Module: Mesa
Branch: shader-work
Commit: fa93dadda31decb7869fc856f58b5eaade284923
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=fa93dadda31decb7869fc856f58b5eaade284923
Author: Luca Barbieri <l...@luca-barbieri.com>
Date: Tue Sep 14 04:56:34 2010 +0200
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 files changed, 76 insertions(+), 54 deletions(-)
diff --git a/src/glsl/loop_unroll.cpp b/src/glsl/loop_unroll.cpp
index 90797bd..6308907 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);
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