--- /dev/null
+/*
+ * Copyright © 2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file brw_wm_channel_expressions.cpp
+ *
+ * Breaks vector operations down into operations on each component.
+ *
+ * The 965 fragment shader receives 8 or 16 pixels at a time, so each
+ * channel of a vector is laid out as 1 or 2 8-float registers. Each
+ * ALU operation operates on one of those channel registers. As a
+ * result, there is no value to the 965 fragment shader in tracking
+ * "vector" expressions in the sense of GLSL fragment shaders, when
+ * doing a channel at a time may help in constant folding, algebraic
+ * simplification, and reducing the liveness of channel registers.
+ *
+ * The exception to the desire to break everything down to floats is
+ * texturing. The texture sampler returns a writemasked masked
+ * 4/8-register sequence containing the texture values. We don't want
+ * to dispatch to the sampler separately for each channel we need, so
+ * we do retain the vector types in that case.
+ */
+
+extern "C" {
+#include "main/core.h"
+#include "brw_wm.h"
+}
+#include "../glsl/ir.h"
+#include "../glsl/ir_expression_flattening.h"
+#include "../glsl/glsl_types.h"
+
+class ir_channel_expressions_visitor : public ir_hierarchical_visitor {
+public:
+ ir_channel_expressions_visitor()
+ {
+ this->progress = false;
+ this->mem_ctx = NULL;
+ }
+
+ ir_visitor_status visit_leave(ir_assignment *);
+
+ ir_rvalue *get_element(ir_variable *var, unsigned int element);
+ void assign(ir_assignment *ir, int elem, ir_rvalue *val);
+
+ bool progress;
+ void *mem_ctx;
+};
+
+static bool
+channel_expressions_predicate(ir_instruction *ir)
+{
+ ir_expression *expr = ir->as_expression();
+ unsigned int i;
+
+ if (!expr)
+ return false;
+
+ for (i = 0; i < expr->get_num_operands(); i++) {
+ if (expr->operands[i]->type->is_vector())
+ return true;
+ }
+
+ return false;
+}
+
+extern "C" {
+GLboolean
+brw_do_channel_expressions(exec_list *instructions)
+{
+ ir_channel_expressions_visitor v;
+
+ /* Pull out any matrix expression to a separate assignment to a
+ * temp. This will make our handling of the breakdown to
+ * operations on the matrix's vector components much easier.
+ */
+ do_expression_flattening(instructions, channel_expressions_predicate);
+
+ visit_list_elements(&v, instructions);
+
+ return v.progress;
+}
+}
+
+ir_rvalue *
+ir_channel_expressions_visitor::get_element(ir_variable *var, unsigned int elem)
+{
+ ir_dereference *deref;
+
+ if (var->type->is_scalar())
+ return new(mem_ctx) ir_dereference_variable(var);
+
+ assert(elem < var->type->components());
+ deref = new(mem_ctx) ir_dereference_variable(var);
+ return new(mem_ctx) ir_swizzle(deref, elem, 0, 0, 0, 1);
+}
+
+void
+ir_channel_expressions_visitor::assign(ir_assignment *ir, int elem, ir_rvalue *val)
+{
+ ir_dereference *lhs = ir->lhs->clone(mem_ctx, NULL);
+ ir_assignment *assign;
+ ir_swizzle *val_swiz;
+
+ /* This assign-of-expression should have been generated by the
+ * expression flattening visitor (since we never short circit to
+ * not flatten, even for plain assignments of variables), so the
+ * writemask is always full.
+ */
+ assert(ir->write_mask == (1 << ir->lhs->type->components()) - 1);
+
+ /* Smear the float across all the channels for the masked write. */
+ val_swiz = new(mem_ctx) ir_swizzle(val, 0, 0, 0, 0,
+ ir->lhs->type->components());
+ assign = new(mem_ctx) ir_assignment(lhs, val_swiz, NULL, (1 << elem));
+ ir->insert_before(assign);
+}
+
+ir_visitor_status
+ir_channel_expressions_visitor::visit_leave(ir_assignment *ir)
+{
+ ir_expression *expr = ir->rhs->as_expression();
+ bool found_vector = false;
+ unsigned int i, vector_elements = 1;
+ ir_variable *op_var[2];
+
+ if (!expr)
+ return visit_continue;
+
+ if (!this->mem_ctx)
+ this->mem_ctx = talloc_parent(ir);
+
+ for (i = 0; i < expr->get_num_operands(); i++) {
+ if (expr->operands[i]->type->is_vector()) {
+ found_vector = true;
+ vector_elements = expr->operands[i]->type->vector_elements;
+ break;
+ }
+ }
+ if (!found_vector)
+ return visit_continue;
+
+ /* Store the expression operands in temps so we can use them
+ * multiple times.
+ */
+ for (i = 0; i < expr->get_num_operands(); i++) {
+ ir_assignment *assign;
+ ir_dereference *deref;
+
+ assert(!expr->operands[i]->type->is_matrix());
+
+ op_var[i] = new(mem_ctx) ir_variable(expr->operands[i]->type,
+ "channel_expressions",
+ ir_var_temporary);
+ ir->insert_before(op_var[i]);
+
+ deref = new(mem_ctx) ir_dereference_variable(op_var[i]);
+ assign = new(mem_ctx) ir_assignment(deref,
+ expr->operands[i],
+ NULL);
+ ir->insert_before(assign);
+ }
+
+ const glsl_type *element_type = glsl_type::get_instance(ir->lhs->type->base_type,
+ 1, 1);
+
+ /* OK, time to break down this vector operation. */
+ switch (expr->operation) {
+ case ir_unop_bit_not:
+ case ir_unop_logic_not:
+ case ir_unop_neg:
+ case ir_unop_abs:
+ case ir_unop_sign:
+ case ir_unop_rcp:
+ case ir_unop_rsq:
+ case ir_unop_sqrt:
+ case ir_unop_exp:
+ case ir_unop_log:
+ case ir_unop_exp2:
+ case ir_unop_log2:
+ case ir_unop_f2i:
+ case ir_unop_i2f:
+ case ir_unop_f2b:
+ case ir_unop_b2f:
+ case ir_unop_i2b:
+ case ir_unop_b2i:
+ case ir_unop_u2f:
+ case ir_unop_trunc:
+ case ir_unop_ceil:
+ case ir_unop_floor:
+ case ir_unop_fract:
+ case ir_unop_sin:
+ case ir_unop_cos:
+ case ir_unop_dFdx:
+ case ir_unop_dFdy:
+ for (i = 0; i < vector_elements; i++) {
+ ir_rvalue *op0 = get_element(op_var[0], i);
+
+ assign(ir, i, new(mem_ctx) ir_expression(expr->operation,
+ element_type,
+ op0,
+ NULL));
+ }
+ break;
+
+ case ir_binop_add:
+ case ir_binop_sub:
+ case ir_binop_mul:
+ case ir_binop_div:
+ case ir_binop_mod:
+ case ir_binop_min:
+ case ir_binop_max:
+ case ir_binop_pow:
+ case ir_binop_lshift:
+ case ir_binop_rshift:
+ case ir_binop_bit_and:
+ case ir_binop_bit_xor:
+ case ir_binop_bit_or:
+ for (i = 0; i < vector_elements; i++) {
+ ir_rvalue *op0 = get_element(op_var[0], i);
+ ir_rvalue *op1 = get_element(op_var[1], i);
+
+ assign(ir, i, new(mem_ctx) ir_expression(expr->operation,
+ element_type,
+ op0,
+ op1));
+ }
+ break;
+
+ case ir_unop_any: {
+ ir_expression *temp;
+ temp = new(mem_ctx) ir_expression(ir_binop_logic_or,
+ element_type,
+ get_element(op_var[0], 0),
+ get_element(op_var[0], 1));
+
+ for (i = 2; i < vector_elements; i++) {
+ temp = new(mem_ctx) ir_expression(ir_binop_logic_or,
+ element_type,
+ get_element(op_var[0], i),
+ temp);
+ }
+ assign(ir, 0, temp);
+ break;
+ }
+
+ case ir_binop_dot: {
+ ir_expression *last = NULL;
+ for (i = 0; i < vector_elements; i++) {
+ ir_rvalue *op0 = get_element(op_var[0], i);
+ ir_rvalue *op1 = get_element(op_var[1], i);
+ ir_expression *temp;
+
+ temp = new(mem_ctx) ir_expression(ir_binop_mul,
+ element_type,
+ op0,
+ op1);
+ if (last) {
+ last = new(mem_ctx) ir_expression(ir_binop_add,
+ element_type,
+ temp,
+ last);
+ } else {
+ last = temp;
+ }
+ }
+ assign(ir, 0, last);
+ break;
+ }
+
+ case ir_binop_cross: {
+ for (i = 0; i < vector_elements; i++) {
+ int swiz0 = (i + 1) % 3;
+ int swiz1 = (i + 2) % 3;
+ ir_expression *temp1, *temp2;
+
+ temp1 = new(mem_ctx) ir_expression(ir_binop_mul,
+ element_type,
+ get_element(op_var[0], swiz0),
+ get_element(op_var[1], swiz1));
+
+ temp2 = new(mem_ctx) ir_expression(ir_binop_mul,
+ element_type,
+ get_element(op_var[1], swiz0),
+ get_element(op_var[0], swiz1));
+
+ temp2 = new(mem_ctx) ir_expression(ir_unop_neg,
+ element_type,
+ temp2,
+ NULL);
+
+ assign(ir, i, new(mem_ctx) ir_expression(ir_binop_add,
+ element_type,
+ temp1, temp2));
+ }
+ break;
+ }
+
+ case ir_binop_less:
+ case ir_binop_greater:
+ case ir_binop_lequal:
+ case ir_binop_gequal:
+ case ir_binop_logic_and:
+ case ir_binop_logic_xor:
+ case ir_binop_logic_or:
+ ir->print();
+ printf("\n");
+ assert(!"not reached: expression operates on scalars only");
+ break;
+ case ir_binop_equal:
+ case ir_binop_nequal: {
+ ir_expression *last = NULL;
+ for (i = 0; i < vector_elements; i++) {
+ ir_rvalue *op0 = get_element(op_var[0], i);
+ ir_rvalue *op1 = get_element(op_var[1], i);
+ ir_expression *temp;
+ ir_expression_operation join;
+
+ if (expr->operation == ir_binop_equal)
+ join = ir_binop_logic_and;
+ else
+ join = ir_binop_logic_or;
+
+ temp = new(mem_ctx) ir_expression(expr->operation,
+ element_type,
+ op0,
+ op1);
+ if (last) {
+ last = new(mem_ctx) ir_expression(join,
+ element_type,
+ temp,
+ last);
+ } else {
+ last = temp;
+ }
+ }
+ assign(ir, 0, last);
+ break;
+ }
+ }
+
+ ir->remove();
+ this->progress = true;
+
+ return visit_continue;
+}
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