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Re: [Qemu-devel] [PATCH] target/i386: fix phminposuw in-place operation
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] target/i386: fix phminposuw in-place operation |
Date: |
Fri, 11 Aug 2017 16:26:54 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 |
On 11/08/2017 16:23, Joseph Myers wrote:
> The SSE4.1 phminposuw instruction finds the minimum 16-bit element in
> the source vector, putting the value of that element in the low 16
> bits of the destination vector, the index of that element in the next
> three bits and zeroing the rest of the destination. The helper for
> this operation fills the destination from high to low, meaning that
> when the source and destination are the same register, the minimum
> source element can be overwritten before it is copied to the
> destination. This patch fixes it to fill the destination from low to
> high instead, so the minimum source element is always copied first.
> This fixes one gcc test failure in my GCC 6-based testing (and so
> concludes the present sequence of patches, as I don't have any further
> gcc test failures left in that testing that I attribute to QEMU bugs).
>
> Signed-off-by: Joseph Myers <address@hidden>
Nice, thanks for the patches! Queued too.
Paolo