From: Jakub Jelinek <jakub@redhat.com>
To: Stefan Kanthak <stefan.kanthak@nexgo.de.zalov.cz>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Better __ashlDI3, __ashrDI3 and __lshrDI3 functions, plus fixed __bswapsi2 function
Date: Tue, 10 Nov 2020 19:26:52 +0100 [thread overview]
Message-ID: <20201110182652.GW3788@tucnak> (raw)
In-Reply-To: <116F1589A8244FB494091BCD4E6398AB@H270>
On Tue, Nov 10, 2020 at 06:59:30PM +0100, Stefan Kanthak via Gcc-patches wrote:
> The implementation of the __ashlDI3(), __ashrDI3() and __lshrDI3() functions
> is rather bad, it yields bad machine code at least on i386 and AMD64.
> Since GCC knows how to shift integers twice the register size these functions
> can be written as one-liners.
>
> The implementation of the __bswapsi2() function uses SIGNED instead of
> unsigned mask values; cf. __bswapdi2()
The 0xff000000 constant is unsigned, the others are signed, but that doesn't
really matter as the high bits are masked off.
Jakub
next prev parent reply other threads:[~2020-11-10 18:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-10 17:59 Stefan Kanthak
2020-11-10 18:08 ` Eric Botcazou
2020-11-10 19:44 ` Stefan Kanthak
2020-11-10 20:14 ` Jakub Jelinek
2020-11-10 21:09 ` Jeff Law
2020-11-10 21:17 ` Jakub Jelinek
2020-11-10 23:42 ` Jeff Law
2020-11-24 0:21 ` Jeff Law
2020-11-10 22:12 ` Jeff Law
2020-11-10 22:01 ` Jeff Law
2020-11-11 0:00 ` Andreas Schwab
2020-11-24 13:57 ` Stefan Kanthak
2020-11-24 14:34 ` Andreas Schwab
2020-11-24 15:40 ` Stefan Kanthak
2020-11-24 15:49 ` Andreas Schwab
2020-11-25 18:53 ` Jeff Law
2020-11-25 20:22 ` Stefan Kanthak
2020-11-25 20:42 ` Jakub Jelinek
2020-11-25 21:22 ` Stefan Kanthak
2020-11-25 22:06 ` Jeff Law
2020-11-25 23:06 ` Stefan Kanthak
2020-11-25 20:44 ` Jeff Law
2020-11-10 18:09 ` Jakub Jelinek
2020-11-10 18:32 ` Jeff Law
2020-11-10 18:26 ` Jakub Jelinek [this message]
2020-11-10 23:48 ` Jeff Law
2020-11-10 23:53 ` Jakub Jelinek
2020-11-11 8:33 ` Stefan Kanthak
2020-11-11 9:55 ` Jakub Jelinek
2020-11-11 17:54 ` Joseph Myers
2020-11-23 23:01 ` Jeff Law
2020-11-30 1:06 ` Jeff Law
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