diff --git a/crypto/bn/bn_shift.c b/crypto/bn/bn_shift.c
index 0e8211e3..da0abfd1 100644
--- a/crypto/bn/bn_shift.c
+++ b/crypto/bn/bn_shift.c
@@ -168,6 +168,9 @@ BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
 	return (1);
 }
 
+#ifdef _M_ARM64
+#pragma optimize("", off)
+#endif
 int
 BN_rshift(BIGNUM *r, const BIGNUM *a, int n)
 {
@@ -216,3 +219,6 @@ BN_rshift(BIGNUM *r, const BIGNUM *a, int n)
 	bn_check_top(r);
 	return (1);
 }
+#ifdef _M_ARM64
+#pragma optimize("", on)
+#endif
\ No newline at end of file