From: Richard Henderson <rth@twiddle.net>
To: Laurent Vivier <laurent@vivier.eu>, qemu-devel@nongnu.org
Cc: schwab@linux-m68k.org, agraf@suse.de, gerg@uclinux.org
Subject: Re: [Qemu-devel] [PATCH 1/2] target-m68k: add 64bit mull
Date: Mon, 31 Oct 2016 13:11:19 -0600 [thread overview]
Message-ID: <666dd040-7283-1884-500a-55616e0af7ed@twiddle.net> (raw)
In-Reply-To: <927e758c-cc8a-8022-1295-83f1132ac84b@vivier.eu>
On 10/29/2016 02:36 AM, Laurent Vivier wrote:
>
>
> Le 29/10/2016 à 01:25, Richard Henderson a écrit :
>> On 10/28/2016 03:39 PM, Laurent Vivier wrote:
>>> + tcg_gen_movi_i32(QREG_CC_V, 0);
>>> + tcg_gen_mov_i32(QREG_CC_C, QREG_CC_V);
>>
>> movi CC, 0
>
> Just to know, could you explain why it is better?
They're independent sets?
The tcg optimizer *ought* to propagate the constant, but there's no reason to
force this to happen there.
r~
next prev parent reply other threads:[~2016-10-31 19:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-28 22:39 [Qemu-devel] [PATCH 0/2] 680x0 mul and div instructions Laurent Vivier
2016-10-28 22:39 ` [Qemu-devel] [PATCH 1/2] target-m68k: add 64bit mull Laurent Vivier
2016-10-28 23:25 ` Richard Henderson
2016-10-29 8:36 ` Laurent Vivier
2016-10-31 19:11 ` Richard Henderson [this message]
2016-10-28 22:39 ` [Qemu-devel] [PATCH 2/2] target-m68k: add 680x0 divu/divs variants Laurent Vivier
2016-10-28 22:59 ` Laurent Vivier
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