Re: [PATCH] target/i386: Fix caculation of LOCK NEG eflags

[Richard Henderson]

On 10/21/22 23:17, Qi Hu wrote:

                  t0 = tcg_temp_local_new();
+                t1 = tcg_temp_local_new();
                  label1 = gen_new_label();

tcg_gen_mov_tl(a0, s->A0);

                  tcg_gen_mov_tl(t0, s->T0);

gen_set_label(label1);

-                t1 = tcg_temp_new();
                  t2 = tcg_temp_new();
                  tcg_gen_mov_tl(t2, t0);
                  tcg_gen_neg_tl(t1, t0);
                  tcg_gen_atomic_cmpxchg_tl(t0, a0, t0, t1,
                                            s->mem_index, ot | MO_LE);
-                tcg_temp_free(t1);
                  tcg_gen_brcond_tl(TCG_COND_NE, t0, t2, label1);

tcg_temp_free(t2);

+
+                tcg_gen_mov_tl(s->T0, t1);
+                tcg_temp_free(t1);
                  tcg_temp_free(a0);
-                tcg_gen_mov_tl(s->T0, t0);

Instead of creating another temporary stored across the branch,
simply replace this final mov with a neg.


r~