shader: Improve goto removal algorithm complexity

Find sibling node containing a nephew searching from the nephew itself
instead of the uncle.
This commit is contained in:
ReinUsesLisp 2021-04-21 03:39:35 -03:00 committed by ameerj
parent f66851e376
commit cc0fcd1b8d
1 changed files with 28 additions and 49 deletions

View File

@ -222,27 +222,6 @@ std::string DumpTree(const Tree& tree, u32 indentation = 0) {
return ret;
}
bool HasNode(const Tree& tree, ConstNode stmt) {
const auto end{tree.end()};
for (auto it = tree.begin(); it != end; ++it) {
if (it == stmt || (HasChildren(it->type) && HasNode(it->children, stmt))) {
return true;
}
}
return false;
}
Node FindStatementWithLabel(Tree& tree, ConstNode goto_stmt) {
const ConstNode label_stmt{goto_stmt->label};
const ConstNode end{tree.end()};
for (auto it = tree.begin(); it != end; ++it) {
if (it == label_stmt || (HasChildren(it->type) && HasNode(it->children, label_stmt))) {
return it;
}
}
throw LogicError("Lift label not in tree");
}
void SanitizeNoBreaks(const Tree& tree) {
if (std::ranges::find(tree, StatementType::Break, &Statement::type) != tree.end()) {
throw NotImplementedException("Capturing statement with break nodes");
@ -288,22 +267,6 @@ bool IsIndirectlyRelated(Node goto_stmt, Node label_stmt) {
return goto_stmt->up != label_stmt->up && !IsDirectlyRelated(goto_stmt, label_stmt);
}
bool SearchNode(const Tree& tree, ConstNode stmt, size_t& offset) {
++offset;
const auto end = tree.end();
for (ConstNode it = tree.begin(); it != end; ++it) {
++offset;
if (stmt == it) {
return true;
}
if (HasChildren(it->type) && SearchNode(it->children, stmt, offset)) {
return true;
}
}
return false;
}
bool AreSiblings(Node goto_stmt, Node label_stmt) noexcept {
Node it{goto_stmt};
do {
@ -321,6 +284,30 @@ bool AreSiblings(Node goto_stmt, Node label_stmt) noexcept {
return false;
}
Node SiblingFromNephew(Node uncle, Node nephew) noexcept {
Statement* const parent{uncle->up};
Statement* it{&*nephew};
while (it->up != parent) {
it = it->up;
}
return Tree::s_iterator_to(*it);
}
bool AreOrdered(Node left_sibling, Node right_sibling) noexcept {
const Node end{right_sibling->up->children.end()};
for (auto it = right_sibling; it != end; ++it) {
if (it == left_sibling) {
return false;
}
}
return true;
}
bool NeedsLift(Node goto_stmt, Node label_stmt) noexcept {
const Node sibling{SiblingFromNephew(goto_stmt, label_stmt)};
return AreOrdered(sibling, goto_stmt);
}
class GotoPass {
public:
explicit GotoPass(Flow::CFG& cfg, ObjectPool<IR::Inst>& inst_pool_,
@ -358,7 +345,7 @@ private:
--goto_level;
}
} else { // Level(goto_stmt) < Level(label_stmt)
if (Offset(goto_stmt) > Offset(label_stmt)) {
if (NeedsLift(goto_stmt, label_stmt)) {
// Lift goto_stmt to above stmt containing label_stmt using goto-lifting
// transformations
goto_stmt = Lift(goto_stmt);
@ -378,7 +365,7 @@ private:
if (std::next(goto_stmt) == label_stmt) {
// Simply eliminate the goto if the label is next to it
goto_stmt->up->children.erase(goto_stmt);
} else if (Offset(goto_stmt) < Offset(label_stmt)) {
} else if (AreOrdered(goto_stmt, label_stmt)) {
// Eliminate goto_stmt with a conditional
EliminateAsConditional(goto_stmt, label_stmt);
} else {
@ -523,8 +510,8 @@ private:
[[nodiscard]] Node MoveInward(Node goto_stmt) {
Statement* const parent{goto_stmt->up};
Tree& body{parent->children};
const Node label_nested_stmt{FindStatementWithLabel(body, goto_stmt)};
const Node label{goto_stmt->label};
const Node label_nested_stmt{SiblingFromNephew(goto_stmt, label)};
const u32 label_id{label->id};
Statement* const goto_cond{goto_stmt->cond};
@ -562,7 +549,7 @@ private:
Tree& body{parent->children};
const Node label{goto_stmt->label};
const u32 label_id{label->id};
const Node label_nested_stmt{FindStatementWithLabel(body, goto_stmt)};
const Node label_nested_stmt{SiblingFromNephew(goto_stmt, label)};
Tree loop_body;
loop_body.splice(loop_body.begin(), body, label_nested_stmt, goto_stmt);
@ -627,14 +614,6 @@ private:
return parent_tree.insert(std::next(loop), *new_goto);
}
size_t Offset(ConstNode stmt) const {
size_t offset{0};
if (!SearchNode(root_stmt.children, stmt, offset)) {
throw LogicError("Node not found in tree");
}
return offset;
}
ObjectPool<IR::Inst>& inst_pool;
ObjectPool<IR::Block>& block_pool;
ObjectPool<Statement>& pool;