6-8 are
Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net>
On Sat, Sep 15, 2018 at 12:45 AM Caio Marcelo de Oliveira Filho <
caio.olive...@intel.com> wrote:
> These are covered by another pass now.
> ---
> src/compiler/nir/nir_opt_copy_prop_vars.c | 84 +++--------------------
> 1 file changed, 8 insertions(+), 76 deletions(-)
>
> diff --git a/src/compiler/nir/nir_opt_copy_prop_vars.c
> b/src/compiler/nir/nir_opt_copy_prop_vars.c
> index 9fecaf0eeec..5276aa176d8 100644
> --- a/src/compiler/nir/nir_opt_copy_prop_vars.c
> +++ b/src/compiler/nir/nir_opt_copy_prop_vars.c
> @@ -38,10 +38,7 @@
> * 1) Copy-propagation on variables that have indirect access. This
> includes
> * propagating from indirect stores into indirect loads.
> *
> - * 2) Dead code elimination of store_var and copy_var intrinsics based on
> - * killed destination values.
> - *
> - * 3) Removal of redundant load_deref intrinsics. We can't trust
> regular CSE
> + * 2) Removal of redundant load_deref intrinsics. We can't trust
> regular CSE
> * to do this because it isn't aware of variable writes that may
> alias the
> * value and make the former load invalid.
> *
> @@ -51,6 +48,8 @@
> * rapidly get out of hand. Fortunately, for anything that is only ever
> * accessed directly, we get SSA based copy-propagation which is extremely
> * powerful so this isn't that great a loss.
> + *
> + * Removal of dead writes to variables is handled by another pass.
> */
>
> struct value {
> @@ -64,9 +63,6 @@ struct value {
> struct copy_entry {
> struct list_head link;
>
> - nir_instr *store_instr[4];
> -
> - unsigned comps_may_be_read;
> struct value src;
>
> nir_deref_instr *dst;
> @@ -114,44 +110,6 @@ copy_entry_remove(struct copy_prop_var_state *state,
> struct copy_entry *entry)
> list_add(&entry->link, &state->copy_free_list);
> }
>
> -static void
> -remove_dead_writes(struct copy_prop_var_state *state,
> - struct copy_entry *entry, unsigned write_mask)
> -{
> - /* We're overwriting another entry. Some of it's components may not
> - * have been read yet and, if that's the case, we may be able to delete
> - * some instructions but we have to be careful.
> - */
> - unsigned dead_comps = write_mask & ~entry->comps_may_be_read;
> -
> - for (unsigned mask = dead_comps; mask;) {
> - unsigned i = u_bit_scan(&mask);
> -
> - nir_instr *instr = entry->store_instr[i];
> -
> - /* We may have already deleted it on a previous iteration */
> - if (!instr)
> - continue;
> -
> - /* See if this instr is used anywhere that it's not dead */
> - bool keep = false;
> - for (unsigned j = 0; j < 4; j++) {
> - if (entry->store_instr[j] == instr) {
> - if (dead_comps & (1 << j)) {
> - entry->store_instr[j] = NULL;
> - } else {
> - keep = true;
> - }
> - }
> - }
> -
> - if (!keep) {
> - nir_instr_remove(instr);
> - state->progress = true;
> - }
> - }
> -}
> -
> static struct copy_entry *
> lookup_entry_for_deref(struct copy_prop_var_state *state,
> nir_deref_instr *deref,
> @@ -165,16 +123,6 @@ lookup_entry_for_deref(struct copy_prop_var_state
> *state,
> return NULL;
> }
>
> -static void
> -mark_aliased_entries_as_read(struct copy_prop_var_state *state,
> - nir_deref_instr *deref, unsigned components)
> -{
> - list_for_each_entry(struct copy_entry, iter, &state->copies, link) {
> - if (nir_compare_derefs(iter->dst, deref) & nir_derefs_may_alias_bit)
> - iter->comps_may_be_read |= components;
> - }
> -}
> -
> static struct copy_entry *
> get_entry_and_kill_aliases(struct copy_prop_var_state *state,
> nir_deref_instr *deref,
> @@ -191,11 +139,6 @@ get_entry_and_kill_aliases(struct copy_prop_var_state
> *state,
> }
>
> nir_deref_compare_result comp = nir_compare_derefs(iter->dst,
> deref);
> - /* This is a store operation. If we completely overwrite some
> value, we
> - * want to delete any dead writes that may be present.
> - */
> - if (comp & nir_derefs_b_contains_a_bit)
> - remove_dead_writes(state, iter, write_mask);
>
> if (comp & nir_derefs_equal_bit) {
> assert(entry == NULL);
> @@ -228,25 +171,19 @@ apply_barrier_for_modes(struct copy_prop_var_state
> *state,
>
> static void
> store_to_entry(struct copy_prop_var_state *state, struct copy_entry
> *entry,
> - const struct value *value, unsigned write_mask,
> - nir_instr *store_instr)
> + const struct value *value, unsigned write_mask)
> {
> - entry->comps_may_be_read &= ~write_mask;
> if (value->is_ssa) {
> entry->src.is_ssa = true;
> /* Only overwrite the written components */
> for (unsigned i = 0; i < 4; i++) {
> - if (write_mask & (1 << i)) {
> - entry->store_instr[i] = store_instr;
> + if (write_mask & (1 << i))
> entry->src.ssa[i] = value->ssa[i];
> - }
> }
> } else {
> /* Non-ssa stores always write everything */
> entry->src.is_ssa = false;
> entry->src.deref = value->deref;
> - for (unsigned i = 0; i < 4; i++)
> - entry->store_instr[i] = store_instr;
> }
> }
>
> @@ -490,9 +427,6 @@ copy_prop_vars_block(struct copy_prop_var_state *state,
> case nir_intrinsic_load_deref: {
> nir_deref_instr *src = nir_src_as_deref(intrin->src[0]);
>
> - uint8_t comps_read =
> nir_ssa_def_components_read(&intrin->dest.ssa);
> - mark_aliased_entries_as_read(state, src, comps_read);
> -
> struct copy_entry *src_entry =
> lookup_entry_for_deref(state, src,
> nir_derefs_a_contains_b_bit);
> struct value value;
> @@ -549,7 +483,7 @@ copy_prop_vars_block(struct copy_prop_var_state *state,
> * subsequent store.
> */
> store_to_entry(state, store_entry, &value,
> - ((1 << intrin->num_components) - 1), NULL);
> + ((1 << intrin->num_components) - 1));
> break;
> }
>
> @@ -565,7 +499,7 @@ copy_prop_vars_block(struct copy_prop_var_state *state,
> unsigned wrmask = nir_intrinsic_write_mask(intrin);
> struct copy_entry *entry =
> get_entry_and_kill_aliases(state, dst, wrmask);
> - store_to_entry(state, entry, &value, wrmask, &intrin->instr);
> + store_to_entry(state, entry, &value, wrmask);
> break;
> }
>
> @@ -579,8 +513,6 @@ copy_prop_vars_block(struct copy_prop_var_state *state,
> continue;
> }
>
> - mark_aliased_entries_as_read(state, src, 0xf);
> -
> struct copy_entry *src_entry =
> lookup_entry_for_deref(state, src,
> nir_derefs_a_contains_b_bit);
> struct value value;
> @@ -610,7 +542,7 @@ copy_prop_vars_block(struct copy_prop_var_state *state,
>
> struct copy_entry *dst_entry =
> get_entry_and_kill_aliases(state, dst, 0xf);
> - store_to_entry(state, dst_entry, &value, 0xf, &intrin->instr);
> + store_to_entry(state, dst_entry, &value, 0xf);
> break;
> }
>
> --
> 2.19.0
>
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> mesa-dev@lists.freedesktop.org
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