| Message ID | 1349202750-16815-10-git-send-email-rth@twiddle.net |
|---|---|
| State | New |
| Headers | show |
On Tue, Oct 02, 2012 at 11:32:29AM -0700, Richard Henderson wrote: > When x86_64 guest is not in 64-bit mode, the high-part of the 64-bit > add is dead. When the host is 32-bit, we can simplify to 32-bit > arithmetic. > > Signed-off-by: Richard Henderson <rth@twiddle.net> > --- > tcg/tcg.c | 34 +++++++++++++++++++++++++++++++++- > 1 file changed, 33 insertions(+), 1 deletion(-) > > diff --git a/tcg/tcg.c b/tcg/tcg.c > index c069e44..21c1074 100644 > --- a/tcg/tcg.c > +++ b/tcg/tcg.c > @@ -1306,8 +1306,39 @@ 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; > @@ -1321,6 +1352,7 @@ 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++; Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/tcg/tcg.c b/tcg/tcg.c index c069e44..21c1074 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -1306,8 +1306,39 @@ 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; @@ -1321,6 +1352,7 @@ 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++;
When x86_64 guest is not in 64-bit mode, the high-part of the 64-bit add is dead. When the host is 32-bit, we can simplify to 32-bit arithmetic. Signed-off-by: Richard Henderson <rth@twiddle.net> --- tcg/tcg.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-)