From a4b7ed7a42c716ab9f05e351f003d589124fd55d Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:18:58 +0200
Subject: Adding upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../rustc_data_structures/src/graph/dominators/mod.rs   | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

(limited to 'compiler/rustc_data_structures/src/graph/dominators')

diff --git a/compiler/rustc_data_structures/src/graph/dominators/mod.rs b/compiler/rustc_data_structures/src/graph/dominators/mod.rs
index 00913a483..471457f61 100644
--- a/compiler/rustc_data_structures/src/graph/dominators/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/dominators/mod.rs
@@ -22,7 +22,7 @@ struct PreOrderFrame<Iter> {
 }
 
 rustc_index::newtype_index! {
-    struct PreorderIndex { .. }
+    struct PreorderIndex {}
 }
 
 pub fn dominators<G: ControlFlowGraph>(graph: G) -> Dominators<G::Node> {
@@ -135,7 +135,10 @@ pub fn dominators<G: ControlFlowGraph>(graph: G) -> Dominators<G::Node> {
         // This loop computes the semi[w] for w.
         semi[w] = w;
         for v in graph.predecessors(pre_order_to_real[w]) {
-            let v = real_to_pre_order[v].unwrap();
+            // Reachable vertices may have unreachable predecessors, so ignore any of them
+            let Some(v) = real_to_pre_order[v] else {
+                continue
+            };
 
             // eval returns a vertex x from which semi[x] is minimum among
             // vertices semi[v] +> x *> v.
@@ -268,21 +271,17 @@ pub struct Dominators<N: Idx> {
 }
 
 impl<Node: Idx> Dominators<Node> {
-    pub fn dummy() -> Self {
-        Self { post_order_rank: IndexVec::new(), immediate_dominators: IndexVec::new() }
-    }
-
     pub fn is_reachable(&self, node: Node) -> bool {
         self.immediate_dominators[node].is_some()
     }
 
     pub fn immediate_dominator(&self, node: Node) -> Node {
-        assert!(self.is_reachable(node), "node {:?} is not reachable", node);
+        assert!(self.is_reachable(node), "node {node:?} is not reachable");
         self.immediate_dominators[node].unwrap()
     }
 
     pub fn dominators(&self, node: Node) -> Iter<'_, Node> {
-        assert!(self.is_reachable(node), "node {:?} is not reachable", node);
+        assert!(self.is_reachable(node), "node {node:?} is not reachable");
         Iter { dominators: self, node: Some(node) }
     }
 
@@ -296,7 +295,7 @@ impl<Node: Idx> Dominators<Node> {
     /// of two unrelated nodes will also be consistent, but otherwise the order has no
     /// meaning.) This method cannot be used to determine if either Node dominates the other.
     pub fn rank_partial_cmp(&self, lhs: Node, rhs: Node) -> Option<Ordering> {
-        self.post_order_rank[lhs].partial_cmp(&self.post_order_rank[rhs])
+        self.post_order_rank[rhs].partial_cmp(&self.post_order_rank[lhs])
     }
 }
 
-- 
cgit v1.2.3