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Re: [Qemu-devel] [PATCH 4/7] tcg: Optimize double-word comparisons again
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH 4/7] tcg: Optimize double-word comparisons against zero |
Date: |
Mon, 01 Oct 2012 11:47:15 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120911 Thunderbird/15.0.1 |
On 2012-10-01 11:43, Aurelien Jarno wrote:
> While it's a nice optimization to have, one that seems to happen a lot
> more often is the two high parts being equal. It happens when the guest
> is working on (u)int32_t.
It depends on what target you're looking at. For alpha guest, all branches
are comparisons vs zero, so LT/GE happens with some regularity.
r~