* DEALINGS IN THE SOFTWARE.
*/
-#include <climits>
+#include <limits.h>
#include "main/compiler.h"
#include "glsl_types.h"
#include "loop_analysis.h"
calculate_iterations(ir_rvalue *from, ir_rvalue *to, ir_rvalue *increment,
enum ir_expression_operation op)
{
- void *mem_ctx = talloc_init(__func__);
+ 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);
}
}
- talloc_free(mem_ctx);
+ ralloc_free(mem_ctx);
return (valid_loop) ? iter_value : -1;
}
+namespace {
class loop_control_visitor : public ir_hierarchical_visitor {
public:
bool progress;
};
+} /* anonymous namespace */
ir_visitor_status
loop_control_visitor::visit_leave(ir_loop *ir)
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.
+ if (ls->limiting_terminator != NULL) {
+ /* If the limiting terminator has an iteration count of zero, then we've
+ * proven that the loop cannot run, so delete it.
+ */
+ int iterations = ls->limiting_terminator->iterations;
+ if (iterations == 0) {
+ ir->remove();
+ this->progress = true;
+ return visit_continue;
+ }
+ }
+
+ /* Remove the conditional break statements associated with all terminators
+ * that are associated with a fixed iteration count, except for the one
+ * associated with the limiting terminator--that one needs to stay, since
+ * it terminates the loop. Exception: if the loop still has a normative
+ * bound, then that terminates the loop, so we don't even need the limiting
+ * terminator.
*/
- int max_iterations = (ls->max_iterations < 0) ? INT_MAX : ls->max_iterations;
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;
- }
+ if (t->iterations < 0)
+ continue;
- default:
- break;
+ if (t != ls->limiting_terminator) {
+ t->ir->remove();
+
+ assert(ls->num_loop_jumps > 0);
+ ls->num_loop_jumps--;
+
+ this->progress = true;
}
}
- /* 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;
}
projects / mesa.git / blobdiff