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authorLuca Barbieri <luca@luca-barbieri.com>2010-12-01 15:12:07 -0800
committerIan Romanick <ian.d.romanick@intel.com>2010-12-09 16:42:05 -0800
commit0e50c21e247b6d4246fcc2b583563a8f44bc4249 (patch)
treecf9d9a9a2b5099bb2dfb42e8f203bd751e40e1b4
parent13c45c590b69341487acf21f339bf1e502eedee6 (diff)
glsl: Unroll loops with conditional breaks anywhere (not just the end)7.10-branchpoint
Currently we only unroll loops with conditional breaks at the end, which is the form that lower_jumps generates. However, if breaks are not lowered, they tend to appear at the beginning, so add support for a conditional break anywhere. Signed-off-by: Luca Barbieri <luca@luca-barbieri.com> Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
-rw-r--r--src/glsl/loop_unroll.cpp114
1 files changed, 68 insertions, 46 deletions
diff --git a/src/glsl/loop_unroll.cpp b/src/glsl/loop_unroll.cpp
index c5001ba9530..46000524ba1 100644
--- a/src/glsl/loop_unroll.cpp
+++ b/src/glsl/loop_unroll.cpp
@@ -81,42 +81,74 @@ 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());
-
+ 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 (is_break(last)) {
- continue_from_then_branch = false;
- } else {
- last = (ir_instruction *) last_if->else_instructions.get_tail();
-
- if (is_break(last))
- continue_from_then_branch = true;
- else
- /* Bail out if neither if-statement branch ends with a break.
+ if (is_break(last_ir)) {
+ /* 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 = NULL;
+ ir_instruction *break_ir = NULL;
+ 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;
+
+ ir_if = cur_ir->as_if();
+ if (ir_if != NULL) {
+ /* 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.
*/
- return visit_continue;
- }
+ ir_instruction *ir_if_last =
+ (ir_instruction *) ir_if->then_instructions.get_tail();
+
+ if (is_break(ir_if_last)) {
+ continue_from_then_branch = false;
+ break_ir = ir_if_last;
+ break;
+ } else {
+ ir_if_last =
+ (ir_instruction *) ir_if->else_instructions.get_tail();
+
+ if (is_break(ir_if_last)) {
+ break_ir = ir_if_last;
+ continue_from_then_branch = true;
+ break;
+ }
+ }
+ }
+ }
+
+ if (break_ir == NULL)
+ return visit_continue;
- /* Remove the break from the if-statement.
- */
- last->remove();
+ /* 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;
@@ -127,8 +159,8 @@ loop_unroll_visitor::visit_leave(ir_loop *ir)
copy_list.make_empty();
clone_ir_list(mem_ctx, &copy_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 != NULL);
ir_to_replace->insert_before(&copy_list);
ir_to_replace->remove();
@@ -138,7 +170,7 @@ loop_unroll_visitor::visit_leave(ir_loop *ir)
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);
}
@@ -147,17 +179,7 @@ loop_unroll_visitor::visit_leave(ir_loop *ir)
this->progress = true;
return visit_continue;
- } else if (is_break(last_ir)) {
- /* 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);