1 files changed, 69 insertions, 0 deletions
diff --git a/include/llvm/CodeGen/GlobalISel/GISelWorkList.h b/include/llvm/CodeGen/GlobalISel/GISelWorkList.h
new file mode 100644
index 0000000000000..167905dc9aa1a
--- /dev/null
+++ b/include/llvm/CodeGen/GlobalISel/GISelWorkList.h
@@ -0,0 +1,69 @@
+//===- GISelWorkList.h - Worklist for GISel passes ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_GISEL_WORKLIST_H
+#define LLVM_GISEL_WORKLIST_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Debug.h"
+
+namespace llvm {
+
+class MachineInstr;
+
+// Worklist which mostly works similar to InstCombineWorkList, but on MachineInstrs.
+// The main difference with something like a SetVector is that erasing an element doesn't
+// move all elements over one place - instead just nulls out the element of the vector.
+// FIXME: Does it make sense to factor out common code with the instcombinerWorkList?
+template<unsigned N>
+class GISelWorkList {
+  SmallVector<MachineInstr*, N> Worklist;
+  DenseMap<MachineInstr*, unsigned> WorklistMap;
+
+public:
+  GISelWorkList() = default;
+
+  bool empty() const { return WorklistMap.empty(); }
+
+  unsigned size() const { return WorklistMap.size(); }
+
+  /// Add - Add the specified instruction to the worklist if it isn't already
+  /// in it.
+  void insert(MachineInstr *I) {
+    if (WorklistMap.try_emplace(I, Worklist.size()).second) {
+      Worklist.push_back(I);
+    }
+  }
+
+  /// Remove - remove I from the worklist if it exists.
+  void remove(MachineInstr *I) {
+    auto It = WorklistMap.find(I);
+    if (It == WorklistMap.end()) return; // Not in worklist.
+
+    // Don't bother moving everything down, just null out the slot.
+    Worklist[It->second] = nullptr;
+
+    WorklistMap.erase(It);
+  }
+
+  MachineInstr *pop_back_val() {
+    MachineInstr *I;
+    do {
+      I = Worklist.pop_back_val();
+    } while(!I);
+    assert(I && "Pop back on empty worklist");
+    WorklistMap.erase(I);
+    return I;
+  }
+};
+
+} // end namespace llvm.
+
+#endif