From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:40896) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TLziJ-0002AT-4N for qemu-devel@nongnu.org; Wed, 10 Oct 2012 13:05:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TLziB-00057V-D5 for qemu-devel@nongnu.org; Wed, 10 Oct 2012 13:04:55 -0400 Received: from mail-pa0-f45.google.com ([209.85.220.45]:65017) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TLziB-00057I-7G for qemu-devel@nongnu.org; Wed, 10 Oct 2012 13:04:47 -0400 Received: by mail-pa0-f45.google.com with SMTP id fb10so810958pad.4 for ; Wed, 10 Oct 2012 10:04:46 -0700 (PDT) Sender: Richard Henderson Message-ID: <5075AAAD.8060707@twiddle.net> Date: Wed, 10 Oct 2012 10:04:45 -0700 From: Richard Henderson MIME-Version: 1.0 References: <1349812584-19551-1-git-send-email-aurelien@aurel32.net> <50751CDF.7000300@redhat.com> <20121010074207.GA7444@ohm.aurel32.net> In-Reply-To: <20121010074207.GA7444@ohm.aurel32.net> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 00/26] tcg: rework liveness analysis and register allocator List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Aurelien Jarno Cc: Paolo Bonzini , qemu-devel@nongnu.org On 10/10/2012 12:42 AM, Aurelien Jarno wrote: >> > - constant propagation using constraints. This would let tcg-i386 use >> > effectively the mov $imm,(addr) instruction for spills of known-constant >> > values. > This is indeed something quite frustrating and even more when the > same immediate value is loaded multiple time. One way to do that would > be to provide an optional tcg_out_st_immediate(). I think it should be possible to "simulate" a tcg opcode for this, without having to have a specific entry point for it. We've already got all the information we need from the backend in the form of constraints... r~