From 8bfee9473a3796ed1fb4fbc2a06f566dd6a11e81 Mon Sep 17 00:00:00 2001
From: Maxime Chevalier-Boisvert <maxime.chevalierboisvert@shopify.com>
Date: Tue, 3 Dec 2024 15:26:02 -0500
Subject: [PATCH] Add dumb loop microbenchmark

This is a modified version of a microbenchmark circulated on
twitter by "TheDumbTechGuy". It's obviously not representative of
most Ruby code, but it does show areas where we could perform
much better with better inlining and better quality code
generation.
---
 benchmarks.yml            |  4 ++++
 benchmarks/loops-times.rb | 21 +++++++++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 benchmarks/loops-times.rb

diff --git a/benchmarks.yml b/benchmarks.yml
index 038bf2d8..65465a90 100644
--- a/benchmarks.yml
+++ b/benchmarks.yml
@@ -147,3 +147,7 @@ ruby-xor:
   desc: pure-Ruby string XOR microbenchmark, analogous to xorcist C extension.
   category: micro
   single_file: true
+loops-times:
+  desc: nested loop Integer#times and array access microbenchmark
+  category: micro
+  single_file: true
diff --git a/benchmarks/loops-times.rb b/benchmarks/loops-times.rb
new file mode 100644
index 00000000..485fa891
--- /dev/null
+++ b/benchmarks/loops-times.rb
@@ -0,0 +1,21 @@
+require_relative '../harness/loader'
+
+# Fix these values for determinism
+u = 5
+r = 7
+
+run_benchmark(10) do
+  a = Array.new(10000, 0)
+
+  4_000.times do |i|
+    4_000.times do |j|
+      a[i] += j % u
+    end
+    a[i] += r
+  end
+
+  result = a[r]
+  if result != 8007
+    raise "incorrect result"
+  end
+end