From: George Spelvin <lkml@sdf.org>
To: heiko.carstens@de.ibm.com, lkml@sdf.org
Cc: linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mips@vger.kernel.org, linux-alpha@vger.kernel.org
Subject: Re: CONFIG_ARCH_SUPPORTS_INT128: Why not mips, s390, powerpc, and alpha?
Date: Sat, 30 Mar 2019 13:00:17 GMT [thread overview]
Message-ID: <201903301300.x2UD0H0C020934@sdf.org> (raw)
In-Reply-To: <201903301030.x2UAUNOg026448@sdf.org>
I've been tracking down when "umulditi3" support was added to various
gcc platforms. So far, I've found:
ia64: 2005-07-28, gcc 4.1.0
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=102463
mips: 2008-06-09, gcc 4.4.0
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=136600
alpha: 2013-02-01, gcc 4.8.0
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=195668
s390: 2011-10-07, gcc 4.7.0
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=179647
ppc64: 2013-02-01, gcc 4.8.0
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=195667
Here's a revised s390 patch.
From e8ea8c0a5d618385049248649b8c13717b598a42 Mon Sep 17 00:00:00 2001
From: George Spelvin <lkml@sdf.org>
Date: Sat, 30 Mar 2019 10:27:14 +0000
Subject: [PATCH v2] s390: Enable CONFIG_ARCH_SUPPORTS_INT128 on 64-bit builds
If a platform supports a 64x64->128-bit widening multiply,
that allows more efficient scaling of 64-bit values in various
parts of the kernel. GCC advertises __int128 support with the
__INT128__ #define, but we care about efficient inline
support, so this is a separate flag.
For s390, that was added on 2011-10-07 by
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=179647
which is part of GCC 4.7.
Signed-off-by: George Spelvin <lkml@sdf.org>
---
arch/s390/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index ed554b09eb3f..6ddaee6573f4 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -372,6 +372,7 @@ endchoice
config 64BIT
def_bool y
+ select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 40700 || CC_IS_CLANG
config COMPAT
def_bool y
--
2.20.1
next prev parent reply other threads:[~2019-03-30 13:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-29 13:07 CONFIG_ARCH_SUPPORTS_INT128: Why not mips, s390, powerpc, and alpha? George Spelvin
2019-03-29 20:00 ` Michael Cree
2019-03-30 23:14 ` Segher Boessenkool
2019-03-29 20:25 ` Segher Boessenkool
2019-03-30 11:28 ` George Spelvin
2019-03-30 23:52 ` Segher Boessenkool
2019-03-30 8:43 ` Heiko Carstens
2019-03-30 10:30 ` George Spelvin
2019-03-30 13:00 ` George Spelvin [this message]
2019-03-31 0:30 ` Segher Boessenkool
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