2 files changed, 21 insertions, 9 deletions

diff --git a/mlir/lib/Transforms/RemoveDeadValues.cpp b/mlir/lib/Transforms/RemoveDeadValues.cpp
index e0c65b0..41f3f9d 100644
--- a/mlir/lib/Transforms/RemoveDeadValues.cpp
+++ b/mlir/lib/Transforms/RemoveDeadValues.cpp
@@ -432,8 +432,7 @@ static void processRegionBranchOp(RegionBranchOpInterface regionBranchOp,
 
   // Return the successors of `region` if the latter is not null. Else return
   // the successors of `regionBranchOp`.
-  auto getSuccessors = [&](Region *region = nullptr) {
-    auto point = region ? region : RegionBranchPoint::parent();
+  auto getSuccessors = [&](RegionBranchPoint point) {
     SmallVector<RegionSuccessor> successors;
     regionBranchOp.getSuccessorRegions(point, successors);
     return successors;
@@ -456,7 +455,8 @@ static void processRegionBranchOp(RegionBranchOpInterface regionBranchOp,
   // `nonForwardedOperands`.
   auto markNonForwardedOperands = [&](BitVector &nonForwardedOperands) {
     nonForwardedOperands.resize(regionBranchOp->getNumOperands(), true);
-    for (const RegionSuccessor &successor : getSuccessors()) {
+    for (const RegionSuccessor &successor :
+         getSuccessors(RegionBranchPoint::parent())) {
       for (OpOperand *opOperand : getForwardedOpOperands(successor))
         nonForwardedOperands.reset(opOperand->getOperandNumber());
     }
@@ -469,10 +469,13 @@ static void processRegionBranchOp(RegionBranchOpInterface regionBranchOp,
         for (Region &region : regionBranchOp->getRegions()) {
           if (region.empty())
             continue;
+          // TODO: this isn't correct in face of multiple terminators.
           Operation *terminator = region.front().getTerminator();
           nonForwardedRets[terminator] =
               BitVector(terminator->getNumOperands(), true);
-          for (const RegionSuccessor &successor : getSuccessors(&region)) {
+          for (const RegionSuccessor &successor :
+               getSuccessors(RegionBranchPoint(
+                   cast<RegionBranchTerminatorOpInterface>(terminator)))) {
             for (OpOperand *opOperand :
                  getForwardedOpOperands(successor, terminator))
               nonForwardedRets[terminator].reset(opOperand->getOperandNumber());
@@ -489,8 +492,13 @@ static void processRegionBranchOp(RegionBranchOpInterface regionBranchOp,
           DenseMap<Region *, BitVector> &argsToKeep, Region *region = nullptr) {
         Operation *terminator =
             region ? region->front().getTerminator() : nullptr;
+        RegionBranchPoint point =
+            terminator
+                ? RegionBranchPoint(
+                      cast<RegionBranchTerminatorOpInterface>(terminator))
+                : RegionBranchPoint::parent();
 
-        for (const RegionSuccessor &successor : getSuccessors(region)) {
+        for (const RegionSuccessor &successor : getSuccessors(point)) {
           Region *successorRegion = successor.getSuccessor();
           for (auto [opOperand, input] :
                llvm::zip(getForwardedOpOperands(successor, terminator),
@@ -517,7 +525,8 @@ static void processRegionBranchOp(RegionBranchOpInterface regionBranchOp,
         resultsOrArgsToKeepChanged = false;
 
         // Recompute `resultsToKeep` and `argsToKeep` based on `operandsToKeep`.
-        for (const RegionSuccessor &successor : getSuccessors()) {
+        for (const RegionSuccessor &successor :
+             getSuccessors(RegionBranchPoint::parent())) {
           Region *successorRegion = successor.getSuccessor();
           for (auto [opOperand, input] :
                llvm::zip(getForwardedOpOperands(successor),
@@ -551,7 +560,9 @@ static void processRegionBranchOp(RegionBranchOpInterface regionBranchOp,
           if (region.empty())
             continue;
           Operation *terminator = region.front().getTerminator();
-          for (const RegionSuccessor &successor : getSuccessors(&region)) {
+          for (const RegionSuccessor &successor :
+               getSuccessors(RegionBranchPoint(
+                   cast<RegionBranchTerminatorOpInterface>(terminator)))) {
             Region *successorRegion = successor.getSuccessor();
             for (auto [opOperand, input] :
                  llvm::zip(getForwardedOpOperands(successor, terminator),
diff --git a/mlir/lib/Transforms/ViewOpGraph.cpp b/mlir/lib/Transforms/ViewOpGraph.cpp
index 08cac1f..5790a77 100644
--- a/mlir/lib/Transforms/ViewOpGraph.cpp
+++ b/mlir/lib/Transforms/ViewOpGraph.cpp
@@ -158,7 +158,8 @@ private:
 
   /// Emit a cluster (subgraph). The specified builder generates the body of the
   /// cluster. Return the anchor node of the cluster.
-  Node emitClusterStmt(function_ref<void()> builder, std::string label = "") {
+  Node emitClusterStmt(function_ref<void()> builder,
+                       const std::string &label = "") {
     int clusterId = ++counter;
     os << "subgraph cluster_" << clusterId << " {\n";
     os.indent();
@@ -269,7 +270,7 @@ private:
   }
 
   /// Emit a node statement.
-  Node emitNodeStmt(std::string label, StringRef shape = kShapeNode,
+  Node emitNodeStmt(const std::string &label, StringRef shape = kShapeNode,
                     StringRef background = "") {
     int nodeId = ++counter;
     AttributeMap attrs;