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Subject: Re: [Qemu-devel] [Consult] tilegx: Is it a qemu's system bug?
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To: Chen Gang <xili_gchen_5257@hotmail.com>, Peter Maydell <peter.maydell@linaro.org>, Chris Metcalf <cmetcalf@ezchip.com>, =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= <afaerber@suse.de>, Riku Voipio <riku.voipio@iki.fi>, "walt@tilera.com" <walt@tilera.com>
Cc: qemu-devel <qemu-devel@nongnu.org>

On 04/25/2015 05:12 AM, Chen Gang wrote:
> Hello All:
> 
> I want to consult an issue I met below for the latest master branch, is
> it a qemu's bug? (it is about ctz/cnttz instruction for tilegx)
> 
>   OP: 
>    ld_i32 tmp0,env,$0xfffffffffffffffc
>    movi_i32 tmp1,$0x0
>    brcond_i32 tmp0,tmp1,ne,$L0
>    movi_i64 tmp3,$0x0                    /* Initialize tmp3 */
>    set_label $L1 
>    shr_i64 tmp2,r2,tmp3

You can't keep temporaries live across basic blocks.
That is, across set_label, br, or brcond.  In that case
you'd have to use tcg_new_local_temp() instead.

That said, you shouldn't open-code ctz but instead use
a helper function and use ctz64().


r~