[Mesa-dev] [RFC v2 10/11] glsl: teach copy_propagation_elements to deal with whole variables
Caio Marcelo de Oliveira Filho
caio.oliveira at intel.com
Mon Jul 9 17:53:24 UTC 2018
Keep information in acp_entry whether the entry is full or not, and
use the ACP in more nodes when visiting the instructions:
- add_copy: write whole variables to the ACP state (regardless the
type).
- visit(ir_dereference_variable *): perform the propagation here if we have a
full candidate. Element-wise here doesn't apply because the mask
isn't available at this point.
- visit_leave(ir_assignment *): process beyond scalar and vector, as
the full variables might have other types.
Also import an improvement from opt_copy_propagation.cpp: if ir_call
is an intrinsic, we know the variables affected, so keep going.
---
.../glsl/opt_copy_propagation_elements.cpp | 142 ++++++++++++++----
1 file changed, 113 insertions(+), 29 deletions(-)
diff --git a/src/compiler/glsl/opt_copy_propagation_elements.cpp b/src/compiler/glsl/opt_copy_propagation_elements.cpp
index d2c24697203..701cce2dd30 100644
--- a/src/compiler/glsl/opt_copy_propagation_elements.cpp
+++ b/src/compiler/glsl/opt_copy_propagation_elements.cpp
@@ -27,18 +27,9 @@
* Replaces usage of recently-copied components of variables with the
* previous copy of the variable.
*
- * This pass can be compared with opt_copy_propagation, which operands
- * on arbitrary whole-variable copies. However, in order to handle
- * the copy propagation of swizzled variables or writemasked writes,
- * we want to track things on a channel-wise basis. I found that
- * trying to mix the swizzled/writemasked support here with the
- * whole-variable stuff in opt_copy_propagation.cpp just made a mess,
- * so this is separate despite the ACP handling being somewhat
- * similar.
- *
* This should reduce the number of MOV instructions in the generated
- * programs unless copy propagation is also done on the LIR, and may
- * help anyway by triggering other optimizations that live in the HIR.
+ * programs and help triggering other optimizations that live in GLSL
+ * level.
*/
#include "ir.h"
@@ -58,6 +49,7 @@ class acp_entry
public:
DECLARE_LINEAR_ZALLOC_CXX_OPERATORS(acp_entry)
+ ir_variable *rhs_full;
ir_variable *rhs_element[4];
unsigned rhs_channel[4];
@@ -88,6 +80,7 @@ public:
void erase(ir_variable *var, unsigned write_mask)
{
acp_entry *entry = pull_acp(var);
+ entry->rhs_full = NULL;
for (int i = 0; i < 4; i++) {
if (!entry->rhs_element[i])
@@ -121,6 +114,8 @@ public:
if (dst_entry->rhs_element[i] == var)
dst_entry->rhs_element[i] = NULL;
}
+ if (dst_entry->rhs_full == var)
+ dst_entry->rhs_full = NULL;
}
_mesa_set_clear(entry->dsts, NULL);
}
@@ -135,11 +130,16 @@ public:
return NULL;
}
- void write(ir_variable *lhs, ir_variable *rhs, unsigned write_mask, int swizzle[4])
+ void write_elements(ir_variable *lhs, ir_variable *rhs, unsigned write_mask, int swizzle[4])
{
acp_entry *lhs_entry = pull_acp(lhs);
+ lhs_entry->rhs_full = NULL;
+ bool already_reference_rhs = false;
for (int i = 0; i < 4; i++) {
+ if (lhs_entry->rhs_element[i] == rhs)
+ already_reference_rhs = true;
+
if ((write_mask & (1 << i)) == 0)
continue;
ir_variable *to_remove = lhs_entry->rhs_element[i];
@@ -160,8 +160,38 @@ public:
}
}
+ if (!already_reference_rhs) {
+ acp_entry *rhs_entry = pull_acp(rhs);
+ _mesa_set_add(rhs_entry->dsts, lhs);
+ }
+ }
+
+ void write_full(ir_variable *lhs, ir_variable *rhs)
+ {
+ acp_entry *lhs_entry = pull_acp(lhs);
+ if (lhs_entry->rhs_full == rhs)
+ return;
+
+ if (lhs_entry->rhs_full) {
+ remove_from_dsts(lhs_entry->rhs_full, lhs);
+ } else if (lhs->type->is_vector()) {
+ for (int i = 0; i < 4; i++) {
+ if (lhs_entry->rhs_element[i])
+ remove_from_dsts(lhs_entry->rhs_element[i], lhs);
+ }
+ }
+
+ lhs_entry->rhs_full = rhs;
acp_entry *rhs_entry = pull_acp(rhs);
_mesa_set_add(rhs_entry->dsts, lhs);
+
+ /* TODO: Consider moving this consolidation to write_elements / erase. */
+ if (lhs->type->is_vector()) {
+ for (int i = 0; i < 4; i++) {
+ lhs_entry->rhs_element[i] = rhs;
+ lhs_entry->rhs_channel[i] = i;
+ }
+ }
}
private:
@@ -205,6 +235,14 @@ private:
return entry;
}
+ void
+ remove_from_dsts(ir_variable *var, ir_variable *to_remove)
+ {
+ acp_entry *entry = pull_acp(var);
+ assert(entry);
+ _mesa_set_remove(entry->dsts, _mesa_set_search(entry->dsts, to_remove));
+ }
+
/** Available Copy to Propagate table, from variable to the entry
* containing the current sources that can be used. */
hash_table *acp;
@@ -248,6 +286,8 @@ public:
ralloc_free(mem_ctx);
}
+ virtual ir_visitor_status visit(ir_dereference_variable *);
+
void handle_loop(ir_loop *, bool keep_acp);
virtual ir_visitor_status visit_enter(class ir_loop *);
virtual ir_visitor_status visit_enter(class ir_function_signature *);
@@ -283,6 +323,21 @@ public:
} /* unnamed namespace */
+ir_visitor_status
+ir_copy_propagation_elements_visitor::visit(ir_dereference_variable *ir)
+{
+ if (this->in_assignee)
+ return visit_continue;
+
+ const acp_entry *entry = state->read(ir->var);
+ if (entry && entry->rhs_full) {
+ ir->var = (ir_variable *) entry->rhs_full;
+ progress = true;
+ }
+
+ return visit_continue;
+}
+
ir_visitor_status
ir_copy_propagation_elements_visitor::visit_enter(ir_function_signature *ir)
{
@@ -317,16 +372,14 @@ ir_copy_propagation_elements_visitor::visit_leave(ir_assignment *ir)
ir_dereference_variable *lhs = ir->lhs->as_dereference_variable();
ir_variable *var = ir->lhs->variable_referenced();
- if (var->type->is_scalar() || var->type->is_vector()) {
- kill_entry *k;
+ kill_entry *k;
- if (lhs)
- k = new(this->lin_ctx) kill_entry(var, ir->write_mask);
- else
- k = new(this->lin_ctx) kill_entry(var, ~0);
+ if (lhs && var->type->is_vector())
+ k = new(this->lin_ctx) kill_entry(var, ir->write_mask);
+ else
+ k = new(this->lin_ctx) kill_entry(var, ~0);
- kill(k);
- }
+ kill(k);
add_copy(ir);
@@ -461,11 +514,25 @@ ir_copy_propagation_elements_visitor::visit_enter(ir_call *ir)
}
}
- /* Since we're unlinked, we don't (necessarily) know the side effects of
- * this call. So kill all copies.
- */
- this->state->erase_all();
- this->killed_all = true;
+ if (!ir->callee->is_intrinsic()) {
+ state->erase_all();
+ this->killed_all = true;
+ } else {
+ if (ir->return_deref) {
+ kill(new(this->lin_ctx) kill_entry(ir->return_deref->var, ~0));
+ }
+
+ foreach_two_lists(formal_node, &ir->callee->parameters,
+ actual_node, &ir->actual_parameters) {
+ ir_variable *sig_param = (ir_variable *) formal_node;
+ if (sig_param->data.mode == ir_var_function_out ||
+ sig_param->data.mode == ir_var_function_inout) {
+ ir_rvalue *ir = (ir_rvalue *) actual_node;
+ ir_variable *var = ir->variable_referenced();
+ kill(new(this->lin_ctx) kill_entry(var, ~0));
+ }
+ }
+ }
return visit_continue_with_parent;
}
@@ -586,12 +653,29 @@ ir_copy_propagation_elements_visitor::kill(kill_entry *k)
void
ir_copy_propagation_elements_visitor::add_copy(ir_assignment *ir)
{
- int orig_swizzle[4] = {0, 1, 2, 3};
- int swizzle[4];
-
if (ir->condition)
return;
+ {
+ ir_variable *lhs_var = ir->whole_variable_written();
+ ir_dereference_variable *rhs = ir->rhs->as_dereference_variable();
+
+ if (lhs_var != NULL && rhs && rhs->var != NULL && lhs_var != rhs->var) {
+ if (lhs_var->data.mode == ir_var_shader_storage ||
+ lhs_var->data.mode == ir_var_shader_shared ||
+ rhs->var->data.mode == ir_var_shader_storage ||
+ rhs->var->data.mode == ir_var_shader_shared ||
+ lhs_var->data.precise != rhs->var->data.precise) {
+ return;
+ }
+ state->write_full(lhs_var, rhs->var);
+ return;
+ }
+ }
+
+ int orig_swizzle[4] = {0, 1, 2, 3};
+ int swizzle[4];
+
ir_dereference_variable *lhs = ir->lhs->as_dereference_variable();
if (!lhs || !(lhs->type->is_scalar() || lhs->type->is_vector()))
return;
@@ -646,7 +730,7 @@ ir_copy_propagation_elements_visitor::add_copy(ir_assignment *ir)
if (lhs->var->data.precise != rhs->var->data.precise)
return;
- state->write(lhs->var, rhs->var, write_mask, swizzle);
+ state->write_elements(lhs->var, rhs->var, write_mask, swizzle);
}
bool
--
2.18.0
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