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Re: [Qemu-arm] [PATCH 09/10] target/i386: optimize indirect branches wit
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-arm] [PATCH 09/10] target/i386: optimize indirect branches with TCG's jr op |
Date: |
Wed, 12 Apr 2017 11:43:45 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 |
On 12/04/2017 09:17, Emilio G. Cota wrote:
>
> The fact that NBench is not very sensitive to changes here is a
> little surprising, especially given the significant improvements for
> ARM shown in the previous commit. I wonder whether the compiler is doing
> a better job compiling the x86_64 version (I'm using gcc 5.4.0), or I'm simply
> missing some i386 instructions to which the jr optimization should
> be applied.
Maybe it is "ret"? That would be a straightforward "bx lr" on ARM, but
it is missing in your i386 patch.
Paolo