[AMDGPU] IGLP: Fix static variables

Replace global / class-level static variables with instance members and
guarantee thread-safety.

Author: ro-i

llvm/include/llvm/CodeGen/ScheduleDAG.h

@@ -734,7 +734,8 @@ class TargetRegisterInfo;
     /// Makes a DFS traversal and mark all nodes affected by the edge insertion.
     /// These nodes will later get new topological indexes by means of the Shift
     /// method.
-    void DFS(const SUnit *SU, int UpperBound, bool& HasLoop);
+    void DFS(const SUnit *SU, int UpperBound, bool &HasLoop,
+             std::optional<SDep::Kind> OnlyDepKind = std::nullopt);
 
     /// Reassigns topological indexes for the nodes in the DAG to
     /// preserve the topological ordering.
@@ -767,7 +768,9 @@ class TargetRegisterInfo;
                                  bool &Success);
 
     /// Checks if \p SU is reachable from \p TargetSU.
-    bool IsReachable(const SUnit *SU, const SUnit *TargetSU);
+    /// If OnlyDepKind is given, consider only dependencies of this kind.
+    bool IsReachable(const SUnit *SU, const SUnit *TargetSU,
+                     std::optional<SDep::Kind> OnlyDepKind = std::nullopt);
 
     /// Returns true if addPred(TargetSU, SU) creates a cycle.
     bool WillCreateCycle(SUnit *TargetSU, SUnit *SU);

llvm/include/llvm/CodeGen/ScheduleDAGInstrs.h

@@ -287,8 +287,10 @@ namespace llvm {
     }
 
     /// IsReachable - Checks if SU is reachable from TargetSU.
-    bool IsReachable(SUnit *SU, SUnit *TargetSU) {
-      return Topo.IsReachable(SU, TargetSU);
+    /// If OnlyDepKind is given, only dependencies of this kind are considered.
+    bool IsReachable(SUnit *SU, SUnit *TargetSU,
+                     std::optional<SDep::Kind> OnlyDepKind = std::nullopt) {
+      return Topo.IsReachable(SU, TargetSU, OnlyDepKind);
     }
 
     /// Whether regions with a single MI should be scheduled.

llvm/lib/CodeGen/ScheduleDAG.cpp

@@ -570,7 +570,8 @@ void ScheduleDAGTopologicalSort::RemovePred(SUnit *M, SUnit *N) {
 }
 
 void ScheduleDAGTopologicalSort::DFS(const SUnit *SU, int UpperBound,
-                                     bool &HasLoop) {
+                                     bool &HasLoop,
+                                     std::optional<SDep::Kind> OnlyDepKind) {
   std::vector<const SUnit*> WorkList;
   WorkList.reserve(SUnits.size());
 
@@ -580,6 +581,8 @@ void ScheduleDAGTopologicalSort::DFS(const SUnit *SU, int UpperBound,
     WorkList.pop_back();
     Visited.set(SU->NodeNum);
     for (const SDep &SuccDep : llvm::reverse(SU->Succs)) {
+      if (OnlyDepKind && SuccDep.getKind() != *OnlyDepKind)
+        continue;
       unsigned s = SuccDep.getSUnit()->NodeNum;
       // Edges to non-SUnits are allowed but ignored (e.g. ExitSU).
       if (s >= Node2Index.size())
@@ -722,8 +725,9 @@ void ScheduleDAGTopologicalSort::AddSUnitWithoutPredecessors(const SUnit *SU) {
   Visited.resize(Node2Index.size());
 }
 
-bool ScheduleDAGTopologicalSort::IsReachable(const SUnit *SU,
-                                             const SUnit *TargetSU) {
+bool ScheduleDAGTopologicalSort::IsReachable(
+    const SUnit *SU, const SUnit *TargetSU,
+    std::optional<SDep::Kind> OnlyDepKind) {
   assert(TargetSU != nullptr && "Invalid target SUnit");
   assert(SU != nullptr && "Invalid SUnit");
   FixOrder();
@@ -737,7 +741,7 @@ bool ScheduleDAGTopologicalSort::IsReachable(const SUnit *SU,
   if (LowerBound < UpperBound) {
     Visited.reset();
     // There may be a path from TargetSU to SU. Check for it.
-    DFS(TargetSU, UpperBound, HasLoop);
+    DFS(TargetSU, UpperBound, HasLoop, OnlyDepKind);
   }
   return HasLoop;
 }