Date: Tue, 31 Aug 2010 13:10:09 GMT From: Tijl Coosemans <tijl@coosemans.org> To: freebsd-bugs@FreeBSD.org Subject: Re: gnu/148926: [patch] make gcc generate i486 code by default Message-ID: <201008311310.o7VDA9A2006039@freefall.freebsd.org>
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The following reply was made to PR gnu/148926; it has been noted by GNATS.
From: Tijl Coosemans <tijl@coosemans.org>
To: bug-followup@freebsd.org, tech@askold.net
Cc:
Subject: Re: gnu/148926: [patch] make gcc generate i486 code by default
Date: Tue, 31 Aug 2010 14:56:36 +0200
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Hi Yuri,
On my system, it seems gcc already compiles for i486 by default. The
output of "cc -E -dM - < /dev/null" shows that __i486__ is defined and
atomic builtins such as __sync_fetch_and_add are defined and produce
i486 instructions. Only when you explicitly specify -march=i386 does
gcc produce i386 code.
However, it does look like libstdc++ can be optimised somewhat now that
FreeBSD doesn't support the 80386 anymore. Can you test the attached
patch and verify that it accomplishes what you want?
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diff --git a/gnu/lib/libstdc++/Makefile b/gnu/lib/libstdc++/Makefile
index e0a7bb2..56ca626 100644
=2D-- a/gnu/lib/libstdc++/Makefile
+++ b/gnu/lib/libstdc++/Makefile
@@ -83,7 +83,7 @@ ATOMICITY_H=3D ${SRCDIR}/config/cpu/${MARCHDIR}/atomicity=
=2Eh
ATOMICITY_H=3D ${SRCDIR}/config/cpu/generic/atomicity_mutex/atomicity.h
.endif
=20
=2D.if ${MACHINE_ARCH} =3D=3D "amd64"
+.if ${MACHINE_ARCH} =3D=3D "amd64" || ${MACHINE_ARCH} =3D=3D "i386"
.if exists(${SRCDIR}/config/cpu/generic/atomicity_builtins/atomicity.h)
ATOMICITY_H=3D ${SRCDIR}/config/cpu/generic/atomicity_builtins/atomicity.h
.endif
diff --git a/gnu/lib/libstdc++/config.h b/gnu/lib/libstdc++/config.h
index de4641d..8bc099f 100644
=2D-- a/gnu/lib/libstdc++/config.h
+++ b/gnu/lib/libstdc++/config.h
@@ -671,7 +671,7 @@
/* #undef VERSION */
=20
/* Define if builtin atomic operations are supported on this host. */
=2D#if defined(__amd64__)
+#if defined(__amd64__) || defined(__i386__)
#define _GLIBCXX_ATOMIC_BUILTINS 1
#endif
=20
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