From 45256520e1b076fdfb8c32be38c77b88f5bbeb74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johannes=20M=C3=BCller?= <straightshoota@gmail.com>
Date: Wed, 27 Nov 2024 12:06:05 +0100
Subject: [PATCH] Optimize `Slice#<=>` and `#==` with reference check

---
 src/slice.cr | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/slice.cr b/src/slice.cr
index ace008e53e05..266d7bb31249 100644
--- a/src/slice.cr
+++ b/src/slice.cr
@@ -825,6 +825,9 @@ struct Slice(T)
   # Bytes[1, 2] <=> Bytes[1, 2] # => 0
   # ```
   def <=>(other : Slice(U)) forall U
+    # If both slices are identical references, we can skip the memory comparison.
+    return 0 if same?(other)
+
     min_size = Math.min(size, other.size)
     {% if T == UInt8 && U == UInt8 %}
       cmp = to_unsafe.memcmp(other.to_unsafe, min_size)
@@ -847,8 +850,13 @@ struct Slice(T)
   # Bytes[1, 2] == Bytes[1, 2, 3] # => false
   # ```
   def ==(other : Slice(U)) : Bool forall U
+    # If both slices are of different sizes, they cannot be equal.
     return false if size != other.size
 
+    # If both slices are identical references, we can skip the memory comparison.
+    # Not using `same?` here because we have already compared sizes.
+    return true if to_unsafe == other.to_unsafe
+
     {% if T == UInt8 && U == UInt8 %}
       to_unsafe.memcmp(other.to_unsafe, size) == 0
     {% else %}