Alignment fix

crates/prover/src/core/backend/simd/blake2s.rs

@@ -6,6 +6,7 @@ use std::iter::repeat;
 use std::mem::transmute;
 use std::simd::u32x16;
 
+use bytemuck::cast_slice;
 use itertools::Itertools;
 #[cfg(feature = "parallel")]
 use rayon::prelude::*;
@@ -49,7 +50,7 @@ impl MerkleOps<Blake2sMerkleHasher> for SimdBackend {
         prev_layer: Option<&Vec<Blake2sHash>>,
         columns: &[&Col<Self, BaseField>],
     ) -> Vec<Blake2sHash> {
-        if log_size < N_LANES as u32 {
+        if log_size < LOG_N_LANES {
             #[cfg(not(feature = "parallel"))]
             let iter = 0..1 << log_size;
 
@@ -65,6 +66,7 @@ impl MerkleOps<Blake2sMerkleHasher> for SimdBackend {
                 })
                 .collect();
         }
+        println!("B");
 
         if let Some(prev_layer) = prev_layer {
             assert_eq!(prev_layer.len(), 1 << (log_size + 1));
@@ -84,8 +86,11 @@ impl MerkleOps<Blake2sMerkleHasher> for SimdBackend {
             let mut state: [u32x16; 8] = unsafe { std::mem::zeroed() };
             // Hash prev_layer, if exists.
             if let Some(prev_layer) = prev_layer {
-                let ptr = prev_layer[(i << 5)..((i + 1) << 5)].as_ptr() as *const u32x16;
-                let msgs: [u32x16; 16] = array::from_fn(|j| unsafe { *ptr.add(j) });
+                let prev_chunk_u32s = cast_slice::<_, u32>(&prev_layer[(i << 5)..((i + 1) << 5)]);
+                // Note: prev_layer might be unaligned.
+                let msgs: [u32x16; 16] = array::from_fn(|j| {
+                    u32x16::from_array(std::array::from_fn(|k| prev_chunk_u32s[16 * j + k]))
+                });
                 state = compress16(state, transpose_msgs(msgs), zeros, zeros, zeros, zeros);
             }
 

crates/prover/src/core/vcs/blake2_hash.rs

@@ -1,10 +1,11 @@
 use std::fmt;
 
 use blake2::{Blake2s256, Digest};
+use bytemuck::{Pod, Zeroable};
 
 // Wrapper for the blake2s hash type.
-#[repr(align(32))]
-#[derive(Clone, Copy, PartialEq, Default, Eq)]
+#[repr(C, align(32))]
+#[derive(Clone, Copy, PartialEq, Default, Eq, Pod, Zeroable)]
 pub struct Blake2sHash([u8; 32]);
 
 impl From<Blake2sHash> for Vec<u8> {