Re: [dpdk-dev] [PATCH] acl: fix build issue with some arm64 compiler

[Michael Santana Francisco <msantana@redhat.com>]

On 6/6/19 10:50 AM, jerinj@marvell.com wrote:
> From: Jerin Jacob <jerinj@marvell.com>
>
> Some compilers reporting the following error, though the existing
> code doesn't have any uninitialized variable case.
> Just to make compiler happy, initialize the int32x4_t variable
> one shot in C language.
>
> ../lib/librte_acl/acl_run_neon.h: In function 'search_neon_4'
> ../lib/librte_acl/acl_run_neon.h:230:12: error: 'input' may be
> used uninitialized in this function [-Werror=maybe-uninitialized]
>    int32x4_t input;
>
> Fixes: 34fa6c27c156 ("acl: add NEON optimization for ARMv8")
> Cc: stable@dpdk.org
>
> Signed-off-by: Jerin Jacob <jerinj@marvell.com>
> ---
>   lib/librte_acl/acl_run_neon.h | 29 ++++++++++++-----------------
>   1 file changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/lib/librte_acl/acl_run_neon.h b/lib/librte_acl/acl_run_neon.h
> index 01b9766d8..dc9e9efe9 100644
> --- a/lib/librte_acl/acl_run_neon.h
> +++ b/lib/librte_acl/acl_run_neon.h
> @@ -165,7 +165,6 @@ search_neon_8(const struct rte_acl_ctx *ctx, const uint8_t **data,
>   	uint64_t index_array[8];
>   	struct completion cmplt[8];
>   	struct parms parms[8];
> -	int32x4_t input0, input1;
>   
>   	acl_set_flow(&flows, cmplt, RTE_DIM(cmplt), data, results,
>   		     total_packets, categories, ctx->trans_table);
> @@ -181,17 +180,14 @@ search_neon_8(const struct rte_acl_ctx *ctx, const uint8_t **data,
>   
>   	while (flows.started > 0) {
>   		/* Gather 4 bytes of input data for each stream. */
> -		input0 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 0), input0, 0);
> -		input1 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 4), input1, 0);
> -
> -		input0 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 1), input0, 1);
> -		input1 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 5), input1, 1);
> -
> -		input0 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 2), input0, 2);
> -		input1 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 6), input1, 2);
> -
> -		input0 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 3), input0, 3);
> -		input1 = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 7), input1, 3);
> +		int32x4_t input0 = {GET_NEXT_4BYTES(parms, 0),
> +				    GET_NEXT_4BYTES(parms, 1),
> +				    GET_NEXT_4BYTES(parms, 2),
> +				    GET_NEXT_4BYTES(parms, 3)};
> +		int32x4_t input1 = {GET_NEXT_4BYTES(parms, 4),
> +				    GET_NEXT_4BYTES(parms, 5),
> +				    GET_NEXT_4BYTES(parms, 6),
> +				    GET_NEXT_4BYTES(parms, 7)};
>   
>   		/* Process the 4 bytes of input on each stream. */
>   
> @@ -227,7 +223,6 @@ search_neon_4(const struct rte_acl_ctx *ctx, const uint8_t **data,
>   	uint64_t index_array[4];
>   	struct completion cmplt[4];
>   	struct parms parms[4];
> -	int32x4_t input;
>   
>   	acl_set_flow(&flows, cmplt, RTE_DIM(cmplt), data, results,
>   		     total_packets, categories, ctx->trans_table);
> @@ -242,10 +237,10 @@ search_neon_4(const struct rte_acl_ctx *ctx, const uint8_t **data,
>   
>   	while (flows.started > 0) {
>   		/* Gather 4 bytes of input data for each stream. */
> -		input = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 0), input, 0);
> -		input = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 1), input, 1);
> -		input = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 2), input, 2);
> -		input = vsetq_lane_s32(GET_NEXT_4BYTES(parms, 3), input, 3);
> +		int32x4_t input = {GET_NEXT_4BYTES(parms, 0),
> +				   GET_NEXT_4BYTES(parms, 1),
> +				   GET_NEXT_4BYTES(parms, 2),
> +				   GET_NEXT_4BYTES(parms, 3)};
>   
>   		/* Process the 4 bytes of input on each stream. */
>   		input = transition4(input, flows.trans, index_array);

Fixed on travis: https://travis-ci.com/Maickii/dpdk-2/builds/114612090

Acked-by: Michael Santana <msantana@redhat.com>