From 2b4a858f0da83c5b0c4491d356218e387becf13c Mon Sep 17 00:00:00 2001
From: Vladislav Shchapov <phprus@gmail.com>
Date: Sun, 13 Feb 2022 23:19:59 +0500
Subject: [PATCH] Clz builtin may be not constexpr (Issue #2761)

---
 include/fmt/format.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index afcba52ed043..b97930ffddb7 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -991,7 +991,7 @@ FMT_CONSTEXPR20 inline auto count_digits(uint64_t n) -> int {
 template <int BITS, typename UInt>
 FMT_CONSTEXPR auto count_digits(UInt n) -> int {
 #ifdef FMT_BUILTIN_CLZ
-  if (num_bits<UInt>() == 32)
+  if (!is_constant_evaluated() && num_bits<UInt>() == 32)
     return (FMT_BUILTIN_CLZ(static_cast<uint32_t>(n) | 1) ^ 31) / BITS + 1;
 #endif
   // Lambda avoids unreachable code warnings from NVHPC.