diff options
Diffstat (limited to 'tcg')
| -rw-r--r-- | tcg/tcg.c | 34 |
1 files changed, 33 insertions, 1 deletions
@@ -1307,8 +1307,39 @@ static void tcg_liveness_analysis(TCGContext *s) break; case INDEX_op_end: break; - /* XXX: optimize by hardcoding common cases (e.g. triadic ops) */ + + case INDEX_op_add2_i32: + case INDEX_op_sub2_i32: + args -= 6; + nb_iargs = 4; + nb_oargs = 2; + /* Test if the high part of the operation is dead, but not + the low part. The result can be optimized to a simple + add or sub. This happens often for x86_64 guest when the + cpu mode is set to 32 bit. */ + if (dead_temps[args[1]]) { + if (dead_temps[args[0]]) { + goto do_remove; + } + /* Create the single operation plus nop. */ + if (op == INDEX_op_add2_i32) { + op = INDEX_op_add_i32; + } else { + op = INDEX_op_sub_i32; + } + gen_opc_buf[op_index] = op; + args[1] = args[2]; + args[2] = args[4]; + assert(gen_opc_buf[op_index + 1] == INDEX_op_nop); + tcg_set_nop(s, gen_opc_buf + op_index + 1, args + 3, 3); + /* Fall through and mark the single-word operation live. */ + nb_iargs = 2; + nb_oargs = 1; + } + goto do_not_remove; + default: + /* XXX: optimize by hardcoding common cases (e.g. triadic ops) */ args -= def->nb_args; nb_iargs = def->nb_iargs; nb_oargs = def->nb_oargs; @@ -1322,6 +1353,7 @@ static void tcg_liveness_analysis(TCGContext *s) if (!dead_temps[arg]) goto do_not_remove; } + do_remove: tcg_set_nop(s, gen_opc_buf + op_index, args, def->nb_args); #ifdef CONFIG_PROFILER s->del_op_count++; |