Commit 8488abc84a for openssl.org

commit 8488abc84a46dcecd4ea352f218c9aaee6f6e13f
Author: Milan Broz <gmazyland@gmail.com>
Date:   Mon May 4 14:13:27 2026 +0000

    bn_nist.c: remove unreachable BN_BITS2 == 64

    The block in BN_nist_mod_224() is gated by

      #if defined(NIST_INT64) && BN_BITS2 != 64

    so the #if

      #if BN_BITS2 == 64
              rp[7] = carry;
      #endif

    is unreachable. Remove it.

    The code is actualy relic of an earlier design where the NIST_INT64
    accumulator path was meant 64-bit too.

    Disabling 64-bit path above with BN_BITS2 != 64 resulted in
    #if BN_BITS2 == 64 was left unreachable

    The outer condition is correct, it is meant to be 32bit only,
    otherwise it would need to introduce load_u32/store_lo32 as in other
    functions to avoid clang strict-aliasing optimizer issues.

    Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

    Reviewed-by: Saša Nedvědický <sashan@openssl.org>
    Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
    Reviewed-by: Neil Horman <nhorman@openssl.org>
    MergeDate: Thu May  7 20:11:12 2026
    (Merged from https://github.com/openssl/openssl/pull/31076)

diff --git a/crypto/bn/bn_nist.c b/crypto/bn/bn_nist.c
index aa084996e4..a4cea81adc 100644
--- a/crypto/bn/bn_nist.c
+++ b/crypto/bn/bn_nist.c
@@ -585,9 +585,6 @@ int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
         rp[6] = (unsigned int)acc;

         carry = (int)(acc >> 32);
-#if BN_BITS2 == 64
-        rp[7] = carry;
-#endif
     }
 #else
     {