From 07497ce2c529eeb3045b35ae20eba50409cdf608 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Sat, 16 Nov 2024 22:03:55 +0100
Subject: [PATCH] perf: `get_kind_tree_root` result caching added

---
 src/core/include/mp-units/framework/quantity_spec.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/core/include/mp-units/framework/quantity_spec.h b/src/core/include/mp-units/framework/quantity_spec.h
index 835ae2c9..7d99f053 100644
--- a/src/core/include/mp-units/framework/quantity_spec.h
+++ b/src/core/include/mp-units/framework/quantity_spec.h
@@ -1476,7 +1476,7 @@ template<typename Self, NamedQuantitySpec auto QS, auto... Args>
 }
 
 template<QuantitySpec Q>
-[[nodiscard]] consteval QuantitySpec auto get_kind_tree_root(Q q)
+[[nodiscard]] consteval QuantitySpec auto get_kind_tree_root_impl(Q q)
 {
   auto defined_as_kind = []<typename QQ>(QQ qq) {
     if constexpr (requires { defined_as_kind_impl(qq); })
@@ -1501,6 +1501,15 @@ template<QuantitySpec Q>
   // NOLINTEND(bugprone-branch-clone)
 }
 
+template<QuantitySpec Q>
+constexpr QuantitySpec auto get_kind_tree_root_result = get_kind_tree_root_impl(Q{});
+
+template<QuantitySpec Q>
+[[nodiscard]] consteval QuantitySpec auto get_kind_tree_root(Q)
+{
+  return get_kind_tree_root_result<Q>;
+}
+
 }  // namespace detail
 
 MP_UNITS_EXPORT_BEGIN