128.rs
+++ b/compiler/rustc_data_structures/src/sip128.rs
@@ -1,5 +1,8 @@
 //! This is a copy of `core::hash::sip` adapted to providing 128 bit hashes.
 
+// This code is very hot and uses lots of arithmetic, avoid overflow checks for performance.
+// See https://github.com/rust-lang/rust/pull/119440#issuecomment-1874255727
+use rustc_serialize::int_overflow::{DebugStrictAdd, DebugStrictSub};
 use std::hash::Hasher;
 use std::mem::{self, MaybeUninit};
 use std::ptr;
@@ -103,19 +106,19 @@ unsafe fn copy_nonoverlapping_small(src: *const u8, dst: *mut u8, count: usize)
         }
 
         let mut i = 0;
-        if i + 3 < count {
+        if i.debug_strict_add(3) < count {
             ptr::copy_nonoverlapping(src.add(i), dst.add(i), 4);
-            i += 4;
+            i = i.debug_strict_add(4);
         }
 
-        if i + 1 < count {
+        if i.debug_strict_add(1) < count {
             ptr::copy_nonoverlapping(src.add(i), dst.add(i), 2);
-            i += 2
+            i = i.debug_strict_add(2)
         }
 
         if i < count {
             *dst.add(i) = *src.add(i);
-            i += 1;
+            i = i.debug_strict_add(1);
         }
 
         debug_assert_eq!(i, count);
@@ -211,14 +214,14 @@ impl SipHasher128 {
         debug_assert!(nbuf < BUFFER_SIZE);
         debug_assert!(nbuf + LEN < BUFFER_WITH_SPILL_SIZE);
 
-        if nbuf + LEN < BUFFER_SIZE {
+        if nbuf.debug_strict_add(LEN) < BUFFER_SIZE {
             unsafe {
                 // The memcpy call is optimized away because the size is known.
                 let dst = (self.buf.as_mut_ptr() as *mut u8).add(nbuf);
                 ptr::copy_nonoverlapping(bytes.as_ptr(), dst, LEN);
             }
 
-            self.nbuf = nbuf + LEN;
+            self.nbuf = nbuf.debug_strict_add(LEN);
 
             return;
         }
@@ -265,8 +268,9 @@ impl SipHasher128 {
             // This function should only be called when the write fills the buffer.
             // Therefore, when LEN == 1, the new `self.nbuf` must be zero.
             // LEN is statically known, so the branch is optimized away.
-            self.nbuf = if LEN == 1 { 0 } else { nbuf + LEN - BUFFER_SIZE };
-            self.processed += BUFFER_SIZE;
+            self.nbuf =
+                if LEN == 1 { 0 } else { nbuf.debug_strict_add(LEN).debug_strict_sub(BUFFER_SIZE) };
+            self.processed = self.processed.debug_strict_add(BUFFER_SIZE);
         }
     }
 
@@ -277,7 +281,7 @@ impl SipHasher128 {
         let nbuf = self.nbuf;
         debug_assert!(nbuf < BUFFER_SIZE);
 
-        if nbuf + length < BUFFER_SIZE {
+        if nbuf.debug_strict_add(length) < BUFFER_SIZE {
             unsafe {
                 let dst = (self.buf.as_mut_ptr() as *mut u8).add(nbuf);
 
@@ -289,7 +293,7 @@ impl SipHasher128 {
                 }
             }
 
-            self.nbuf = nbuf + length;
+            self.nbuf = nbuf.debug_strict_add(length);
 
             return;
         }
@@ -315,7 +319,7 @@ impl SipHasher128 {
             // This function should only be called when the write fills the buffer,
             // so we know that there is enough input to fill the current element.
             let valid_in_elem = nbuf % ELEM_SIZE;
-            let needed_in_elem = ELEM_SIZE - valid_in_elem;
+            let needed_in_elem = ELEM_SIZE.debug_strict_sub(valid_in_elem);
 
             let src = msg.as_ptr();
             let dst = (self.buf.as_mut_ptr() as *mut u8).add(nbuf);
@@ -327,7 +331,7 @@ impl SipHasher128 {
             // ELEM_SIZE` to show the compiler that this loop's upper bound is > 0.
             // We know that is true, because last step ensured we have a full
             // element in the buffer.
-            let last = nbuf / ELEM_SIZE + 1;
+            let last = (nbuf / ELEM_SIZE).debug_strict_add(1);
 
             for i in 0..last {
                 let elem = self.buf.get_unchecked(i).assume_init().to_le();
@@ -338,7 +342,7 @@ impl SipHasher128 {
 
             // Process the remaining element-sized chunks of input.
             let mut processed = needed_in_elem;
-            let input_left = length - processed;
+            let input_left = length.debug_strict_sub(processed);
             let elems_left = input_left / ELEM_SIZE;
             let extra_bytes_left = input_left % ELEM_SIZE;
 
@@ -347,7 +351,7 @@ impl SipHasher128 {
                 self.state.v3 ^= elem;
                 Sip13Rounds::c_rounds(&mut self.state);
                 self.state.v0 ^= elem;
-                processed += ELEM_SIZE;
+                processed = processed.debug_strict_add(ELEM_SIZE);
             }
 
             // Copy remaining input into start of buffer.
@@ -356,7 +360,7 @@ impl SipHasher128 {
             copy_nonoverlapping_small(src, dst, extra_bytes_left);
 
             self.nbuf = extra_bytes_left;
-            self.processed += nbuf + processed;
+            self.processed = self.processed.debug_strict_add(nbuf.debug_strict_add(processed));
         }
     }
 
@@ -394,7 +398,7 @@ impl SipHasher128 {
         };
 
         // Finalize the hash.
-        let length = self.processed + self.nbuf;
+        let length = self.processed.debug_strict_add(self.nbuf);
         let b: u64 = ((length as u64 & 0xff) << 56) | elem;
 
         state.v3 ^= b;