commit 5c56bcc8338881fa2b75538bef6c29551076ffd7
Author: Andriy Gapon <avg@icyb.net.ua>
Date:   Sun Oct 7 23:08:11 2012 +0300

    boot: use -march=i386 for both i386 and amd64 builds
    
    .. so that identical binaries are produced for both architectures.
    Previously i386 used default setting which were equivalent to
    -march=i486 -mtune generic.
    The only difference is using smaller but slower "leave" instructions.

diff --git a/sys/boot/efi/Makefile.inc b/sys/boot/efi/Makefile.inc
index 7e75a6c..7446d31 100644
--- a/sys/boot/efi/Makefile.inc
+++ b/sys/boot/efi/Makefile.inc
@@ -2,8 +2,12 @@
 
 BINDIR?=	/boot
 
+.if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"
+CFLAGS+=        -march=i386
+.endif
+
 .if ${MACHINE_CPUARCH} == "amd64"
-CFLAGS+=        -m32 -march=i386
+CFLAGS+=        -m32
 ACFLAGS+=       -m32
 LDFLAGS+=       -m elf_i386_fbsd
 AFLAGS+=        --32
diff --git a/sys/boot/ficl/Makefile b/sys/boot/ficl/Makefile
index 1f8de9b..971faa7 100644
--- a/sys/boot/ficl/Makefile
+++ b/sys/boot/ficl/Makefile
@@ -8,6 +8,7 @@ SRCS=		${BASE_SRCS} sysdep.c softcore.c
 CLEANFILES=	softcore.c testmain testmain.o
 CFLAGS+=	-ffreestanding
 .if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"
+CFLAGS+=	-march=i386
 CFLAGS+=	-mpreferred-stack-boundary=2
 CFLAGS+=	-mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 -msoft-float
 .endif
@@ -39,7 +40,7 @@ SOFTWORDS=	softcore.fr jhlocal.fr marker.fr freebsd.fr ficllocal.fr \
 #SOFTWORDS+=	oo.fr classes.fr
 
 .if ${MACHINE_CPUARCH} == "amd64"
-CFLAGS+=	-m32 -march=i386 -I.
+CFLAGS+=	-m32 -I.
 .endif
 
 .if ${MACHINE_ARCH} == "powerpc64"
diff --git a/sys/boot/i386/Makefile.inc b/sys/boot/i386/Makefile.inc
index 0cad7d2..f5faec7 100644
--- a/sys/boot/i386/Makefile.inc
+++ b/sys/boot/i386/Makefile.inc
@@ -5,12 +5,12 @@
 BINDIR?=	/boot
 
 LOADER_ADDRESS?=0x200000
-CFLAGS+=	-ffreestanding -mpreferred-stack-boundary=2 \
+CFLAGS+=	-march=i386 -ffreestanding -mpreferred-stack-boundary=2 \
 		-mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 -msoft-float
 LDFLAGS+=	-nostdlib
 
 .if ${MACHINE_CPUARCH} == "amd64"
-CFLAGS+=	-m32 -march=i386
+CFLAGS+=	-m32
 ACFLAGS+=	-m32
 LDFLAGS+=	-m elf_i386_fbsd
 AFLAGS+=	--32
diff --git a/sys/boot/userboot/ficl/Makefile b/sys/boot/userboot/ficl/Makefile
index af5d1461..42b9309 100644
--- a/sys/boot/userboot/ficl/Makefile
+++ b/sys/boot/userboot/ficl/Makefile
@@ -12,6 +12,7 @@ SRCS=		${BASE_SRCS} sysdep.c softcore.c
 CLEANFILES=	softcore.c testmain testmain.o
 CFLAGS+=	-ffreestanding -fPIC
 .if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"
+#CFLAGS+=	-march=i386
 CFLAGS+=	-mno-mmx -mno-3dnow -mno-sse -mno-sse2
 .endif
 .if ${MACHINE_CPUARCH} == "i386"
@@ -46,7 +47,7 @@ SOFTWORDS=	softcore.fr jhlocal.fr marker.fr freebsd.fr ficllocal.fr \
 #SOFTWORDS+=	oo.fr classes.fr
 
 #.if ${MACHINE_CPUARCH} == "amd64"
-#CFLAGS+=	-m32 -march=i386 -I.
+#CFLAGS+=	-m32 -I.
 #.endif
 
 .if ${MACHINE_ARCH} == "powerpc64"
diff --git a/sys/boot/zfs/Makefile b/sys/boot/zfs/Makefile
index ff423a0..9b900e4 100644
--- a/sys/boot/zfs/Makefile
+++ b/sys/boot/zfs/Makefile
@@ -12,6 +12,7 @@ CFLAGS+=	-I${.CURDIR}/../../cddl/boot/zfs
 
 CFLAGS+=	-ffreestanding
 .if ${MACHINE_CPUARCH} == "i386" || ${MACHINE_CPUARCH} == "amd64"
+CFLAGS+=	-march=i386
 CFLAGS+=	-mpreferred-stack-boundary=2
 CFLAGS+=	-mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 -msoft-float
 .endif
@@ -19,7 +20,7 @@ CFLAGS+=	-mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 -msoft-float
 CFLAGS+=	-msoft-float
 .endif
 .if ${MACHINE_CPUARCH} == "amd64"
-CFLAGS+=	-m32 -march=i386
+CFLAGS+=	-m32
 .endif
 
 CFLAGS+=	-Wformat -Wall