chore: Fix the verify_dict_indices codegen (#20920)

Author: coastalwhite

crates/polars-parquet/src/arrow/read/deserialize/dictionary_encoded/mod.rs

@@ -179,52 +179,20 @@ fn no_more_bitpacked_values() -> ParquetError {
 }
 
 #[inline(always)]
-#[cfg(feature = "simd")]
-fn verify_dict_indices(indices: &[u32; 32], dict_size: usize) -> ParquetResult<()> {
-    // You would think that the compiler can do this itself, but it does not always do this
-    // properly. So we help it a bit.
+fn verify_dict_indices(indices: &[u32], dict_size: usize) -> ParquetResult<()> {
+    debug_assert!(dict_size <= u32::MAX as usize);
+    let dict_size = dict_size as u32;
 
-    use std::simd::cmp::SimdPartialOrd;
-    use std::simd::u32x32;
-
-    let dict_size = u32x32::splat(dict_size as u32);
-    let indices = u32x32::from_slice(indices);
-
-    let is_invalid = indices.simd_ge(dict_size);
-    if is_invalid.any() {
-        Err(oob_dict_idx())
-    } else {
-        Ok(())
-    }
-}
-
-#[inline(always)]
-#[cfg(not(feature = "simd"))]
-fn verify_dict_indices(indices: &[u32; 32], dict_size: usize) -> ParquetResult<()> {
     let mut is_valid = true;
     for &idx in indices {
-        is_valid &= (idx as usize) < dict_size;
+        is_valid &= idx < dict_size;
     }
 
     if is_valid {
-        return Ok(());
-    }
-
-    Err(oob_dict_idx())
-}
-
-#[inline(always)]
-fn verify_dict_indices_slice(indices: &[u32], dict_size: usize) -> ParquetResult<()> {
-    let mut is_valid = true;
-    for &idx in indices {
-        is_valid &= (idx as usize) < dict_size;
-    }
-
-    if is_valid {
-        return Ok(());
+        Ok(())
+    } else {
+        Err(oob_dict_idx())
     }
-
-    Err(oob_dict_idx())
 }
 
 /// Skip over entire chunks in a [`HybridRleDecoder`] as long as all skipped chunks do not include

crates/polars-parquet/src/arrow/read/deserialize/dictionary_encoded/required.rs

@@ -1,9 +1,6 @@
 use arrow::types::AlignedBytes;
 
-use super::{
-    oob_dict_idx, required_skip_whole_chunks, verify_dict_indices, verify_dict_indices_slice,
-    IndexMapping,
-};
+use super::{oob_dict_idx, required_skip_whole_chunks, verify_dict_indices, IndexMapping};
 use crate::parquet::encoding::hybrid_rle::{HybridRleChunk, HybridRleDecoder};
 use crate::parquet::error::ParquetResult;
 
@@ -55,7 +52,7 @@ pub fn decode<B: AlignedBytes, D: IndexMapping<Output = B>>(
 
                     if let Some((chunk, chunk_size)) = decoder.chunked().next_inexact() {
                         let chunk = &chunk[num_rows_to_skip..chunk_size];
-                        verify_dict_indices_slice(chunk, dict.len())?;
+                        verify_dict_indices(chunk, dict.len())?;
                         target.extend(chunk.iter().map(|&idx| {
                             // SAFETY: The dict indices were verified before.
                             unsafe { dict.get_unchecked(idx) }
@@ -73,7 +70,7 @@ pub fn decode<B: AlignedBytes, D: IndexMapping<Output = B>>(
                 }
 
                 if let Some((chunk, chunk_size)) = chunked.remainder() {
-                    verify_dict_indices_slice(&chunk[..chunk_size], dict.len())?;
+                    verify_dict_indices(&chunk[..chunk_size], dict.len())?;
                     target.extend(chunk[..chunk_size].iter().map(|&idx| {
                         // SAFETY: The dict indices were verified before.
                         unsafe { dict.get_unchecked(idx) }