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From: Bruce Richardson <bruce.richardson@intel.com>
To: Michael Qiu <qdy220091330@gmail.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] test-pmd: Fix pointer aliasing error
Date: Wed, 3 Dec 2014 11:42:58 +0000
Message-ID: <20141203114258.GA2396@bricha3-MOBL3> (raw)
In-Reply-To: <1417606099-3489-1-git-send-email-michael.qiu@intel.com>

On Wed, Dec 03, 2014 at 07:28:19PM +0800, Michael Qiu wrote:
> app/test-pmd/csumonly.c: In function ‘get_psd_sum’:
> build/include/rte_ip.h:161: error: dereferencing pointer ‘u16’
> 	does break strict-aliasing rules
> build/include/rte_ip.h:157: note: initialized from here
> 	...
> 
> The root cause is that, compile enable strict aliasing by default,
> while in function rte_raw_cksum() try to convert 'const char *'
> to 'const uint16_t *'.
>

What compiler version is this with? Is there any other way to fix this
other than disabling the compiler warnings. Turning off strict aliasing may
affect performance as it reduces the number of optimizations that the compiler
can perform.

/Bruce

> Need to add CFLAG '-Wno-strict-aliasing' to avoid this issue.
> 
> Signed-off-by: Michael Qiu <michael.qiu@intel.com>
> ---
>  app/test-pmd/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/app/test-pmd/Makefile b/app/test-pmd/Makefile
> index 97dc2e6..995c874 100644
> --- a/app/test-pmd/Makefile
> +++ b/app/test-pmd/Makefile
> @@ -38,7 +38,7 @@ ifeq ($(CONFIG_RTE_TEST_PMD),y)
>  #
>  APP = testpmd
>  
> -CFLAGS += -O3
> +CFLAGS += -O3 -Wno-strict-aliasing
>  CFLAGS += $(WERROR_FLAGS)
>  
>  ifeq ($(CONFIG_RTE_LIBRTE_PMD_PCAP),y)
> -- 
> 1.9.3
> 

       reply	other threads:[~2014-12-03 11:43 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1417606044-3432-1-git-send-email-michael.qiu@intel.com>
     [not found] ` <1417606099-3489-1-git-send-email-michael.qiu@intel.com>
2014-12-03 11:42   ` Bruce Richardson [this message]
2014-12-03 13:59     ` Qiu, Michael
2014-12-03 14:51       ` Bruce Richardson
2014-12-03 15:19         ` Qiu, Michael
2014-12-03 15:36           ` Bruce Richardson
2014-12-04  2:38             ` Qiu, Michael
2014-12-04  3:28               ` [dpdk-dev] [PATCH v2] " Michael Qiu
2014-12-04  4:16                 ` [dpdk-dev] [PATCH v3] " Michael Qiu
2014-12-05  5:34                   ` Qiu, Michael
2014-12-05  9:24                     ` Thomas Monjalon
2014-12-08  1:28                       ` Qiu, Michael
2014-12-08  1:30                   ` Qiu, Michael
2014-12-10  3:44                     ` Qiu, Michael
2014-12-11  0:54                     ` Thomas Monjalon
2014-12-11 17:51                       ` r k
2014-12-12  6:49                         ` Qiu, Michael
2014-12-04 12:54                 ` [dpdk-dev] [PATCH v2] " Ananyev, Konstantin
2014-12-03 15:24     ` [dpdk-dev] [PATCH] " Olivier MATZ
2014-12-03 16:03       ` Dayu Qiu
2014-12-03 15:57     ` Dayu Qiu
2014-12-03 16:26 ` [dpdk-dev] [PATCH] test-pmd: Fix "__BYTE_ORDER__" not defined error Qiu, Michael
2014-12-03 19:59   ` Thomas Monjalon
2014-12-03 20:47     ` [dpdk-dev] [PATCH 0/2] fix endianness in EAL Thomas Monjalon
2014-12-03 20:47       ` [dpdk-dev] [PATCH 1/2] eal: detect endianness Thomas Monjalon
2014-12-04  2:28         ` Qiu, Michael
2014-12-04  9:00           ` Thomas Monjalon
2014-12-04 10:28             ` Qiu, Michael
2014-12-04 12:19               ` Thomas Monjalon
2014-12-04 12:50                 ` Qiu, Michael
2014-12-03 20:47       ` [dpdk-dev] [PATCH 2/2] app/testpmd: fix endianness detection Thomas Monjalon
2014-12-04  9:28       ` [dpdk-dev] [PATCH 0/2] fix endianness in EAL Chao Zhu
2014-12-05 16:01         ` Thomas Monjalon

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