--- v8/src/base/atomicops.h.orig	2025-11-06 10:11:34 UTC
+++ v8/src/base/atomicops.h
@@ -57,10 +57,10 @@ using Atomic64 = SbAtomic64;
 using Atomic8 = char;
 using Atomic16 = int16_t;
 using Atomic32 = int32_t;
-#if defined(V8_HOST_ARCH_64_BIT)
+#if defined(V8_HOST_ARCH_64_BIT) || defined(V8_OS_OPENBSD)
 // We need to be able to go between Atomic64 and AtomicWord implicitly.  This
 // means Atomic64 and AtomicWord should be the same type on 64-bit.
-#if defined(__ILP32__)
+#if defined(__ILP32__) && !defined(V8_OS_OPENBSD)
 using Atomic64 = int64_t;
 #else
 using Atomic64 = intptr_t;
@@ -281,7 +281,7 @@ inline Atomic32 SeqCst_Load(volatile const Atomic32* p
                                    std::memory_order_seq_cst);
 }
 
-#if defined(V8_HOST_ARCH_64_BIT)
+#if defined(V8_HOST_ARCH_64_BIT) || defined(V8_OS_OPENBSD)
 
 inline Atomic64 Relaxed_CompareAndSwap(volatile Atomic64* ptr,
                                        Atomic64 old_value, Atomic64 new_value) {
