From 26b44e651dedc2868027dcdc3ccf60f8ffbe0c25 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Tue, 6 Dec 2022 15:47:59 +0100
Subject: [PATCH] Change safe_{sub,add,mul} so they perform the operation only
 once

---
 luna/include/luna/SafeArithmetic.h | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/luna/include/luna/SafeArithmetic.h b/luna/include/luna/SafeArithmetic.h
index b0336d6d..31d59856 100644
--- a/luna/include/luna/SafeArithmetic.h
+++ b/luna/include/luna/SafeArithmetic.h
@@ -18,21 +18,27 @@ template <typename T> constexpr bool mul_will_overflow(T a, T b)
 
 template <typename T> Result<T> safe_add(T a, T b)
 {
-    if (add_will_overflow(a, b)) return err(EOVERFLOW);
+    T result;
 
-    return a + b;
+    if (__builtin_add_overflow(a, b, &result)) return err(EOVERFLOW);
+
+    return result;
 }
 
 template <typename T> Result<T> safe_sub(T a, T b)
 {
-    if (sub_will_overflow(a, b)) return err(EOVERFLOW);
+    T result;
 
-    return a - b;
+    if (__builtin_sub_overflow(a, b, &result)) return err(EOVERFLOW);
+
+    return result;
 }
 
 template <typename T> Result<T> safe_mul(T a, T b)
 {
-    if (mul_will_overflow(a, b)) return err(EOVERFLOW);
+    T result;
 
-    return a * b;
+    if (__builtin_mul_overflow(a, b, &result)) return err(EOVERFLOW);
+
+    return result;
 }
\ No newline at end of file