[ARROW-11051] [Rust] Array sum result is wrong with remainder fields when simd is on

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Invalid
• Affects Version/s: 2.0.0
• Component/s: Rust
• Environment: Ubuntu 20.04. rustc nightly
• External issue URL: https://github.com/apache/arrow/issues/26967
• Assignee: Unassigned
• Reporter: Ziru Niu
• Created: 28/Dec/20 18:59
• Updated: 11/Jan/23 08:17
• Resolved: 26/Apr/21 12:43

Description

Minimal example

 

use arrow::{array::PrimitiveArray, datatypes::Int64Type};

fn main() {
    let mut s = vec![];
    for _ in 0..32  
     
     {
        s.push(Some(1i64));         s.push(None);     
    }
    let v: PrimitiveArray<Int64Type> = s.into();
    dbg!(arrow::compute::sum(&v));
}
 

 dependency

arrow = {version = "2", features = ["simd"]}

The following code in `compute::sum` is wrong. The bit mask is checked reversed.

            remainder.iter().enumerate().for_each(|(i, value)| {
                if remainder_bits & (1 << i) != 0  {

                    remainder_sum = remainder_sum + *value;

                 }

            });