From e3e0053fbe27a3c2e537f5ab5866aa620631d66f Mon Sep 17 00:00:00 2001
From: Johannes Stoelp <johannes.stoelp@gmail.com>
Date: Wed, 24 Aug 2022 18:29:49 +0200
Subject: gcc: Enhance builtin_expect description

---
 src/development/gcc.md | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'src')

diff --git a/src/development/gcc.md b/src/development/gcc.md
index 88e44fc..39ae753 100644
--- a/src/development/gcc.md
+++ b/src/development/gcc.md
@@ -29,6 +29,10 @@ Give the compiler a hint which branch is hot, so it can lay out the code
 accordingly to reduce number of jump instructions.
 See on [compiler explorer](https://godbolt.org/z/MbTHAP).
 
+The semantics of this hint are as follows, the compiler prioritises `expr ==
+cond`. So `__builtin_expect(expr, 0)` means that we expect the `expr` to be `0`
+most of the time.
+
 ```bash
 echo "
 extern void foo();
-- 
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