1 files changed, 44 insertions, 17 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/Combiner.cpp b/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
index a2f220aa3d4..90fd54ec244 100644
--- a/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
@@ -1,4 +1,4 @@
-//===-- lib/CodeGen/GlobalISel/GICombiner.cpp -----------------------===//
+//===-- lib/CodeGen/GlobalISel/Combiner.cpp -------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -29,36 +29,62 @@ using namespace llvm;
 namespace {
 /// This class acts as the glue the joins the CombinerHelper to the overall
 /// Combine algorithm. The CombinerHelper is intended to report the
-/// modifications it makes to the MIR to the CombinerChangeObserver and the
+/// modifications it makes to the MIR to the GISelChangeObserver and the
 /// observer subclass will act on these events. In this case, instruction
 /// erasure will cancel any future visits to the erased instruction and
 /// instruction creation will schedule that instruction for a future visit.
 /// Other Combiner implementations may require more complex behaviour from
-/// their CombinerChangeObserver subclass.
-class WorkListMaintainer : public GISelChangeObserver {
+/// their GISelChangeObserver subclass.
+class WorkListMaintainer : public GISelChangeObserver,
+                           public MachineFunction::Delegate {
   using WorkListTy = GISelWorkList<512>;
+  MachineFunction &MF;
   WorkListTy &WorkList;
+  /// The instructions that have been created but we want to report once they
+  /// have their operands. This is only maintained if debug output is requested.
+  SmallPtrSet<const MachineInstr *, 4> CreatedInstrs;
 
 public:
-  WorkListMaintainer(WorkListTy &WorkList) : WorkList(WorkList) {}
-  virtual ~WorkListMaintainer() {}
+  WorkListMaintainer(MachineFunction &MF, WorkListTy &WorkList)
+      : GISelChangeObserver(), MF(MF), WorkList(WorkList) {
+    MF.setDelegate(this);
+  }
+  virtual ~WorkListMaintainer() {
+    MF.resetDelegate(this);
+  }
 
-  void erasingInstr(MachineInstr &MI) override {
+  void erasingInstr(const MachineInstr &MI) override {
     LLVM_DEBUG(dbgs() << "Erased: " << MI << "\n");
     WorkList.remove(&MI);
   }
-  void createdInstr(MachineInstr &MI) override {
-    LLVM_DEBUG(dbgs() << "Created: " << MI << "\n");
+  void createdInstr(const MachineInstr &MI) override {
+    LLVM_DEBUG(dbgs() << "Creating: " << MI << "\n");
     WorkList.insert(&MI);
+    LLVM_DEBUG(CreatedInstrs.insert(&MI));
   }
-  void changingInstr(MachineInstr &MI) override {
+  void changingInstr(const MachineInstr &MI) override {
     LLVM_DEBUG(dbgs() << "Changing: " << MI << "\n");
-    WorkList.remove(&MI);
+    WorkList.insert(&MI);
   }
-  // Currently changed conservatively assumes erased.
-  void changedInstr(MachineInstr &MI) override {
+  void changedInstr(const MachineInstr &MI) override {
     LLVM_DEBUG(dbgs() << "Changed: " << MI << "\n");
-    WorkList.remove(&MI);
+    WorkList.insert(&MI);
+  }
+
+  void reportFullyCreatedInstrs() {
+    LLVM_DEBUG(for (const auto *MI
+                    : CreatedInstrs) {
+      dbgs() << "Created: ";
+      MI->print(dbgs());
+    });
+    LLVM_DEBUG(CreatedInstrs.clear());
+  }
+
+  void MF_HandleInsertion(const MachineInstr &MI) override {
+    createdInstr(MI);
+  }
+  void MF_HandleRemoval(const MachineInstr &MI) override {
+    erasingInstr(MI);
   }
 };
 }
@@ -90,8 +116,8 @@ bool Combiner::combineMachineInstrs(MachineFunction &MF) {
     // insert with list bottom up, so while we pop_back_val, we'll traverse top
     // down RPOT.
     Changed = false;
-    GISelWorkList<512> WorkList;
-    WorkListMaintainer Observer(WorkList);
+    GISelWorkList<512> WorkList(&MF);
+    WorkListMaintainer Observer(MF, WorkList);
     for (MachineBasicBlock *MBB : post_order(&MF)) {
       if (MBB->empty())
         continue;
@@ -110,8 +136,9 @@ bool Combiner::combineMachineInstrs(MachineFunction &MF) {
     // Main Loop. Process the instructions here.
     while (!WorkList.empty()) {
       MachineInstr *CurrInst = WorkList.pop_back_val();
-      LLVM_DEBUG(dbgs() << "Try combining " << *CurrInst << "\n";);
+      LLVM_DEBUG(dbgs() << "\nTry combining " << *CurrInst;);
       Changed |= CInfo.combine(Observer, *CurrInst, Builder);
+      Observer.reportFullyCreatedInstrs();
     }
     MFChanged |= Changed;
   } while (Changed);