From 4b8ca5f897278fffd5893fd5ebb55832adb5b2b0 Mon Sep 17 00:00:00 2001
From: Tony Arcieri <bascule@gmail.com>
Date: Mon, 29 Dec 2025 08:35:20 -0700
Subject: [PATCH] aes: change AES-NI `ParBlocksSize` back to 8

Changes it from 9 back to 8, like it was in `aes` v0.8.

Anecdotally we've had some reports of better performance: #515

I also think an odd number of blocks just seems a bit unusual to me,
and 8 blocks is what I've typically seen in other implementations.
---
 aes/src/x86.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/aes/src/x86.rs b/aes/src/x86.rs
index 6fa1f1fb..e479e502 100644
--- a/aes/src/x86.rs
+++ b/aes/src/x86.rs
@@ -17,7 +17,7 @@ use cipher::{
     AlgorithmName, BlockCipherDecBackend, BlockCipherDecClosure, BlockCipherDecrypt,
     BlockCipherEncBackend, BlockCipherEncClosure, BlockCipherEncrypt, BlockSizeUser, InOut, Key,
     KeyInit, KeySizeUser, ParBlocksSizeUser,
-    consts::{U9, U16, U24, U32},
+    consts::{U8, U16, U24, U32},
     crypto_common::WeakKeyError,
 };
 #[cfg(all(target_arch = "x86_64", any(aes_avx256, aes_avx512)))]
@@ -447,7 +447,7 @@ macro_rules! define_aes_impl {
         }
 
         impl<'a> ParBlocksSizeUser for $name_backend::Ni<'a> {
-            type ParBlocksSize = U9;
+            type ParBlocksSize = U8;
         }
         #[cfg(all(target_arch = "x86_64", any(aes_avx256, aes_avx512)))]
         impl<'a> ParBlocksSizeUser for $name_backend::Vaes256<'a> {