From patchwork Thu Jan 24 04:03:22 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [38/57] target-i386: Update cc_op before TCG branches Date: Wed, 23 Jan 2013 18:03:22 -0000 From: Richard Henderson X-Patchwork-Id: 215209 Message-Id: <1359000221-19834-39-git-send-email-rth@twiddle.net> To: qemu-devel@nongnu.org Cc: Blue Swirl , Paolo Bonzini Placing the CC_OP_DYNAMIC at the join is less effective than before the branch, as the branch will have forced global registers to their home locations. This way we have a chance to discard CC_SRC2 before it gets stored. Signed-off-by: Richard Henderson --- target-i386/translate.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/target-i386/translate.c b/target-i386/translate.c index 9f031a8..b3ba93e 100644 --- a/target-i386/translate.c +++ b/target-i386/translate.c @@ -1552,8 +1552,9 @@ static void gen_shift_rm_T1(DisasContext *s, int ot, int op1, gen_op_mov_reg_T0(ot, op1); } - /* update eflags */ + /* Update eflags data because we cannot predict flags afterward. */ gen_update_cc_op(s); + set_cc_op(s, CC_OP_DYNAMIC); tcg_gen_mov_tl(t1, cpu_T[0]); @@ -1580,7 +1581,6 @@ static void gen_shift_rm_T1(DisasContext *s, int ot, int op1, } gen_set_label(shift_label); - set_cc_op(s, CC_OP_DYNAMIC); /* cannot predict flags after */ tcg_temp_free(t0); tcg_temp_free(t1); @@ -1965,8 +1965,9 @@ static void gen_shiftd_rm_T1(DisasContext *s, int ot, int op1, gen_op_mov_reg_v(ot, op1, t0); } - /* update eflags */ + /* Update eflags data because we cannot predict flags afterward. */ gen_update_cc_op(s); + set_cc_op(s, CC_OP_DYNAMIC); label2 = gen_new_label(); tcg_gen_brcondi_tl(TCG_COND_EQ, t2, 0, label2); @@ -1979,7 +1980,6 @@ static void gen_shiftd_rm_T1(DisasContext *s, int ot, int op1, tcg_gen_movi_i32(cpu_cc_op, CC_OP_SHLB + ot); } gen_set_label(label2); - set_cc_op(s, CC_OP_DYNAMIC); /* cannot predict flags after */ tcg_temp_free(t0); tcg_temp_free(t1);