Skip to content

[TableGen] Split DAGISelMatcherOpt FactorNodes into 2 functions. NFC #125330

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Feb 3, 2025
Merged

[TableGen] Split DAGISelMatcherOpt FactorNodes into 2 functions. NFC #125330

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
91ac2de
TableGen] Split DAGISelMatcherOpt FactorNodes into 2 functions. NFC
topperc Feb 1, 2025
909a083
fixup! Cleanup comments a little.
topperc Feb 2, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
40 changes: 21 additions & 19 deletions llvm/utils/TableGen/DAGISelMatcherOpt.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -191,7 +191,9 @@ static Matcher *FindNodeWithKind(Matcher *M, Matcher::KindTy Kind) {
return nullptr;
}

/// FactorNodes - Turn matches like this:
static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr);

/// Turn matches like this:
/// Scope
/// OPC_CheckType i32
/// ABC
Expand All @@ -203,22 +205,8 @@ static Matcher *FindNodeWithKind(Matcher *M, Matcher::KindTy Kind) {
/// ABC
/// XYZ
///
static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) {
// Look for a push node. Iterates instead of recurses to reduce stack usage.
ScopeMatcher *Scope = nullptr;
std::unique_ptr<Matcher> *RebindableMatcherPtr = &InputMatcherPtr;
while (!Scope) {
// If we reached the end of the chain, we're done.
Matcher *N = RebindableMatcherPtr->get();
if (!N)
return;

// If this is not a push node, just scan for one.
Scope = dyn_cast<ScopeMatcher>(N);
if (!Scope)
RebindableMatcherPtr = &(N->getNextPtr());
}
std::unique_ptr<Matcher> &MatcherPtr = *RebindableMatcherPtr;
static void FactorScope(std::unique_ptr<Matcher> &MatcherPtr) {
ScopeMatcher *Scope = cast<ScopeMatcher>(MatcherPtr.get());

// Okay, pull together the children of the scope node into a vector so we can
// inspect it more easily.
Expand Down Expand Up @@ -353,7 +341,7 @@ static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) {
Shared->setNext(new ScopeMatcher(std::move(EqualMatchers)));

// Recursively factor the newly created node.
FactorNodes(Shared->getNextPtr());
FactorScope(Shared->getNextPtr());
}

// Put the new Matcher where we started in OptionsToMatch.
Expand Down Expand Up @@ -470,7 +458,7 @@ static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) {
for (auto &M : Cases) {
if (ScopeMatcher *SM = dyn_cast<ScopeMatcher>(M.second)) {
std::unique_ptr<Matcher> Scope(SM);
FactorNodes(Scope);
FactorScope(Scope);
M.second = Scope.release();
assert(M.second && "null matcher");
}
Expand All @@ -492,6 +480,20 @@ static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) {
Scope->resetChild(i, OptionsToMatch[i]);
}

/// Search a ScopeMatcher to factor with FactorScope.
static void FactorNodes(std::unique_ptr<Matcher> &InputMatcherPtr) {
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I don't see why this is referencing unique_ptr at all. This could be done in terms of Matcher* or Matcher&

Copy link
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The code change the contents of the unique_ptr by calling unique_ptr::reset in several places. It replaces the ScopeMatcher with a SwitchOpcodeMatcher/SwitchType matcher by changing what the owner of ScopeMatcher is pointing to. This requires being able to modify the unique_ptr inside the owner.

// Look for a scope matcher. Iterates instead of recurses to reduce stack
// usage.
std::unique_ptr<Matcher> *MatcherPtr = &InputMatcherPtr;
do {
if (isa<ScopeMatcher>(*MatcherPtr))
return FactorScope(*MatcherPtr);

// If this is not a scope matcher, go to the next node.
MatcherPtr = &(MatcherPtr->get()->getNextPtr());
} while (MatcherPtr->get());
}

void llvm::OptimizeMatcher(std::unique_ptr<Matcher> &MatcherPtr,
const CodeGenDAGPatterns &CGP) {
ContractNodes(MatcherPtr, CGP);
Expand Down