[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] i386: fix icount processing for repz instructio
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] i386: fix icount processing for repz instructions |
Date: |
Thu, 23 Oct 2014 22:19:15 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 |
On 10/23/2014 07:05 PM, Richard Henderson wrote:
> On 10/21/2014 06:03 AM, Pavel Dovgalyuk wrote:
>> + dc->repz_opt = dc->jmp_opt
>> + /* Do not optimize repz jumps at all in icount mode,
>> because
>> + rep movsS instructions are execured with different
>> paths
>> + in repz_opt and !repz_opt modes. The first one was
>> used
>> + always except single step mode. And this setting
>> + disables jumps optimization and control paths become
>> + equivalent in run and single step modes.
>> + Now there will be no jump optimization for repz in
>> + trace and replay modes and there will always be an
>> + additional step for ecx=0.
>> + */
>> + || use_icount;
>
> My aesthetics are offended by the placement of this comment. Please write
>
> /* Comment */
> dc->repz_opt = x || y;
>
> That said, surely that test should be !use_icount.
And "&& !use_icount", even (it becomes "|| use_icount" in the ifs)?
Paolo