From: Oleg Endo <oleg.endo@t-online.de>
To: Stefan Franke <stefan@franke.ms>, gcc-help@gcc.gnu.org
Subject: Re: AW: optimizer discards sign information
Date: Thu, 11 Apr 2024 09:32:22 +0900 [thread overview]
Message-ID: <3ae43538e724dcbcd2a8cad2ac8248b73e17f7c7.camel@t-online.de> (raw)
In-Reply-To: <51BFC92A-35A4-4287-8FB0-F8258DAF0D9D@franke.ms>
On Wed, 2024-04-10 at 16:25 +0200, Stefan Franke wrote:
>
> Thank you for the detailed explanation.
> It still doesn't fit together, since if the compiler knows that it's unsigned, why does it emit code for sign extension on the m68k target?
>
> Well. Since there are enough explanations and my expectations are simply wrong consider this as closed.
>
>
By the way, on targets that can do widening multiplication the sign
extensions are omitted. E.g. on SH -- https://godbolt.org/z/7hr4njEx8
_foo:
mulu.w r4,r5
sts macl,r1
sts macl,r0
shll r1
rts
subc r1,r1
Best regards,
Oleg Endo
prev parent reply other threads:[~2024-04-11 0:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-10 8:52 stefan
2024-04-10 9:16 ` Alexander Monakov
2024-04-10 9:19 ` Xi Ruoyao
2024-04-10 9:40 ` LIU Hao
2024-04-10 9:44 ` Xi Ruoyao
2024-04-10 9:51 ` LIU Hao
2024-04-10 9:52 ` Xi Ruoyao
2024-04-10 10:07 ` LIU Hao
2024-04-10 10:17 ` Xi Ruoyao
2024-04-10 10:03 ` AW: " stefan
2024-04-10 10:34 ` Xi Ruoyao
2024-04-10 9:24 ` stefan
2024-04-10 9:49 ` stefan
2024-04-10 9:54 ` Xi Ruoyao
2024-04-10 9:57 ` LIU Hao
2024-04-10 10:03 ` Xi Ruoyao
2024-04-10 11:52 ` David Brown
2024-04-10 14:25 ` Stefan Franke
2024-04-10 16:51 ` David Brown
2024-04-11 0:32 ` Oleg Endo [this message]
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