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authorEric Anholt <eric@anholt.net>2014-03-05 17:05:54 -0800
committerEric Anholt <eric@anholt.net>2014-04-08 00:59:47 -0700
commite9822f77a9cc024f528d30382fd5ad21c73a173b (patch)
treea4ac719a37841c77a8112d598323a9a1752a5758
parentdff3439fef8690192bcc40108729da711fcf706b (diff)
glsl: Skip making a temporary for assignments when we don't need one.
While we wish our optimization passes could identify all the cases where we can coalesce our variables, we miss out on a lot of opportunities. total instructions in shared programs: 1673849 -> 1673166 (-0.04%) instructions in affected programs: 299521 -> 298838 (-0.23%) GAINED: 7 LOST: 0 Note that many programs are "hurt". The notable ones are where we produce unrolling in cases we didn't before (presumably just because of the lower instruction count). But there are also some cases where pushing things right into the variables prevents copy propagation and tree grafting, since we don't split our variable usage webs apart. Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
-rw-r--r--src/glsl/ast.h13
-rw-r--r--src/glsl/ast_to_hir.cpp171
2 files changed, 123 insertions, 61 deletions
diff --git a/src/glsl/ast.h b/src/glsl/ast.h
index ae70b003cfe..6b136f51879 100644
--- a/src/glsl/ast.h
+++ b/src/glsl/ast.h
@@ -217,6 +217,13 @@ public:
virtual ir_rvalue *hir(exec_list *instructions,
struct _mesa_glsl_parse_state *state);
+ virtual void hir_no_rvalue(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state);
+
+ ir_rvalue *do_hir(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state,
+ bool needs_rvalue);
+
virtual void print(void) const;
enum ast_operators oper;
@@ -287,6 +294,9 @@ public:
virtual ir_rvalue *hir(exec_list *instructions,
struct _mesa_glsl_parse_state *state);
+ virtual void hir_no_rvalue(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state);
+
private:
/**
* Is this function call actually a constructor?
@@ -359,6 +369,9 @@ public:
virtual ir_rvalue *hir(exec_list *instructions,
struct _mesa_glsl_parse_state *state);
+
+ virtual void hir_no_rvalue(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state);
};
/**
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 8f6e90174e0..8d55ee31713 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -56,6 +56,9 @@
#include "glsl_types.h"
#include "program/hash_table.h"
#include "ir.h"
+#include "ir_builder.h"
+
+using namespace ir_builder;
static void
detect_conflicting_assignments(struct _mesa_glsl_parse_state *state,
@@ -733,10 +736,12 @@ mark_whole_array_access(ir_rvalue *access)
}
}
-ir_rvalue *
+static bool
do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
const char *non_lvalue_description,
- ir_rvalue *lhs, ir_rvalue *rhs, bool is_initializer,
+ ir_rvalue *lhs, ir_rvalue *rhs,
+ ir_rvalue **out_rvalue, bool needs_rvalue,
+ bool is_initializer,
YYLTYPE lhs_loc)
{
void *ctx = state;
@@ -855,27 +860,33 @@ do_assignment(exec_list *instructions, struct _mesa_glsl_parse_state *state,
* to handle things like:
*
* i = j += 1;
- *
- * So we always just store the computed value being assigned to a
- * temporary and return a deref of that temporary. If the rvalue
- * ends up not being used, the temp will get copy-propagated out.
*/
- ir_variable *var = new(ctx) ir_variable(rhs->type, "assignment_tmp",
- ir_var_temporary);
- ir_dereference_variable *deref_var = new(ctx) ir_dereference_variable(var);
- instructions->push_tail(var);
- instructions->push_tail(new(ctx) ir_assignment(deref_var, rhs));
- deref_var = new(ctx) ir_dereference_variable(var);
+ if (needs_rvalue) {
+ ir_variable *var = new(ctx) ir_variable(rhs->type, "assignment_tmp",
+ ir_var_temporary);
+ instructions->push_tail(var);
+ instructions->push_tail(assign(var, rhs));
+
+ if (!error_emitted) {
+ ir_dereference_variable *deref_var = new(ctx) ir_dereference_variable(var);
+ instructions->push_tail(new(ctx) ir_assignment(lhs, deref_var));
+ }
+ ir_rvalue *rvalue = new(ctx) ir_dereference_variable(var);
- if (!error_emitted)
- instructions->push_tail(new(ctx) ir_assignment(lhs, deref_var));
+ if (extract_channel) {
+ rvalue = new(ctx) ir_expression(ir_binop_vector_extract,
+ rvalue,
+ extract_channel->clone(ctx, NULL));
+ }
- if (extract_channel) {
- return new(ctx) ir_expression(ir_binop_vector_extract,
- new(ctx) ir_dereference_variable(var),
- extract_channel->clone(ctx, NULL));
+ *out_rvalue = rvalue;
+ } else {
+ if (!error_emitted)
+ instructions->push_tail(new(ctx) ir_assignment(lhs, rhs));
+ *out_rvalue = NULL;
}
- return new(ctx) ir_dereference_variable(var);
+
+ return error_emitted;
}
static ir_rvalue *
@@ -906,6 +917,20 @@ ast_node::hir(exec_list *instructions,
return NULL;
}
+void
+ast_function_expression::hir_no_rvalue(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state)
+{
+ (void)hir(instructions, state);
+}
+
+void
+ast_aggregate_initializer::hir_no_rvalue(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state)
+{
+ (void)hir(instructions, state);
+}
+
static ir_rvalue *
do_comparison(void *mem_ctx, int operation, ir_rvalue *op0, ir_rvalue *op1)
{
@@ -1075,6 +1100,21 @@ ir_rvalue *
ast_expression::hir(exec_list *instructions,
struct _mesa_glsl_parse_state *state)
{
+ return do_hir(instructions, state, true);
+}
+
+void
+ast_expression::hir_no_rvalue(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state)
+{
+ do_hir(instructions, state, false);
+}
+
+ir_rvalue *
+ast_expression::do_hir(exec_list *instructions,
+ struct _mesa_glsl_parse_state *state,
+ bool needs_rvalue)
+{
void *ctx = state;
static const int operations[AST_NUM_OPERATORS] = {
-1, /* ast_assign doesn't convert to ir_expression. */
@@ -1148,11 +1188,11 @@ ast_expression::hir(exec_list *instructions,
op[0] = this->subexpressions[0]->hir(instructions, state);
op[1] = this->subexpressions[1]->hir(instructions, state);
- result = do_assignment(instructions, state,
- this->subexpressions[0]->non_lvalue_description,
- op[0], op[1], false,
- this->subexpressions[0]->get_location());
- error_emitted = result->type->is_error();
+ error_emitted =
+ do_assignment(instructions, state,
+ this->subexpressions[0]->non_lvalue_description,
+ op[0], op[1], &result, needs_rvalue, false,
+ this->subexpressions[0]->get_location());
break;
}
@@ -1418,11 +1458,12 @@ ast_expression::hir(exec_list *instructions,
ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper], type,
op[0], op[1]);
- result = do_assignment(instructions, state,
- this->subexpressions[0]->non_lvalue_description,
- op[0]->clone(ctx, NULL), temp_rhs, false,
- this->subexpressions[0]->get_location());
- error_emitted = (op[0]->type->is_error());
+ error_emitted =
+ do_assignment(instructions, state,
+ this->subexpressions[0]->non_lvalue_description,
+ op[0]->clone(ctx, NULL), temp_rhs,
+ &result, needs_rvalue, false,
+ this->subexpressions[0]->get_location());
/* GLSL 1.10 does not allow array assignment. However, we don't have to
* explicitly test for this because none of the binary expression
@@ -1444,11 +1485,12 @@ ast_expression::hir(exec_list *instructions,
temp_rhs = new(ctx) ir_expression(operations[this->oper], type,
op[0], op[1]);
- result = do_assignment(instructions, state,
- this->subexpressions[0]->non_lvalue_description,
- op[0]->clone(ctx, NULL), temp_rhs, false,
- this->subexpressions[0]->get_location());
- error_emitted = type->is_error();
+ error_emitted =
+ do_assignment(instructions, state,
+ this->subexpressions[0]->non_lvalue_description,
+ op[0]->clone(ctx, NULL), temp_rhs,
+ &result, needs_rvalue, false,
+ this->subexpressions[0]->get_location());
break;
}
@@ -1460,11 +1502,12 @@ ast_expression::hir(exec_list *instructions,
&loc);
ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper],
type, op[0], op[1]);
- result = do_assignment(instructions, state,
- this->subexpressions[0]->non_lvalue_description,
- op[0]->clone(ctx, NULL), temp_rhs, false,
- this->subexpressions[0]->get_location());
- error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
+ error_emitted =
+ do_assignment(instructions, state,
+ this->subexpressions[0]->non_lvalue_description,
+ op[0]->clone(ctx, NULL), temp_rhs,
+ &result, needs_rvalue, false,
+ this->subexpressions[0]->get_location());
break;
}
@@ -1477,11 +1520,12 @@ ast_expression::hir(exec_list *instructions,
state, &loc);
ir_rvalue *temp_rhs = new(ctx) ir_expression(operations[this->oper],
type, op[0], op[1]);
- result = do_assignment(instructions, state,
- this->subexpressions[0]->non_lvalue_description,
- op[0]->clone(ctx, NULL), temp_rhs, false,
- this->subexpressions[0]->get_location());
- error_emitted = op[0]->type->is_error() || op[1]->type->is_error();
+ error_emitted =
+ do_assignment(instructions, state,
+ this->subexpressions[0]->non_lvalue_description,
+ op[0]->clone(ctx, NULL), temp_rhs,
+ &result, needs_rvalue, false,
+ this->subexpressions[0]->get_location());
break;
}
@@ -1589,11 +1633,12 @@ ast_expression::hir(exec_list *instructions,
temp_rhs = new(ctx) ir_expression(operations[this->oper], type,
op[0], op[1]);
- result = do_assignment(instructions, state,
- this->subexpressions[0]->non_lvalue_description,
- op[0]->clone(ctx, NULL), temp_rhs, false,
- this->subexpressions[0]->get_location());
- error_emitted = op[0]->type->is_error();
+ error_emitted =
+ do_assignment(instructions, state,
+ this->subexpressions[0]->non_lvalue_description,
+ op[0]->clone(ctx, NULL), temp_rhs,
+ &result, needs_rvalue, false,
+ this->subexpressions[0]->get_location());
break;
}
@@ -1617,12 +1662,14 @@ ast_expression::hir(exec_list *instructions,
*/
result = get_lvalue_copy(instructions, op[0]->clone(ctx, NULL));
- (void)do_assignment(instructions, state,
- this->subexpressions[0]->non_lvalue_description,
- op[0]->clone(ctx, NULL), temp_rhs, false,
- this->subexpressions[0]->get_location());
+ ir_rvalue *junk_rvalue;
+ error_emitted =
+ do_assignment(instructions, state,
+ this->subexpressions[0]->non_lvalue_description,
+ op[0]->clone(ctx, NULL), temp_rhs,
+ &junk_rvalue, false, false,
+ this->subexpressions[0]->get_location());
- error_emitted = op[0]->type->is_error();
break;
}
@@ -1744,9 +1791,9 @@ ast_expression::hir(exec_list *instructions,
}
}
type = NULL; /* use result->type, not type. */
- assert(result != NULL);
+ assert(result != NULL || !needs_rvalue);
- if (result->type->is_error() && !error_emitted)
+ if (result && result->type->is_error() && !error_emitted)
_mesa_glsl_error(& loc, state, "type mismatch");
return result;
@@ -1767,7 +1814,7 @@ ast_expression_statement::hir(exec_list *instructions,
* anything in that case.
*/
if (expression != NULL)
- expression->hir(instructions, state);
+ expression->hir_no_rvalue(instructions, state);
/* Statements do not have r-values.
*/
@@ -2831,10 +2878,12 @@ process_initializer(ir_variable *var, ast_declaration *decl,
*/
const glsl_type *initializer_type;
if (!type->qualifier.flags.q.uniform) {
- result = do_assignment(initializer_instructions, state,
- NULL,
- lhs, rhs, true,
- type->get_location());
+ do_assignment(initializer_instructions, state,
+ NULL,
+ lhs, rhs,
+ &result, true,
+ true,
+ type->get_location());
initializer_type = result->type;
} else
initializer_type = rhs->type;