From 1e139d5f540774853a6b74dce296c4c754022b51 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Sat, 24 Dec 2011 19:01:31 +0000
Subject: [PATCH] When building the kernel for amd64 with clang, don't attempt
 to use the -frename-registers option, as it is not supported.  No change for
 builds with gcc.

MFC after:	1 week
---
 sys/conf/kern.pre.mk | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index 6fff65c1b824..cbd0de5d300a 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -34,8 +34,12 @@ _MINUS_O=	-O2
 .endif
 .endif
 .if ${MACHINE_CPUARCH} == "amd64"
+.if ${CC:T:Mclang} != "clang"
 COPTFLAGS?=-O2 -frename-registers -pipe
 .else
+COPTFLAGS?=-O2 -pipe
+.endif
+.else
 COPTFLAGS?=${_MINUS_O} -pipe
 .endif
 .if !empty(COPTFLAGS:M-O[23s]) && empty(COPTFLAGS:M-fno-strict-aliasing)