From 4a919b1bbc00c8084aea2a4e8196d2b38e657946 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Thu, 29 Aug 2019 12:29:47 +0200
Subject: [PATCH] * src/floatfns.c: Check against __FINITE_MATH_ONLY__
 (bug#37140)

---
 src/floatfns.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/floatfns.c b/src/floatfns.c
index 0a85df47dec..49068bee770 100644
--- a/src/floatfns.c
+++ b/src/floatfns.c
@@ -48,6 +48,14 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 #include <count-leading-zeros.h>
 
+/* Emacs needs proper handling of ±inf; correct printing as well as
+   important packages depend on it.  Make sure the user didn't specify
+   -ffinite-math-only, either directly or implicitly with -Ofast or
+   -ffast-math.  */
+#if defined __FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__
+ #error Emacs cannot be built with -ffinite-math-only
+#endif
+
 /* Check that X is a floating point number.  */
 
 static void
-- 
2.39.2