From b8481d8366604f949cf5c33c8ccc34d90d46f9a0 Mon Sep 17 00:00:00 2001 From: Luca Barbieri Date: Tue, 14 Sep 2010 04:56:34 +0200 Subject: glsl/loop_unroll: unroll loops with cond breaks anywhere, not just the end Currently we only unroll loops with conditional breaks at the end, which is the form that ir_lower_jumps generates. However, if breaks are not lowered, they tend to appear at the beginning, so add support for a conditional break anywhere. --- src/glsl/loop_unroll.cpp | 130 +++++++++++++++++++++++++++-------------------- 1 file changed, 76 insertions(+), 54 deletions(-) diff --git a/src/glsl/loop_unroll.cpp b/src/glsl/loop_unroll.cpp index 90797bde37..6308907d1d 100644 --- a/src/glsl/loop_unroll.cpp +++ b/src/glsl/loop_unroll.cpp @@ -73,44 +73,77 @@ loop_unroll_visitor::visit_leave(ir_loop *ir) if (ls->num_loop_jumps > 1) return visit_continue; else if (ls->num_loop_jumps) { - /* recognize loops in the form produced by ir_lower_jumps */ - ir_instruction *last_ir = - ((ir_instruction*)ir->body_instructions.get_tail()); - - assert(last_ir != NULL); - - ir_if *last_if = last_ir->as_if(); - if (last_if) { - bool continue_from_then_branch; - - /* Determine which if-statement branch, if any, ends with a break. - * The branch that did *not* have the break will get a temporary - * continue inserted in each iteration of the loop unroll. - * - * Note that since ls->num_loop_jumps is <= 1, it is impossible for - * both branches to end with a break. - */ - ir_instruction *last = - (ir_instruction *) last_if->then_instructions.get_tail(); - - if (last && last->ir_type == ir_type_loop_jump - && ((ir_loop_jump*) last)->is_break()) { - continue_from_then_branch = false; - } else { - last = (ir_instruction *) last_if->then_instructions.get_tail(); - - if (last && last->ir_type == ir_type_loop_jump - && ((ir_loop_jump*) last)->is_break()) - continue_from_then_branch = true; - else - /* Bail out if neither if-statement branch ends with a break. - */ - return visit_continue; - } - - /* Remove the break from the if-statement. - */ - last->remove(); + ir_instruction *last_ir = ((ir_instruction*)ir->body_instructions.get_tail()); + + if (last_ir->ir_type == ir_type_loop_jump + && ((ir_loop_jump*)last_ir)->is_break()) { + /* If the only loop-jump is a break at the end of the loop, the loop + * will execute exactly once. Remove the break, set the iteration + * count, and fall through to the normal unroller. + */ + last_ir->remove(); + iterations = 1; + + this->progress = true; + } else { + ir_if *ir_if = 0; + ir_instruction *break_ir = 0; + bool continue_from_then_branch = false; + + foreach_list(node, &ir->body_instructions) { + /* recognize loops in the form produced by ir_lower_jumps */ + ir_instruction* cur_ir = (ir_instruction*)node; + + assert(last_ir != NULL); + + ir_if = cur_ir->as_if(); + if (ir_if) { + /* Determine which if-statement branch, if any, ends with a break. + * The branch that did *not* have the break will get a temporary + * continue inserted in each iteration of the loop unroll. + * + * Note that since ls->num_loop_jumps is <= 1, it is impossible for + * both branches to end with a break. + */ + ir_instruction *ir_if_last = + (ir_instruction *) ir_if->then_instructions.get_tail(); + + if (ir_if_last && ir_if_last->ir_type == ir_type_loop_jump + && ((ir_loop_jump*) ir_if_last)->is_break()) { + continue_from_then_branch = false; + break_ir = ir_if_last; + break; + } else { + ir_if_last = (ir_instruction *) ir_if->then_instructions.get_tail(); + + if (ir_if_last && ir_if_last->ir_type == ir_type_loop_jump + && ((ir_loop_jump*) ir_if_last)->is_break()) + { + break_ir = ir_if_last; + continue_from_then_branch = true; + break; + } + } + } + } + + if(!break_ir) + return visit_continue; + + /* move instructions after then if in the continue branch */ + while (!ir_if->get_next()->is_tail_sentinel()) { + ir_instruction *move_ir = (ir_instruction *)ir_if->get_next(); + + move_ir->remove(); + if(continue_from_then_branch) + ir_if->then_instructions.push_tail(move_ir); + else + ir_if->else_instructions.push_tail(move_ir); + } + + /* Remove the break from the if-statement. + */ + break_ir->remove(); void *const mem_ctx = talloc_parent(ir); ir_instruction *ir_to_replace = ir; @@ -121,18 +154,18 @@ loop_unroll_visitor::visit_leave(ir_loop *ir) copy_list.make_empty(); clone_ir_list(mem_ctx, ©_list, &ir->body_instructions); - last_if = ((ir_instruction*)copy_list.get_tail())->as_if(); - assert(last_if); + ir_if = ((ir_instruction*)copy_list.get_tail())->as_if(); + assert(ir_if); ir_to_replace->insert_before(©_list); ir_to_replace->remove(); /* placeholder that will be removed in the next iteration */ ir_to_replace = - new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_continue); + new(mem_ctx) ir_loop_jump(ir_loop_jump::jump_continue); exec_list *const list = (continue_from_then_branch) - ? &last_if->then_instructions : &last_if->else_instructions; + ? &ir_if->then_instructions : &ir_if->else_instructions; list->push_tail(ir_to_replace); } @@ -141,18 +174,7 @@ loop_unroll_visitor::visit_leave(ir_loop *ir) this->progress = true; return visit_continue; - } else if (last_ir->ir_type == ir_type_loop_jump - && ((ir_loop_jump *)last_ir)->is_break()) { - /* If the only loop-jump is a break at the end of the loop, the loop - * will execute exactly once. Remove the break, set the iteration - * count, and fall through to the normal unroller. - */ - last_ir->remove(); - iterations = 1; - - this->progress = true; - } else - return visit_continue; + } } void *const mem_ctx = talloc_parent(ir); -- cgit v1.2.3