From 1efe86bb373525ffa08c26c6db94bfc542e96b6d Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Fri, 6 Dec 2013 21:44:13 +0000
Subject: [PATCH] Disallow optimizations which potentially remove boundary
 checks for signed values due to a compiler authors considering integer
 overflow as impossible.

The change follows suit of other projects taking the same measure.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
---
 sys/conf/kern.mk | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sys/conf/kern.mk b/sys/conf/kern.mk
index 2939a59cb0b..6e6ba92c4db 100644
--- a/sys/conf/kern.mk
+++ b/sys/conf/kern.mk
@@ -147,6 +147,12 @@ INLINE_LIMIT?=	8000
 #
 CFLAGS+=	-ffreestanding
 
+#
+# Do not allow a compiler to optimize out overflow checks for signed
+# types.
+#
+CFLAGS+=	-fno-strict-overflow
+
 #
 # GCC SSP support
 #