From 6872117bae6bf63de8ab86e89c3875f53675fa85 Mon Sep 17 00:00:00 2001
From: Chip Hogg <chogg@aurora.tech>
Date: Sat, 19 Mar 2022 17:35:20 +0000
Subject: [PATCH] Replace `reduce` with bespoke implementation

If _this_ isn't `constexpr` compatible, I'm going to propose removing
support for the MacOS clang build.
---
 src/core/include/units/bits/prime.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/core/include/units/bits/prime.h b/src/core/include/units/bits/prime.h
index 648dcce8..585a3b50 100644
--- a/src/core/include/units/bits/prime.h
+++ b/src/core/include/units/bits/prime.h
@@ -101,7 +101,11 @@ constexpr auto coprimes_up_to(std::size_t n, const std::array<std::size_t, N>& b
 template<std::size_t N>
 constexpr std::size_t product(const std::array<std::size_t, N>& values)
 {
-  return std::reduce(values.begin(), values.end(), std::size_t{1}, std::multiplies{});
+  std::size_t product = 1;
+  for (const auto& v : values) {
+    product *= v;
+  }
+  return product;
 }
 
 // A configurable instantiation of the "wheel factorization" algorithm [1] for prime numbers.