These are handled by a separate pass now.
---
src/compiler/nir/nir_opt_copy_prop_vars.c | 67 +----------------------
1 file changed, 3 insertions(+), 64 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..b6a5b9c2bb4 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 {
@@ -66,7 +65,6 @@ struct copy_entry {
nir_instr *store_instr[4];
- unsigned comps_may_be_read;
struct value src;
nir_deref_instr *dst;
@@ -114,44 +112,6 @@ 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 +125,6 @@ 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 +141,6 @@ 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);
@@ -231,7 +176,6 @@ store_to_entry(struct copy_prop_var_state *state, struct
copy_entry *entry,
const struct value *value, unsigned write_mask,
nir_instr *store_instr)
{
- entry->comps_may_be_read &= ~write_mask;
if (value->is_ssa) {
entry->src.is_ssa = true;
/* Only overwrite the written components */
@@ -490,9 +434,6 @@ 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;
@@ -579,8 +520,6 @@ 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;
--
2.18.0
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
