From 8a8f4825a3eb93276f7e693c3c597619a7c6c1e5 Mon Sep 17 00:00:00 2001
From: Alex Dewar <a.dewar@imperial.ac.uk>
Date: Thu, 2 May 2024 14:46:57 +0100
Subject: [PATCH] Fix: isnan() shouldn't cause FP exceptions

Fixes #3948.
---
 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 f4b2c53d13b3..95df0ad00d3b 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -2695,7 +2695,7 @@ FMT_CONSTEXPR20 auto write_float(OutputIt out, const DecimalFP& f,
 }
 
 template <typename T> constexpr auto isnan(T value) -> bool {
-  return !(value >= value);  // std::isnan doesn't support __float128.
+  return value != value;  // std::isnan doesn't support __float128.
 }
 
 template <typename T, typename Enable = void>