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Re: [Qemu-devel] [PATCH 5/8] tcg: Add interpreter for bytecode

From: Avi Kivity
Subject: Re: [Qemu-devel] [PATCH 5/8] tcg: Add interpreter for bytecode
Date: Mon, 19 Sep 2011 14:56:17 +0300
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:6.0.2) Gecko/20110906 Thunderbird/6.0.2

On 09/19/2011 09:52 AM, Andi Kleen wrote:
>  I think it also improves branch target prediction - if you have a tight
>  loop of a few opcodes the predictor can guess where you're headed (since
>  there is a separate lookup key for each opcode), whereas with the
>  original code, there's a single key which cannot be used to predict the
>  branch target.

At least usually. I caught at least one version of gcc to CSE the jump
instruction into a common location in one of my interpreters
:-( But not all do it at least, and I hope gcc gets fixed.

You generally want CSE, yes? So you can't blame gcc for getting it wrong sometimes.

error compiling committee.c: too many arguments to function

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