From: Aurelien Jarno <aurelien@aurel32.net>
To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 13/13] tcg: rework TCG ops flags
Date: Fri, 28 Sep 2012 01:08:05 +0200 [thread overview]
Message-ID: <20120927230805.GA22257@hall.aurel32.net> (raw)
In-Reply-To: <5064CC6F.90806@twiddle.net>
On Thu, Sep 27, 2012 at 03:00:15PM -0700, Richard Henderson wrote:
> On 09/27/2012 01:37 PM, Aurelien Jarno wrote:
> >> > I don't agree with SIDE_EFFECTS implying exceptions. How can "br" cause an
> >> > exception? Or for that matter "st_i32", recalling that we're not storing
> >> > to guest memory.
> > That's exactly why SIDE_EFFECTS has been removed from this op in the
> > previous patch.
>
> Well, you removed it from br, but not st.
Oh correct. st doesn't need one as it has zero output arguments, so it
won't be removed.
> > I think it implies exception, because I don't see why an op shouldn't be
> > removed otherwise (remember ops without outputs are never removed).
>
> In which case, because the non-qemu store insns cannot raise exceptions,
> there ought to be exactly zero instances of TCG_OPF_SIDE_EFFECTS remaining.
> At which point we simply ought to remove it.
>
I don't understand, the qemu/load store still need to keep this
TCG_OPF_SIDE_EFFECTS. Even a load to a dead output argument might
trigger a TLB miss exception, and thus should be fixed.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@aurel32.net http://www.aurel32.net
next prev parent reply other threads:[~2012-09-27 23:08 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-27 17:15 [Qemu-devel] [PATCH 00/13] tcg: rework liveness analysis and register allocator Aurelien Jarno
2012-09-27 17:15 ` [Qemu-devel] [PATCH 01/13] tcg: add temp_dead() Aurelien Jarno
2012-09-27 18:19 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 02/13] tcg: add tcg_reg_sync() Aurelien Jarno
2012-09-27 18:24 ` Richard Henderson
2012-09-27 20:00 ` Aurelien Jarno
2012-09-27 17:15 ` [Qemu-devel] [PATCH 03/13] tcg: add temp_sync() Aurelien Jarno
2012-09-27 18:30 ` Richard Henderson
2012-09-27 20:02 ` Aurelien Jarno
2012-09-27 17:15 ` [Qemu-devel] [PATCH 04/13] tcg: sync output arguments on liveness request Aurelien Jarno
2012-09-27 18:39 ` Richard Henderson
2012-09-27 20:05 ` Aurelien Jarno
2012-09-27 20:10 ` Richard Henderson
2012-09-27 20:25 ` Aurelien Jarno
2012-09-27 17:15 ` [Qemu-devel] [PATCH 05/13] tcg: rework liveness analysis Aurelien Jarno
2012-09-27 18:54 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 06/13] tcg: improve tcg_reg_alloc_movi() Aurelien Jarno
2012-09-27 18:55 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 07/13] tcg: rewrite tcg_reg_alloc_mov() Aurelien Jarno
2012-09-27 19:09 ` Richard Henderson
2012-09-27 20:17 ` Aurelien Jarno
2012-09-27 22:18 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 08/13] tcg: always mark dead input arguments as dead Aurelien Jarno
2012-09-27 19:10 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 09/13] tcg: start with local temps in TEMP_VAL_MEM state Aurelien Jarno
2012-09-27 19:10 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 10/13] tcg: don't explicitely save globals and temps Aurelien Jarno
2012-09-27 19:13 ` Richard Henderson
2012-09-27 20:23 ` Aurelien Jarno
2012-09-27 17:15 ` [Qemu-devel] [PATCH 11/13] tcg: sync globals for pure helpers instead of saving them Aurelien Jarno
2012-09-27 19:39 ` Richard Henderson
2012-09-27 20:34 ` Aurelien Jarno
2012-09-27 22:02 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 12/13] tcg: fix some op flags Aurelien Jarno
2012-09-27 19:44 ` Richard Henderson
2012-09-27 17:15 ` [Qemu-devel] [PATCH 13/13] tcg: rework TCG ops flags Aurelien Jarno
2012-09-27 19:56 ` Richard Henderson
2012-09-27 20:37 ` Aurelien Jarno
2012-09-27 22:00 ` Richard Henderson
2012-09-27 23:08 ` Aurelien Jarno [this message]
2012-09-27 23:11 ` Richard Henderson
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