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Re: [Qemu-devel] [PULL 03/13] target-ppc: Use 32-bit rotate instead of d

From: Richard Henderson
Subject: Re: [Qemu-devel] [PULL 03/13] target-ppc: Use 32-bit rotate instead of deposit + 64-bit rotate
Date: Thu, 16 Jun 2016 12:04:04 -0700
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0

On 06/15/2016 10:19 PM, David Gibson wrote:
> On Wed, Jun 15, 2016 at 10:17:19PM +1000, Anton Blanchard wrote:
>> Hi,
>>> From: Richard Henderson <address@hidden>
>>> A 32-bit rotate insn is more common on hosts than a deposit insn,
>>> and if the host has neither the result is truely horrific.
>>> At the same time, tidy up the temporaries within these functions,
>>> drop the over-use of "likely", drop some checks for identity that
>>> will also be checked by tcg-op.c functions, and special case mask
>>> without rotate within rlwinm.
>> This breaks masks that wrap:
>>         li      r3,-1
>>         li      r4,-1
>>         rlwnm   r3,r3,r4,22,8
>> We expect:
>> ffffffffff8003ff
>> But get:
>> ff8003ff
>> Anton
> Bother.  I've tentatively put a revert into ppc-for-2.7.  Richard, do
> you have a better idea how to fix it?

Please try the following.


Attachment: 0001-target-ppc-Fix-rlwimi-rlwinm-rlwnm.patch
Description: Text Data

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