allwpilib/upstream_utils/llvm_patches/0013-MathExtras-add-Lerp-and-sgn.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: PJ Reiniger <pj.reiniger@gmail.com>
Date: Tue, 3 May 2022 22:50:24 -0400
Subject: [PATCH 13/34] MathExtras: add Lerp() and sgn()

---
 llvm/include/llvm/Support/MathExtras.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/llvm/include/llvm/Support/MathExtras.h b/llvm/include/llvm/Support/MathExtras.h
index b8e858f9c530e31430f824cc2d93ff1cc78a92f7..0735d9c9f756349a19c5aa2ec34ceca5d8274f16 100644
--- a/llvm/include/llvm/Support/MathExtras.h
+++ b/llvm/include/llvm/Support/MathExtras.h
@@ -764,6 +764,27 @@ using stack_float_t = volatile float;
 using stack_float_t = float;
 #endif
 
+// Typesafe implementation of the signum function.
+// Returns -1 if negative, 1 if positive, 0 if 0.
+template <typename T>
+constexpr int sgn(T val) {
+  return (T(0) < val) - (val < T(0));
+}
+
+/**
+ * Linearly interpolates between two values.
+ *
+ * @param startValue The start value.
+ * @param endValue The end value.
+ * @param t The fraction for interpolation.
+ *
+ * @return The interpolated value.
+ */
+template <typename T>
+constexpr T Lerp(const T& startValue, const T& endValue, double t) {
+  return startValue + (endValue - startValue) * t;
+}
+
 } // namespace llvm
 
 #endif