[PATCH] ARC: bpf_jit_arcv2: Remove redundant condition check

Hardevsinh Palaniya posted 1 patch 1 week, 5 days ago
arch/arc/net/bpf_jit_arcv2.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
[PATCH] ARC: bpf_jit_arcv2: Remove redundant condition check
Posted by Hardevsinh Palaniya 1 week, 5 days ago
The condition 'if (ARC_CC_AL)' is always true, as ARC_CC_AL is a constant 
integer. This makes the check redundant, so it is safe to remove.

Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
---
 arch/arc/net/bpf_jit_arcv2.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/arc/net/bpf_jit_arcv2.c b/arch/arc/net/bpf_jit_arcv2.c
index 4458e409ca0a..19792ce952be 100644
--- a/arch/arc/net/bpf_jit_arcv2.c
+++ b/arch/arc/net/bpf_jit_arcv2.c
@@ -2916,10 +2916,7 @@ bool check_jmp_32(u32 curr_off, u32 targ_off, u8 cond)
 	addendum = (cond == ARC_CC_AL) ? 0 : INSN_len_normal;
 	disp = get_displacement(curr_off + addendum, targ_off);
 
-	if (ARC_CC_AL)
-		return is_valid_far_disp(disp);
-	else
-		return is_valid_near_disp(disp);
+	return is_valid_far_disp(disp);
 }
 
 /*
-- 
2.43.0
Re: [PATCH] ARC: bpf_jit_arcv2: Remove redundant condition check
Posted by Vadim Fedorenko 1 week, 5 days ago
On 11/11/2024 14:19, Hardevsinh Palaniya wrote:
> The condition 'if (ARC_CC_AL)' is always true, as ARC_CC_AL is a constant
> integer. This makes the check redundant, so it is safe to remove.
> 
> Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
> ---
>   arch/arc/net/bpf_jit_arcv2.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/arch/arc/net/bpf_jit_arcv2.c b/arch/arc/net/bpf_jit_arcv2.c
> index 4458e409ca0a..19792ce952be 100644
> --- a/arch/arc/net/bpf_jit_arcv2.c
> +++ b/arch/arc/net/bpf_jit_arcv2.c
> @@ -2916,10 +2916,7 @@ bool check_jmp_32(u32 curr_off, u32 targ_off, u8 cond)
>   	addendum = (cond == ARC_CC_AL) ? 0 : INSN_len_normal;
>   	disp = get_displacement(curr_off + addendum, targ_off);
>   
> -	if (ARC_CC_AL)
> -		return is_valid_far_disp(disp);
> -	else
> -		return is_valid_near_disp(disp);
> +	return is_valid_far_disp(disp);
>   }
>   
>   /*

The original code is obviously optimized out, but the intention, I
believe, was to check if the jump is conditional or not.

So the proper fix should change the code to check cond:

-	if (ARC_CC_AL)
+	if (cond == ARC_CC_AL)
Re: [PATCH] ARC: bpf_jit_arcv2: Remove redundant condition check
Posted by Shahab Vahedi 1 week, 3 days ago
Vadim Fedorenko wrote:
 
> The original code is obviously optimized out, but the intention, I
> believe, was to check if the jump is conditional or not.
> So the proper fix should change the code to check cond:
> 
> - if (ARC_CC_AL)
> + if (cond == ARC_CC_AL)

That is absolutely correct. If a new patch is not submitted soon
I'll try to fix it myself.

Cheers,
Shahab