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Date: Mon, 11 Jul 2016 10:56:20 +0800
From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: dev@dpdk.org, Huawei Xie <huawei.xie@intel.com>
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Subject: Re: [dpdk-dev] [PATCH] net/virtio: fix gcc6 i686 compiler error
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On Thu, Jul 07, 2016 at 02:49:08PM +0100, Ferruh Yigit wrote:
> This is for target i686-native-linuxapp-gcc and gcc6,
> 
> Compilation error is:
> == Build drivers/net/virtio
>   CC virtio_rxtx_simple.o
> In file included from
> .../build/include/rte_mempool.h:77:0,
>                  from
> .../drivers/net/virtio/virtio_rxtx_simple.c:46:
> .../drivers/net/virtio/virtio_rxtx_simple.c: In
> function ‘virtio_xmit_pkts_simple’:
> .../build/include/rte_memcpy.h:551:2: error: array
> subscript is above array bounds [-Werror=array-bounds]
>   rte_mov16((uint8_t *)dst + 1 * 16, (const uint8_t *)src + 1 * 16);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
...
> 
> The compiler traces the array all through the call stack and knows the
> size of array is 128 and generates a warning on above [1] which tries to
> access beyond byte 128.
> But unfortunately it ignores the "(size > 256)" check.
> 
> Giving a hint to compiler that variable "size" is related to the size of
> the source buffer fixes compiler warning.
> 
> Fixes: 863bfb474493 ("mempool: optimize copy in cache")
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>

Applied to dpdk-next-virtio.

Thanks.

	--yliu