Richard Henderson <richard.hender...@linaro.org> writes:
> The only fixed_reg is cpu_env, and it should not be modified
> during any TB. Therefore code that tries to special-case moves
> into a fixed_reg is dead. Remove it.
>
> Reviewed-by: David Hildenbrand <da...@redhat.com>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
> ---
> tcg/tcg.c | 87 +++++++++++++++++++++++++------------------------------
> 1 file changed, 40 insertions(+), 47 deletions(-)
>
> diff --git a/tcg/tcg.c b/tcg/tcg.c
> index f7bef51de8..70ca113c26 100644
> --- a/tcg/tcg.c
> +++ b/tcg/tcg.c
> @@ -3274,11 +3274,8 @@ static void tcg_reg_alloc_do_movi(TCGContext *s,
> TCGTemp *ots,
> tcg_target_ulong val, TCGLifeData arg_life,
> TCGRegSet preferred_regs)
> {
> - if (ots->fixed_reg) {
> - /* For fixed registers, we do not do any constant propagation. */
> - tcg_out_movi(s, ots->type, ots->reg, val);
> - return;
> - }
> + /* ENV should not be modified. */
> + tcg_debug_assert(!ots->fixed_reg);
>
> /* The movi is not explicitly generated here. */
> if (ots->val_type == TEMP_VAL_REG) {
> @@ -3314,6 +3311,9 @@ static void tcg_reg_alloc_mov(TCGContext *s, const
> TCGOp *op)
> ots = arg_temp(op->args[0]);
> ts = arg_temp(op->args[1]);
>
> + /* ENV should not be modified. */
> + tcg_debug_assert(!ots->fixed_reg);
> +
> /* Note that otype != itype for no-op truncation. */
> otype = ots->type;
> itype = ts->type;
> @@ -3338,7 +3338,7 @@ static void tcg_reg_alloc_mov(TCGContext *s, const
> TCGOp *op)
> }
>
> tcg_debug_assert(ts->val_type == TEMP_VAL_REG);
> - if (IS_DEAD_ARG(0) && !ots->fixed_reg) {
> + if (IS_DEAD_ARG(0)) {
> /* mov to a non-saved dead register makes no sense (even with
> liveness analysis disabled). */
> tcg_debug_assert(NEED_SYNC_ARG(0));
> @@ -3351,7 +3351,7 @@ static void tcg_reg_alloc_mov(TCGContext *s, const
> TCGOp *op)
> }
> temp_dead(s, ots);
> } else {
> - if (IS_DEAD_ARG(1) && !ts->fixed_reg && !ots->fixed_reg) {
> + if (IS_DEAD_ARG(1) && !ts->fixed_reg) {
> /* the mov can be suppressed */
> if (ots->val_type == TEMP_VAL_REG) {
> s->reg_to_temp[ots->reg] = NULL;
> @@ -3504,6 +3504,10 @@ static void tcg_reg_alloc_op(TCGContext *s, const
> TCGOp *op)
> arg = op->args[i];
> arg_ct = &def->args_ct[i];
> ts = arg_temp(arg);
> +
> + /* ENV should not be modified. */
> + tcg_debug_assert(!ts->fixed_reg);
> +
> if ((arg_ct->ct & TCG_CT_ALIAS)
> && !const_args[arg_ct->alias_index]) {
> reg = new_args[arg_ct->alias_index];
> @@ -3512,29 +3516,21 @@ static void tcg_reg_alloc_op(TCGContext *s, const
> TCGOp *op)
> i_allocated_regs | o_allocated_regs,
> op->output_pref[k], ts->indirect_base);
> } else {
> - /* if fixed register, we try to use it */
> - reg = ts->reg;
> - if (ts->fixed_reg &&
> - tcg_regset_test_reg(arg_ct->u.regs, reg)) {
> - goto oarg_end;
> - }
> reg = tcg_reg_alloc(s, arg_ct->u.regs, o_allocated_regs,
> op->output_pref[k], ts->indirect_base);
> }
> tcg_regset_set_reg(o_allocated_regs, reg);
> - /* if a fixed register is used, then a move will be done
> afterwards */
> - if (!ts->fixed_reg) {
> - if (ts->val_type == TEMP_VAL_REG) {
> - s->reg_to_temp[ts->reg] = NULL;
> - }
> - ts->val_type = TEMP_VAL_REG;
> - ts->reg = reg;
> - /* temp value is modified, so the value kept in memory is
> - potentially not the same */
> - ts->mem_coherent = 0;
> - s->reg_to_temp[reg] = ts;
> + if (ts->val_type == TEMP_VAL_REG) {
> + s->reg_to_temp[ts->reg] = NULL;
> }
> - oarg_end:
> + ts->val_type = TEMP_VAL_REG;
> + ts->reg = reg;
> + /*
> + * Temp value is modified, so the value kept in memory is
> + * potentially not the same.
> + */
> + ts->mem_coherent = 0;
> + s->reg_to_temp[reg] = ts;
> new_args[i] = reg;
> }
> }
> @@ -3550,10 +3546,10 @@ static void tcg_reg_alloc_op(TCGContext *s, const
> TCGOp *op)
> /* move the outputs in the correct register if needed */
> for(i = 0; i < nb_oargs; i++) {
> ts = arg_temp(op->args[i]);
> - reg = new_args[i];
> - if (ts->fixed_reg && ts->reg != reg) {
> - tcg_out_mov(s, ts->type, ts->reg, reg);
> - }
> +
> + /* ENV should not be modified. */
> + tcg_debug_assert(!ts->fixed_reg);
> +
> if (NEED_SYNC_ARG(i)) {
> temp_sync(s, ts, o_allocated_regs, 0, IS_DEAD_ARG(i));
> } else if (IS_DEAD_ARG(i)) {
> @@ -3674,26 +3670,23 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp
> *op)
> for(i = 0; i < nb_oargs; i++) {
> arg = op->args[i];
> ts = arg_temp(arg);
> +
> + /* ENV should not be modified. */
> + tcg_debug_assert(!ts->fixed_reg);
> +
> reg = tcg_target_call_oarg_regs[i];
> tcg_debug_assert(s->reg_to_temp[reg] == NULL);
> -
> - if (ts->fixed_reg) {
> - if (ts->reg != reg) {
> - tcg_out_mov(s, ts->type, ts->reg, reg);
> - }
> - } else {
> - if (ts->val_type == TEMP_VAL_REG) {
> - s->reg_to_temp[ts->reg] = NULL;
> - }
> - ts->val_type = TEMP_VAL_REG;
> - ts->reg = reg;
> - ts->mem_coherent = 0;
> - s->reg_to_temp[reg] = ts;
> - if (NEED_SYNC_ARG(i)) {
> - temp_sync(s, ts, allocated_regs, 0, IS_DEAD_ARG(i));
> - } else if (IS_DEAD_ARG(i)) {
> - temp_dead(s, ts);
> - }
> + if (ts->val_type == TEMP_VAL_REG) {
> + s->reg_to_temp[ts->reg] = NULL;
> + }
> + ts->val_type = TEMP_VAL_REG;
> + ts->reg = reg;
> + ts->mem_coherent = 0;
> + s->reg_to_temp[reg] = ts;
> + if (NEED_SYNC_ARG(i)) {
> + temp_sync(s, ts, allocated_regs, 0, IS_DEAD_ARG(i));
> + } else if (IS_DEAD_ARG(i)) {
> + temp_dead(s, ts);
> }
> }
> }
--
Alex Bennée
