From 4ed3ad59e96d3aee9c5251a3dfee32a68753cfd5 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Mon, 28 Oct 2024 15:24:18 +0100
Subject: [PATCH] Math: make sign() branchless and constexpr

---
 src/Magnum/Math/Functions.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/Magnum/Math/Functions.h b/src/Magnum/Math/Functions.h
index f358cd51c..2cd3c4594 100644
--- a/src/Magnum/Math/Functions.h
+++ b/src/Magnum/Math/Functions.h
@@ -399,10 +399,9 @@ template<std::size_t size, class T> inline Vector<size, T> clamp(const Vector<si
 
 Returns `1` if @p x > 0, `0` if @p x = 0 and `-1` if @p x < 0.
 */
-template<class T> inline typename std::enable_if<IsScalar<T>::value, UnderlyingTypeOf<T>>::type sign(T scalar) {
-    if(scalar > T(0)) return UnderlyingTypeOf<T>(1);
-    if(scalar < T(0)) return UnderlyingTypeOf<T>(-1);
-    return UnderlyingTypeOf<T>(0);
+template<class T> constexpr inline typename std::enable_if<IsScalar<T>::value, UnderlyingTypeOf<T>>::type sign(T x) {
+    using U = UnderlyingTypeOf<T>;
+    return U(U(bool(x > T(0))) - U(bool(x < T(0))));
 }
 
 /** @overload */