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@xxxxxxx> 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@xxxxxxx> --- 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
