diff --git a/target/arm/helper-a64.h b/target/arm/helper-a64.h
index 94065d1917..ff56807247 100644
--- a/target/arm/helper-a64.h
+++ b/target/arm/helper-a64.h
@@ -50,8 +50,6 @@ DEF_HELPER_FLAGS_2(frecpx_f16, TCG_CALL_NO_RWG, f16, f16, ptr)
 DEF_HELPER_FLAGS_2(fcvtx_f64_to_f32, TCG_CALL_NO_RWG, f32, f64, env)
 DEF_HELPER_FLAGS_3(crc32_64, TCG_CALL_NO_RWG_SE, i64, i64, i64, i32)
 DEF_HELPER_FLAGS_3(crc32c_64, TCG_CALL_NO_RWG_SE, i64, i64, i64, i32)
-DEF_HELPER_5(casp_le_parallel, void, env, i32, i64, i64, i64)
-DEF_HELPER_5(casp_be_parallel, void, env, i32, i64, i64, i64)
 DEF_HELPER_FLAGS_3(advsimd_maxh, TCG_CALL_NO_RWG, f16, f16, f16, ptr)
 DEF_HELPER_FLAGS_3(advsimd_minh, TCG_CALL_NO_RWG, f16, f16, f16, ptr)
 DEF_HELPER_FLAGS_3(advsimd_maxnumh, TCG_CALL_NO_RWG, f16, f16, f16, ptr)
diff --git a/target/arm/helper-a64.c b/target/arm/helper-a64.c
index 7dbdb2c233..0972a4bdd0 100644
--- a/target/arm/helper-a64.c
+++ b/target/arm/helper-a64.c
@@ -505,49 +505,6 @@ uint64_t HELPER(crc32c_64)(uint64_t acc, uint64_t val, uint32_t bytes)
     return crc32c(acc, buf, bytes) ^ 0xffffffff;
 }
 
-/* Writes back the old data into Rs.  */
-void HELPER(casp_le_parallel)(CPUARMState *env, uint32_t rs, uint64_t addr,
-                              uint64_t new_lo, uint64_t new_hi)
-{
-    Int128 oldv, cmpv, newv;
-    uintptr_t ra = GETPC();
-    int mem_idx;
-    MemOpIdx oi;
-
-    assert(HAVE_CMPXCHG128);
-
-    mem_idx = cpu_mmu_index(env, false);
-    oi = make_memop_idx(MO_LE | MO_128 | MO_ALIGN, mem_idx);
-
-    cmpv = int128_make128(env->xregs[rs], env->xregs[rs + 1]);
-    newv = int128_make128(new_lo, new_hi);
-    oldv = cpu_atomic_cmpxchgo_le_mmu(env, addr, cmpv, newv, oi, ra);
-
-    env->xregs[rs] = int128_getlo(oldv);
-    env->xregs[rs + 1] = int128_gethi(oldv);
-}
-
-void HELPER(casp_be_parallel)(CPUARMState *env, uint32_t rs, uint64_t addr,
-                              uint64_t new_hi, uint64_t new_lo)
-{
-    Int128 oldv, cmpv, newv;
-    uintptr_t ra = GETPC();
-    int mem_idx;
-    MemOpIdx oi;
-
-    assert(HAVE_CMPXCHG128);
-
-    mem_idx = cpu_mmu_index(env, false);
-    oi = make_memop_idx(MO_LE | MO_128 | MO_ALIGN, mem_idx);
-
-    cmpv = int128_make128(env->xregs[rs + 1], env->xregs[rs]);
-    newv = int128_make128(new_lo, new_hi);
-    oldv = cpu_atomic_cmpxchgo_be_mmu(env, addr, cmpv, newv, oi, ra);
-
-    env->xregs[rs + 1] = int128_getlo(oldv);
-    env->xregs[rs] = int128_gethi(oldv);
-}
-
 /*
  * AdvSIMD half-precision
  */
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index bd97666ddc..6678894ec7 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -2694,53 +2694,28 @@ static void gen_compare_and_swap_pair(DisasContext *s, int rs, int rt,
             tcg_gen_extr32_i64(s2, s1, cmp);
         }
         tcg_temp_free_i64(cmp);
-    } else if (tb_cflags(s->base.tb) & CF_PARALLEL) {
-        if (HAVE_CMPXCHG128) {
-            TCGv_i32 tcg_rs = tcg_constant_i32(rs);
-            if (s->be_data == MO_LE) {
-                gen_helper_casp_le_parallel(cpu_env, tcg_rs,
-                                            clean_addr, t1, t2);
-            } else {
-                gen_helper_casp_be_parallel(cpu_env, tcg_rs,
-                                            clean_addr, t1, t2);
-            }
-        } else {
-            gen_helper_exit_atomic(cpu_env);
-            s->base.is_jmp = DISAS_NORETURN;
-        }
     } else {
-        TCGv_i64 d1 = tcg_temp_new_i64();
-        TCGv_i64 d2 = tcg_temp_new_i64();
-        TCGv_i64 a2 = tcg_temp_new_i64();
-        TCGv_i64 c1 = tcg_temp_new_i64();
-        TCGv_i64 c2 = tcg_temp_new_i64();
-        TCGv_i64 zero = tcg_constant_i64(0);
+        TCGv_i128 cmp = tcg_temp_new_i128();
+        TCGv_i128 val = tcg_temp_new_i128();
 
-        /* Load the two words, in memory order.  */
-        tcg_gen_qemu_ld_i64(d1, clean_addr, memidx,
-                            MO_64 | MO_ALIGN_16 | s->be_data);
-        tcg_gen_addi_i64(a2, clean_addr, 8);
-        tcg_gen_qemu_ld_i64(d2, a2, memidx, MO_64 | s->be_data);
+        if (s->be_data == MO_LE) {
+            tcg_gen_concat_i64_i128(val, t1, t2);
+            tcg_gen_concat_i64_i128(cmp, s1, s2);
+        } else {
+            tcg_gen_concat_i64_i128(val, t2, t1);
+            tcg_gen_concat_i64_i128(cmp, s2, s1);
+        }
 
-        /* Compare the two words, also in memory order.  */
-        tcg_gen_setcond_i64(TCG_COND_EQ, c1, d1, s1);
-        tcg_gen_setcond_i64(TCG_COND_EQ, c2, d2, s2);
-        tcg_gen_and_i64(c2, c2, c1);
+        tcg_gen_atomic_cmpxchg_i128(cmp, clean_addr, cmp, val, memidx,
+                                    MO_128 | MO_ALIGN | s->be_data);
+        tcg_temp_free_i128(val);
 
-        /* If compare equal, write back new data, else write back old data.  */
-        tcg_gen_movcond_i64(TCG_COND_NE, c1, c2, zero, t1, d1);
-        tcg_gen_movcond_i64(TCG_COND_NE, c2, c2, zero, t2, d2);
-        tcg_gen_qemu_st_i64(c1, clean_addr, memidx, MO_64 | s->be_data);
-        tcg_gen_qemu_st_i64(c2, a2, memidx, MO_64 | s->be_data);
-        tcg_temp_free_i64(a2);
-        tcg_temp_free_i64(c1);
-        tcg_temp_free_i64(c2);
-
-        /* Write back the data from memory to Rs.  */
-        tcg_gen_mov_i64(s1, d1);
-        tcg_gen_mov_i64(s2, d2);
-        tcg_temp_free_i64(d1);
-        tcg_temp_free_i64(d2);
+        if (s->be_data == MO_LE) {
+            tcg_gen_extr_i128_i64(s1, s2, cmp);
+        } else {
+            tcg_gen_extr_i128_i64(s2, s1, cmp);
+        }
+        tcg_temp_free_i128(cmp);
     }
 }
 
