diff options
Diffstat (limited to 'mesalib/src/glsl/loop_controls.cpp')
-rw-r--r-- | mesalib/src/glsl/loop_controls.cpp | 608 |
1 files changed, 304 insertions, 304 deletions
diff --git a/mesalib/src/glsl/loop_controls.cpp b/mesalib/src/glsl/loop_controls.cpp index 9acbadc50..9b77ef460 100644 --- a/mesalib/src/glsl/loop_controls.cpp +++ b/mesalib/src/glsl/loop_controls.cpp @@ -1,304 +1,304 @@ -/* - * 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. - */ - -#include <limits.h> -#include "main/compiler.h" -#include "glsl_types.h" -#include "loop_analysis.h" -#include "ir_hierarchical_visitor.h" - -/** - * Find an initializer of a variable outside a loop - * - * Works backwards from the loop to find the pre-loop value of the variable. - * This is used, for example, to find the initial value of loop induction - * variables. - * - * \param loop Loop where \c var is an induction variable - * \param var Variable whose initializer is to be found - * - * \return - * The \c ir_rvalue assigned to the variable outside the loop. May return - * \c NULL if no initializer can be found. - */ -ir_rvalue * -find_initial_value(ir_loop *loop, ir_variable *var) -{ - for (exec_node *node = loop->prev; - !node->is_head_sentinel(); - node = node->prev) { - ir_instruction *ir = (ir_instruction *) node; - - switch (ir->ir_type) { - case ir_type_call: - case ir_type_loop: - case ir_type_loop_jump: - case ir_type_return: - case ir_type_if: - return NULL; - - case ir_type_function: - case ir_type_function_signature: - assert(!"Should not get here."); - return NULL; - - case ir_type_assignment: { - ir_assignment *assign = ir->as_assignment(); - ir_variable *assignee = assign->lhs->whole_variable_referenced(); - - if (assignee == var) - return (assign->condition != NULL) ? NULL : assign->rhs; - - break; - } - - default: - break; - } - } - - return NULL; -} - - -int -calculate_iterations(ir_rvalue *from, ir_rvalue *to, ir_rvalue *increment, - enum ir_expression_operation op) -{ - if (from == NULL || to == NULL || increment == NULL) - return -1; - - void *mem_ctx = ralloc_context(NULL); - - ir_expression *const sub = - new(mem_ctx) ir_expression(ir_binop_sub, from->type, to, from); - - ir_expression *const div = - new(mem_ctx) ir_expression(ir_binop_div, sub->type, sub, increment); - - ir_constant *iter = div->constant_expression_value(); - - if (iter == NULL) - return -1; - - if (!iter->type->is_integer()) { - ir_rvalue *cast = - new(mem_ctx) ir_expression(ir_unop_f2i, glsl_type::int_type, iter, - NULL); - - iter = cast->constant_expression_value(); - } - - int iter_value = iter->get_int_component(0); - - /* Make sure that the calculated number of iterations satisfies the exit - * condition. This is needed to catch off-by-one errors and some types of - * ill-formed loops. For example, we need to detect that the following - * loop does not have a maximum iteration count. - * - * for (float x = 0.0; x != 0.9; x += 0.2) - * ; - */ - const int bias[] = { -1, 0, 1 }; - bool valid_loop = false; - - for (unsigned i = 0; i < Elements(bias); i++) { - iter = (increment->type->is_integer()) - ? new(mem_ctx) ir_constant(iter_value + bias[i]) - : new(mem_ctx) ir_constant(float(iter_value + bias[i])); - - ir_expression *const mul = - new(mem_ctx) ir_expression(ir_binop_mul, increment->type, iter, - increment); - - ir_expression *const add = - new(mem_ctx) ir_expression(ir_binop_add, mul->type, mul, from); - - ir_expression *const cmp = - new(mem_ctx) ir_expression(op, glsl_type::bool_type, add, to); - - ir_constant *const cmp_result = cmp->constant_expression_value(); - - assert(cmp_result != NULL); - if (cmp_result->get_bool_component(0)) { - iter_value += bias[i]; - valid_loop = true; - break; - } - } - - ralloc_free(mem_ctx); - return (valid_loop) ? iter_value : -1; -} - - -class loop_control_visitor : public ir_hierarchical_visitor { -public: - loop_control_visitor(loop_state *state) - { - this->state = state; - this->progress = false; - } - - virtual ir_visitor_status visit_leave(ir_loop *ir); - - loop_state *state; - - bool progress; -}; - - -ir_visitor_status -loop_control_visitor::visit_leave(ir_loop *ir) -{ - loop_variable_state *const ls = this->state->get(ir); - - /* If we've entered a loop that hasn't been analyzed, something really, - * really bad has happened. - */ - if (ls == NULL) { - assert(ls != NULL); - return visit_continue; - } - - /* Search the loop terminating conditions for one of the form 'i < c' where - * i is a loop induction variable, c is a constant, and < is any relative - * operator. - */ - int max_iterations = ls->max_iterations; - - if(ir->from && ir->to && ir->increment) - max_iterations = calculate_iterations(ir->from, ir->to, ir->increment, (ir_expression_operation)ir->cmp); - - if(max_iterations < 0) - max_iterations = INT_MAX; - - foreach_list(node, &ls->terminators) { - loop_terminator *t = (loop_terminator *) node; - ir_if *if_stmt = t->ir; - - /* If-statements can be either 'if (expr)' or 'if (deref)'. We only care - * about the former here. - */ - ir_expression *cond = if_stmt->condition->as_expression(); - if (cond == NULL) - continue; - - switch (cond->operation) { - case ir_binop_less: - case ir_binop_greater: - case ir_binop_lequal: - case ir_binop_gequal: { - /* The expressions that we care about will either be of the form - * 'counter < limit' or 'limit < counter'. Figure out which is - * which. - */ - ir_rvalue *counter = cond->operands[0]->as_dereference_variable(); - ir_constant *limit = cond->operands[1]->as_constant(); - enum ir_expression_operation cmp = cond->operation; - - if (limit == NULL) { - counter = cond->operands[1]->as_dereference_variable(); - limit = cond->operands[0]->as_constant(); - - switch (cmp) { - case ir_binop_less: cmp = ir_binop_gequal; break; - case ir_binop_greater: cmp = ir_binop_lequal; break; - case ir_binop_lequal: cmp = ir_binop_greater; break; - case ir_binop_gequal: cmp = ir_binop_less; break; - default: assert(!"Should not get here."); - } - } - - if ((counter == NULL) || (limit == NULL)) - break; - - ir_variable *var = counter->variable_referenced(); - - ir_rvalue *init = find_initial_value(ir, var); - - foreach_list(iv_node, &ls->induction_variables) { - loop_variable *lv = (loop_variable *) iv_node; - - if (lv->var == var) { - const int iterations = calculate_iterations(init, limit, - lv->increment, - cmp); - if (iterations >= 0) { - /* If the new iteration count is lower than the previously - * believed iteration count, update the loop control values. - */ - if (iterations < max_iterations) { - ir->from = init->clone(ir, NULL); - ir->to = limit->clone(ir, NULL); - ir->increment = lv->increment->clone(ir, NULL); - ir->counter = lv->var; - ir->cmp = cmp; - - max_iterations = iterations; - } - - /* Remove the conditional break statement. The loop - * controls are now set such that the exit condition will be - * satisfied. - */ - if_stmt->remove(); - - assert(ls->num_loop_jumps > 0); - ls->num_loop_jumps--; - - this->progress = true; - } - - break; - } - } - break; - } - - default: - break; - } - } - - /* If we have proven the one of the loop exit conditions is satisifed before - * running the loop once, remove the loop. - */ - if (max_iterations == 0) - ir->remove(); - else - ls->max_iterations = max_iterations; - - return visit_continue; -} - - -bool -set_loop_controls(exec_list *instructions, loop_state *ls) -{ - loop_control_visitor v(ls); - - v.run(instructions); - - return v.progress; -} +/*
+ * 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.
+ */
+
+#include <limits.h>
+#include "main/compiler.h"
+#include "glsl_types.h"
+#include "loop_analysis.h"
+#include "ir_hierarchical_visitor.h"
+
+/**
+ * Find an initializer of a variable outside a loop
+ *
+ * Works backwards from the loop to find the pre-loop value of the variable.
+ * This is used, for example, to find the initial value of loop induction
+ * variables.
+ *
+ * \param loop Loop where \c var is an induction variable
+ * \param var Variable whose initializer is to be found
+ *
+ * \return
+ * The \c ir_rvalue assigned to the variable outside the loop. May return
+ * \c NULL if no initializer can be found.
+ */
+ir_rvalue *
+find_initial_value(ir_loop *loop, ir_variable *var)
+{
+ for (exec_node *node = loop->prev;
+ !node->is_head_sentinel();
+ node = node->prev) {
+ ir_instruction *ir = (ir_instruction *) node;
+
+ switch (ir->ir_type) {
+ case ir_type_call:
+ case ir_type_loop:
+ case ir_type_loop_jump:
+ case ir_type_return:
+ case ir_type_if:
+ return NULL;
+
+ case ir_type_function:
+ case ir_type_function_signature:
+ assert(!"Should not get here.");
+ return NULL;
+
+ case ir_type_assignment: {
+ ir_assignment *assign = ir->as_assignment();
+ ir_variable *assignee = assign->lhs->whole_variable_referenced();
+
+ if (assignee == var)
+ return (assign->condition != NULL) ? NULL : assign->rhs;
+
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+
+ return NULL;
+}
+
+
+int
+calculate_iterations(ir_rvalue *from, ir_rvalue *to, ir_rvalue *increment,
+ enum ir_expression_operation op)
+{
+ if (from == NULL || to == NULL || increment == NULL)
+ return -1;
+
+ void *mem_ctx = ralloc_context(NULL);
+
+ ir_expression *const sub =
+ new(mem_ctx) ir_expression(ir_binop_sub, from->type, to, from);
+
+ ir_expression *const div =
+ new(mem_ctx) ir_expression(ir_binop_div, sub->type, sub, increment);
+
+ ir_constant *iter = div->constant_expression_value();
+
+ if (iter == NULL)
+ return -1;
+
+ if (!iter->type->is_integer()) {
+ ir_rvalue *cast =
+ new(mem_ctx) ir_expression(ir_unop_f2i, glsl_type::int_type, iter,
+ NULL);
+
+ iter = cast->constant_expression_value();
+ }
+
+ int iter_value = iter->get_int_component(0);
+
+ /* Make sure that the calculated number of iterations satisfies the exit
+ * condition. This is needed to catch off-by-one errors and some types of
+ * ill-formed loops. For example, we need to detect that the following
+ * loop does not have a maximum iteration count.
+ *
+ * for (float x = 0.0; x != 0.9; x += 0.2)
+ * ;
+ */
+ const int bias[] = { -1, 0, 1 };
+ bool valid_loop = false;
+
+ for (unsigned i = 0; i < Elements(bias); i++) {
+ iter = (increment->type->is_integer())
+ ? new(mem_ctx) ir_constant(iter_value + bias[i])
+ : new(mem_ctx) ir_constant(float(iter_value + bias[i]));
+
+ ir_expression *const mul =
+ new(mem_ctx) ir_expression(ir_binop_mul, increment->type, iter,
+ increment);
+
+ ir_expression *const add =
+ new(mem_ctx) ir_expression(ir_binop_add, mul->type, mul, from);
+
+ ir_expression *const cmp =
+ new(mem_ctx) ir_expression(op, glsl_type::bool_type, add, to);
+
+ ir_constant *const cmp_result = cmp->constant_expression_value();
+
+ assert(cmp_result != NULL);
+ if (cmp_result->get_bool_component(0)) {
+ iter_value += bias[i];
+ valid_loop = true;
+ break;
+ }
+ }
+
+ ralloc_free(mem_ctx);
+ return (valid_loop) ? iter_value : -1;
+}
+
+
+class loop_control_visitor : public ir_hierarchical_visitor {
+public:
+ loop_control_visitor(loop_state *state)
+ {
+ this->state = state;
+ this->progress = false;
+ }
+
+ virtual ir_visitor_status visit_leave(ir_loop *ir);
+
+ loop_state *state;
+
+ bool progress;
+};
+
+
+ir_visitor_status
+loop_control_visitor::visit_leave(ir_loop *ir)
+{
+ loop_variable_state *const ls = this->state->get(ir);
+
+ /* If we've entered a loop that hasn't been analyzed, something really,
+ * really bad has happened.
+ */
+ if (ls == NULL) {
+ assert(ls != NULL);
+ return visit_continue;
+ }
+
+ /* Search the loop terminating conditions for one of the form 'i < c' where
+ * i is a loop induction variable, c is a constant, and < is any relative
+ * operator.
+ */
+ int max_iterations = ls->max_iterations;
+
+ if(ir->from && ir->to && ir->increment)
+ max_iterations = calculate_iterations(ir->from, ir->to, ir->increment, (ir_expression_operation)ir->cmp);
+
+ if(max_iterations < 0)
+ max_iterations = INT_MAX;
+
+ foreach_list(node, &ls->terminators) {
+ loop_terminator *t = (loop_terminator *) node;
+ ir_if *if_stmt = t->ir;
+
+ /* If-statements can be either 'if (expr)' or 'if (deref)'. We only care
+ * about the former here.
+ */
+ ir_expression *cond = if_stmt->condition->as_expression();
+ if (cond == NULL)
+ continue;
+
+ switch (cond->operation) {
+ case ir_binop_less:
+ case ir_binop_greater:
+ case ir_binop_lequal:
+ case ir_binop_gequal: {
+ /* The expressions that we care about will either be of the form
+ * 'counter < limit' or 'limit < counter'. Figure out which is
+ * which.
+ */
+ ir_rvalue *counter = cond->operands[0]->as_dereference_variable();
+ ir_constant *limit = cond->operands[1]->as_constant();
+ enum ir_expression_operation cmp = cond->operation;
+
+ if (limit == NULL) {
+ counter = cond->operands[1]->as_dereference_variable();
+ limit = cond->operands[0]->as_constant();
+
+ switch (cmp) {
+ case ir_binop_less: cmp = ir_binop_gequal; break;
+ case ir_binop_greater: cmp = ir_binop_lequal; break;
+ case ir_binop_lequal: cmp = ir_binop_greater; break;
+ case ir_binop_gequal: cmp = ir_binop_less; break;
+ default: assert(!"Should not get here.");
+ }
+ }
+
+ if ((counter == NULL) || (limit == NULL))
+ break;
+
+ ir_variable *var = counter->variable_referenced();
+
+ ir_rvalue *init = find_initial_value(ir, var);
+
+ foreach_list(iv_node, &ls->induction_variables) {
+ loop_variable *lv = (loop_variable *) iv_node;
+
+ if (lv->var == var) {
+ const int iterations = calculate_iterations(init, limit,
+ lv->increment,
+ cmp);
+ if (iterations >= 0) {
+ /* If the new iteration count is lower than the previously
+ * believed iteration count, update the loop control values.
+ */
+ if (iterations < max_iterations) {
+ ir->from = init->clone(ir, NULL);
+ ir->to = limit->clone(ir, NULL);
+ ir->increment = lv->increment->clone(ir, NULL);
+ ir->counter = lv->var;
+ ir->cmp = cmp;
+
+ max_iterations = iterations;
+ }
+
+ /* Remove the conditional break statement. The loop
+ * controls are now set such that the exit condition will be
+ * satisfied.
+ */
+ if_stmt->remove();
+
+ assert(ls->num_loop_jumps > 0);
+ ls->num_loop_jumps--;
+
+ this->progress = true;
+ }
+
+ break;
+ }
+ }
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+
+ /* If we have proven the one of the loop exit conditions is satisifed before
+ * running the loop once, remove the loop.
+ */
+ if (max_iterations == 0)
+ ir->remove();
+ else
+ ls->max_iterations = max_iterations;
+
+ return visit_continue;
+}
+
+
+bool
+set_loop_controls(exec_list *instructions, loop_state *ls)
+{
+ loop_control_visitor v(ls);
+
+ v.run(instructions);
+
+ return v.progress;
+}
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