From f5231e0677e51c7aa8ec767b7f184b3d9bb85128 Mon Sep 17 00:00:00 2001
From: Mel Henning <mhenning@darkrefraction.com>
Date: Mon, 12 May 2025 14:58:49 -0400
Subject: [PATCH] nak: Also use rustc-hash for UnionFind

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34865>
---
 src/nouveau/compiler/nak/assign_regs.rs |  4 ++--
 src/nouveau/compiler/nak/repair_ssa.rs  |  4 ++--
 src/nouveau/compiler/nak/union_find.rs  | 28 +++++++++++++------------
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/nouveau/compiler/nak/assign_regs.rs b/src/nouveau/compiler/nak/assign_regs.rs
index 5c3eee9ff3c..e0cbaa2b2e0 100644
--- a/src/nouveau/compiler/nak/assign_regs.rs
+++ b/src/nouveau/compiler/nak/assign_regs.rs
@@ -7,7 +7,7 @@ use crate::liveness::{BlockLiveness, Liveness, SimpleLiveness};
 use crate::union_find::UnionFind;
 
 use compiler::bitset::BitSet;
-use rustc_hash::{FxHashMap, FxHashSet};
+use rustc_hash::{FxBuildHasher, FxHashMap, FxHashSet};
 use std::cmp::{max, min, Ordering};
 
 struct KillSet {
@@ -164,7 +164,7 @@ impl SSAUseMap {
 ///     Architectures and Synthesis for Embedded Systems (CASES), Taipei,
 ///     Taiwan, 2011, pp. 45-54, doi: 10.1145/2038698.2038708.
 struct PhiWebs {
-    uf: UnionFind<SSAValue>,
+    uf: UnionFind<SSAValue, FxBuildHasher>,
     assignments: FxHashMap<SSAValue, u32>,
 }
 
diff --git a/src/nouveau/compiler/nak/repair_ssa.rs b/src/nouveau/compiler/nak/repair_ssa.rs
index e1b38677453..d33cba15506 100644
--- a/src/nouveau/compiler/nak/repair_ssa.rs
+++ b/src/nouveau/compiler/nak/repair_ssa.rs
@@ -5,7 +5,7 @@ use crate::ir::*;
 use crate::union_find::UnionFind;
 
 use compiler::bitset::BitSet;
-use rustc_hash::FxHashMap;
+use rustc_hash::{FxBuildHasher, FxHashMap};
 use std::cell::RefCell;
 use std::cmp::Reverse;
 use std::collections::BinaryHeap;
@@ -257,7 +257,7 @@ impl Function {
 
         // For loop back-edges, we inserted a phi whether we need one or not.
         // We want to eliminate any redundant phis.
-        let mut ssa_map = UnionFind::new();
+        let mut ssa_map = UnionFind::<SSAValue, FxBuildHasher>::new();
         if cfg.has_loop() {
             let mut to_do = true;
             while to_do {
diff --git a/src/nouveau/compiler/nak/union_find.rs b/src/nouveau/compiler/nak/union_find.rs
index fb727ec6669..360c858109e 100644
--- a/src/nouveau/compiler/nak/union_find.rs
+++ b/src/nouveau/compiler/nak/union_find.rs
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: MIT
 
 use std::collections::HashMap;
-use std::hash::Hash;
+use std::hash::{BuildHasher, Hash};
 
 #[derive(Copy, Clone)]
 struct Root<X: Copy> {
@@ -24,12 +24,12 @@ enum Node<X: Copy> {
 /// Robert E. Tarjan and Jan van Leeuwen. 1984. Worst-case Analysis of Set
 ///     Union Algorithms. J. ACM 31, 2 (April 1984), 245–281.
 ///     <https://doi.org/10.1145/62.2160>
-pub struct UnionFind<X: Copy + Hash + Eq> {
-    idx_map: HashMap<X, usize>,
+pub struct UnionFind<X: Copy + Hash + Eq, H: BuildHasher + Default> {
+    idx_map: HashMap<X, usize, H>,
     nodes: Vec<Node<X>>,
 }
 
-impl<X: Copy + Hash + Eq> UnionFind<X> {
+impl<X: Copy + Hash + Eq, H: BuildHasher + Default> UnionFind<X, H> {
     /// Create a new union-find structure
     ///
     /// At initialization, each possible value is in its own set
@@ -128,7 +128,9 @@ mod tests {
     use crate::union_find::Node;
     use crate::union_find::UnionFind;
     use std::cmp::max;
+    use std::hash::BuildHasher;
     use std::hash::Hash;
+    use std::hash::RandomState;
 
     fn ceil_log2(x: usize) -> u32 {
         assert!(x > 0);
@@ -140,13 +142,13 @@ mod tests {
         size: usize,
     }
 
-    pub struct HeightCalc<'a, X: Copy + Hash + Eq> {
-        uf: &'a UnionFind<X>,
+    pub struct HeightCalc<'a, X: Copy + Hash + Eq, H: BuildHasher + Default> {
+        uf: &'a UnionFind<X, H>,
         downward_edges: Vec<Vec<usize>>,
     }
 
-    impl<'a, X: Copy + Hash + Eq> HeightCalc<'a, X> {
-        fn new(uf: &'a UnionFind<X>) -> Self {
+    impl<'a, X: Copy + Hash + Eq, H: BuildHasher + Default> HeightCalc<'a, X, H> {
+        fn new(uf: &'a UnionFind<X, H>) -> Self {
             let mut downward_edges: Vec<Vec<usize>> =
                 uf.nodes.iter().map(|_| Vec::new()).collect();
             for (i, node) in uf.nodes.iter().enumerate() {
@@ -194,14 +196,14 @@ mod tests {
             return max_height;
         }
 
-        pub fn check(uf: &'a UnionFind<X>) -> u32 {
+        pub fn check(uf: &'a UnionFind<X, H>) -> u32 {
             HeightCalc::new(uf).check_roots()
         }
     }
 
     #[test]
     fn test_basic() {
-        let mut f = UnionFind::new();
+        let mut f = UnionFind::<u32, RandomState>::new();
         assert_eq!(f.find(10), 10);
         assert_eq!(f.find(12), 12);
 
@@ -241,7 +243,7 @@ mod tests {
 
     #[test]
     fn test_chain_a_height() {
-        let mut f = UnionFind::new();
+        let mut f = UnionFind::<u32, RandomState>::new();
         for i in 0..1000 {
             f.union(i, i + 1);
             HeightCalc::check(&f);
@@ -251,7 +253,7 @@ mod tests {
 
     #[test]
     fn test_chain_b_height() {
-        let mut f = UnionFind::new();
+        let mut f = UnionFind::<u32, RandomState>::new();
         for i in 0..1000 {
             f.union(i + 1, i);
             HeightCalc::check(&f);
@@ -264,7 +266,7 @@ mod tests {
         let height = 8;
         let count = 1 << height;
 
-        let mut f = UnionFind::new();
+        let mut f = UnionFind::<usize, RandomState>::new();
         for current_height in 0..height {
             let stride = 1 << current_height;
             for i in (0..count).step_by(2 * stride) {